Physical Sciences and Mathematics Commons^™

May Graduation, Samuel Coskey

Mathematics Faculty Publications and Presentations

Here I narrate the story of the last few days of my graduate program in mathematics. After the completion of the thesis and the delivery of the defense, several twists and turns await in the hours and even minutes before the last deadline.

Widely Digitally Delicate Brier Primes And Irreducibility Results For Some Classes Of Polynomials, Thomas David Luckner

Theses and Dissertations

This dissertation considers three different sections of results. In the first part of the dissertation, a result on consecutive primes which are widely digitally delicate and Brier numbers is discussed. Making use of covering systems and a theorem of D. Shiu, M. Filaseta and J. Juillerat showed that for every positive integer k, there exist k consecutive widely digitally delicate primes. They also noted that for every positive integer k, there exist k consecutive primes which are Brier numbers. We show that for every positive integer k, there exist k consecutive primes that are both widely digitally …

Study Of Non-Covalent Interactions Using Molecular Rotors And Balances, Daniel Onyekachi Madukwe

Theses and Dissertations

The main focus of this dissertation is on the quantification of non-covalent interactions using molecular rotors and balances. While molecular rotors were used to measure kinetic effects of weak non-covalent interactions, molecular balances were used to measure their thermodynamic effects. Chapters 1 and 2 focus on the use of molecular rotors in measuring and studying the kinetic effects of the hydrogen bonding interaction on the bond rotation transition states. Chapters 3 and 4 focus on the quantification of lone pair – lone pair and sp²-CH/π interactions respectively, using molecular balances. These studies were carried out in the …

Groundwater Flow And Salt Marsh Migration: The Forest/Marsh Boundary, Camille Rossiello

Theses and Dissertations

Salt marshes migrate landward in response to sea level rise, but the rate of this migration is not constant and can be influenced by pulse disturbances. Long term observations at Sapelo Island, Georgia, show that salt marsh migration has occurred during droughts, but the mechanism for this migration is unclear. Drought is thought to influence salt marsh migration by reducing fresh groundwater discharge from the upland. Rising sea level also encroaches on the upland, which could cause movement of the freshwater lens inland. A two-dimensional numerical model was built to simulate groundwater flow and solute transport based on the Marsh …

Expanding On The Solid State Chemistry Of F-Element Chalcogenides, Logan Skyler Breton

Theses and Dissertations

An overarching goal in solid state chemistry is to achieve predictability regarding the synthesis of compounds with desired properties. While this goal is far from being reached, solid state chemists are hard at work synthesizing and characterizing new materials to further our understanding of structure-property relationships, and to expand our fundamental knowledge to rationalize the outcomes of solid-state syntheses. With the advent of new solid state synthetic methods, novel compounds exhibiting exciting properties are still being discovered today. The infancy of these synthetic methods promises a myriad of undiscovered compounds with potentially interesting properties which has resulted in a recent …

A Bayesian Spatial Scan Statistic For Normal Data, Laasya Velamakanni

Theses and Dissertations

Scan statistics are useful methods for detecting spatial clustering. While they were initially developed to detect regions with an excess of binomial or Poisson events, spatial scan statistics have been extended to detect hotspots in other types of data including continuous data. They have many applications in different fields such as epidemiology (e.g. detecting disease outbreaks), sociology (e.g. detecting crime hotspots), and environmental health (e.g. detecting high-pollution areas). Spatial scan statistics identify a ‘most likely cluster’ and then use a likelihood ratio test to determine if this cluster is statistically significant. Spatial scan statistics have been extended to the Bayesian …

Yield Extraction For The Γd → Λ X Reaction, K H P Nishadi Hasarangi Silva

Theses and Dissertations

Improving and adding new experimental measurements of hyperon-nucleon (YN) and hyperon-deuteron (Yd) cross sections is an active area in nuclear physics research. Scientists use such cross-section data to understand the composition of neutron stars and develop a comprehensive picture of the baryon-baryon interaction. Using high luminosity photon beam incident on a long liquid deuterium target and the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility (JLab), a sample of hyperon-deuteron elastic scattering events was previously identified. The E06-103 (g13) experiment was originally designed to address the scarcity of experimental data on hyperon photoproduction off the neutron …

Machine-Learning Classification To Predict The Dimensionality Of Hybrid Organic-Inorganic Halide Perovskites, Yatiwelle Koralalage Samuditha Sandaru Yatiwella

Theses and Dissertations

Low dimensional hybrid perovskites have demonstrated remarkable performance in photovoltaic applications, primarily due to their exceptional optical and electronic properties. As the search for potential candidates for novel materials continues, understanding the structure of these materials is crucial for investigating their stability. In this study, we implement a framework to find novel material based on a machine-learning model. The machine learning model was trained to predict the dimensionality of the polyhedral network based on the connectivity of the polyhedral network in different directions. The polyhedral connectivity of low-dimensional structures can be classified into three dimensions: 0D, 1D, and 2D. This …

The Synthesis Of Novel Rare Earth Thiosilicates Using The Boron Chalcogen Mixture Method For An Interest In Their Magnetic And Optical Properties, Adam Alexander King

Theses and Dissertations

The chalcogens or the group sixteen elements excluding oxygen, are of interest due to their wide variety of structures and compositions, which gives the potential for a plethora of desired physical properties. This is due to their increased ability to catenate, forming stable chalcogen-chalcogen bonds. When the chalcogens combine with certain main group elements and transition metals they form anionic framework building blocks known as chalcometallates. One such chalcometallate of interest is the thiosilicates, compounds containing Si-S bonds as the anionic frameworks. These compounds are of interest due to their potentials in both their optical and magnetic properties. However, traditional …

Approaches To Detecting And Modeling Over-And Underdispersion In Alternative Count Data Distributions And An Application Of Logistic Regression And Random Forest Modeling To Improve Screening Tools For Tic Disorders In Children, Rebecca C. Wardrop

Theses and Dissertations

This dissertation focuses on theory and application of discrete data methods, particularly approaches to over- and underdispersion relative to the Poisson distribution and an application of random forest and logistic regression modeling. The first chapter derives a score test for over- and underdispersion in the heaped generalized Poisson distribution. Equi-, over-, and underdispersed heaped generalized Poisson and heaped negative binomial data are simulated to evaluate the performance of the score test by comparing the power it achieves to that of Wald and likelihood ratio tests. We find that the score test we derive performs comparably to both the Wald and …

Computational Studies Of Bond Dissociation Energies And Organic Reaction Mechanisms, Shehani Thishakkya Wetthasinghe

Theses and Dissertations

This dissertation presents the progress of two independent projects. Chapter 2 and Chapter 3 focus on the first project, which involves material exploration utilizing machine learning techniques. We explore the potential use of cobaltocenium (CoCp⁺₂) derivatives as metal cations in anion exchange membranes (AEMs) for alkaline fuel cells, highlighting their superior thermal and alkaline stability compared to ammonium derivatives. The stability of CoCp⁺₂ can be fine-tuned by varying the substituent groups attached to the cyclopentadienyl ring (Cp) in CoCp⁺₂ .These derivatives encompass a variety of electron-donating and electron-withdrawing groups as substituents on both …

Statistical Methods For Single Cell Sequencing Data Analysis, Fei Qin

Theses and Dissertations

The recent emergence of single cell sequencing (SCS) technology has provided us with single-cell DNA or RNA sequencing (scDNA/RNA-seq) information to investigate cellular evolutionary relationships. Despite many analysis methods have been developed to infer intra-tumor genetic heterogeneity, cluster cellular subclones, detect genetic mutations, and investigate spatially variable (SV) genes, exploring SCS data remains statistically challenging due to its noisy nature.

To identify subclones with scDNA-seq data, many existing studies use an independent statistical model to detect copy number profile in the first step, followed by classical clustering methods for subclone identification in downstream analyses. However, spurious results might be generated …

Hf Radar: Shining A Light On Ocean Currents, Douglas Cahl

Theses and Dissertations

High Frequency (HF) radar systems are commonly used to estimate surface ocean currents over the coastal ocean. Their range depends on their operational frequency and low frequency systems (≤ 10 MHz) can reach distances up to 200 km from the coastline. These systems are used to estimate surface currents by measuring the phase speed of wind-driven waves and comparing the measured speed with that expected theoretically; deviations from the theoretical still-water phase speed are attributed to ocean surface currents. Although HF radar systems are considered a mature technology and the accuracy of the radar-derived surface current estimates is well studied, …

Deep Learning Methods For Some Problems In Scientific Computing, Yuankai Teng

Theses and Dissertations

Deep learning has emerged as a powerful approach for solving complex problems in scientific computing due to the increasing availability of large-scale data and computational resources. This thesis explores the potential of deep learning methods for three specific problems in scientific computing: (i) reducing the dimensions of variables in function approximation, (ii) solving linear reaction-diffusion equations, and (iii) finding the parametric representations of parameters in the numerical schemes for solving time-dependent partial differential equations.

For the first problem, a novel deep learning architecture is developed for reducing the dimensions of variables in function approximation. The proposed method achieves state-of-the-art performance …

Measurement Of The Total Cross-Section Of Muon Neutrino Charged-Current Coherent Pion Production In Nova Near Detector, Kuruppumullage Don Chatura Dilshan Kuruppu

Theses and Dissertations

Charged Current (CC) coherent neutrino-nucleus pion production is characterized by small momentum transferred to the nucleus, which is left in its ground state. Despite the relatively large uncertainties on the production cross-section, coherent production of mesons by neutrinos represents an important process, as it can shed light on the structure of the weak current and can also constitute a potential source of background for modern neutrino oscillation experiments and searches for Beyond Standard Model (BSM) physics. This Ph.D. thesis presents a new measurement of CC coherent pion production in the NOvA near detector at the Fermi National Accelerator Laboratory (Fermilab). …

Identification Of New Disinfection Byproducts In Drinking Water And Impacts Of Algae, Md. Tareq Aziz

Theses and Dissertations

The disinfection of water has been hailed as one of the most important triumphs for public health in the 20th century. Drinking water treatment plants produce safe drinking water by inactivating microorganisms through the use of disinfectants, including chlorine, chloramine, chlorine dioxide, UV irradiation, and ozone. However, these disinfectants also produce toxic disinfection by-products (DBPs), through reactions with natural organic matter and anthropogenic pollutants, as well as bromide and iodide present in source waters. The presence of bromide and iodide results in the formation of bromo- and iodo-DBPs which are much more toxic than DBPs containing chlorine. DBPs are always …

Freestanding Graphene Heat Engine Analyzed Using Stochastic Thermodynamics, J. Durbin, J. M. Mangum, M. N. Gikunda, F. Harerimana, P. Kumar, L. L. Bonilla, P. M. Thibado

Physics Faculty Publications and Presentations

We present an Ito-Langevin model for freestanding graphene connected to an electrical circuit. The graphene is treated as a Brownian particle in a double-well potential and is adjacent to a fixed electrode to form a variable capacitor. The capacitor is connected in series with a battery and a load resistor. The capacitor and resistor are given separate thermal reservoirs. We have solved the coupled Ito-Langevin equations for a broad range of temperature differences between the two reservoirs. Using ensemble averages, we report the rate of change in energy, heat, and work using stochastic thermodynamics. When the resistor is held at …

Forecasting Sea Level Rise-Driven Inundation In Diked And Tidally Restricted Coastal Lowlands, K. M. Befus, A. P.D. Kurnizki, K. D. Kroeger, M. J. Eagle, T. P. Smith

Geosciences Faculty Publications and Presentations

Diked and drained coastal lowlands rely on hydraulic and protective infrastructure that may not function as designed in areas with relative sea-level rise. The slow and incremental loss of the hydraulic conditions required for a well-drained system make it difficult to identify if and when the flow structures no longer discharge enough water, especially in tidal settings where two-way flows occur through the dike. We developed and applied a hydraulic mass-balance model to quantify how water levels in the diked and tidally restricted coastal wetlands and water bodies dynamically respond to sea-level rise, specifically applied to the Herring River Estuary …

Theme Park Visitors Prefer Human-Like Robots In Customer Service Interactions, Ady Milman, Asli D.A. Tasci

Rosen Research Review

Service robots are becoming increasingly popular in many industries and social settings, including education, childcare, elderly therapy centers, and even theme parks. Tourism and hospitality industries are adopting robots enthusiastically and are being closely studied to observe guest engagement and reaction to robotic services. Service robots are becoming increasingly popular in many industries and social settings, including education, childcare, elderly therapy centers, and even theme parks. Tourism and hospitality industries are adopting robots enthusiastically and are being closely studied to observe guest engagement and reaction to robotic services. UCF Rosen College of Hospitality Management researchers, Dr. Ady Milman and Dr. …

Maintaining Grassland Plant Diversity While Controlling Woody Plant Encroachment, James Stubbendieck, Kay L. Kottas, S. J. Tunnell, S. J. Palazzolo

IGC Proceedings (1993-2023)

The tallgrass prairie region of the United States is a fragmented grassland ecosystem. Much of the 1 to 2% of the remaining prairie is being degraded by invading woody plants, which frequently results in a shift from grassland to woodland. Smooth sumac (Rhus glabra L.), a shrub native to the region, can rapidly increase in density and become dominant in the plant community. Prescribed fire alone is not a constraint to this resprouting species (Stubbendieck et al., 2003). Herbicides are useful tools for managing woody plants in grasslands, but the negative response of desirable plants to herbicides is …

Do Species And Functional Diversity Indices Reflect Changes In Grazing Regimes And Climatic Conditions In Northeastern Spain?, F. De Bello, J. Leps, M. T. Sebastià

IGC Proceedings (1993-2023)

Understanding the mechanisms that maintain biodiversity in various ecosystems enables the development of management practices that prevent degradation (Canals & Sebastia, 2000). Each diversity index reflects some compositional properties and could be influenced differently by stress and disturbance factors (Magurran, 2004). In this study, we aim to reveal 1) which management practices and environmental factors affect biodiversity in rangelands of northeastern Spain and 2) the relationship between species diversity and functional diversity (SD and FD).

Impact Of Grazing Regimes On Mean Sward Height: Implications For The Management Of Bird Habitats In Agricultural Landscapes, M. Tichit, D. Durant, E. Kernéïs

IGC Proceedings (1993-2023)

Grazing in wet grasslands is a key process to manage foraging and nesting habitats for waders. Grazing has positive and negative effects related to the importance of sward conditions for these species and to nest-trampling by cattle. For settlement and nesting, lapwings need a short sward ( ≤ 10cm; see Durant et al., this congress). However, when lapwings settle in early spring, grasslands seldom are grazed yet, due to low soil carrying capacity. We studied the effect of autumn and winter grazing regimes on sward structure in early spring, and the effect of grazing regime in early spring on …

Soil Carbon Sequestration Under Three Years Of No-Till Forage Cropping Systems, D. H. Min, J. D. Deyoung, Richard Leep

IGC Proceedings (1993-2023)

The effects of reduced tillage on soil organic carbon (SOC) are generally well established (Chan et al., 2002; Cabardella & Elliott, 1992). The effects of different crops are also somewhat understood (Drinkwater et al., 1998). However, many of these studies are done in the laboratory to study the effects of crop residues on SOC. Many forage-based systems have very little crop residue returned to the field. What residue does return is often in the form of manure or compost, which is usually broken down much more rapidly than most crop residues. The objective of this study is to …

Number And Viability Of Seeds Recovered From Faeces Of Ruminant Animals, Alaba O. Jolaosho, Olufemi S. Onifade, O. M. Arigbede, Jimoh A. Olanite, T. O. Akinola

IGC Proceedings (1993-2023)

Ruminants play a significant role in the dissemination of plant seeds as a result of ingested seeds during grazing on pasture escaping digestion that are voided with the faeces and returned to the seed bank (Russi et al., 1992).

Population Changes Of Invasive Annuals In California Annual And Perennial Grasslands, Richard King

IGC Proceedings (1993-2023)

Some non-native annual forbs and grasses can be invasive in California's annual grassland region. Taeniatherum caput-medusae (L.) Nevski and Centaurea solstitialis L. can spread quickly, become nearly monospecific stands, and reduce carrying capacity for livestock and wildlife. Centaurea also can be toxic to horses. Lathyrus hirsutus L. is less invasive, but the seed is toxic to various livestock. Since 1991, the author has raised beef cattle on 16 ha of predominantly annual grassland where these 3 species occur, and a family member has raised cattle on approximately 40 ha of adjacent property. Surface soils in this hilly land are …

The Effect Of Sheep Grazing At Two Stocking Rates On The Seedling Recruitment Of Grassland Forbs, Johannes Isselstein, Markus Kowarschik, S. Bonn, M. Hofmann

IGC Proceedings (1993-2023)

Limitations for seedling recruitment are major constraints to maintain and enhance plant species diversity in productive grasslands (Bakker & Berendse 1999). Grass sward condition plus species-specific requirements for germination and survival determine the recruitment success. Therefore, a field experiment investigated the establishment of oversown seeds from wildflower forbs in relation to grass sward management.

Adsorption Performance Of Mg0.33ni0.33co0.33fe2o4 Nanoparticles Doped With Gadolinium And Lanthanum For Lead (Ii) Removal, Mariam Rabaa, Amani Aridi, Ghassan Younes, Ramadan Awad

BAU Journal - Science and Technology

The issue of water pollution has become a major concern in recent times, and the need for effective strategies for treating contaminated water sources has become more urgent. One promising approach that has been gaining attention in the field of wastewater treatment is the use of nano-ferrites. In this regard, novel Mg_0.33Ni_0.33Co_0.33La_xFe_2-xO₄ and Mg_0.33Ni_0.33Co_0.33Gd_xFe_2-xO₄ nanoparticles (NPs), where x = 0.00, 0.01 and 0.08, were synthesized to test their adsorption performance for the removal of Pb (II). The structural …

Robust And Parallel Segmentation Model (Rpsm) For Early Detection Of Skin Cancer Disease Using Heterogeneous Distributions, Nancy Zreika, Ali El-Zaart, Abdallah El Chakik

BAU Journal - Science and Technology

Melanoma is the most common dangerous type of skin cancer; however, it is preventable if it is diagnosed early. Diagnosis of Melanoma would be improved if an accurate skin image segmentation model is available. Many computer vision methods have been investigated, yet the problem of finding a consistent and robust model that extracts the best threshold value, persists. This paper suggests a novel image segmentation approach using a multilevel cross entropy thresholding algorithm based on heterogeneous distributions. The proposed strategy searches the problem space by segmenting the image into several levels, and applying for each level one of the three …

Size Effect On The Optical Response Of Cylindrical Palladium Nanoparticles, Salem Marhaba, Mohammed Khalaf

BAU Journal - Science and Technology

In this work, a computational study is carried out to investigate the optical response of palladium nano-cylinders. The Finite Element Method (FEM) is employed using the COMSOL MULTIPHYSICS simulation program to calculate the scattering, absorption, and extinction cross-sections. The influence of the size of the cylindrical nanoparticles on their optical properties is discussed. The results are plotted for a broad spectral range of wavelengths from ultra-violet to infra-red of the incident electromagnetic wave on the cylindrical nanoparticles.

Localized Surface Plasmon Resonance Of Palladium Parallelepiped Nanoparticles, Salem Marhaba, Nourhan El Kawni

BAU Journal - Science and Technology

Localized surface plasmon resonance (LSPR) of palladium parallelepiped nanoparticle have been investigated using Finite Element Method (FEM) in the frame of COMSOL Multiphysics Software. Spectral characteristics (magnitude, peak position and width) of LSPR of a single Pd nanoparticle having the shape of a parallelepiped are investigated in two different cases. The first case studied the size effect on LSPR by fixing the height with varying both length and width. However, the second case studied the shape effect on the LSPR by rounding the corners of the parallelepiped for different radii while fixing its dimensions. The extinction cross-section spectra of these …