Physical Sciences and Mathematics Commons^™

Ultraviolet Photoelectron Spectroscopy Of Complexes Of Bromine With N-Donors In The Vapor Phase, S. Ananthavel, Salai Ammal, P. Venuvanalingam, J. Chandrasekhar, M. Hegde

Salai C. Ammal

No abstract provided.

Using Spatiotemporal Methods To Fill Gaps In Energy Usage Interval Data, Kristin K. Graves

Theses and Dissertations

Researchers analyzing spatiotemporal or panel data, which varies both in location and over time, often find that their data has holes or gaps. This thesis explores alternative methods for filling those gaps and also suggests a set of techniques for evaluating those gap-filling methods to determine which works best.

Crystal Growth And Electronic Phase Diagram Of 4D-Doped Na1-ΔFe1-XRhXAs In Comparison To 3D-Doped Na1-ΔFe1-XCoXAs, Frank Steckel, Maria Roslova, Robert Beck, Igor Morozov, Saicharan Aswartham, Daniil Evtushinsky, Christian G. F. Blum, Mahmoud Abdel-Hafiez, Dirk Bombor, Janek Maletz, Sergey Borisenko, Andrei V. Shevelkov, Anja U. B. Wolter, Christian Hess, Sabine Wurmehl, Bernd Büchner

Physics and Astronomy Faculty Publications

Single crystals of Na_1−δFe_1−xT_xAs with T = Co, Rh have been grown using a self-flux technique. The crystals were thoroughly characterized by powder x-ray diffraction, magnetic susceptibility, and electronic transport with particular focus on the Rh-doped samples. Measurements of the specific heat and ARPES were conducted exemplarily for the optimally doped compositions. The spin-density wave transition (SDW) observed for samples with low Rh concentration (0≤x≤0.013) is fully suppressed in the optimally doped sample. The superconducting transition temperature (T_c) is enhanced from 10 K in Na_1−δFeAs to 21 …

Proceedings Of The Twentieth Conference Of The Association Of Christians In The Mathematical Sciences, Association Of Christians In The Mathematical Sciences

ACMS Conference Proceedings 2015

The proceedings of the twentieth conference of the Associate of Christians in the Mathematical Sciences held at Redeemer University College from May 27-30, 2015.

This Is Our Home - So Please Help Care For It, Alaina Bernard

UCF Forum

I love the movie “Contact” about a scientist played by Jodie Foster, who has an extraordinary experience traveling through space. In the end, when she could not explain the experience, she ended up finding her faith in something unexplainable.

Geometric Separation And Packing Problems, Ivo Vigan

Dissertations, Theses, and Capstone Projects

The first part of this thesis investigates combinatorial and algorithmic aspects of geometric separation problems in the plane. In such a setting one is given a set of points and a set of separators such as lines, line segments or disks. The goal is to select a small subset of those separators such that every path between any two points is intersected by at least one separator. We first look at several problems which arise when one is given a set of points and a set of unit disks embedded in the plane and the goal is to separate the …

New Results On Randomized Matrix Computations, Jesse Lowell Wolf

Dissertations, Theses, and Capstone Projects

The aim of this thesis is to present new results in randomized matrix computations. Specifically, and ultimately, we show how to modify, or preprocess an ill conditioned matrix having small numerical nullity (co-rank) into a nonsingular well conditioned matrix. This has intrinsic theoretical interest and we show a sample application to accurate solutions of nonsingular and ill conditioned linear systems. We discuss both multiplicative and additive preprocessing; in fact the multiplicative case assists in the derivation of the additive case. In the additive case, we approximate a nonsingular ill conditioned matrix by a singular well conditioned matrix which is then …

Disorder Effects In Charge Transport And Spin Response Of Topological Insulators, Lukas Zhonghua Zhao

Dissertations, Theses, and Capstone Projects

Topological insulators are a class of solids in which the non-trivial inverted bulk band structure gives rise to metallic surface states that are robust against impurity backscattering. First principle calculations predicted Bi₂Te₃, Sb₂Te₃ and Bi₂Se₃ to be three-dimensional (3D) topological insulators with a single Dirac cone on the surface. The topological surface states were subsequently observed by angle-resolved photoemission (ARPES) and scanning tunneling microscopy (STM). The investigations of charge transport through topological surfaces of 3D topological insulators, however, have faced a major challenge due to large charge carrier densities in …

Microfossils As Proxies For Holocene Climate In Semi-Enclosed Basins: The Hudson River Estuary, New York, Usa And The Marmara Sea, Turkey, Damayanti Gurung

Dissertations, Theses, and Capstone Projects

The transition from the late Pleistocene glacial to the warmer Holocene interglacial occurred within a series of climatic oscillations. The Holocene, a relatively warm and stable period, was also marked by smaller climatic variability of millennial- to-centennial-scale oscillations. Furthermore, during this period global sea level was much lower than at present. My present study will analyze micro-fossils as proxies for their response to these climatic fluctuations, as well as marine influences during the late Pleistocene to Holocene periods. Sediments from marginal basin environments have been selected for the study due to their connection to the open sea and terrestrial environments, …

The State Of The Oligocene Icehouse World: Sedimentology, Provenance, And Stable Isotopes Of Marine Sediments From The Antarctic Continental Margin, Daniel William Hauptvogel

Dissertations, Theses, and Capstone Projects

The Oligocene Epoch (34-23 Ma) was a dynamic time in Antarctica, with previous ice volume estimates suggesting fluctuations from below 50 % up to 140 % of modern all while atmospheric CO₂ decreased from above 1,000 ppm in the Early Oligocene to near modern levels by the Late Oligocene. Most of what is known about the Oligocene Antarctic cryosphere however, is derived from distal sedimentary records that can only provide a generalized view of the cryospheric dynamics in Antarctica. To better understand regional differences in Antarctic glacial dynamics, proximal records are needed. This dissertation advances our understanding of these …

Surface Plasmon And The Effect Of Coupled Resonances In The Enhancement Of Phonon And Molecular Modes In Semiconductors, Syed Islam

Dissertations, Theses, and Capstone Projects

The presence of surface plasmon resonance in semiconductors is not a typical point of discussion in the research community. While the presence of surface plasmon resonance in metals is widely accepted due to the presence of free electrons in conduction bands, the existence of surface plasmon in semiconductors has been generally ruled out due to the absence of free electrons in conduction bands. In this dissertation, we show that semiconductors are able to support surface plasmon in valence band. We also demonstrate, by using the Mie theory, that semiconductor nanoparticles can be designed so that the surface plasmon can be …

Climate-Smart Agriculture: Farmer's Bane Or Boon?, Jeeva Mary Jacob

Dissertations, Theses, and Capstone Projects

Climate-Smart Agriculture (CSA) is one of the solutions that simultaneously address the issues of food security, climate change and agricultural productivity. It has been gaining momentum in the last five years among policy circles and development organizations have prioritized CSA interventions in developing countries around the world. In this paper, CSA interventions are examined from the small farmer's perspective and the purpose of this paper is to find out whether Climate-Smart Agriculture truly empowers the farmer in the face of climate change. Such a study emerged from the fact that in the past, agricultural interventions like the Green Revolution promised …

Force To Change Large Cardinal Strength, Erin Kathryn Carmody

Dissertations, Theses, and Capstone Projects

This dissertation includes many theorems which show how to change large cardinal properties with forcing. I consider in detail the degrees of inaccessible cardinals (an analogue of the classical degrees of Mahlo cardinals) and provide new large cardinal definitions for degrees of inaccessible cardinals extending the hyper-inaccessible hierarchy. I showed that for every cardinal $\kappa$, and ordinal $\alpha$, there is a notion of forcing $\mathbb{P}$ such that $\kappa$ is still $\beta$-inaccessible in the extension, for every $\beta < \alpha$, but not $\alpha$-inaccessible. I also consider Mahlo cardinals and degrees of Mahlo cardinals. I showed that for every cardinal $\kappa$, and ordinal $\alpha$, there is a notion of forcing $\mathbb{P}$ such that for every $\beta < \alpha$, the cardinal $\kappa$ is still $\beta$-Mahlo in the extension, but not $\alpha$-Mahlo. I also show that a cardinal $\kappa$ which is Mahlo in the ground model can have every possible inaccessible degree in the forcing extension, but no longer be Mahlo there. The thesis includes a collection of results which give forcing notions which change large cardinal strength from weakly compact to weakly measurable, including some earlier work by others that fit this theme. I consider in detail measurable cardinals and Mitchell rank. I show how to change a class of measurable cardinals by forcing to an extension where all measurable cardinals above some fixed ordinal $\alpha$ have Mitchell rank below $\alpha.$ Finally, I consider supercompact cardinals, and strongly compact cardinals. I show how to change the Mitchell rank for supercompactness for a class of cardinals.

The Holomorphic Couch Theorem, Maxime Fortier Bourque

Dissertations, Theses, and Capstone Projects

We prove that if two conformal embeddings between Riemann surfaces with finite topology are homotopic, then they are isotopic through conformal embeddings. Furthermore, we show that the space of all conformal embeddings in a given homotopy class deformation retracts into a point, a circle, a torus, or the unit tangent bundle of the codomain, depending on the induced homomorphism on fundamental groups. Quadratic differentials play a central role in the proof.

Dynamics And Kinetics Of Singlet Oxygen Mediated Oxidation Of Methionine In The Gas Phase, Hydrated Clusters And Solution, Fangwei Liu

Dissertations, Theses, and Capstone Projects

The reaction between methionine (Met) and electronically excited singlet molecular oxygen (O₂[a¹Δ_g]) has been investigated in a systematic fashion, using a home-built electrospray ionization (ESI) guided-ion-beam tandem mass spectrometer (MS). The study started from probing the reaction dynamics between the isolated protonated/deprotonated methionine ions with ¹O₂ in the gas phase, transited through the same systems micro-solvated with explicit water molecules in gaseous hydrated clusters, and concluded with real-time methionine oxidation kinetics determination in aqueous solution. The reaction products, cross sections, and collision energy dependence were measured by ESI-MS. Density functional theory (DFT) …

Bad Apple: Complexities Of New York City Food Aid Programs, Rose Meagan Jimenez

Dissertations, Theses, and Capstone Projects

The only universal thing about food is that everyone needs to eat. In the United States, there are more instances of food insecurity than impoverishment. Governmental and local food aid programs are complex but are essentially motivated by socioeconomic issues. Food aid programs, from community gardening to Food Stamps, initially stem from a depression-era need to stimulate the economy. However, as socioeconomic issues change, food aid programs also evolve to meet those needs. By excavating different pieces of literature that discuss issues in food aid, the forms of structural violence that cause hunger come to life. This piece discusses community …

Low-Rank Based Algorithms For Rectification, Repetition Detection And De-Noising In Urban Images, Juan Liu

Dissertations, Theses, and Capstone Projects

In this thesis, we aim to solve the problem of automatic image rectification and repeated patterns detection on 2D urban images, using novel low-rank based techniques. Repeated patterns (such as windows, tiles, balconies and doors) are prominent and significant features in urban scenes.

Detection of the periodic structures is useful in many applications such as photorealistic 3D reconstruction, 2D-to-3D alignment, facade parsing, city modeling, classification, navigation, visualization in 3D map environments, shape completion, cinematography and 3D games. However both of the image rectification and repeated patterns detection problems are challenging due to scene occlusions, varying illumination, pose variation and sensor …

Exploring Non-Equilibrium Dynamics In Time Dependent Density Functional Theory, Kai Luo

Dissertations, Theses, and Capstone Projects

Time-dependent density functional theory (TDDFT) is a method of choice for calculations of excitation spectra and response properties in materials science and quantum chemistry. The many-body problem is mapped into a set of one-body Schrödinger equations, called the Kohn-Sham (KS) equations. In principle, the one-body potential can be chosen such that the density of the interacting system is exactly reproduced by the KS system. However, one component of the one-body potential has to be approximated and is typically "adiabatic". Though in linear response regime adiabatic approximations give quite good spectra, it is important to explore their performances in non-equilibrium dynamics. …

Some Applications Of Noncommutative Groups And Semigroups To Information Security, Lisa Bromberg

Dissertations, Theses, and Capstone Projects

We present evidence why the Burnside groups of exponent 3 could be a good candidate for a platform group for the HKKS semidirect product key exchange protocol. We also explore hashing with matrices over SL₂(F_p), and compute bounds on the girth of the Cayley graph of the subgroup of SL₂(F_p) for specific generators A, B. We demonstrate that even without optimization, these hashes have comparable performance to hashes in the SHA family.

A Static And Dynamic Investigation Of Quantum Nonlinear Transport In Highly Dense And Mobile 2d Electron Systems, Scott A. Dietrich

Dissertations, Theses, and Capstone Projects

Heterostructures made of semiconductor materials may be one of most versatile environments for the study of the physics of electron transport in two dimensions. These systems are highly customizable and demonstrate a wide range of interesting physical phenomena. In response to both microwave radiation and DC excitations, strongly nonlinear transport that gives rise to non-equilibrium electron states has been reported and investigated. We have studied GaAs quantum wells with a high density of high mobility two-dimensional electrons placed in a quantizing magnetic field. This study presents the observation of several nonlinear transport mechanisms produced by the quantum nature of these …

Theory And Applications Of Outsider Anonymity In Broadcast Encryption, Irippuge Deshan Milinda Perera

Dissertations, Theses, and Capstone Projects

Broadcast Encryption (BE) allows efficient one-to-many secret communication of data over a broadcast channel. In the standard setting of BE, information about receivers is transmitted in the clear together with ciphertexts. This could be a serious violation of recipient privacy since the identities of the users authorized to access the secret content in certain broadcast scenarios are as sensitive as the content itself. Anonymous Broadcast Encryption (AnoBe) prevents this leakage of recipient identities from ciphertexts but at a cost of a linear lower bound (in the number of receivers) on the length of ciphertexts. A linear ciphertext length is a …

Quantum State Discrimination And Quantum Cloning: Optimization And Implementation, Andi Shehu

Dissertations, Theses, and Capstone Projects

In our work we explore the field of quantum state discrimination and quantum cloning. Recently the problem of optimal state discrimination with a Fixed Rate of Inconclusive Outcomes (FRIO strategy) has been solved for two pure quantum states and a few other highly symmetric cases. An optical implementation to FRIO for pure states is provided. The physical implementation can be carried out with the use of a six-port interferometer constructed with optical fibers beam splitters, phase shifters and mirrors. The input states are composed of qubits which are realized as photons in the dual-rail representation. The non-unitary measurements are carried …

U.S. Drought Monitor, May 26, 2015, Brad Rippey

United States Agricultural Commodities in Drought Archive

Drought map of U.S. for May 26, 2015 (5/26/15) plus: U.S. crop areas experiencing drought (map), Approximate percentage of crop located in drought, by state (bar graph), Percent of crop area located in drought, past 52 weeks (line graph) for: Corn, Soybeans, Hay, Cattle, Winter wheat.

Effect Of Seam-Height On Curveballs, Joseph S. Carroll

Senior Theses

The difference in seam-height between raised and flat-seam baseballs causes them to react differently when thrown by a pitcher. Altering the seam-height on the ball changes the amount of drag force on it as it travels through the air. The goal of this experiment is to measure the difference in vertical deflection between the two types of balls when pitched with curveball topspin. It was discovered that the baseball with raised-seams experiences more vertical deflection than the flat-seam ball.

Second Order Inference For The Mean Of A Variable Missing At Random, Ivan Diaz, Marco Carone, Mark J. Van Der Laan

U.C. Berkeley Division of Biostatistics Working Paper Series

We present a second order estimator of the mean of a variable subject to missingness, under the missing at random assumption. The estimator improves upon existing methods by using an approximate second order expansion of the parameter functional, in addition to the first order expansion employed by standard doubly robust methods. This results in weaker assumptions about the convergence rates necessary to establish consistency, local efficiency, and asymptotic linearity. The general estimation strategy is developed under the targeted minimum loss based estimation (TMLE) framework. We present a simulation comparing the sensitivity of the first and second order estimators to the …

On The Probabilistic Cauchy Theory Of The Cubic Nonlinear Schrödinger Equation On Rd, D≥3, Árpád Bényi, Tadahiro Oh, Oana Pocovnicu

Mathematics Faculty Publications

We consider the Cauchy problem of the cubic nonlinear Schrödinger equation (NLS) : i∂_tu + Δu = ±|u|²u on R ^d, d ≥ 3, with random initial data and prove almost sure well-posedness results below the scaling-critical regularity ^scrit = d-2/2. More precisely, given a function on R ^d, we introduce a randomization adapted to the Wiener decomposition, and, intrinsically, to the so-called modulation spaces. Our goal in this paper is three-fold. (i) We prove almost sure local well-posedness of the cubic NLS below the scaling-critical regularity …

Including Fine-Grained Sediment Processes Within Numerical Representations Of A Partially-Mixed Estuary, The York River, Virginia, Danielle Tarpley, Courtney Harris, Carl Friedrichs, Kelsey Fall

Presentations

The Community Sediment Transport Modeling System (CSTMS) is being used to represent conditions in the York River, Virginia, a partially-mixed tidal tributary of Chesapeake Bay. Our modeling approach includes both an idealized two-dimensional longitudinal representation of the estuary, and a more realistic full three-dimensional model of the York River. Both have been implemented using versions of the Regional Ocean Modeling System (ROMS). Our modeling efforts have been motivated by a rich set of observation data from in-situ measurements made by acoustic Doppler velocimeters (ADVs), a pulse coherent acoustic Doppler profiler (PC-ADP), a laser in-situ scattering and transmissometry (LISST), and a …

Threshold Behavior Of A Marine‐Based Sector Of The East Antarctic Ice Sheet In Response To Early Pliocene Ocean Warming, Melissa A. Hansen, Sandra Passchier, Boo‐Keun Khim, Buhan Song, Trevor Williams

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

We investigate the stability of the East Antarctic Ice Sheet (EAIS) on the Wilkes Land continental margin, Antarctica, utilizing a high‐resolution record of ice‐rafted debris (IRD) mass accumulation rates (MAR) from Integrated Ocean Drilling Program Site U1359. The relationship between orbital variations in the IRD record and climate drivers was evaluated to capture changes in the dynamics of a marine‐based ice sheet in response to early Pliocene warming. Three IRD MAR excursions were observed and confirmed via scanning electron microscope microtextural analysis of sand grains. Time series analysis of the IRD MAR reveals obliquity‐paced expansions of the ice sheet to …

Methods And Systems For Biclustering Algorithm, Donald C. Wunsch, Rui Xu, Sejun Kim

Electrical and Computer Engineering Faculty Research & Creative Works

Methods and systems for improved unsupervised learning are described. The unsupervised learning can consist of biclustering a data set, e.g., by biclustering subsets of the entire data set. In an example, the biclustering does not include feeding know and proven results into the biclustering methodology or system. A hierarchical approach can be used that feeds proven clusters back into the biclustering methodology or system as the input. Data that does not cluster may be discarded. Thus, a very large unknown data set can be acted on to learn about the data. The system is also amenable to parallelization.

Bayesian Model For Antarctic Accumulation And Proposing Field Measurement, Philip White, Shane Reese

Journal of Undergraduate Research

Antarctica’s significance to the global climate is due to the vast amounts of water stored in its ice sheet. Indeed, its ice sheet stores enough water to increase the global sea level by about 200 feet if it were to melt. Even though radical climate change could not melt the entire Antarctic ice sheet for thousands of years, smaller, more realistic changes would still make a significant impact in the global climate, sea level, and growing seasons. For this reason, climatologists and geologists model water accumulation and loss over the Antarctic ice sheet. Accumulation, as defined here, is the net …