Physical Sciences and Mathematics Commons^™

Development Of Transition Metal-Catalyzed Polymerization Reactions And Their Applications For The Preparation Of Well-Defined Conjugated Polymer Architectures, Carlos Anthony Chavez

LSU Doctoral Dissertations

The synthesis of conjugated polymers and design of complex materials based on them have become increasingly popular as the demand for low-cost efficient and processible optoelectronic and semiconducting devices escalates. While advanced applications of polymeric materials require some degree of sophistication, success can be achieved through careful consideration of polymerization techniques and methodologies. Controlling critical aspects of the polymerization process allows for synthesis of complex macromolecular architectures possessing unique and novel properties that may be worth of further comprehensive investigation. This dissertation primarily focuses on the development and preparation of well-defined hierarchical macromolecular architectures. The foundation of this work encompasses …

Nuclear Structure Of 26si And 32cl For Astrophysics, Liudmyla Afanasieva

LSU Doctoral Dissertations

We studied the nuclear structure of two isotopes, 26Si and 32Cl, important for understanding stellar explosions like novae and Type I X-ray bursts. The 31S(p,γ)32Cl reaction rate influences the enrichment of sulfur observed in some nova ejecta, but the uncertainty in the rate spans as much as an order of magnitude and arises from uncertainties in the properties of resonances corresponding to excited states in 32Cl. We populated states in 32Cl via the 10B(24Mg,2n)32Cl reaction using the Argonne Tandem-Linac Accelerator System (ATLAS), with a 75 MeV beam of 24Mg bombarding a 200 μg/cm2 10B target. Gamma rays emitted from recoiling …

Magnetic Susceptibility Of North American Ordovician Epicontinental Seas: Spatial Variability And Sandbian-Katian Boundary Correlation, Thomas J. Schramm

LSU Doctoral Dissertations

Magnetic susceptibility (χ) has gained increased usage as a stratigraphic correlation tool. This project evaluates the utility of a χ correlation tool, including its shortcomings, and attempts its integration with other datasets. The Upper Ordovician of eastern North America represent the stratigraphic interval in which these experiments were conducted. 4566 samples were collected for the purposes of this study, and χ was measured on 3345 of the samples. This project includes three major facets, 1) the spatial variability of χ, 2) correlation of Sandbian-Katian boundary interval strata in eastern North America using χ, and 3) utility of χ for interpreting …

Investigating The Photorecombination Dynamics In Molecular High-Harmonic Spectra, Benjamin Parker Wilson

LSU Doctoral Dissertations

The work presented in this dissertation will relate the photorecombination dynamics to photoionization dynamics in SF6 utilizing the self-probing mechanism, high harmonic generation (HHG). This work specifically aims to establish parameters for which the comparison is applicable and the macroscopic complications inherent in HHG do not interfere with the extraction of dynamic information. The first part of this work established the macroscopic experimental apparatus necessary for consistent spectroscopic observation. It is shown that using a gas jet that is an order of magnitude shorter than the Rayleigh length of the driving laser results in more consistent harmonic spatial profiles and …

Scanning Probe Investigations Of Nanopatterned And Thermo-Responsive Polypeptoids And The Design Of A Sample Stage For Force Modulation Microscopy, Lu Lu

LSU Doctoral Dissertations

Protocols for patterning nanostructures of polymers were developed to enable scanning probe microscopy (SPM) studies of surface properties at the molecular level. A chemically selective surface for patterning polymers was generated by combining particle lithography with organosilane immersion. Poly(N-allyl glycine), a biocompatible and backbone degradable polypeptoid, was grown on Si(111) at confined amine sites using surface-initiated polymerization (also known as the “graft from” approach). A thermo-responsive random copolypeptoid, poly[(N-ethyl glycine)32-r-(N-butyl glycine17)], was pre-synthesized and attached onto a patterned organosilane surface using a thiol-ene click reaction (“graft to” approach). The phase transitions of the copolypeptoid nanostructures in an aqueous environment was …

Cellulose Nanofibers From Energycane Bagasse And Their Applications In Core-Shell Structured Hydrogels, Yiying Yue

LSU Doctoral Dissertations

Cellulose fibers (Cellulose I, cellulose II and cellulose I/II Hybrid fibers) were successfully extracted from energycane bagasse by using a combined NaOH and NaClO2 treatment. After the delignification process, most lignin and hemicellulose were removed with a 27.4wt% yield of cellulose fibers, and the mean diameter of cellulose fibers decreased from 137±46 (raw fiber bundles) to 12±5μm (unpacked fibers). The raw bagasse fibers showed a three-step pyrolysis process, while isolated cellulose fibers had a one-step pyrolysis process. NaClO2 treatment caused the reduction of cellulose thermal stability due to its acting on lignin and cellulose. With 10h NaOH treatment, the ribbon …

Analysis Of Nonlinear Dispersive Model Equations, Jacob Grey

LSU Doctoral Dissertations

In this work we begin with a brief survey of the classical fluid dynamics problem of water waves, and then proceed to derive well known evolution equations via a Hamiltonian Variational approach. This method was first introduced in the seminal work of Walter Craig, et al. \cite{CG}. The distinguishing feature of this scheme is that the Dirichlet-Neumann operator of the fluid domain appears explicitly in the Hamiltonian. In the second and third chapters, we utilize the Hamiltonian perturbation theory introduced in \cite{CG} to derive the Benjamin-Bona-Mahony (BBM) and Benjamin-Bona-Mahony-Kadomtsev-Petviashvili (BBM-KP)equations. Finally, we briefly review the existence theory for their corresponding …

Optimized Aperiodic Multilayer Structures For Absorbers And Thermal Emitters, Christopher H. Granier

LSU Doctoral Dissertations

In this dissertation, we begin with a brief introduction to nanophotonics. In particular, we will focus on the theory of computational electricity and magnetism, specifically, the method used for this research, the transfer-matrix method. We will also provide discussions of the principles which motivate the analysis of the multilayer structures: Planck's blackbody distribution, Kirchoff's law, and thermodynamics. Finally, we will provide a brief discussion of computer-based optimization algorithms, specifically NLOPT (a library which provides computational packages for nonlinear optimization) and genetic algorithms. This background information is necessary to understand discussions which occur in later chapters.

Chapter 2 will discuss multilayer …

String Searching With Ranking Constraints And Uncertainty, Sudip Biswas

LSU Doctoral Dissertations

Strings play an important role in many areas of computer science. Searching pattern in a string or string collection is one of the most classic problems. Different variations of this problem such as document retrieval, ranked document retrieval, dictionary matching has been well studied. Enormous growth of internet, large genomic projects, sensor networks, digital libraries necessitates not just efficient algorithms and data structures for the general string indexing, but indexes for texts with fuzzy information and support for queries with different constraints. This dissertation addresses some of these problems and proposes indexing solutions. One such variation is document retrieval query …

Rényi Quantum Conditional Mutual Information And Parity Quantum Optical Metrology, Kaushik Parasuram Seshadreesan

LSU Doctoral Dissertations

This is a two-part thesis strung together by a common underlying theme—quantum correlations. We present some new characterizations and quantifications of quantum correlations and an application of one such correlation—entanglement—for quantum technology.

In Part I of the thesis, we use a Rényi generalization of the quantum conditional mutual information (QCMI) to define and study new measures of quantum entanglement and quantum discord. In particular, using a quantity derived from a Rényi QCMI, we introduce: a) the geometric squashed entanglement, a faithful entanglement measure, which is a lower bound on the squashed entanglement and which reduces to the geometric measure of …

Three Year Assessment Of Nearshore Crude Oil Contamination In The Gulf Of Mexico Using Gulf Menhaden (Brevoortia Patronus) As An Indicator Species: Menhaden Watch, Gregory Michael Olson

LSU Doctoral Dissertations

Approximately 4.9 million barrels of crude oil along with natural gas were released into the Gulf of Mexico (GoM) from April to July 2010 (Deepwater Horizon, DWH, spill). Impacts of this magnitude seldom occur in the GoM (Ixtoc I was the last spill close to this magnitude occurring in 1979), and one cannot predict when they will happen. Major constituents of concern found in crude oil are Polycyclic Aromatic Hydrocarbons (PAHs), which often have low volatility that allows for prolonged existence in the environment. PAHs are compounds of concern according to the United States Environmental Protection Agency (USEPA), with one …

Towards The Realization Of Systematic, Self-Consistent Typical Medium Theory For Interacting Disordered Systems, Chinedu Ekuma Ekuma

LSU Doctoral Dissertations

This work is devoted to the development of a systematic method for studying electron localization. The developed method is Typical Medium Dynamical Cluster Approximation (TMDCA) using the Anderson-Hubbard model. The TMDCA incorporates non-local correlations beyond the local typical environment in a self-consistent way utilizing the momentum resolved typical-density-of-states and the non-local hybridization function to characterize the localization transition. For the (non-interacting) Anderson model, I show that the TMDCA provides a proper description of the Anderson localization transition in one, two, and three dimensions. In three-dimensions, as a function of cluster size, the TMDCA systematically recovers the re-entrance behavior of the …

Polycyclic Aromatic Hydrocarbons Dynamics In The Northern Gulf Of Mexico, Puspa Lal Adhikari

LSU Doctoral Dissertations

Polycyclic aromatic hydrocarbons (PAHs) are introduced into the marine environment via oil seeps/spills, riverine discharges, continental runoff, coastal erosion, and atmospheric deposition. An estimated 2.1 x 1010g of PAHs entered into the northern Gulf of Mexico (GOM) during the Deepwater Horizon (DWH) oil spill in 2010. It became evident following the oil spill that accurate quantification of ultimate fate of these potentially carcinogenic and/or mutagenic organic pollutants is extremely challenging. In general, very little is known about PAHs fate, distribution and accumulation in the open ocean ecosystems. This study determines the upper ocean vertical fluxes and sedimentary PAHs accumulation rates …

Seismic Velocity Characteristics Of Partially Saturated Unconsolidated Sediments, Jie Shen

LSU Doctoral Dissertations

Seismic velocity models of the near-surface (< 30 m) better explain seismic velocities when all elements of total effective stress are considered, particularly in materials with large cohesive and soil suction stress such as clays. Traditional constitutive elastic models assume interparticle and soil suction stresses are negligible. This study proposes a new methodology which corrects total effective stress in Hertz-Mindlin theory for interparticle and soil suction and calculates the elastic moduli by extending Biot-Gassmann theory to include pressure effects induced by water saturation changes and cohesion. The proposed model predicts seismic velocities that correlate well with measured field velocities from the literature. Soil density, porosity, elastic moduli and the soil-water characteristic curve (SWCC) are important properties for soil characterization. Currently, geotechnical and laboratory tests for soil properties are costly and limited to point sampling sites. Seismic surveys can potentially provide laterally continuous soil property values that may complement geotechnical borehole tests with low cost. We propose a new method to invert for soil properties and the SWCC from seismic P- and S-wave velocity-vs.-depth profiles interpreted from shallow (< 25 m depth) unconsolidated sediments under conditions of near-full saturation (> 99%). The results from seismic soil property inversion are validated by comparison to geotechnical and laboratory results conducted independently in the same area as the seismic survey. Knowledge of homogeneous and heterogeneous fluid-distribution patterns is important for the estimation of oil reserves, reservoir simulation, the interpretation of time-lapse seismic, and the selection of remediation techniques for groundwater contamination. Problems exist in determining in-situ fluid-distribution patterns in unconsolidated sediments because laboratory tests on core samples may not be representative of in-situ conditions. We propose a new method to determine in-situ fluid-distribution patterns by inverting …

Game Theoretic Analyses Of The United States-Canada Softwood Lumber Trade, Rajan Parajuli

LSU Doctoral Dissertations

The ongoing softwood lumber trade dispute between the United States (U.S.) and Canada is one of the most contentious and largest bilateral trade battles over the recent decades. The bilateral trade debate is mostly because of the different forestland ownership systems in the U.S. and Canada, and the alleged timber subsidies by provincial governments to Canadian lumber producers. The Softwood Lumber Agreement (SLA) 2006 between the U.S. and Canada is the latest transitory solution of this dispute, entailing Canada to impose mandatory export charges on its lumber shipments to the U.S. In order to understand this trade dispute from a …

Left-Orderability, Cyclic Branched Covers And Representations Of The Knot Group, Ying Hu

LSU Doctoral Dissertations

A group G is called left-orderable if one can find a total order on G, which is preserved under left multiplication. In this paper we first give a sufficient condition for the fundamental group of the nth cyclic branched cover of the three sphere over a prime knot K to be left-orderable, in terms of representations of the knot group. Then we make use of this criterion to study the left-orderability of fundamental groups of cyclic branched covers over two-bridge knots and satellite knots.

Holocene Palynology Of The Gulf Of Papua, Papua New Guinea: Using Modern Palynomorph Distribution To Better Constrain Paleoenvironmental Changes, Marie Louise Thomas

LSU Doctoral Dissertations

Multiple NSF (National Science Foundation)-funded MARGINS Source-to-Sink cruises were conducted in the Gulf of Papua (GoP), Papua New Guinea (PNG), from 2003 through 2005 to better understand how sediment is created, transported, and deposited. Although much work has been done on the data collected during these cruises, palynological analysis has never been conducted on the hundreds of available cores. The first phase of this project (Chapters 2 and 3) examines the connection between modern depositional regimes in the GoP and species assemblages recovered. Statistical analysis of palynomaceral assemblages (Chapter 2) indicates a correlation between their distribution and bathymetry, sedimentation rate, …

Effects Of Inbreeding On Endangered Red Wolves (Canis Rufus), Kristin E. Brzeski

LSU Doctoral Dissertations

Inbreeding depression, the reduction in offspring fitness caused by mating among close relatives, is widespread in small populations and a major concern in conservation biology because it can affect population persistence. The negative effects of inbreeding results in the evolution of inbreeding avoidance behaviors; within small populations, such behaviors may encourage individuals to select mates outside of their respective species. Mate choice may also be facilitated by variation at major histocompatibility complex (MHC) genes, a gene group critical for immune response and disease resistance. Given broad impacts of inbreeding and MHC variation on fitness and behavior, evaluating their effects is …

A Spatial Dynamic Model Of Population Changes In A Vulnerable Coastal Environment, Kenan Li

LSU Doctoral Dissertations

Achieving coastal sustainability in low-lying coastal areas is a great challenge. This study developed a spatial dynamic model to study the coupled natural-human responses in the form of population changes in the Lower Mississippi River Basin region. The goal was to identify the key social-economic factors (utility) and selected environmental factors (such as hazards damage, elevation, and subsidence rate) that affect population changes, as well as how population changes affect the local utility and the local environment reciprocally. The study area was partitioned into the “north’ and the “south” by a hypothetical boundary to test the differences of the emergence. …

Using Trace Fossils To Determine The Role Of Oceanic Anoxic Event Ii On The Cretaceous Western Interior Seaway Paleoenvironment, Jacob Frederick Grosskopf

LSU Doctoral Dissertations

Did well-oxygenated benthic conditions exist in all parts of the Cretaceous Western Interior Seaway (CWIS) during the deposition of Bed 63 at the onset Oceanic Anoxic Event II (OAE II), as suggested by findings from two cores from the central portion of the CWIS? This problem was approached by categorizing the bioturbation that is prevalent through Bed 63 into oxygen-related ichnofabrics (ORI) in order to describe benthic oxygen conditions. These data were collected from outcrop and core among seven different sites along West–East and North–South transects that traversed portions of the CWIS with differing depositional settings and proximities to the …

Synthetic Methods Development Towards The Total Synthesis Of Chlorosulfolipids, Andres Villalpando

LSU Doctoral Dissertations

The focus of this dissertation is the development of a novel chlorination reaction utilizing a triphosgene-amine based mixture towards the total synthesis of chlorosulfolipids, a subclass of naturally occurring organohalogen natural products. This novel, mild chlorination reaction will be utilized under a global chlorination strategy to chlorinate multiple alcohol substituents in one synthetic operation. Chapter one details the history of chlorosulfolipids from the early stages of their isolation, relevant structural elucidation techniques, appropriate biosynthetic discoveries, and their biological relevance to a thorough investigation of the total syntheses completed to date. These compounds demonstrate a range of biological activities and have …

On The Development Of Analytical Methodologies To Interrogate The Lipid Dynamics And Phase Transition Resulting From The Reduction Of Stimuli-Responsive Vesicles, James Edward Winter

LSU Doctoral Dissertations

The potential is great for liposome drug delivery systems that provide specific contents release at diseased tissue sites upon activation by upregulated enzymes; however, this potential will only come to fruition with mechanistic knowledge of the contents release process. NAD(P)H:quinone oxidoreductase type 1 (NQO1) is a target for reductively-responsive liposomes, as it is an enzyme upregulated in numerous cancer tissues and is capable of reducing quinone propionic acid (QPA) trigger groups to hydroquinones that self-cleave from dioleolylphosphatidylethanolamine (DOPE) liposome surfaces, thereby initiating contents release. This research targets the development of analytical methodologies to observe and characterize the dynamics and resulting …

Pattern Mining And Events Discovery In Molecular Dynamics Simulations Data, Shobhit Sandesh Shakya

LSU Doctoral Dissertations

Molecular dynamics simulation method is widely used to calculate and understand a wide range of properties of materials. A lot of research efforts have been focused on simulation techniques but relatively fewer works are done on methods for analyzing the simulation results. Large-scale simulations usually generate massive amounts of data, which make manual analysis infeasible, particularly when it is necessary to look into the details of the simulation results. In this dissertation, we propose a system that uses computational method to automatically perform analysis of simulation data, which represent atomic position-time series. The system identifies, in an automated fashion, the …

Real-Time Shadows For Gigapixel Displacement Maps, Kevin Anthony Cherry

LSU Doctoral Dissertations

Shadows portray helpful information in scenes. From a scientific visualization standpoint, they help to add data without unnecessary clutter. In video games they add realism and depth. In common graphics pipelines, due to the independent and parallel rendering of geometric primitives, shadows are difficult to achieve. Objects require knowledge of each other and therefore multiple renders are needed to collect the necessary data. The collection of this data comes with its own set of trade offs. Our research involves adding shadows into a lunar rendering framework developed by Dr. Robert Kooima. The NASA-collected data contains a multi-gigapixel displacement map describing …

Design And Validation Of A Prototype Collimation System With Reduced Applicator Weights For Elekta Electron Therapy Beams, Garrett Michael Pitcher

LSU Doctoral Dissertations

The objective of this study was to design an electron collimation system for Elekta Infinity accelerators with significantly reduced applicator weights, while maintaining acceptable in-field beam flatness and out-of-field leakage dose. The design was restricted to 6-20 MeV beams for 6x6 to 25x25 cm2 applicators at 100 cm SSD with the MLCi2 treatment head. In Aim1, measured off-axis profiles showed that the current Elekta collimation system met dose flatness (4%) and IEC leakage dose specifications in the patient plane for custom 7, 13, and 20 MeV beams at MBPCC. Also, Monte Carlo (MC) calculations based on MBPCC beam models sufficiently …

Developing Recognition Criteria For Current-Wave-Enhanced Sediment Gravity Flows, Kathryn Christine Denommee

LSU Doctoral Dissertations

Sedimentary fabrics preserved in the rock record provide some of the best evidence for interpreting paleo-depositional conditions. Muddy sediments in particular are important paleoenvironmental archives, preserving the most complete stratigraphic record of any rock type in basinal settings. However, the full range of mechanisms responsible for the deposition of muddy sediments, particularly in high-energy settings, remains poorly understood. Although frequently observed in modern settings, muddy prodeltaic deposits are rarely identified in the rock record, in part because no catalogue of easily distinguishable recognition criteria exists for this class of mudstones. In order to help overcome this deficiency, this dissertation project …

I. Synthesis Of Ascarosides For Biological Evaluation And Ii. Development Of Visible Light-Promoted Selenofunctionalization And Grafting Of Aryl Iodides, Elizabeth Susan Conner Balapitiya

LSU Doctoral Dissertations

This dissertation focuses on analog synthesis for biological evaluation and visible light promoted method development. Chapter 1 centers upon the synthesis of Caenorhabditis elegans dauer pheromone analogs. C. elegans is a nematode which, in times of environmental stress, enters a dauer stage. Two highly conserved pathways, which play important roles in some diseases in higher organisms, monitor dauer formation: TGF-β and IGF-1. Dauer formation is triggered by the nematode’s chemosensation of the dauer pheromone, consisting of a group of previously-isolated ascarosides. These compounds differ in chain length, saturation, terminal functionality of side chain, ω vs. ω-1 oxygenation and presence of …

Classification In The Presence Of Ordered Classes And Weighted Evaluative Attributes, Forrest Justin Osterman

LSU Doctoral Dissertations

We are interested in an important family of problems in the interface of the Multi-Attribute Decision-Making and Data Mining fields. This is a special case of the general classification problem, in which records describing entities of interest have been expressed in terms of a number of evaluative attributes. These attributes are associated with weights of importance, and both the data and the classes are ordinal. Our goal is to use historical records and the corresponding decisions to best estimate the class values of new data points in a way consistent with prior classification decisions, without knowledge of the weights of …

Surface Structure/Property Relationship For (001) Surface Of Magnetite, Fangyang Liu

LSU Doctoral Dissertations

Magnetite (Fe3O4), a well-known magnetic material, is still attracting intense study because of its great application in catalyst and technology development. These useful properties are related to the coexistence and coupling of several degrees of freedom, including charge, lattice, orbital and spin. The interaction between Fe3O4 and hydrogen is one of the most important issues, which guides the development of catalytic efficiency and material practicality. In this work, natural single crystal Fe3O4 (001) surfaces are studied with a variety of techniques. It is discovered that the Fe3O4 (001) surface structure and properties are dependent on the surface preparation methods. Conventional …

Knots, Skein Theory And Q-Series, Mustafa Hajij

LSU Doctoral Dissertations

The tail of a sequence {P_n(q)} of formal power series in Z[q^{-1}][[q]], if it exists, is the formal power series whose first $n$ coefficients agree up to a common sign with the first n coefficients of P_n. The colored Jones polynomial is link invariant that associates to every link in S^3 a sequence of Laurent polynomials. In the first part of this work we study the tail of the unreduced colored Jones polynomial of alternating links using the colored Kauffman skein relation. This gives a natural extension of a result by Kauffman, Murasugi, and Thistlethwaite regarding the highest and lowest …