Understanding Of Processing Additives Influence In Tin Halide Perovskites: Chemistry, Defect, And Photovoltaic Performance, Syed Rahmath Ullah Joy

Theses and Dissertations--Chemistry

Metal halide perovskite semiconductors have attracted much interest for various applications, such as solar cells, light emitting diodes, photodetectors, and lasers, due to their excellent optoelectronic properties. Photovoltaic cell development is centered on Pb-based perovskites, which have equal photovoltaic performance compared to the traditional silicon photovoltaic. But concerns arising from the usage of toxic lead metal have motivated the research community to seek an alternative derivative. Among those, tin halide perovskites show much promise as an alternative to Pb-counterparts due to their ideal bandgap for single junction photovoltaics and similar optoelectronic properties to Pb perovskites. Nevertheless, tin perovskites suffer from …

Synthetic Strategies Toward The Development Of Stable Gold-Based Anticancer Agents And Their Mechanistic Insight, Adedamola Arojojoye

Theses and Dissertations--Chemistry

Despite notable advancements in the design and synthesis of novel chemotherapeutic drugs, cancer continues to be a leading cause of death in the United States. Metallodrugs, especially Au complexes, have played a prominent role in the search for the next generation of chemotherapeutic agents. Herein, I report on the synthetic strategies towards the rational design of stable Au (Au)-based agents, study their reactivity in biological environment, and offer insights into the cytotoxic mechanism of action in cancer. Chemotherapeutic Au compounds exist mainly in +I or +III oxidation states. Repurposing of the Au(I) FDA approved auranofin for the treatment of diseases …

Synthesis, Functionalization, And Application Of Polymeric Membrane Blends Of Polysulfone, Poly-Ether Ether-Ketone, And Natural Fiber Additive Biochar For Optimal Water Treatment., Abelline Katusiime Fionah

Theses and Dissertations--Chemistry

According to the Center for disease control (CDC), an estimated 1.7 to 2.2 million persons die from waterborne diseases annually. The majority of individuals dying from diseases resulting from unsafe drinking water, such as diarrhea and gastroenteritis, are children. This has in turn created a global water crisis. Different methods have been developed to treat contaminated water in response to the global water crisis such as adsorption, filtration, ozonolysis, catalysis, etc. Of the methods available, filtration via polymeric membranes has been one of the most successfully applied. A membrane is a thin semi-permeable barrier (often made of a polymer) used …

Hunting Types In North American Eocene And Oligocene Carnivores And Implications For Nimravid Extinction, Miguel Andres Castellanos

Graduate Research Theses & Dissertations

The late Eocene and Oligocene is traditionally seen as a time of great climactic shift, with open habitats beginning to appear and forests receding. This time period saw both the diversification and subsequent extinction of North American nimravids. The causes of the extinction of this early sabertooth group in the Arikareean remain unclear. One possibility for their decline is that nimravids were competitively disadvantaged in open habitats relative to contemporary, possibly more cursorial caniform predators. Here I analyze and compare the hunting styles of Eocene and Oligocene predators in correlation with their ecological implications via discriminant function analysis of the …

Microwave Simulations Of A Beam Position Monitor And Circuit Designs Assisting Its Beam Testing, Marc Jacob Crowell

Graduate Research Theses & Dissertations

Beam position monitors (BPMs) are non-destructive diagnostic devices widely used in particle accelerators. I will first introduce the need for precision beam position measurement in particle accelerators, and then provide an overview of various types of BPMs. For the first part of my work, I focus on the design and simulation of a button-BPM. Microwave and wakefield simulations were performed to characterize the output signals. Such a design could find a potential application at the Argonne Wakefield Accelerator (AWA) at the Argonne National Laboratory. Although no BPMs have been fabricated to this date, a future beam experiment will be needed …

Theory Of Ultrafast Spin Crossover In Divalent Iron Systems, William Baker

Graduate Research Theses & Dissertations

A theory to account for the ultrafast, i.e. femtosecond timescale, singlet to quintet spin crossover in divalent iron molecules is developed. The model considers an iron cluster with ligands extending in all 6 cardinal directions initially at rest in a low spin singlet ground state. An optical excitation excites an electron from the d orbitals to the ligands, changing the system from the metal centered (MC) singlet state to the metal to ligand charge transfer (MLCT) singlet state. Experimentally, it is known that the system eventually relaxes into the quintet MC state, but there are no satisfactory explanations that model …

Applying Synchrotron Saxs And Xas To Study The Microstructure Of Energy Conversion And Storage Materials, Lingzhe Fang

Graduate Research Theses & Dissertations

The microstructure of energy conversion and storage materials is a key determinant of physical properties and electrochemical performance. Synchrotron X-ray techniques, with their strengths of high flux and exceptional brightness, play an irreplaceable role in understanding nano and sub-nano structures. This helps the study of reaction mechanisms and benefits material design in energy conversion and storage area. Electrifying CO2 transformation using renewable energy offers a carbon-neutral solution to CO2 recycling and fuel generation. Among various feedstocks from the CO2 reduction reaction, CO, HCOOH, and CH4 have approached the performance thresholds for industry implementation. The application of single atom catalysts (SACs) …

Gas-Phase Mass Spectrometry Studies Of Ternary Metal Carboxylate Complexes, Anthony James Fanizza

Graduate Research Theses & Dissertations

In the wake of climate change from rising CO2 emissions and with peak oil looming, the dive into sustainable fuels and energy is becoming increasingly essential. This dissertation investigates ternary ligand-metal cationic complexes for potential catalytic applications in the decarboxylation of carboxylic acids to produce bioavailable and carbon-neutral fuel sources. By utilizing gas-phase reactivity studies via mass spectrometry, namely, collision-induced dissociation and ion-molecule reactions, mechanisms can be elucidated in a regulated chemical environment. When paired with density functional theory calculations for molecular geometries, chemical interactions, charge densities, and energetics, system efficiencies can be further clarified presenting a more complete mechanistic …

Pathology And Diagnosis In Inflammatory-Related Diseases: Covid-19 And Age-Related Macular Degeneration, Zane Russell Lacasse

Graduate Research Theses & Dissertations

Chronic inflammation and dysfunctional inflammatory responses are believed to be contributing factors to the severity of many diseases. Since the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), it has been recognized that levels of inflammatory markers and the severity of coronavirus disease-2019 (COVID-19) cases are closely related. The work within this dissertation begins with establishing an alternative platform for the diagnosis of COVID-19 and explores ways to enhance the diagnostic utility of this platform. An alternative route for COVID-19 diagnosis was explored using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF MS). The platform utilizes a non-invasive sampling technique …

Forecasting The One Month Ahead Joint Distribution Of The Carhart Four Factor Model Using A Copula Method, Michael Nebor

Graduate Research Theses & Dissertations

The Fama and French created factors of Market minus Risk Free (Mkt-RF), Small minusBig (SMB), High minus Low (HML), and the Carhart developed factor of Momentum (MOM) are frequently used together as a four factor model to explain the variation in returns of financial equities. This paper analyzes the joint distribution of these factors by forecasting the one month ahead joint distribution using various copula based methods. The VaR quantiles are calculated throughout the forecasted distribution at the .01, .05, .25, .50, .75, .95, and .99 quantiles. The forecasted distributions are compared against each other by analyzing the exceedances of …

Mixed Mechanisms Of Multi-Site Phosphorylation, Suha Jayyousi Dajani

Graduate Research Theses & Dissertations

Multi-site phosphorylation is an important mechanism in cell biology that regulates protein function and activity. It also plays a critical role in a wide variety of cellular processes that control intra-cellular signaling. Studies on mono- and dual-site phosphorylation have been conducted theoretically and experimentally by researchers. However, there is little research on triple-site and multi-site mixed mechanism phosphorylation.

The aim of this research is to study and identify the number of positive steady states (multistationarity) in a mathematical model of a triple-site mixed mechanism, processive and distributive, phosphorylation network. This research is accomplished by means of ordinary differential equations, Jacobian …

On The Ground And From Above: A Multi-Factor Analysis Of The Direct And Indirect Drivers Of Tallgrass Prairie Small Mammal Communities, Erin Rowland-Schaefer

Graduate Research Theses & Dissertations

Tallgrass prairies are among the most globally threatened ecosystems, with only one percent of the historical extent remaining in Illinois. Prairie restoration is an essential strategy to preserve biodiversity and reestablish threatened species. Practitioners use management tools to shift the landscape context of prairie restoration sites, such as prescribed fire and land cover change. Managers can also impact the landscape connectivity and edge proximity of certain areas through the use of mowed driving lanes. The effects of these factors on small mammals, which are central in tallgrass prairie food webs and relevant to human health and restoration success, are not …

Effort Of Reproducibility: Metrics, Methods, And Models To Navigate The Landscape Of Reproducible Research, Akhil Pandey Akella

Graduate Research Theses & Dissertations

Validating scientific claims is an elaborate process that involves researchers investing considerable time and effort to discover the validity of claims. It involves repeatability, reproducibility, and replicability, where each subsequent step requires increased effort and time. With the evolving nature of computational experiments and the exponential pace at which scientific publications are disseminated, researchers find it challenging to devote time, energy, and resources to assess claims made in papers of interest. Preemptive signals for reproducible effort can be helpful to researchers in filtering academic works of interest, thereby allowing them to adjust efforts based on need. Through this research, I …

Using Ex-Situ And In-Situ Mössbauer Spectroscopy To Study The Degradation Of Nafe(1−X)(Ni0.5mn0.5)X O2 Batteries, Iddrisu Bachokun Abdul Razak

Graduate Research Theses & Dissertations

Sodium-ion batteries are an attractive alternative to traditional lithium-ion batteries due to their low cost and eco-friendly components. The Fe3+/Fe4+ redox reaction provides similar operating voltages and specific energy densities to that of lithium-ion batteries. Mössbauer spectroscopy is a useful x-ray technique for measuring the chemical environment inside of the metal enclosure of batteries. In particular, it can measure the relative concentration of Fe3+/Fe4+ ions as a function of the battery’s voltage. In this dissertation ex-situ and in-situ Mössbauer spectroscopy were used to map out the effect of various electrolytes on the performance of NaFe(1−x)(Ni0.5Mn0.5)xO2 batteries. This was done by …

The Future Of Convective Mode In The United States, Jeremy Malcolm Corner

Graduate Research Theses & Dissertations

This work examines potential changes in convective mode associated with hazardous convective weather (HCW) using a suite of high-resolution regional climate simulations and artificial intelligence/machine learning (AI/ML). An AI/ML model called a convolutional neural network (CNN) is first generated and validated using an existing dataset of composite reflectivity images centered on tornado reports from 1996 – 2017 called SVRIMG (SeVeRe IMaGes). Each image in SVRIMG is annotated with four possible convective modes: 1) cellular; 2) mixed mode; 3) linear; and 4) other. The best-performing model, which achieves an accuracy exceeding 90% on testing images, is then used to diagnose storm …

Evaluating Computational Reproducibility Of Jupyter Notebooks Using Machine Learning And Natural Language Processing, A S M Shahadat Hossain

Graduate Research Theses & Dissertations

In recent years, computational reproducibility, which refers to achieving consistent results upon rerunning an experiment, has become one of the major concerns of various research communities. Jupyter Notebook, as a web-based computational notebook application, offers useful features for running and publishing computational experiments through interactive environments. However, rerunning notebooks does not always reproduce the experimental results. This thesis aims to develop novel methods to evaluate reproducibility by comparing different types of outputs between original and rerun notebooks. It also explores the idea of using machine learning models to predict reproducibility of notebooks automatically without the need of rerunning them. Through …

A Climatology And Characteristics Of Midwest Heavy Snowfall, Benjamin William Warren

Graduate Research Theses & Dissertations

Understanding the characteristics of snowfall across the Midwest U.S. is critical for regional ecosystems, water cycles, and socioeconomic activities. The Midwest, however, has not been the primary focus of snow-related research in recent years. Therefore, this research uses observational and reanalysis data in the Midwest from 1991 through 2020 and radar data from 2009 through 2020 to create a comprehensive snowfall climatology, investigate regional trends in heavy snowfall, and determine the frequency of banded versus non-banded snowfall. As expected, heavy snowfall (i.e., daily snowfall accumulation >4") is most frequent in northern Midwest (e.g., Iowa, Minnesota, and Wisconsin), with the frequency …

Iodp U1537: Scotia Sea Climatic And Frontal Variation Reflected In Diatom Productivity And Assemblages Since The Lgm, Garrett Lewis Strittmatter

Graduate Research Theses & Dissertations

Located off the coast of the West Antarctic Ice Sheet, the Scotia Sea is a site of great significance in palaeoclimatological studies due to the nature of its sedimentary record. This site of interest is at the tip of the Antarctic Peninsula on the Eastern side, in the direct flow of the Antarctic Circumpolar Current thereby concentrating icebergs from around the continent. Additionally, these sediments are rich in diatoms. Finally, this site, within the analyzed section, has an average sedimentation rate of ~48 cm/Kyr.

By collecting sediment cores rich in diatoms, among material used to generate other paleoclimate proxies, we …

Univariate Extreme Value Analysis Of Quantitative Investment Management, George Agbenyega Zumanu

Graduate Research Theses & Dissertations

The evolution of product development within the variable annuity (VA) business have sparked interest in quantitative investment management, particularly as most VA issuers have integrated volatility-controlled funds into their annuity portfolios. Despite the existence of empirical research on statistical analysis of extreme values in conventional investments, there has been a notable gap in research focus towards risk modeling in volatility-controlled funds.

This study contributes by analyzing and modeling the extreme values of investments in volatility-controlled funds, comparing them to conventional equity funds. The financial returns of S&P Dow Jones Indices (SPDJI) indices - SPXTR, risk control SPXT18UT, and managed risk …

Dna I-Motifs: Biophysical Characterization And Structure-Property Correlation As Foundation For Functional Material Design, Alexander Minasyan

Graduate Research Theses & Dissertations

Over the past decades, nucleic acids have emerged as crucial frameworks with significance in biological systems and functional material engineering. Cytosine-rich deoxyribonucleotide sequences can form quadruplex structures a.k.a. i-motifs. Recently, i-motifs have attracted scientific interest in biological and material design areas.

In this work, we systematically investigate an effect of structured and unstructured modifications such as hairpins, stems, loops and overhangs on the kinetic and thermodynamic properties of DNA i-motifs. We demonstrate that the modifications can influence i-motif’s stability and folding/unfolding rates: thus, double stranded stems and hairpins are the best at stabilizing i-motifs and increasing kinetic rates of folding. …

Explicit Proximal Gradient Methods: Bridging Theory And Practice In Optimization, Cassandra Mohr

Graduate Research Theses & Dissertations

Convex optimization problems are central to numerous fields, including machine learning, signal processing, and image reconstruction. The development and analysis of algorithms for solving splitting optimization problems constitutes a significant area of research. In particular, we investigate a proximal gradient splitting method (PGM) with an explicit linesearch for finding the solution of nonsmooth optimization problems, where the objective function is the sum of two convex functions.

We focus on cases where one of the functions is differentiable, without imposing any Lipschitz continuity assumption on its gradient. We establish the proper definition of the linesearch, and demonstrate that this version of …

Gmm And Asset Pricing Model, Yuzhou Liu

Graduate Research Theses & Dissertations

The traditional two-pass regression to estimate risk premium has shortcomings. To get the correct asymptotic standard errors, we need to estimate both time-series regressions and cross-sectional regressions simultaneously. The Generalized Method of Moments (GMM) effectively addresses this issue by its nature fit of asset pricing model. In this paper, I re-examine the risk premium of Carhart’s four-factor model by integrating time-series and cross-sectional regressions within the GMM framework, which enhances the accuracy and reliability of the risk premium estimates.

Studies Towards Mechanistic Understanding Of The Suzuki-Miyaura Catalyst-Transfer Polymerization, Mitchell Tyler Howell

Graduate Research Theses & Dissertations

Semiconducting organic conjugated polymers show major promise for the manufacturing of organic electronic and optoelectronic devices. Their utility comes from inherent conductivity, elasticity, processability and low weight paving the way towards novel materials and applications. The molecular weight, polydispersity, and precise incorporation of structural elements into the conjugated backbone are among the important parameters that affect a conjugated polymer’s mechanical and electrical properties. Therefore, precise control over such parameters provides a path for electronic materials with tunable properties tailored for a specific application. Recent success in this endeavor has been achieved with Suzuki-Miyaura Catalyst-Transfer Polymerization (SCTP) which is a transition …

Tracing Past Climate Signals Through Multi-Proxy Analysis: Insights From Sedimentary Plant Wax Hydrogen Isotope Data And Long-Term Hydroclimate Records In Estonia, Mariliis Eensalu

Graduate Research Theses & Dissertations

In light of the rising global temperatures, there is an increasing need to understand the potential shifts in hydroclimate. Past climate reconstructions offer a glimpse into the possible temperature-moisture dynamics by providing quantitative constraints for hydroclimate variability under different temperature conditions, which can ultimately aid in decreasing the uncertainty in future climate projections. The research presented in this dissertation focuses on utilizing various proxies to reconstruct past hydroclimate conditions, particularly in the Baltic region, with a specific emphasis on Estonia. The second and third chapter aim to improve the understanding of sedimentary plant wax hydrogen isotope (δ2H) data by first …

Julia Limiting Directions Of Quasiregular Maps, Julie Marie Steranka

Graduate Research Theses & Dissertations

In this dissertation, we study the set of Julia limiting directions of quasiregular maps. The work combines the study of dynamics of quasiregular maps and applications of nonlinear potential theory to quasiregular maps. Our main result shows that the set of Julia limiting directions of a transcendental-type $K$-quasiregular map $f:\R^n\to \R^n$ must contain a component of a certain measure, depending on the dimension $n$, the maximal dilatation $K$, and the order of growth of $f$. In particular, we show that if the order of growth is small enough, then every direction is a Julia limiting direction. The main tool in …

Cold Testing Of A Prototype Superconducting Radiofrequency Electron Gun And Ancillary Systems For The Lcls-Ii-He Project, Kaela Michele Villafania

Graduate Research Theses & Dissertations

Argonne National Laboratory is collaborating with Michigan State University (MSU), Helmholtz-Zentrum Dresden-Rossendorf (HZDR), and Stanford Linear Accelerator Center (SLAC) on the design, fabrication, and testing of a prototype superconducting radiofrequency (SRF) gun for the planned LCLS-II-HE upgrade at SLAC. This electron source will enable the generation of higher-brightness beams at a high repetition rate opening the path to expand LCLS-II-HE FEL performances. This thesis focuses on the cold testing of the prototype gun cavity and ancillary structures including the fundamental input-power coupler and tuning system. Numerical simulations are also presented to understand fields inside of the cavity as well as …

Bidirectional In-Situ Analysis And Visualization Of Fluid Structure Interactions With Applications In Blood Flow, Nazariy Tishchenko

Graduate Research Theses & Dissertations

Interactive blood flow simulation has applications in the understanding of complex fluids,training medical professionals, diagnostics, and surgical procedure planning. Bidirectional in situ visualization and analysis are much needed to streamline the analysis of large-scale patient-specific blood flow simulations. The in situ component ensures the live visualization of the simulation results while the simulation is running, and the bidirectional component allows for real-time control and configuration of the simulation parameters (i.e., setting and retrieving the simulation parameters and data based on need). In this project, a highly accurate multiphysics simulation was instrumented to work with an existing bidirectional in situ framework. …

Temporal Microplastic Concentration Fluctuations Within An Agricultural Creek And Groundwater In Relation To Farming Practices, Jennifer Abel

Graduate Research Theses & Dissertations

Microplastics (MPs) in agriculture have been well-documented. Agrochemicals, organic fertilizers, and farming equipment all contribute plastic to agricultural soils, groundwater, and surface water and are utilized in different capacities throughout the year. It is unknown how the specific utilization of these products affects the concentration of MPs being input into the environment. Previous research has been primarily related to detection and transport of MPs in soils, groundwater, and surface water. I am unaware of any studies that have taken into consideration farming practices and seasons, and how they may affect any fluctuations in MP concentrations. Water samples (20 L) were …

Quantifying Chemical Erosion In The Lithologically-Heterogenous Appalachian Valley And Ridge, Amelia Jayne Zanoni

Graduate Theses, Dissertations, and Problem Reports (ETD)

Quantifying chemical erosion in the lithologically-heterogenous Appalachian Valley and Ridge

Amelia J. Zanoni

The interplay between physical and chemical erosion is well understood in landscapes underlain by a uniform rock type, but many regions are underlain by a mixture of rock types with varying erosion resistance and solubility. We used measurements of stream-water chemistry to estimate chemical erosion rates in the Appalachian Valley and Ridge, a region where the mechanisms of lithologic control over topography are poorly understood. Newly acquired stream water samples were collected from 51 locations across the research area during the Fall of 2023. The sampled waters …

Synthetic Elaboration Of Β-Carbonyl Alkylboronic Esters, Mason D. Hamilton Ph.D.

Graduate Theses, Dissertations, and Problem Reports (ETD)

Organoboron compounds are some of the most synthetically versatile compounds in organic chemistry due to the many valuable transformations of the C-B bond. This synthetic versatility combined with the pharmacophoric nature of carboxylic acids has led to an increased interest in the one-pot difunctionalization of vinyl arenes using CO₂ and pinacol boranes. Recently, much progress has been made to improve the scope and versatility of boracarboxylation reactions to now include electron-deficient and α-methyl substituted vinyl arenes. However, the potential transformations of boracarboxylated products have remained unexplored. Here, methodologies to transform the β-aryl alkylboronic ester into new C-C, C-N, and …