Physical Sciences and Mathematics Commons^™

Struggling To Be Positive Problem Solvers – A Study On The Relationship Of Elementary Mathematical Self-Concept, Gender, Learner Identification, And Productive Struggle Trajectories On Constructed Response Questions When Being Taught With A Standardized Curriculum, Kali D. Rogers

LSU Doctoral Dissertations

Mathematical word problems are some of the most difficult problems for students to solve due to their complexity and relationship to real-world situations (Şahin et al., 2014; Verschaffel et al., 2020). With math being known for right-or-wrong answers, these open-ended questions cause much confusion and frustration, specifically for students of various subgroups. In the last several decades, educational teaching expectations have shifted from engaging, self-created learning to robotic and redundant curriculum expectations that induce a ‘teaching to the test’ environment (Shafiyeva, 2021). Mathematics is the powerhouse of where students can experience and succeed with productive struggle learning that teaches the …

Examining The Authenticity Of The 'Ether Model' In Certain O-Glycosylation Reactions, Varad Vinayak Agarkar

LSU Doctoral Dissertations

Acinetobacter baumannii is a gram-negative bacterium species that is responsible for nosocomial infections. It has shown antibiotic resistance and has been designated an urgent threat by the CDC. In Chapter 1, I highlight my efforts in the synthesis of a Kdo building block in the journey towards the construction of an A. baumannii lipooligosaccharide (LOS) core pentasaccharide- a potential candidate for glycoconjugate vaccine against A. baumannii infection. I talk about various optimizations and improvements in the Kdo monosaccharide synthesis and the mechanistic insights I provided about a critical transformation in the synthetic sequence.

Chemical O-glycosylation is a significant research …

Multiphoton Quantum Sensing, Fatemeh Mostafavikhatam

LSU Doctoral Dissertations

While the fundamental principles of light-matter interaction are well-understood and drive countless technologies, the world of multiphoton processes remains a fascinating puzzle, holding the potential to drastically alter our understanding of how light interacts with matter at its most basic level [1–4]. This rich interplay of light and matter unveils novel phenomena that can be harnessed for sensing with exceptional precision, as exemplified by multiphoton quantum sensing. This thesis delves into the applications of multiphoton quantum protocols, particularly in imaging, communication, and plasmonic sensing, to surpass classical limitations and achieve enhanced sensitivity. We explore the potential of multiphoton quantum processes, …

Molybdenum Alkylidyne Complexes With Phenoxide Ligands For Alkyne Metathesis, Marvin L. Stewart Jr

LSU Doctoral Dissertations

Abstract

Alkyne metathesis is a powerful synthetic tool, which provides easy access to complex organic molecules in a single-step. It is a dynamic covalent reaction that scrambles alkynes, carbon-carbon triple bonds (C≡C). Molybdenum- or tungsten-alkylidyne (Mo≡C, W≡C) complexes are typically used as catalyst to cleave and reform alkyne bonds. Our goal has been to gain a deeper understanding of the intrinsic differences between functional ligands by the development of novel phenoxide ligands.

In chapter 2 we explore the detailed synthesis of novel phenoxide podand ligands in an effort to identify their mo-alkylidyne complexes. We were able to synthesize a variety …

Benthic Community Response To The Impacts Of Proposed Sediment Diversions In Louisiana Estuaries, Jillian C. Tupitza

LSU Doctoral Dissertations

Sediment diversions designed to mitigate land loss in coastal Louisiana will likely cause ecosystem-wide shifts. The first diversion, planned for Barataria Bay, will divert fresh water and sediment from the Mississippi River into the surrounding wetlands to help them keep pace with high rates of relative sea-level rise (RSLR). Estuarine benthic communities were used in this study as tools to characterize ecological patterns in the context of anticipated salinity changes. I reviewed relevant literature, conducted a two-year survey of Barataria Bay benthos, executed a reciprocal transplant experiment to describe changes that might occur in both community composition and trophic dynamics, …

The Lowest Discriminant Ideal Of Cayley-Hamilton Hopf Algebras, Zhongkai Mi

LSU Doctoral Dissertations

Discriminant ideals are defined for an algebra R with central subalgebra C and trace tr : R → C. They are indexed by positive integers and more general than discriminants. Usually R is required to be a finite module over C. Unlike the abundace of work on discriminants, there is hardly any literature on discriminant ideals. The levels of discriminant ideals relate to the sums of squares of dimensions of irreducible modules over maximal ideals of C containing these discriminant ideals. We study the lowest level when R is a Cayley-Hamilton Hopf algebra, i.e. C is also a Hopf subalgebra, …

Post-Modeling Adjustments And Delivered Dose Verification Of The 6fff Beam Model Commissioned For The Monaco Treatment Planning System, Grant C. Debevec

LSU Master's Theses

External beam radiation therapy has been shown to be an effective treatment method for tumors and abnormalities of the spine and vertebral region. Treating the spine using a stereotactic body radiation therapy (SBRT) technique can reduce toxicity to the spinal cord. The 6 MV flattening filter free (6FFF) beam model is currently used to plan and calculate dose for SBRT treatment plans, and the treatment plans are delivered using a linear accelerator (LINAC).

The commissioned beam model represents an invariant component of a LINAC. For volumetric modulated arc therapy (VMAT) treatment plans, the multileaf collimator (MLC) positions are changing throughout …

All-Optical Probes Of Particle-Like Charge Migration Dynamics, Kyle A. Hamer

LSU Doctoral Dissertations

Particle-like charge migration (CM) is the coherent, back-and-forth motion of a positively-charged electron hole along the backbone of a molecule following a sudden ionization. CM in small molecules generally occurs on an Angstrom (10^-10 m) spatial scale and an attosecond (10^-18 s) timescale. I use time-dependent density-functional theory (TDDFT) to simulate CM modes in organic molecules, and to explore all-optical probes of this attosecond electron dynamics using high-harmonic spectroscopy (HHS). By leveraging my results from previous studies of two-center interferences in carbon dichalcogens, in which I separated the harmonic signal into contributions from individual Kohn-Sham orbitals, I first …

Examination Of The Effects Of Ultraviolet Radiation On The Toxicity Of An Array Of Pesticides, Polyaromatic Hydrocarbons, And Pharmaceuticals Via In-Vitro Bioassays, Jessica R. Stephens

LSU Master's Theses

Chemicals are often released via anthropogenic means both intentionally and unintentionally into aquatic environments. The chemical fate of these compounds can vary greatly depending on numerous factors that can include but are not limited to salinity, pH, dissolved oxygen, and exposure to ultraviolet radiation. The goal of this study was to investigate the effect of UV radiation on the level of toxicity of different chemicals over time. Chemicals were selected based on previous studies of the toxicity of both parent and metabolites formed as a result of photolysis. Anthracene, phenanthrene, anthraquinone, dicloran, chlorothalonil, hydroxy chlorothalonil, benzobicyclon hydrolysate, and sertraline were …

Estimating Crustal Thickness In Northwest Louisiana Using The Receiver Function Method, Delton Samuel

LSU Master's Theses

I aim to constrain the crustal thickness of the Sabine Block in the Sabine Uplift region of northwest Louisiana, using the frequency domain receiver function deconvolution technique followed by H-κ stacking. The passive margin on the southern edge of the North American continent experienced an active tectonic history, including the spreading events that led to the formation of the Gulf of Mexico. A previous study proposed the Sabine Block is a residual fragment of Proterozoic orogenic origin; however, its full extent and geometry are up for debate. It is now overlain by thick sedimentary sequences ranging from ~4-6 km deposited …

Reducibility Of Schrödinger Operators On Multilayer Graphs, Jorge Villalobos Alvarado

LSU Doctoral Dissertations

A local defect in an atomic structure can engender embedded eigenvalues when the associated Schrödinger operator is either block reducible or Fermi reducible, and having multilayer structures appears to be typically necessary for obtaining such types of reducibility. Discrete and quantum graph models are commonly used in this context as they often capture the relevant features of the physical system in consideration.

This dissertation lays out the framework for studying different types of multilayer discrete and quantum graphs that enjoy block or Fermi reducibility. Schrödinger operators with both electric and magnetic potentials are considered. We go on to construct a …

Finite Monodromy And Artin Representations, Emma Lien

LSU Doctoral Dissertations

Artin representations, which are complex representations of finite Galois groups, appear in many contexts in number theory. The Langlands program predicts that Galois representations like these should arise from automorphic representations and many examples of this correspondence have been found such as in the proof of Fermat's Last Theorem. This dissertation aims to make an analysis of explicitly computable examples of Artin representations from both sides of this correspondence. On the automorphic side, certain weight 1 modular forms have been shown to be related to Artin representations and an explicit analysis of their Fourier coefficients allows us to identify the …

Quantification Of Belowground Biomass And Sediment Accretion In Mangroves Of Different Coastal Environmental Settings Of The Costa Rican Pacific Coast, Denise M. Poveda

LSU Master's Theses

The adaptation of intertidal ecosystems such as mangroves to anticipated accelerated relative sea level rise is dependent on net increase of sediment surface elevations and forest migration inland. Ecosystem models developed to simulate trajectories of ecosystem adaptations have determined that rates of soil formation are most sensitive to surface sediment (organic and inorganic) deposition and subsurface organic production by mangrove roots. Mangrove belowground biomass contributes to soil organic matter accumulation, while mangrove litter has minor contribution due to export and annual decay. In addition to belowground biomass production, inorganic sediment loading is also key contribution to soil formation and accretion. …

Two New Catalysts For Oxidation Of Water To Oxygen, Takia Sultana

LSU Master's Theses

If fuels, such as hydrogen or methanol, are to be produced from renewable energy (solar or wind) in the future, efficient catalysts will be needed, not only for fuel production reactions but for the essential simultaneous oxidation of water to O₂. Ruthenium complexes are among the more promising water oxidation catalysts (WOCs). Two new isomeric ruthenium WOCs have been prepared based on the benzylpyridyltriazole ligand (Figure 3); trans-py-[Ru(tpy)(bpt)(H₂O)]²⁺ (trans-py-1) and trans-trz-[Ru(tpy)(bpt)(H₂O)]²⁺ (trans-trz-1) (tpy = 2,2’:6’,2’’-terpyridine, bpt = benzylpyridyltriazole). Ceric ammonium nitrate [(CAN)/Ce(IV)] oxidants were …

The Modular Generalized Springer Correspondence For The Symplectic Group, Joseph Dorta

LSU Doctoral Dissertations

The Modular Generalized Springer Correspondence (MGSC), as developed by Achar, Juteau, Henderson, and Riche, stands as a significant extension of the early groundwork laid by Lusztig's Springer Correspondence in characteristic zero which provided crucial insights into the representation theory of finite groups of Lie type. Building upon Lusztig's work, a generalized version of the Springer Correspondence was later formulated to encompass broader contexts.

In the realm of modular representation theory, Juteau's efforts gave rise to the Modular Springer Correspondence, offering a framework to explore the interplay between algebraic geometry and representation theory in positive characteristic. Achar, Juteau, Henderson, and Riche …

Subgroups Of Coxeter Groups And Stallings Foldings, Jake A. Murphy

LSU Doctoral Dissertations

For each finitely generated subgroup of a Coxeter group, we define a cell complex called a completion. We show that these completions characterizes the index and normality of the subgroup. We construct a completion corresponding to the intersection of two subgroups and use this construction to characterize malnormality of subgroups of right-angled Coxeter groups. Finally, we show that if a completion of a subgroup is finite, then the subgroup is quasiconvex. Using this, we show that certain reflection subgroups of a Coxeter are quasiconvex.

Analytic Wavefront Sets Of Spherical Distributions On The De Sitter Space, Iswarya Sitiraju

LSU Doctoral Dissertations

In this work, we determine the wavefront set of certain eigendistributions of the Laplace-Beltrami operator on the de Sitter space. Let G′ = O_1,n(R) be the Lorentz group, and let H′ = O_1,n−1(R) ⊂ G′ be its subset. The de Sitter space dSⁿ is a one-sheeted hyperboloid in R^1,n isomorphic to G′/H′. A spherical distribution is an H′-invariant eigendistribution of the Laplace-Beltrami operator on dSⁿ. The space of spherical distributions with eigenvalue λ, denoted by D_λ^H'(dSⁿ), has dimension 2. We construct a basis for the space of …

Applied Depositional Geosystems Of The Coos Bay Basin, Oregon: Organic Geochemistry, Maturation, Paleoenvironmental Reconstruction And Biostratigraphy Of The Coaledo Delta During The Middle Eocene Climatic Optimum (Meco), Allison K. Barbato

LSU Doctoral Dissertations

The Coos Bay Basin on the southwestern coast of Oregon is a forearc basin that contains exceptionally preserved Eocene to Miocene, tidal to wave-dominated, shallow deltaic to deep marine sediments of the Coaledo Delta. Coastal depositional environments are known to host source, reservoir, and seal rocks. Climate, topographic relief, and geographical position all play an important role in regional vegetation development and oceanic setting. This study assesses 84 outcrop and 12 core samples from Coos Bay for their organic geochemical characteristics and microfossil assemblage to provide source rock characterization information, organofacies descriptions, environmental reconstructions, and age control.

Results indicate the …

Thermal Frontal Polymerization – Applications In Coatings And Composites, Maria Martinez

LSU Doctoral Dissertations

Thermal frontal polymerization has long been used as a method to cure composites and coatings. However, this is the first time these applications have been used without the use of a catalyst, for the case of composites and coatings.

Chapter 2 discusses how to optimize cure-on-demand, thin layer coatings, using frontal polymerization. Previously, for the use of curing thin layer coating using thermal FP, it was known to just make the formulation viscous enough, as this would prevent premature quenching caused by heat loss. It was discovered that for a given layer thickness, a minimum viscosity and initiator concentration were …

Improving Implicit Communication In Remote Collaboration Through Augmented Reality And Digital Twins, Nicholas Levergne

LSU Master's Theses

Large scale digital twinning projects are beginning to emerge across the tech industry. Within these projects is a desire to integrate augmented reality capabilities into industrial workflows. However, research on augmented reality technology for remote collaboration lacks ecologically valid studies of real world scenarios. Additionally, prior remote collaboration literature is focused on white-collar applications instead of blue-collar field work. Prior AR collaboration software is similarly limited, with most software allowing mixed camera views and annotation that requires participants to be stationary. This thesis introduces SpectAR, an augmented reality and desktop remote collaboration software suite developed in Unreal Engine 5.1.1. SpectAR …

Modeling And Numerical Analysis Of The Cholesteric Landau-De Gennes Model, Andrew L. Hicks

LSU Doctoral Dissertations

This thesis gives an analysis of modeling and numerical issues in the Landau-de Gennes (LdG) model of nematic liquid crystals (LCs) with cholesteric effects. We derive various time-step restrictions for a (weighted) $L^2$ gradient flow scheme to be energy decreasing. Furthermore, we prove a mesh size restriction, for finite element discretizations, that is critical to avoid spurious numerical artifacts in discrete minimizers that is not well-known in the LC literature, particularly when simulating cholesteric LCs that exhibit ``twist''. Furthermore, we perform a computational exploration of the model and present several numerical simulations in 3-D, on both slab geometries and spherical …

Interactive Effects Of Co2, Temperature, And Nitrate Limitation On The Growth And Physiology Of Marine Cyanobacterium Synechococcus Sp. Ccmp 1334, Alyssa K. Sharbaugh

LSU Master's Theses

The marine cyanobacterium Synechococcus sp. CCMP 1334 was grown in a continuous culture system on a 12:12 h light:dark cycle at all combinations of low and high pCO2 (400 and 1000 ppmv, respectively), nitrate availability (nitrate-limited and nutrient-replete conditions), and temperatures of 21°C, 24°C, 28°C, 32°C, and 35°C. The maximum median nutrient-replete growth rate was ~1.15 d−1 at 32 –35°C. Median growth rates at 1000 ppmv pCO2 were higher than those at 400 ppmv at all temperatures, but most of the differences were statistically insignificant. Carbon:nitrogen ratios were independent of pCO2 at a fixed relative growth rate but decreased with …

Sensor Analytics For Subsea Pipeline And Cable Inspection: A Review, Connor R. Vincent

LSU Master's Theses

Submarine pipelines and cables are vital for transmitting physical and digital resources across bodies of water, necessitating regular inspection to assess maintenance needs. The safety of subsea pipelines and cables is paramount for sustaining industries such as telecommunications, power transmission, water supply, waste management, and oil and gas. Incidents like those involving the Nord Stream subsea pipeline and the SEA-ME-WE 4 subsea communications cable exemplify the severe economic and environmental consequences of damage to these critical infrastructures. Existing inspection methods often fail to meet accuracy requirements, emphasizing the need for advancements in inspection technologies. This comprehensive survey covers the sensors …

An Analysis And Ontology Of Teaching Methods In Cybersecurity Education, Sarah Buckley

LSU Master's Theses

The growing cybersecurity workforce gap underscores the urgent need to address deficiencies in cybersecurity education: the current education system is not producing competent cybersecurity professionals, and current efforts are not informing the non-technical general public of basic cybersecurity practices. We argue that this gap is compounded by a fundamental disconnect between cybersecurity education literature and established education theory. Our research addresses this issue by examining the alignment of cybersecurity education literature concerning educational methods and tools with education literature.

In our research, we endeavor to bridge this gap by critically analyzing the alignment of cybersecurity education literature with education theory. …

Investigation Of Gas Dynamics In Water And Oil-Based Muds Using Das, Dts, And Dss Measurements, Temitayo S. Adeyemi

LSU Master's Theses

Reliable prediction of gas migration velocity, void fraction, and length of gas-affected region in water and oil-based muds is essential for effective planning, control, and optimization of drilling operations. However, there is a gap in our understanding of gas behavior and dynamics in water and oil-based muds. This is a consequence of the use of experimental systems that are not representative of field-scale conditions. This study seeks to bridge the gap via the well-scale deployment of distributed fiber-optic sensors for real-time monitoring of gas behavior and dynamics in water and oil-based mud. The aforementioned parameters were estimated in real-time using …

Characterizing And Mitigating Transient Noise In Ligo Observatories For Gravitational Wave Detection, Jane Glanzer

LSU Doctoral Dissertations

The existence of gravitational waves is predicted by Albert Einstein's Theory of General Relativity. Commonly referred to as "ripples in spacetime", these waves are generated by some of the most violent and energetic processes in the universe. Despite their theoretical prediction over a century ago, it wasn't until 2015 that the Advanced LIGO (aLIGO) interferometers in Hanford, WA and Livingston, LA directly detected gravitational waves for the first time, confirming Einstein's theory and ushering in a new era of astrophysics.

Detecting gravitational waves requires incredible precision. Because of the extreme sensitivity required, it is possible for the gravitational wave data …

The Impacts Of Nature-Based Sediment Restoration Practices On Coastal Wetland Soil Biogeochemistry, Jacob Z. Cheng

LSU Master's Theses

Coastal marshes provide many valuable ecosystem services. However, these wetlands are threatened worldwide, being subject to sea level rise, sediment starvation, subsidence, coastal edge erosion, etc. Many efforts are being made to counteract this wetland loss and preserve the ecosystem services. Two such methods are sediment diversion and the thin layer placement (TLP) of dredged sediment.

Sediment diversion involves reconnecting the main channel of a river body to disconnected wetlands, supplying much needed soil-building materials. However, this method affects the salinity of the waters, introducing large amounts of freshwater into the system. Salinity changes can affect marsh biogeochemistry. Most ecological …

Quasistationary Distribution For The Invasion Model On A Complete Bipartite Graph, Clayton Allard, Iddo Ben-Ari, Shrikant Chand, Van Hovenga, Edith Lee, Julia Shapiro

Journal of Stochastic Analysis

No abstract provided.

The Homotopy Cardinality Of The Representation Category, Justin Murray

LSU Doctoral Dissertations

Given a Legendrian knot in (R^3, ker(dz − ydx)) one can assign a combinatorial invariants called ruling polynomials. These invariants have been shown to recover not only a (normalized) count of augmentations but are also closely related to a categorical count of augmentations in the form of the homotopy cardinality of the augmentation category. In this article, we prove that that the homotopy cardinality of the n-dimensional represen- tation category is a multiple of the n-colored ruling polynomial. Along the way, we establish that two n-dimensional representations are equivalent in the representation category if they are “conjugate homotopic”. We also …

Surface And Bulk Properties Of Multi-Component Metal Alloys, Frank A. Mckay Iii

LSU Doctoral Dissertations

While HEAs have been studied extensively for their material properties, their potential as catalysts remains widely unexplored. To explore the feasibility of CoCrFeNi as a catalyst for the hydrogen evolution reaction, the results of X-ray photoelectron spectroscopy (XPS) and high-resolution electron energy loss spectroscopy (HREELS) experiments are compared to electrochemical experiments and theoretical calculations. XPS shows that this surface forms passive oxides with a propensity of Cr > Fe > Co, with no evidence of Ni oxidation. From comparison to calculations, it is shown that the electrochemical activity is enhanced in a partially oxidized state. The lack of Ni oxidation suggests that …