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Sequence-Defined Ionic Peptoid Polymers: Synthesis, Characterization, And The Role Of Charge Patterning, Bailee N. Barrett

LSU Doctoral Dissertations

This work explores the role of positionally defined charges on the self-assembly behavior of a series of sequence-defined peptoid block copolymers. The unique ability to precisely control the number and position of each monomer unit along the polymer chain makes this system particularly well suited for uncovering how changes in monomer sequence alter the resulting structures. We employ a number of scattering techniques to uncover how systematically repositioning a single ionizable monomer, along an otherwise neutral polymer chain, alters the self-assembled micellar structures and subsequently their responsiveness to changes in their local environment.

Chapter 1 reviews previous efforts to transition …

First-Principles And Machine Learning Investigation Of Refractory High Entropy Alloys And Conventional Alloys., Uttam Bhandari

LSU Doctoral Dissertations

Refractory high entropy alloys (RHEAs) are gaining prominence because of their balanced mechanical properties and are regarded as suitable alloys for a variety of applications such as aerospace, structural material, nuclear, and hydrogen storage. The first part of the dissertation explored the mechanical and thermal properties of RHEAs, specifically HfNbTaTiZr and Hf_0.5Nb_0.5Ta_0.5Ti_1.5Zr, which have potential uses in the health industry. The first-principles method using 100 atom supercell was carried out to compute the lattice constant, density, elastic modulus, Poisson ratio, and Vickers hardness. These calculated results were consistent with the available experimental …

Deciphering The Role Of Molecular Interactions On The Interfacial Structure Of Aqueous And Non-Aqueous Interfaces, Dodangodage Ishara Indunil Senadheera, D I. Senadheera

LSU Doctoral Dissertations

The study focused on "Deciphering the role of molecular interactions on the interfacial structure of aqueous and non-aqueous interfaces" holds immense significance in diverse scientific and industrial domains. Our primary objective is to unravel the intricate web of molecular interactions occurring at the boundaries between aqueous and non-aqueous phases. The research presented here spans a wide scope, encompassing applications in microelectromechanical systems in the semiconductor industry, energy-efficient membranes for electrochemical separations, and renewable energy storage systems. Molecular dynamics simulations were conducted in collaboration with experimental studies, specifically atomic force microscopy, to achieve insights at the molecular level.The first project centered …

Cationic Frontal Polymerization: Front Kinetics, Effects Of Additives, And Applications, Brecklyn R. Groce

LSU Doctoral Dissertations

Cationic frontal polymerization broadens the potential application of frontal polymerization by allowing for use of monomers such as epoxies and vinyl ethers. In this work, the effects of monomer and initiator composition and additives including fillers on front kinetics, along with applications of cationic frontal polymerization were investigated.

Using a radical-induced cationic frontal polymerization (RICFP) method with a superacid generating salt and a thermal radical initiator, the addition of vinyl ethers to epoxy formulations was studied, where an increase of front velocity was seen with increase of divinyl ether to epoxy ratio. Other aspects of vinyl ether systems, such as …

Influences On Participation In The National Flood Insurance Program’S Community Rating System In Coastal Counties In Louisiana, Mississippi, Alabama, And Florida, Jennifer E. Argote

LSU Doctoral Dissertations

The National Flood Insurance Program provides an incentive-based program, the Community Rating System (“CRS”), to encourage communities to improve their hazard mitigation protocols to better protect against and prevent flood-related hazards. This dissertation analyzes factors that influence participation and points scored within the CRS to gain an understanding of the conditions under which communities are willing and able to take advantage of an incentive-based flood hazard mitigation program. It also includes an analysis of survey responses from 41 coastal county floodplain and CRS managers to gauge their opinions on the CRS and how it can be improved to better serve …

The Fabrication Of Nearly Monodisperse Chiral And Achiral Plasmonic Nanostructures And Their Applications, Macayla J. Caso

LSU Doctoral Dissertations

An object is chiral when it holds no lines of symmetry. This quality naturally occurs in chemistry and biology. When an object is chiral it has a unique handedness and objects of opposite chirality are called enantiomers. The importance of handedness was brought to light in the 1960’s when a racemic mixture of thalidomide enantiomers was given to pregnant women. One enantiomer was able to treat morning sickness while the other caused severe birth defects. This case brought to light how enantiomers have unique properties from each other even though they are similar materials. With this knowledge chiral nanomaterials must …

Modeling Of Heat And Mass Transfer In Flat Heat Pipes, Salar Saadatian

LSU Doctoral Dissertations

Phase-change phenomenon is ubiquitous in nature and widely utilized in thermal management of computer chips. Flat heat pipes have been extensively used in thermal management of microelectronic devices. However, existing research mainly concentrates on developing numerical models and lacks a systematic analytical approach to elucidate the working mechanism of flat heat pipes. We consider a horizontal flat heat pipe with an idealized porous wick. The pores in the wick are straight circular capillaries running along and across the wick and are filled with a liquid. The rest of the pipe is filled with its vapor. The mass evaporative rate at …

Cyberinet: Integrated Semi-Modular Sensors For The Computer-Augmented Clarinet, Matthew Bardin

LSU Doctoral Dissertations

The Cyberinet is a new Augmented instrument designed to easily and intuitively provide a method of computer-enhanced performance to the Clarinetist to allow for greater control and expressiveness in a performance. A performer utilizing the Cyberinet is able to seamlessly switch between a traditional performance setting and an augmented one. Towards this, the Cyberinet is a hardware replacement for a portion of a Clarinet containing a variety of sensors embedded within the unit. These sensors collect various real time data motion data of the performer and air fow within the instrument. Additional sensors can be connected to the Cyberinet to …

Optimizing Large-Capacity Key-Value Systems For Efficient Data Management, Kefei Wang

LSU Doctoral Dissertations

In today's Internet services, key-value system is playing a crucial and indispensable role, and has attracted extensive research in both academia and industry. During the past years, we have witnessed an unprecedented quick development of both memory-based and flash-based key-value systems. With the rapid evolution of memory and storage technologies, we are seeing both challenges and research opportunities.

In this dissertation, we focus on understanding and optimizing the efficiency of large-capacity, high-speed key-value systems from the perspective of both software and hardware to meet the ever-growing performance expectations. We first propose a multi-tier mapping structure, called Cascade Mapping, exploring the …

Connecting The Optical Regime To The X-Ray In Neutron Star Low Mass X-Ray Binaries, Alexander B. Igl

LSU Doctoral Dissertations

Using Rossi X-Ray Timing Explorer and Otto Struve Telescope data of low mass X-ray binaries (LMXBs) Cyg X-2 and Sco X-1, the optical regime’s relationship to the X-ray was investigated through several angles. Discrete cross correlations using the optical and X-ray data revealed evidence of reprocessing in both datasets. These were more consistently present in Sco X-1, where both small and obvious features were seen at less than 4 s of optical lag. The size of these lags makes it likely that most of the reprocessing is taking place on the accretion disk. Parameterization of the Z tracks led to …

Nonlinear Optical Studies At Surfaces And Interfaces, Mojgan Dehghani

LSU Doctoral Dissertations

Nonlinear optical studies have revealed that surfaces and interfaces possess unique optical properties due to the lack of inversion symmetry. These properties are significantly different from those of the bulk material. Second harmonic generation (SHG), a second-order nonlinear optical phenomenon, has emerged as a surface-specific technique to study these unique properties. The powerful selection rule allows generation of second harmonic light only in the bulk of noncentrosymmetric media and the regions with broken inversion symmetry, including surfaces and interfaces. The generated second harmonic provides significant information on the electronic and structural properties of the microscopic surface layer at the boundary …

A "Rock To Lean On": Young Singers' Experiences In A Community Choir In Louisiana, Yulene Velásquez

LSU Doctoral Dissertations

The purpose of this intrinsic case study was to investigate young singers’ experiences in the Livingston Parish Children’s Choirs organization (LPCC), a community-based children’s choir program in Denham Springs, Louisiana. I investigated the impact of those experiences on the children’s lives inside and outside of the ensemble from the perspective of the artistic director and co-director, parents, and the singers themselves.

The LPCC was founded in 1991 by Barbara Walker and her mother, Regina Walker. According to Barbara Walker, the mission of the organization is “to prepare children to go out and be lifelong singers.” This choral community is characterized …

The Case For Succession Planning In Higher Education: A Study Of Knowledge Transfer Within Louisiana State University, Leila Shaik Villien

LSU Doctoral Dissertations

The primary purpose of this study was to explore the challenges, benefits, and perceptions of succession planning among currently employed administrators at research universities in the southern portion of the United States at the level of assistant department head or higher and the accessible population was defined as currently employed administrators at Louisiana State University at the level of assistant department head or higher. Deans, Associate Deans, Department Heads, Assistant Department Heads, and Department Chairs were invited to participate in an online survey designed by the researcher to assess the attitude toward succession planning and training, along with a variety …

First-Principles Simulations Of Attosecond Transient X-Ray Absorption, Min Chen

LSU Doctoral Dissertations

The first part of this dissertation presents calculations of the extinction spec- tra of gold-silver/silver-gold core-shell nanospheres. The goal of this projectsis to get a deeper understanding of surface plasmonic resonance in metal nanospheres with core-shell geometry. Here, we used the finite-difference time-domain (FDTD) method and total-field/scattered-field (TFSF) framework to compute the extinction spectra of nanoparticles to determine the geometry of gold-silver/silver-gold core-shell nanoparticles. This supported experimental work on monitoring the growth dynamics of colloidal gold- silver/silver-gold core-shell nanoparticles using in situ second harmonic generation (SHG) and extinction spectroscopy.

The second and main project involved simulating attosecond transient spectra for …

Entanglement In The Hawking Effect: From Astrophysical To Optical Black Holes, Dimitrios Kranas

LSU Doctoral Dissertations

The Hawking effect is an exciting physical prediction lying at the intersection of the two most successful theories of the past century, namely, Einstein’s theory of relativity and quantum mechanics. In this dissertation, we put special emphasis on the quantum aspects of the Hawking process encoded in the entanglement shared by the emitted fluxes of created quanta. In particular, we employ sharp tools from quantum information theory to quantify the entanglement produced by the Hawking effect throughout the black hole evaporation process. Our framework allows us to extend previous calculations of entanglement to a larger set of cases, for instance, …

Characterizing Wind-Wave Flow Physics And Loading Effects On Power Transmission Systems And Offshore Wind Turbines, Tianqi Ma

LSU Doctoral Dissertations

Recent extreme hurricanes caused extensive damage to critical civil infrastructure. Accurate modeling of the extreme complex wind fields and coupled wind-wave fields is essential to quantify the single wind or combined wind-wave loading effects on the structures. This research aims to characterize wind and wind-wave flow physics to quantify the loading effect on power transmission systems and offshore wind turbines.

First, a microscale (∼km) high-fidelity high-resolution computational model is developed to simulate hurricane wind fields with detailed physics. The generated wind field is applied to analyze the structural response of a power transmission system. The proposed hurricane boundary layer (HBL) …

Some New Techniques And Their Applications In The Theory Of Distributions, Kevin Kellinsky-Gonzalez

LSU Doctoral Dissertations

This dissertation is a compilation of three articles in the theory of distributions. Each essay focuses on a different technique or concept related to distributions.

The focus of the first essay is the concept of distributional point values. Distribu- tions are sometimes called generalized functions, as they share many similarities with ordi- nary functions, with some key differences. Distributional point values, among other things, demonstrate that distributions are even more akin to ordinary functions than one might think.

The second essay concentrates on two major topics in analysis, namely asymptotic expansions and the concept of moments. There are many variations …

Rethinking Attention Control: An Individual Differences Approach, Vincent A. Medina

LSU Doctoral Dissertations

While there is extensive literature on visual spatial attention, less is known about auditory spatial attention, especially in terms of attention control. There is also a growing literature highlighting the importance of considering individual differences in attention control ability. Given these points, the purpose of this study was twofold. The first was to understand how auditory attention control is influenced by spatial location as well as vision. The second was to examine whether individual differences in attention control ability can predict task performance in that context. We utilized two tasks for these purposes. Experiment 1a consisted of a cross-modal Stroop …

A Performer's Guide To Two Song Collections: “Mementos Of Innocence” And “Three Yeats Songs” By Malaysian Composer Chee Yean Wong, Wu Ji Khoo

LSU Doctoral Dissertations

Despite the flourishing existence of Asian Art Music for over half a century, relatively little has been done to advance its recognition and prominence. Through this project, the author hopes to shed light on the beauty and richness of Asian Art Music and encourage its inclusion in the repertoire of American classical music. The purpose of this document is to supply a comprehensive performer’s guide to Malaysian composer, Chee Yean Wong’s song collections: “Mementos of Innocence” and “Three Yeats Songs.” The collections feature settings of English poems by Jean Blewett, Christina Rossetti, Edwin C. Ranck, Rabindranath Tagore, and William Butler …

Adaptive Quantum Information Processing In Non-Equilibrium Environments, Arshag Danageozian

LSU Doctoral Dissertations

Solid state and condensed matter systems, such as diamond impurities, superconductors, quantum dots, and ion traps, constitute important physical platforms for various applications in quantum information processing (QIP). However, it has consistently been shown that all such modern platforms suffer from non-equilibrium behavior on timescales that are relevant for many important QIP tasks. The causes range from intrinsic non-equilibrium dynamics (e.g. in diamond) to the presence of various impurities with their own internal dynamics (e.g. in superconductors and quantum dots) or variations in the control fields used to stabilize the quantum matter (e.g. in ion traps). When reserving degrees of …

Phase Transitions And Magnetocaloric Effects In Metastable Phases Of Intermetallic Compounds, Tej Bahadur Poudel Chhetri

LSU Doctoral Dissertations

The interplay between spin and lattice degrees of freedom in magnetic materials often results in interesting magnetoresponsive effects. The magnetocaloric effect is one such magnetothermal phenomenon that may be utilized in energy-efficient magnetic cooling systems. This effect becomes more prominent near a coupling of magnetic and structural transitions, i.e., magnetostructural transitions (MSTs). This dissertation investigates phase transitions (magnetic and structural) in metastable phases of MnNiGe- and MnCoGe-based compounds generated through high-pressure synthesis/annealing and thermal quenching techniques and assesses their magnetocaloric effects.

First, the effects of doping, hydrostatic pressure, and thermal quenching on phase transitions and related magnetocaloric effects in Mn …

Simulations Of Intruder-Free X-Ray Transient Absorption And Time-Resolved X-Ray Scattering For Probing Attosecond Electron Dynamics, Mengqi Yang

LSU Doctoral Dissertations

The motion of electrons plays a fundamental role in both physics and chemistry, and capturing such dynamics requires the ability to resolve changes at the attosecond timescale, which is enabled by the advent of ultrashort laser pulses. This dissertation aims to facilitate the interpretation of ultrafast electron dynamics and attosecond spectroscopy by real-time time-dependent density functional theory (RT-TDDFT) simulations. The first part of this dissertation focuses on improving the simulation of X-ray transient absorption spectra (XTAS) with Gaussian basis sets in RT-TDDFT by applying a filter to the transition dipole matrix. Due to the spatial limitation of atom-centered Gaussian functions, …

Sedimentary Processes And Instability On The Mississippi River Delta Front Near The Wreck Of The Ss Virginia, Nathan Figueredo

LSU Doctoral Dissertations

Multi-cores and piston cores were collected seaward of the Mississippi River Delta’s Southwest Pass at ~80 m water depth in 2017 to better understand sedimentary characteristics and processes on the Mississippi River Delta Front (MRDF) in the vicinity of the SS Virginia shipwreck, and to support marine archeological research. Core analyses were performed to inform our understanding of the dynamics of sediment motion in the study area through radionuclide activity (²¹⁰Pb and ¹³⁷Cs), volume frequency of grain size, bulk density, and fabric (X-Radiography). Sediment accumulation rates (SAR), calculated from multi-core ²¹⁰Pb activity are 0.22 - 0.29 …

Ecology Of Viruses In Marine And Coastal Oxygen-Depleted Waters, Sophie Jurgensen

LSU Doctoral Dissertations

Deoxygenation of marine and coastal waters, both caused and exacerbated by a suite of abiotic and biotic factors, has been documented for more than sixty years. The incidence and severity of low-oxygen areas is predicted to expand globally in the coming decades. Despite their colloquial moniker “dead zones,” low-oxygen areas contain thriving and diverse microorganisms that have significant impacts on global biogeochemical cycles including contributing to positive feedback loops that further expand low-oxygen areas. While the diversity and activity of these microorganisms is beginning to be elucidated, the ecology of their viruses is particularly understudied. In this dissertation, I present …

Synthesis Of An Acinetobacter Baumannii Lipooligosaccharide Subunit, James M. Armstrong Ii

LSU Doctoral Dissertations

Acinetobacter baumannii is a Gram-negative, multi drug-resistant bacterium that was placed on the World Health Organization’s watchlist of drug-resistant bacteria. A. baumannii is an ESKAPE pathogen, one of six increasingly antimicrobial-resistant bacteria that are responsible for nosocomial infections. Alternative therapies, such as vaccines, are required to decrease the world’s reliance on antimicrobial agents. Specifically, glycoconjugate vaccines such as those used against Haemophilus influenzae B, Streptococcus pneumoniae, and Neisseria meningitidis are used globally and are highly effective. These vaccines consist of an antigenic bacterial glycan bound to a carrier protein. The glycan is usually a capsular polysaccharide (CPS), however, the notion …

Reconstruction Of Volumetric Modulated Arc Therapy-Computed Tomography, Chia-Lung Chien

LSU Doctoral Dissertations

Purpose: Volumetric modulated arc therapy-computed tomography (VMAT-CT) was proposed in 2010 as the CBCT reconstruction technique using portal images collected during VMAT. Yet, its clinical applications were impeded by the poor image quality due to motion blurs from fast movements of multi-leaf collimator (MLC) and projection data deficiency due to truncations from MLC. The goal of this study is to develop systematic preprocessing methods, and a novel iterative reconstruction algorithm to generate quality VMAT-CT and lower the number of failure cases of VMAT-CT reconstruction.

Methods: Systematic image preprocessing methods, including Online region-based active contouring (ORACM), MLC motion modeling and outlier …

Learning–Assisted Constraint Filtering To Enhance Power System Optimization Performance, Fouad Hasan

LSU Doctoral Dissertations

Machine learning (ML) is a powerful tool that provides meaningful insights for operators to make fast and efficient decisions by analyzing data from power systems. ML techniques have great potential to assist in solving optimization problems within a shorter time frame and with less computational burden. AC optimal power flow (ACOPF), dynamic economic dispatch (D-ED), and security-constrained unit commitment (SCUC) are the three energy management optimization functions studied in this dissertation. ACOPF is solved every 5~15 minutes. Because of the nonconvex and complex nature of ACOPF, solving this problem for large systems is computationally expensive and time-consuming. Classification and regression …

Behavior Of Gas Influx In Riser And Considerations For Riser Gas Handling, Mahendra Kumar Kunju

LSU Doctoral Dissertations

Conventional methods of managing Gas-in-Riser events are not optimal when the riser is isolated from the formation by a closed subsea blowout preventer (BOP) on rigs equipped with Mud-GasSeparator (MGS), Managed Pressure Drilling (MPD), or Riser Gas Handling (RGH) equipment. As the use of adaptive drilling processes like MPD facilitates drilling of otherwise non-drillable wells with faster corrective action, the drilling industry should include the effect of gas solubility, dispersion, bubble suspension, fluid compressibility as well as riser ballooning to avoid overestimation of riser pressure and produce more efficient well control methods. The IADC Deepwater Well Control Guideline recommends always …

An Evaluation Of Procedures To Increase Medical Device Compliance, Sarah Christian Holmes

LSU Doctoral Dissertations

Behavioral interventions have been implemented to increase compliance with medical devices across patient populations and target devices. Intervention to increase medical device compliance (MDC) can involve a variety of components, including different reinforcement, graduated exposure, extinction, and punishment with varying degrees of acceptability and feasibility. In the current study, we compared the effects of noncontingent (NCR) versus synchronous reinforcement schedules on the duration of MDC and latency to device removal with KN95 face masks with 2 patients with Autism Spectrum Disorder. Following an initial baseline phase demonstrating that both participants engaged in compliance for less than 5 min, we used …

Measurement Of The Β-Decay Properties Of A=105 Isotopes Using The Modular Total Absorption Spectrometer And The Development Of The Beta Spectrum Module, Thomas J. Ruland

LSU Doctoral Dissertations

Nuclear reactors produce an extremely diverse population of beta-decaying isotopes. Accurate and precise knowledge of the beta-decay properties of these isotopes is vital to safe reactor operations as well as informing next-generation reactor design. These beta-decay properties not only impact the design and operation of nuclear reactors, but they influence the expected antineutrino flux and spectrum measured from nuclear reactors. Historical measurements of many of these isotopes are subject to a systematic bias referred to as the Pandemonium Effect, because the low-efficiency, high-precision detectors used to perform the measurements results in misinterpreting weak gamma cascades from high- energy levels as …