Physical Sciences and Mathematics Commons^™

Counterexample To Eremenko's Conjecture, Paradise Low

Graduate Research Theses & Dissertations

Eremenko’s Conjecture is a long-standing problem in complex dynamics that asks whetherevery connected component of the set of escaping points of a transcendental entire function is unbounded. It was finally proven false in a paper by Mart ́ı-Pete, Lasse Rempe, and James Waterman that constructs a counterexample to the conjecture. This thesis seeks to pro- vide a background on Eremenko’s Conjecture, discuss the partial results surrounding it, and explain the construction of the counterexample in Mart ́ı-Pete, et al.’s paper.

Fundamental Study Of Dopant Effect And Toxicity In Perovskite Materials, Xun Li

Graduate Research Theses & Dissertations

This dissertation comprehensively studies the research on organic-inorganic hybrid perovskite to solve the toxicity issue of perovskite-based solar cells under practical conditions, understand the doping effect on hybrid perovskite materials in optoelectronic applications, and improve the photovoltaic performance of perovskite-based solar cells by composition tailoring. Specifically, an innovative and simple chemical approach was invented for on-device sequestration of toxic Pb leakage caused by severe device damage. To mimic the practical conditions, the sequestration of lead leakage was conducted under cold water, warm water, acid water, dripping water, and water with competitive ions. Crucially, it was found that at least 96% …

Precise Phase Space Control For Future Linear Colliders, Tianzhe Xu

Graduate Research Theses & Dissertations

The design of future linear colliders is highly constrained by their cost and footprint. Phase space partitioning offers an attractive path towards cost and complexity reduction through precise tailoring of particle beam distributions. In this dissertation, we discuss a phase space manipulation technique for generating flat electron beams---a type of beam distribution of particular interest to linear colliders. We report the experimental generation of flat beams with transverse-emittance ratio up to 200 at Argonne Wakefield Accelerator facility. We further expand the technique by combining it with transverse-to-longitudinal emittance exchange. We present the conceptual design of an electron injector capable of …

Comparison Of Topsoil Moisture In E3sm Model Simulations And In-Situ Observations Over Illinois, Jacinda Lee Mayer

Graduate Research Theses & Dissertations

Soil moisture stimulates land-atmosphere interactions by modifying energy and water fluxes in the boundary layer and it plays an important role in climate change studies. The objective of this research is to quantify the spatial and temporal variations of the Illinois Climate Network’s (ICN) observed topsoil moisture, as well as evaluate how accurately the new climate model, E3SM, is simulating soil moisture compared to the observed data during 2003-2014. Observed topsoil moisture averaged over growing season during the 12-year period indicates a general dry-north and wet-south pattern in Illinois, and northeast and southwest become drier with the progression of the …

Analysis Of Deformation Near Salt Structures: Geomechanical Modeling And Case Studies From The Paradox Basin, Utah, And Flinders Ranges, South Australia, Mackenzie Anne Wegmann

Graduate Research Theses & Dissertations

This thesis utilizes detailed field studies and numerical simulations to characterize near- salt deformation patterns. Establishing possible deformation patterns and their evolution helps to constrain assumptions within geomechanical models and aids in the evaluation of prospects that rely on trapping at or near the salt-sediment interface. For the field studies, I use a combination of mesoscopic structural analysis, drone photogrammetry, and 3D modeling to analyze variation in deformation patterns at a scale of meters to hundreds of meters along transects moving horizontally away from the salt-sediment interface adjacent to the western end of the Onion Creek salt diapir (OCSD) in …

Compact Wakefield Accelerator With Advanced Beam Manipulations, Wei Hou Tan

Graduate Research Theses & Dissertations

Beam-driven structure wakefield acceleration is an advanced accelerator concept proposedto develop accelerators with much smaller footprints than conventional state-of-the-art accelerators at a similar energy scale. The concept relies on the generation of electromagnetics wakefields through the interaction of a highly charged “drive” beam with a structure, such as a waveguide, to accelerate a following bright “witness” beam with produced wakefields. This dissertation discusses three aspects critical to structure-wakefield accelerators: the manipulation of the drive beam for efficient wakefield acceleration, the development of a photoinjector capable of producing bright witness electron beams, and the investigation of beam instability in a wakefield …

Methods For Computing The Global Optimum Of Non-Convex Objectives, Isaac Michael Hawn

Graduate Research Theses & Dissertations

\begin{abstract}In this thesis, we concern ourselves with solving the unconstrained optimization problem % \begin{gather*} \text{Minimize}\; f(x)\\\text{subject to}\; x\in X \end{gather*} % where $f\colon\mathbb{R}^N\to \mathbb{R}$ is a non-convex function, possibly with infinitely many local minima. Solving such a problem, especially in higher dimensions often proves to be an extraordinarily difficult task, either in time complexity or in the methodology itself. Indeed, mathematicians must often resort to algorithms which make use of problem structure and which may not generalize well. In this thesis, we present two algorithms which solve this problem, albeit with their own shortcomings.

First, we present a new, $N$-dimensional …

Forecasting Bitcoin, Ethereum And Litecoin Prices Using Machine Learning, Sai Prabhu Jaligama

Graduate Research Theses & Dissertations

This research aims to predict the cryptocurrencies Bitcoin, Litecoin and Ethereum using Time Series Modelling with daily data of closing price from 16th of October 2018 to 9th of September 2021for a total of 1073 days. Augmented Dickey Fuller test was first used to check stationarity of the time series, then two forecasting algorithms called ARIMA, and PROPHET were used to make predictions. The findings show similar results for both the models for each of Bitcoin, Ethereum and Litecoin. The results achieved show modelling cryptocurrencies which are volatile using a single variable produces satisfying results.

Impact Of Public And Private Investments On Economic Growth Of Developing Countries, Faruque Ahamed

Graduate Research Theses & Dissertations

This paper aims to study the impact of public and private investments on the economic growth of developing countries. The study uses panel data from 39 developing countries covering the periods 1990-2019. The study is based on the neoclassical growth models or exogenous growth models in which land, labor, capital accumulation, etc., and technology proved substantial for economic growth. The paper uses the impact on overall GDP growth and GDP per capita growth. The study used a mixed-effect regression model and a Bayesian logistic regression model to derive the findings. For private investments, domestic credit has a positive association, but …

Analysis Of Sunscreens And Antibiotics In Groundwater During The Covid-19 Pandemic In The Riviera Maya, Mexico, Jackie Cooney

Graduate Research Theses & Dissertations

Sunscreens and antibiotics are contaminants of emerging concern in groundwater, especially in areas with high tourism. The Riviera Maya in Quintana Roo, Mexico, is an international travel destination with a popular aquatic tourism industry. The region experienced a significant decrease in tourist visits during the COVID-19 pandemic, setting up a natural experiment to characterize the baseline contamination of groundwater in the absence of tourists. Additionally, municipalities installed new sewage disposal systems to combat the poor water quality due to inadequate septic systems and wastewater treatment plants. Water samples were collected during the pandemic from March 2020 to July 2021 from …

Magnetic Charge Ordering Of Pinwheel Artificial Spin Ice In In-Plane External Magnetic Fields And Its Application For Tunable Vortex Pinning, Timothy Draher

Graduate Research Theses & Dissertations

Pinwheel artificial spin ice (ASI) systems fabricated using permalloy nanobars offer tunable control of superconducting vortices in an ASI-superconductor hybrid. Vortex pinningis achieved by tuning the ordering of the ASI’s magnetic charge distribution via an external field to create an optimal potential energy landscape to which superconducting vortex motion can be impeded or pinned. Magnetic charge ordering in a pinwheel ASI is visualized using MuMax3 micromagnetic simulations to aid in characterizing the correlation of charge ordering amongst the spin ice system with the application of the external field. Vortex pinning is characterized in a sample of pinwheel spin ice patterned …

Microfabric Analysis Of Mid-Pliocene Amundsen Sea Interglacial Sediments Demonstrates A Link Between Iceberg Melt And Diatom Productivity (Iodp Exp. 379), Heather Leanne Furlong

Graduate Research Theses & Dissertations

Anthropogenically induced climate change in the polar regions has rapidly become an emergent global issue, especially for low-lying coastal communities, which are most affected by sea-level rise. The future of the West Antarctic Ice Sheet (WAIS) is of significant concern due to its history of instability and retreat, especially in light of the observed ongoing changes. Establishing rates of retreat is critical to forecasting future behavior of the WAIS, and previous studies have been unable to establish rates of ice sheet collapse in part because Antarctic continental shelf records are impacted by erosional hiatuses. In 2019, International Ocean Discovery Program …

An Upgraded Photoinjector For The Argonne Wakefield Accelerator, Emily Frame

Graduate Research Theses & Dissertations

The Argonne Wakefield Accelerator (AWA) is planning an upgrade of the drive-beam accelerator’s photoinjector, the driving force of electron generation. The upgrade’s main goal is to improve beam brightness using linear accelerating cavities and a radiofrequency-gun cavity. In the process of this upgrade, one of the beam focusing solenoids is being redesigned. A beam dynamics optimization is performed for two new solenoid designs, with considerations for producing low-charge (∼ 1 nC) electron bunches as well as operations at higher charges (∼ 50 nC). This project focuses on the optimization study for both the low- and high-charge regimes, exploring the impact …

Climate Change Impacts On Baseflow Contributions In A Semi-Arid, Snowmelt-Dominated Basin Within The Upper Colorado River Basin, Kaelyn Quinlan

Graduate Research Theses & Dissertations

The Upper Colorado River Basin (UCRB) is a significant water resource in the southwestern United States, providing water to Colorado, New Mexico, Utah, and Wyoming. (Reclamation, 2012). Communities and industries within these states are dependent on the Colorado River’s water availability and accessibility. Growing population and development demands, in conjunction with climate change, can have drastic consequences for the ecosystems and municipalities dependent on these reservoirs. It is critical that as watersheds within this region are strained under increased demands and decreased inputs, water use practices use informed decision-making to manage the budget and quality of its water resources.

I …

Monitoring Plants Growth In Indoor Vertical Farms Using Computer Vision And Ai Techniques, Bhama Krishna Pillutla

Graduate Research Theses & Dissertations

Climatic conditions like temperature, drought, and heavy metals disturb plant cell structures and, ultimately, plant growth that significantly affects crop production. Due to increasing climate change, maize crop yields are projected to decline by 24% by the end of century. With the increase in food demands and decrease in agricultural land and water resources, the space for effective farming is left much desired. Though limited to a few crops at this moment, Indoor Vertical Farming is one technique that requires much less land space, water, soil, and sunlight when compared to traditional farming. Vertical farming allows artificial control of temperature, …

Search For Charged Higgs Bosons In The Tau+Nu Final State With 139 Inverse Fb Of Pp Collision Data At Sqrt(S)=13 Tev With The Atlas Experiment, Elliot Wesley Parrish

Graduate Research Theses & Dissertations

This dissertation uses 139 inverse fb of pp collision data collected at a center of mass energy of sqrt(s)=13 TeV by the ATLAS detector to search for charged Higgs bosons decaying to a tau lepton and a neutrino in association with a top quark. Two subchannels are defined based on the leptonic decay (tau+lepton) or hadronic decay (tau+jets) of the associated top quark. Parameterized Neural Networks are investigated and optimized to improve signal separation from background in both subchannels across a wide charged Higgs boson mass range of 80 GeV to 3000 GeV. Expected exclusion limits at 95% confidence on …

Synthesis And Advanced Characterization Of Energy Materials, Erik Sarnello

Graduate Research Theses & Dissertations

Catalysts are used in an extremely broad range of systems including everything from biological systems to industrial processes. An ideal catalyst offers robust stability and high activity. This work focuses on the synthesis and characterization of materials that show promise in the field of catalysis. Advanced synchrotron characterization techniques and unique experimental design are highlighted to provide foundation work that will provide the necessary information to aid in designing and fabricating catalytic materials. Supported metal nanoparticle (SMN) catalysts are enormously crucial for many catalytic applications. However, catalyst deactivation, caused by sintering and coke formation, is a ubiquitous problem that significantly …

Impact Of Type And Shape On The Transport Of Microplastics In Column Experiments, Cheyanne Amanda Schenkel

Graduate Research Theses & Dissertations

The pervasive nature of plastic and the longevity of plastic compounds leaves a legacy of plastics and microplastics (MPs) that contaminate our environment, including drinking water sources. Although MPs have been well documented in every environmental setting, a paucity of research has focused on the transport and fate of MPs in groundwater systems. Previous field and lab studies have shown that MPs can migrate through aquifer material and that their retention and retardation are influenced by changing environmental factors. This study used coarse, well-sorted sand in controlled column experiments to investigate the influence of polymer type (PA, PE, PP, PEST) …

Measuring The Diphoton Production From Higgs Boson Decays And In Association With Heavy Flavor Jets, Brianna Lynn Dwyer

Graduate Research Theses & Dissertations

In this dissertation, two important measurements are presented related to diphoton production, the differential cross-section measurement of the Higgs boson in the diphoton decay channel as well as a measurement on inclusive diphoton production with associated heavy-flavor jets. Selections between the two analyses are complimentary, making them a natural pairing in the context of this dissertation. The cross-section measurement is performed in a fiducial region of phase space to closely matches experimental selections. This allows for a largely model-independent measurement, providing a meticulous test of the Standard Model as well as other theoretical predictions. The production of diphoton + heavy-flavor …

Transport Of Polyethylene Microplastic Spheres In A Sandy Aquifer, Alyssa Marie Graveline

Graduate Research Theses & Dissertations

Microplastic particles are currently listed as a Contaminant of Emerging Concern (CEC) since they are in much of Earth’s water systems and recent studies indicate plastic particles can sorb toxic contaminants. Microplastics (MP) are defined as plastic particles under 5 mm in length. Currently, there is a paucity of data on the transport of MP in the subsurface. This study investigated the transport, filtration, retardation, and influence of 5-100ߎm plastic polyethylene spheres in a shallow sandy aquifer over a distance of 1m by utilizing two forced hydraulic gradient tracer studies. Slug tests were used to estimate hydraulic conductivity prior and …

Analyzing Multistationarity In A Model Of A Dual Phosphorylation Network, Killian Kearney Anderson

Graduate Research Theses & Dissertations

Otero-Muras, Banga, and Alonso in [18] state biological reaction systems exhibit multistationarity, a system with at least two positive steady states. According to Otero-Muras,Banga, and Alonso in [18], initial conditions within the system, however, dictate the number of stable states in that system. Furthermore, multistationarity is an important componenet present in biological reaction systems that manage cellular responses [18]. Signal pathways regulating cell maturation, cell replication, and cell death rely on such systems [18]. Given the importance of multistationarity in biological reaction systems, it is necessary to construct a mathematical model, one in which multistationarity will be configured. More importantly, …

Evaluating Holocene Precipitation Variability In The Baltic Region Using Oxygen Isotopes Of Lacustrine Carbonate From Estonia, Maxwell Gordon Boes

Graduate Research Theses & Dissertations

A high-resolution Holocene record of groundwater isotopic composition from eastern Europe enhances the current understanding of ocean atmosphere interactions and moisture transport dynamics. In the modern system, it has been established that the amount of regional winter precipitation is driven by the strength and direction of the sea level atmospheric pressure gradient over the Atlantic Ocean. This is defined by the North Atlantic Oscillation (NAO) index, that shows a positive correlation with precipitation amount during the cold season. This study aims to discover the link between atmospheric dynamics and the ratio of warm season to cold season precipitation through the …

Data Driven Bayesian Network To Predict Critical Alarm, Joseph Mietkiewicz, Anders Madsen

Articles

Modern industrial plants rely on alarm systems to ensure their safe and effective functioning. Alarms give the operator knowledge about the current state of the industrial plants. Trip alarms indicating a trip event indicate the shutdown of systems. Trip events in power plants can be costly and critical for the running of the operation.This paper demonstrates how trips events based on an alarm log from an offshore gas production can be reliably predicted using a Bayesian network. If a trip event is reliably predicted and the main cause of it is identified, it will allow the operator to prevent it. …

Insurtech And Actuarial, Michael Mcshane, C. Ariel Pinto, Hesamoddin Tahami, Hengameh Fakhravar

Developing Technology Foresight: Case Study of AI in InsurTech

Questions regarding InsurTech and actuarial work.

Temporal Stability Of Seagrass Extent, Leaf Area, And Carbon Storage In St. Joseph Bay, Florida: A Semi-Automated Remote Sensing Analysis, Marie Cindy Lebrasse, Blake A. Schaeffer, Megan M. Coffer, Peter J. Whitman, Richard C. Zimmerman, Victoria J. Hill, Kazi A. Islam, Jiang Li, Christopher L. Osburn

OES Faculty Publications

Seagrasses are globally recognized for their contribution to blue carbon sequestration. However, accurate quantification of their carbon storage capacity remains uncertain due, in part, to an incomplete inventory of global seagrass extent and assessment of its temporal variability. Furthermore, seagrasses are undergoing significant decline globally, which highlights the urgent need to develop change detection techniques applicable to both the scale of loss and the spatial complexity of coastal environments. This study applied a deep learning algorithm to a 30-year time series of Landsat 5 through 8 imagery to quantify seagrass extent, leaf area index (LAI), and belowground organic carbon (BGC) …

Examining Ecological Succession Of Diatoms In California Current System Cyclonic Mesoscale Eddies, Zuzanna M. Abdala, Sophie Clayton, Sveinn V. Einarsson, Kimberly Powell, Claire P. Till, Tyler H. Coale, P. Dreux Chappell

OES Faculty Publications

The California Current System is a diatom-dominated region characterized by seasonal coastal upwelling and additional elevated mesoscale activity. Cyclonic mesoscale eddies in the region trap productive coastal waters with their planktonic communities and transport them offshore with limited interaction with surrounding waters, effectively acting as natural mesocosms, where phytoplankton populations undergo ecological succession as eddies age. This study examines diatom community composition within two mesoscale cyclonic eddies that formed in the same region of the California Current System 2 months apart and in the California Current waters surrounding them. The diatom communities were analyzed in the context of shifting environmental …

Wittgenstein On Miscalculation And The Foundations Of Mathematics, Samuel J. Wheeler

Philosophy Faculty Publications

In Remarks on the Foundations of Mathematics, Wittgenstein notes that he has 'not yet made the role of miscalculating clear' and that 'the role of the proposition: "I must have miscalculated"...is really the key to an understanding of the "foundations" of mathematics.' In this paper, I hope to get clear on how this is the case. First, I will explain Wittgenstein's understanding of a 'foundation' for mathematics. Then, by showing how the proposition 'I must have miscalculated' differentiates mathematics from the physical sciences, we will see how this proposition is the key to understanding the foundations of mathematics.

Using Remote Sensing And Machine Learning To Locate Groundwater Discharge To Salmon-Bearing Streams, Mary E. Gerlach, Kai C. Rains, Edgar J. Guerrón-Orejuela, William J. Kleindl, Joni Downs, Shawn M. Landry, Mark C. Rains

School of Geosciences Faculty and Staff Publications

We hypothesized topographic features alone could be used to locate groundwater discharge, but only where diagnostic topographic signatures could first be identified through the use of limited field observations and geologic data. We built a geodatabase from geologic and topographic data, with the geologic data only covering ~40% of the study area and topographic data derived from airborne LiDAR covering the entire study area. We identified two types of groundwater discharge: shallow hillslope groundwater discharge, commonly manifested as diffuse seeps, and aquifer-outcrop groundwater discharge, commonly manifested as springs. We developed multistep manual procedures that allowed us to accurately predict the …

Boron Isotopes In Boninites Document Rapid Changes In Slab Inputs During Subduction Initiation, Hong-Yan Li, Xiang Li, Jeffrey G. Ryan, Chao Zhang, Yi-Gang Xu

School of Geosciences Faculty and Staff Publications

How subduction-related magmatism starts at convergent plate margins is still poorly understood. Here we show that boron isotope variations in early-formed boninites from the Izu-Bonin arc, combined with radiogenic isotopes and elemental ratios document rapid (~0.5 to 1 Myr) changes in the sources and makeup of slab inputs as subduction begins. Heterogeneous hornblende-granulite facies melts from ocean crust gabbros ± basalts fluxed early melting to generate low silica boninites. Hydrous fluids from slab sediments and basalts later fluxed the low silica boninites mantle source to produce high silica boninites. Our results suggest that initially the uppermost parts of the slab …

Impact Of Model Choice In Predicting Urban Forest Storm Damage When Data Is Uncertain, Casey Lambert, Shawn Landry, Michael G. Andreu, Andrew Koeser, Gregory Starr, Christina Staudhammer

School of Geosciences Faculty and Staff Publications

Research that illuminates causes of urban forest storm damage is valuable for planning and management. However, logistical and safety concerns often delay post-storm surveys in urban areas; thus, surveys may include observations with unverified sources of damage. While this uncertainty is often ignored, it can make up a high proportion of the number of damaged trees. The goal of this research was to improve understanding of techniques for modeling storm damage in urban forests. Using urban forest storm damage inventories collected in Florida, post-Hurricane Irma (2017), we tested how different imputation methods, modeling procedures, and damage frequency levels could impact …