Physical Sciences and Mathematics Commons^™

Paris Talks: Acronyms, Actions & Akon, Juliet Pinto

Sea Level Rise Collection

No abstract provided.

Paris Talks: What's Resilience?, Phaedra Pezzullo

Sea Level Rise Collection

No abstract provided.

Toward A More Scientifically Literate Public, Michael Bass

UCF Forum

As a society we do a terrible job of educating our children to become scientifically literate. Sure, we have STEM (Science, Technology, Engineering and Mathematics) programs throughout the country, and with some justification we can brag about the successes of students that are in or who have graduated from such learning experiences.

Quasi-Platonic Psl2(Q)-Actions On Closed Riemann Surfaces, Sean A. Broughton

S. Allen Broughton

This paper is the first of two papers whose combined goal is to explore the dessins d'enfant and symmetries of quasi-platonic actions of PSL₂(q). A quasi-platonic action of a group G on a closed Riemann S surface is a conformal action for which S/G is a sphere and S->S/G is branched over {0, 1,infinity}. The unit interval in S/G may be lifted to a dessin d'enfant D, an embedded bipartite graph in S. The dessin forms the edges and vertices of a tiling on S by dihedrally symmetric polygons, generalizing the idea of a …

Quasi-Platonic Psl2(Q)-Actions On Closed Riemann Surfaces, Sean A. Broughton

Mathematical Sciences Technical Reports (MSTR)

This paper is the first of two papers whose combined goal is to explore the dessins d'enfant and symmetries of quasi-platonic actions of PSL₂(q). A quasi-platonic action of a group G on a closed Riemann S surface is a conformal action for which S/G is a sphere and S->S/G is branched over {0, 1,infinity}. The unit interval in S/G may be lifted to a dessin d'enfant D, an embedded bipartite graph in S. The dessin forms the edges and vertices of a tiling on S by dihedrally symmetric polygons, generalizing the idea of a …

Relative Proper Motions In The Rho Ophiuchi Cluster, Bruce Wilking, Frederick Vrba, Timothy Sullivan

Physics Faculty Works

Near-infrared images optimized for astrometry have been obtained for four fields in the high-density L 1688 cloud core over a 12 year period. The targeted regions include deeply embedded young stellar objects (YSOs) and very low luminosity objects too faint and/or heavily veiled for spectroscopy. Relative proper motions in R.A. and decl. were computed for 111 sources and again for a subset of 65 YSOs, resulting in a mean proper motion of (0,0) for each field. Assuming each field has the same mean proper motion, YSOs in the four fields were combined to yield estimates of the velocity dispersions in …

An Organic Mixed Ion-Electron Conductor For Power Electronics, Abdellah Malti, Jesper Edberg, Hjalmar Granberg, Zia Ullah Khan, Jens W. Andreasen, Xianjie Liu, Dan Zhao, Hao Zhang, Yulong Yao, Joseph W. Brill, Isak Engquist, Mats Fahlman, Lars Wågberg, Xavier Crispin, Magnus Berggren

Physics and Astronomy Faculty Publications

A mixed ionic–electronic conductor based on nanofibrillated cellulose composited with poly(3,4-ethylene-dioxythio­phene):­poly(styrene-sulfonate) along with high boiling point solvents is demonstrated in bulky electrochemical devices. The high electronic and ionic conductivities of the resulting nanopaper are exploited in devices which exhibit record values for the charge storage capacitance (1F) in supercapacitors and transconductance (1S) in electrochemical transistors.

When Disclosure Is Involuntary: Empowering Users With Control To Reduce Concerns, David W. Wilson, Ryan M. Schuetzler, Bradley Dorn, Jeffrey Gainer Proudfoot

Information Systems and Quantitative Analysis Faculty Proceedings & Presentations

Modern organizations must carefully balance the practice of gathering large amounts of valuable data from individuals with the associated ethical considerations and potential negative public image inherent in breaches of privacy. As it becomes increasingly commonplace for many types of information to be collected without individuals' knowledge or consent, managers and researchers alike can benefit from understanding how individuals react to such involuntary disclosures, and how these reactions can impact evaluations of the data-collecting organizations. This research develops and empirically tests a theoretical model that shows how empowering individuals with a sense of control over their personal information can help …

Information Technology For Development In Small And Medium-Sized Enterprises, Jie Xiong, Sajda Qureshi

Information Systems and Quantitative Analysis Faculty Proceedings & Presentations

Development is a concept that is often used to describe growth in organizations and the regions in which they reside. While research in Information Systems (IS) recognizes the importance of Information Technology (IT) in improving the organizational performance, a great deal of emphasis is given towards understanding large organizations. While social-economic development and transformation relies on new technological infrastructures and organizational changes, there is still a weak link between the organization studies with Information Technology (IT) as it relates to the growth of organizations. It appears that a greater research focus is needed in understanding the use of IT in …

Social Learning Systems: The Design Of Evolutionary, Highly Scalable, Socially Curated Knowledge Systems, Nolan Hemmatazad

Student Work

In recent times, great strides have been made towards the advancement of automated reasoning and knowledge management applications, along with their associated methodologies. The introduction of the World Wide Web peaked academicians’ interest in harnessing the power of linked, online documents for the purpose of developing machine learning corpora, providing dynamical knowledge bases for question answering systems, fueling automated entity extraction applications, and performing graph analytic evaluations, such as uncovering the inherent structural semantics of linked pages. Even more recently, substantial attention in the wider computer science and information systems disciplines has been focused on the evolving study of social …

Estimation Of Deep Drainage Differences Between Till And No-Till Irrigated Agriculture, Justin P. Gibson

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Deep drainage was monitored under two center pivot irrigation sites located in south-central Nebraska during the 2013, and part of the 2014, growing seasons. Both fields underwent similar land management except for tillage practice: no-till in one and disk till in the other. Long term deep drainage rates were also estimated from chemical analysis of extracted soil cores, with the aid of the chloride mass balance equation. Mechanisms underpinning differences in deep drainage between the two fields were investigated through the use of unsaturated zone numerical modeling.

Deep drainage estimates from field monitoring indicated that a greater amount of deep …

Rear-Flank Outflow Dynamics And Thermodynamics In The 10 June 2010 Last Chance, Colorado Supercell, Curtis J. Riganti

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

On 10 June 2010, the second Verification of the Origins of Tornadoes Experiment (VORTEX2) armada observed the non-tornadic phase of a supercell thunderstorm near Last Chance, Colorado. Tempest unmanned aircraft system (UAS) data collected in the rear-flank outflow revealed what appeared to be an elevated outflow head, turbulent wake, and a cold secondary outflow surge. Surface thermodynamic and kinematic data collected by StickNets and mobile mesonets suggested that the outflow wake may have extended to or very near the surface, perhaps cutting off the leading edge of the outflow at times. Single-Doppler data collected by the NOAA X-Pol Mobile Polarimetric …

Occupancy Analysis And Density Estimation Of Kori Bustards (Ardeotis Kori) And Helmeted Guineafowl (Numida Meleagris) For Use In Landscape Conservation Planning In The Northern Tuli Game Reserve, Botswana, Kathryn R. Mccollum

School of Natural Resources: Dissertations, Theses, and Student Research

For understudied species, more informed conservation planning and decision-making on both the local and landscape levels may be attained through the use of occupancy and abundance estimations. Here, we focus on two iconic bird species in eastern Botswana, kori bustards (Ardeotis kori) and helmeted guineafowl (Numida meleagris). The overall goal of this project was to better understand the hierarchy of factors that influence occupancy (ψ) and density of kori bustard and helmeted guineafowl populations within the Northern Tuli Game Reserve and how these factors may interact to affect landscape conservation and usage. We performed distance sampling …

Effects Of Wind Turbine Noise On Male Greater Prairie-Chicken Vocalizations And Chorus, Cara E. Whalen

School of Natural Resources: Dissertations, Theses, and Student Research

Wind energy facilities are constructed without full knowledge of their effects on birds, and the noise generated by wind turbines is a particular concern. I investigated the effects of wind turbine noise on male Greater Prairie-Chicken (Tympanuchus cupido pinnatus) vocalizations and chorus near Ainsworth, NE, USA in 2013 and 2014. I studied 14 leks located in the area surrounding a 36-turbine wind energy facility. I used two main approaches in this study. First, I recorded Greater Prairie-Chicken boom, cackle, whine, and whoop vocalizations at each of the study leks and measured the duration, sound pressure level, peak frequency, …

Mycorrhizal Roots In A Temperate Forest Take Up Organic Nitrogen From 13c- And 15n-Labeled Organic Matter, Matthew A. Vadeboncoeur, Andrew P. Ouimette, Erik A. Hobbie

Earth Systems Research Center

Background and Aims

The importance of the uptake of nitrogen in organic form by plants and mycorrhizal fungi has been demonstrated in various ecosystems including temperate forests. However, in previous experiments, isotopically labeled amino acids were often added to soils in concentrations that may be higher than those normally available to roots and mycorrhizal hyphae in situ, and these high concentrations could contribute to exaggerated uptake.

Methods

We used an experimental approach in which we added ¹³C-labeled and ¹⁵N-labeled whole cells to root-ingrowth cores, allowing proteolytic enzymes to release labeled organic nitrogen at a natural rate, as …

Methodology For Generating Simplified Cross Section Data Sets For Neutron Transport Calculations, Thomas Jay Harrison

Doctoral Dissertations

Neutron shielding problems involve radiation transport calculations over a wide range of energies. Fission neutrons have initial energy on the order of MeV, fusion neutrons have initial energy on the order of 10s of MeV, and space-origin neutrons have initial energy on the order of 100s of MeV or higher. Shielding calculations must track the neutrons from their initial energies until they are no longer of interest; for deep-penetration neutrons, this final energy can be on the order of eV before the neutron is no longer tracked. Thus, for deep-penetration space radiation shielding problems, the calculation may require tracking the …

Randomized Algorithms For Approximating A Connected Dominating Set In Wireless Sensor Networks, Akshaye Dhawan, Michelle Tanco, Aaron Yeiser

Mathematics and Computer Science Faculty Publications

A Connected Dominating Set (CDS) of a graph representing a Wireless Sensor Network can be used as a virtual backbone for routing through the network. Since the sensors in the network are constrained by limited battery life, we desire a minimal CDS for the network, a known NP-hard problem. In this paper we present three randomized algorithms for constructing a CDS. We evaluate our algorithms using simulations and compare them to the two-hop K2 algorithm and two other greedy algorithms from the literature. After pruning, the randomized algorithms construct a CDS that are generally equivalent in size to those constructed …

Positive Influence Dominating Set Generation In Social Networks, Akshaye Dhawan, Matthew Rink

Mathematics and Computer Science Faculty Publications

Current algorithms in the Positive Influence Dominating Set (PIDS) problem domain are focused on a specific type of PIDS, the Total Positive Influence Dominating Set (TPIDS). We have developed an algorithm specifically targeted towards the non-total type of PIDS. In addition to our new algorithm, we adapted two existing TPIDS algorithms to generate PIDS. We ran simulations for all three algorithms, and our new algorithm consistently generates smaller PIDS than both existing algorithms, with our algorithm generating PIDS approximately 5% smaller than the better of the two existing algorithms.

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, …

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 …

Understanding The Influence Of Non-Covalent Interactions And Nanoparticle Geometries In Carbon Based Polymer Nanocomposites, Bradley Carroll Miller

Doctoral Dissertations

Low-loading polymer nanocomposites (PNC) are an area of great interest in polymer science. As nanoparticles (NP) are typically expensive in comparison to matrix materials; the low loading regime makes the most efficient use of materials, and represents the optimum for realizing cost effective, high-performance PNCs. However, formulating effective low-loading composites is not without challenges. In addition to the typical requirement of good dispersion for efficient translation of NP properties to the bulk, low-loading composites can sometimes exhibit anomalous (non-classical) dynamics, and unpredictable properties. It is within this context that this thesis aims to examine the effects of NP geometry and …

Rare Earth Production And Characterization Studies, Jake Anson Stewart

Doctoral Dissertations

The rare earths include elements Sc, Y, and La through Lu are important in many modern technologies. With the exception of Sc and Ce the rare earths are all have similar chemical behaviors with the preferred oxidation state in aqueous solution being +3. Currently, industrial purification of the rare earths is completed by counter current solvent extraction (CCSX). In most CCSX separations, Y extracts with Ho making their separation difficult. However, in a few systems Y exhibits an itinerant behavior. Carboxylic acids of varying sizes and substitutions were investigated in a study of Y itinerant behavior. It was found when …

Interface And Morphology Engineering In Solution-Processed Electronic And Optoelectronic Devices, Sanjib Das

Doctoral Dissertations

The first part of this dissertation focuses on interface and morphology engineering in polymer- and small molecule-based organic solar cells. High-performance devices were fabricated, and the device performance was correlated with nanoscale structures using various electrical, spectroscopic and microscopic characterization techniques, providing guidelines for high-efficiency cell design.

The second part focuses on perovskite solar cells (PSCs), an emerging photovoltaic technology with skyrocketing rise in power conversion efficiency (PCE) and currently showing comparable PCEs with those of existing thin film photovoltaic technologies such as CIGS and CdTe. Fabrication of large-area PSCs without compromising reproducibility and device PCE requires formation of dense, …

Solution And Surface Properties Of Architecturally- And Compositionally-Complex Block Copolymers And Their Binary Mixtures, Jesse Lawrence Davis

Doctoral Dissertations

The spontaneous generation of complex structures from polymeric building blocks provides a simple yet effective route to create useful soft matter structures having potential application in a variety of nanotechnologies. The topology, chemical structure, block composition, and sequence of the constituent building blocks of polymers are tunable through synthetic chemistry. This tunability offers attractive opportunities to generate complex, yet well-defined structures with control over the geometry, packing symmetry, and microdomain structure. This thesis work involves the study of the self-assembly behaviors of architecturally complex amphiphilic block copolymers (ABCs). ABCs are composed of two or more chemically distinct blocks that are …

Effective Field Theory Approach To Collective Motion In Atomic Nuclei, Eduardo Antonio Coello Perez

Doctoral Dissertations

Collective motion in heavy nuclei has been studied within collective and algebraic models, and within density functional theory. While they reproduce the energy spectra of these systems, their predictions for some electromagnetic transitions and moments do not lie within experimental uncertainty; in other words, these predictions are inconsistent with experimental data. An effective field theory approach to collective motion in heavy nuclei solves this long standing problem. Based on symmetry arguments only, the effective field theories, constructed as expansions in powers of a small parameter, consistently describe the energy spectra of nuclei exhibiting collective motion at low order in the …

Solar Modulation Of The Cosmic Ray Intensity And The Measurement Of The Cerenkov Reemission In Nova’S Liquid Scintillator, Philip James Mason

Doctoral Dissertations

The NOνA (NuMI Off-axis electron neutrino Appearance) experiment is a long baseline neutrino oscillation experiment at Fermi National Accelerator Laboratory. Its purpose is to observe the oscillation of ν_μ (muon neutrino) to ν_e (electron neutrino) and to investigate the neutrino mass hierarchy and CP violation in the neutrino sector. Two detectors have been built for this purpose, a Near Detector 300 feet underground at Fermilab, and a Far Detector, on the surface at Ash River, Minnesota.

The completion of NOνA’s Far Detector in October 2014 enabled not only the recent measurement of neutrino oscillations, but an array of …

Computational Simulation Of Mass Transport And Energy Transfer In The Microbial Fuel Cell System, Shiqi Ou

Doctoral Dissertations

This doctoral dissertation introduces the research in the computational modeling and simulation for the microbial fuel cell (MFC) system which is a bio-electrochemical system that drives a current by using bacteria and mimicking bacterial interactions found in nature. The numerical methods, research approaches and simulation comparison with the experiments in the microbial fuel cells are described; the analysis and evaluation for the model methods and results that I have achieved are presented in this dissertation.

The development of the renewable energy has been a hot topic, and scientists have been focusing on the microbial fuel cell, which is an environmentally-friendly …

Neuron Clustering For Mitigating Catastrophic Forgetting In Supervised And Reinforcement Learning, Benjamin Frederick Goodrich

Doctoral Dissertations

Neural networks have had many great successes in recent years, particularly with the advent of deep learning and many novel training techniques. One issue that has affected neural networks and prevented them from performing well in more realistic online environments is that of catastrophic forgetting. Catastrophic forgetting affects supervised learning systems when input samples are temporally correlated or are non-stationary. However, most real-world problems are non-stationary in nature, resulting in prolonged periods of time separating inputs drawn from different regions of the input space.

Reinforcement learning represents a worst-case scenario when it comes to precipitating catastrophic forgetting in neural networks. …

Algorithm-Based Fault Tolerance For Two-Sided Dense Matrix Factorizations, Yulu Jia

Doctoral Dissertations

The mean time between failure (MTBF) of large supercomputers is decreasing, and future exascale computers are expected to have a MTBF of around 30 minutes. Therefore, it is urgent to prepare important algorithms for future machines with such a short MTBF. Eigenvalue problems (EVP) and singular value problems (SVP) are common in engineering and scientific research. Solving EVP and SVP numerically involves two-sided matrix factorizations: the Hessenberg reduction, the tridiagonal reduction, and the bidiagonal reduction. These three factorizations are computation intensive, and have long running times. They are prone to suffer from computer failures.

We designed algorithm-based fault tolerant (ABFT) …

Novel Thermoplastic Elastomers Based On Benzofulvene: Synthesis And Mechanical Properties, Weiyu Wang

Doctoral Dissertations

Thermoplastic elastomers (TPEs) are of great importance both academically and technologically. Currently TPEs are the predominated form of styrene-diene copolymers. However, these styrenic TPEs have serious limitations in applications, especially at higher temperature, because of their low upper service temperature (UST). The work described in this dissertation aimed to developing thermoplastic elastomers with a higher UST and lower cost.

In order to develop TPEs with a higher UST, we employed benzofulvene, an anionically polymerizable monomer in hydrocarbon solvent at room temperature, as the glassy block and copolymerized it with isoprene to prepare polybenzofulvene-polyisoprene-polybenzofulvene (FIF) triblock copolymers. Among all triblock copolymers …