Digital Commons Network^™

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 …

Investigations Into Ecogeomorphodynamics Of Coastal Embryo Dunes At Padre Island National Seashore, Texas, Katherine Anne Renken

LSU Doctoral Dissertations

This dissertation is an investigation into the interplay between vegetation and aeolian processes in the coastal embryo dune environment at Padre Island National Seashore, Texas. Vegetation is a geomorphic agent, altering aeolian process dynamics. This research adopted a three-pronged approach to improving our understanding of ecogeomorphodynamics in the coastal environment. The first study analyzed large-scale spatiotemporal trends in the vegetation community of the embryo dune environment in order to contextualize smaller scale aeolian processes. Results of this study demonstrated that there was a clear transition in community assemblage from the seaward edge of the embryo dune zone, where species functioned …

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 …

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 …

Holecene Paleoenvironmental Reconstruction From The Shark River Estuary, Everglades, Florida, Qiang Yao

LSU Doctoral Dissertations

This dissertation examines the paleoecological records from the Shark River Estuary in the southwestern part of the Everglades National Park (ENP), Florida, with primary goal of reconstructing the Holocene history of the coastal mangrove ecosystem in the Florida Coastal Everglades. Roughly 15 meters of sediments were collected from 4 study sites and subjected to loss-on ignition, palynological, and X-ray fluorescence analyses. According to the literature, the earliest communities of Rhizophora mangle (red mangrove) occurred prior to 8,000 cal yr BP in the south-central area of the Belize Barrier Reef Platform. Between 7,000 and 5,000 cal yr BP, Rhizophora was established …

La Grad Act’S Effects On Developmental Faculty: A Case Study, Patricia Kuhlman Van Brunt

LSU Doctoral Dissertations

Over the past 50 years, state legislatures have placed mandates on higher education institutions to lower attrition, thereby increasing student retention and completion. This study investigated and sought to understand the relationship between the Louisiana Granting Resources and Autonomy for Diplomas Act, or the LA GRAD Act (2010), and developmental education. More specifically, it focused on the perceptions of the mandate held by developmental education faculty who are employed at a public, urban Louisiana community college. This study utilized the four-framework approach by Bolman and Deal (2013) to decipher how developmental classrooms, academic departments, and a higher education institution as …

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 …

A Comprehensive Optimization Framework For Designing Sustainable Renewable Energy Production Systems, Aryan Geraili Nejadfomeshi

LSU Doctoral Dissertations

As the world has recognized the importance of diversifying its energy resource portfolio away from fossil resources and more towards renewable resources such as biomass, there arises a need for developing strategies which can design renewable sustainable value chains that can be scaled up efficiently and provide tangible net environmental benefits from energy utilization. The objective of this research is to develop and implement a novel decision-making framework for the optimal design of renewable energy systems. The proposed optimization framework is based on a distributed, systematic approach which is composed of different layers including systems-based strategic optimization, detailed mechanistic modeling …

Insights Into 5-Lipoxygenase Active Site And Catalysis, Sunayana Mitra

LSU Doctoral Dissertations

Leukotrienes are potent immune-modulatory compounds involved in the inflammatory response. 5-Lipoxygenase (5-LOX) is the enzyme that catalyzes the production of Leukotriene A4 (LTA4), which is further metabolized to pro- and anti-inflammatory compounds derived from the substrate Arachidonic Acid (AA), a polyunsaturated fatty acid. The crystal structure of a stabilized form of 5-LOX has been recently reported (Gilbert, Bartlett et al. 2011). However, the structure does not reveal the mode of substrate entry or recognition. The first step in the enzymatic reaction involves the removal of a hydrogen from the central carbon of a pentadiene present in the substrate. It is …

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 …

Topological Dynamics On Compact Phase Spaces, Lieth Abdalateef Majed

LSU Doctoral Dissertations

Our main focus will be to investigate the various facets of what are commonly called dynamical systems or flows, which are triples $(S,X,\pi)$, where $X$ is a compact Hausdorff space and $\pi:S \times X \longrightarrow X$ is a separately continuous action of a semigroup $S$ on $X$. Historically, as was introduced by R.Ellis 1960, the enveloping semigroup, which is a closure of the set of continuous functions on a compact space $X$, was discovered to be an important tool to study dynamical systems. Soon, a realization of the existence of a universal compactification of a phase semigroup with an extended …

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 …

Optimal Location Of Biomethane Gas Manufacturing Plants And Allocation Of Feedstock And Liquified Carbon Product, Bingqing Wu

LSU Doctoral Dissertations

Biomethane gas (BMG), known for its sustainability, low environmental impact, and high profitability, has received wide attention in recent years. To facilitate the process of making strategic plans for building a BMG production system, this dissertation leverages the mathematical modeling and optimization techniques to minimize the supply chain cost for such a system. Typical elements in a BMG production system consist of the local farms that produce the feedstock, the hubs that collect and store the feedstock produced by farms, the reactors that generate BMG from the feedstock transported from the hubs, the condensers that liquefy the BMG from the …

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 …

Partial Cosine-Funk Transforms At Poles Of The Cosine-Λ Transform On Grassmann Manifolds, Christopher Adam Cross

LSU Doctoral Dissertations

The cosine-λ transform, denoted C^λ, is a family of integral transforms we can define on the sphere and on the Grassmannian manifolds of p-dimensional subspaces in Kⁿ where K is R, C or the skew field H of quaternions. We treat the Grassmannians as the symmetric spaces SO(n)/S(O(p) × O(q)), SU(n)/S(U(p) × U(q)) and Sp(n)/(Sp(p) × Sp(q)) and we work by analogy with the case of the cosine-λ transform on the sphere, which is also a symmetric space.

The family C^λ extends meromorphically in λ to the complex plane with poles at (among other values) λ …

Constructive Aspects Of Kochen's Theorem On P-Adic Closures, Evan Michael Eakins

LSU Doctoral Dissertations

In this work we begin with a brief survey of set theory and arithmetic to provide background for a logical procedure to `cleanse' the Axiom of Choice from a proof of a theorem of Kochen's. We accomplish this in the following chapters. We then discuss certain theorems involving definable Skolem functions. These theorems are used in Chapter 5 to give a construction of a p-adic closure of a p-valued field. Certain further considerations and open questions are addressed in the _x000C_final chapter.

Microfluidic And Nanofluidic Devices - Mixed Scale Systems For Bioanalytical Applications, Michael David Vincent

LSU Doctoral Dissertations

Developments in the field of microfluidics and nanofluidics allow an experimenter to employ new analytical techniques. One direction in which the field is moving towards is developing new devices and or instruments on the smallest scale possible. One way in which this can be achieved is by using a combination of top-down and bottom-up technologies. Some of these top-down techniques have been used in other fields such as the use of photolithography to fabricate semiconductors. Photolithography is a top-down method used to create features normally on the micrometer scale, but in order to create nanometer size features another top-down method …

Educational Aspirations Of Middle And High School Students : A Focus On Turkish - American Youth, Dilek Atmaca Suslu

LSU Doctoral Dissertations

The purpose of this mixed -methods study was to investigate the educational aspirations of Turkish-American middle and high school students. For comparison purposes students from other ethnic groups were also included in the study. Factors related to family, school and the individual student were examined through survey data and interviews. In addition, possible barriers to educational goals, preferred area of study, and perceived parent support were explored. Interview with Turkish-American parents revealed types of parental supports and insights about their understanding of children’s experiences and performance. The results of the ordinal regression analyses revealed that parents’ expectations and school achievement …

Robotics And Inquiry: Addressing The Impact On Student Understanding Of Physics Concepts (Force And Motion) From Select Rural Louisiana Elementary Students Through Robotics Instruction Immersed Within The 5e Learning Cycle Model, Bianca Rodrigue Deliberto

LSU Doctoral Dissertations

This embedded mixed methods study investigates the development of rural elementary students’ conceptual understanding of force and motion as a result of the implementation of robotics instruction immersed within a 5E Learning Cycle Model lessons. Three treatment groups and one controlled comparison group (n=96) participated in pretests and posttests (Science Series Assessment 1, Russell and McGuigan, 2001) the day the activities were completed as well as one week after the completion of the treatment, 5E Learning Cycle Model lessons and draw and tell interviews. Prior to the intervention, the Iowa Test of Basic Skills stanine scores were grouped into three …

Parallel Processes In Hpx: Designing An Infrastructure For Adaptive Resource Management, Vinay Chandra Amatya

LSU Doctoral Dissertations

Advancement in cutting edge technologies have enabled better energy efficiency as well as scaling computational power for the latest High Performance Computing(HPC) systems. However, complexity, due to hybrid architectures as well as emerging classes of applications, have shown poor computational scalability using conventional execution models. Thus alternative means of computation, that addresses the bottlenecks in computation, is warranted. More precisely, dynamic adaptive resource management feature, both from systems as well as application's perspective, is essential for better computational scalability and efficiency. This research presents and expands the notion of Parallel Processes as a placeholder for procedure definitions, targeted at one …

Reformulations For Control Systems And Optimization Problems With Impulses, Jacob Blanton

LSU Doctoral Dissertations

This dissertation studies two different techniques for analyzing control systems whose dynamics include impulses, or more specifically, are measure-driven. In such systems, the state trajectories will have discontinuities corresponding to the atoms of the Borel measure driving the dynamics, and these discontinuities require further definition in order for the control system to be treated with the broad range of results available to non-impulsive systems. Both techniques considered involve a reparameterization of the system variables including state, time, and controls. The first method is that of the graph completion, which provides an explicit reparameterization of the time and state variables. The …

The Gaussian Radon Transform For Banach Spaces, Irina Holmes

LSU Doctoral Dissertations

The classical Radon transform can be thought of as a way to obtain the density of an n-dimensional object from its (n-1)-dimensional sections in diff_x001B_erent directions. A generalization of this transform to infi_x001C_nite-dimensional spaces has the potential to allow one to obtain a function de_x001C_fined on an infi_x001C_nite-dimensional space from its conditional expectations. We work within a standard framework in in_x001C_finite-dimensional analysis, that of abstract Wiener spaces, developed by L. Gross. The main obstacle in infinite dimensions is the absence of a useful version of Lebesgue measure. To overcome this, we work with Gaussian measures. Specifically, we construct Gaussian measures …

Meso-Scale Analysis Of Deformation Induced Heating In Granular Metalized Explosives By Piston Supported Waves, Sunada Srinath Nagamani Chakravarthy

LSU Doctoral Dissertations

Shock sensitivity of heterogeneous explosive composites is dependent on the formation of hot-spots which are small regions of elevated temperatures within the material. Changes in the initial meso-structure (i.e. packing density, composition, particle size and shapes) of the explosives can significantly alter the hot-spot fields in the material and thereby affect its shock sensitivity. In this study, an explicit, 2D, Lagrangian finite and discrete element technique is used to numerically simulate the deformation induced heating of granular mixtures of explosive (HMX), and metal (Al) particles due to piston supported uniaxial deformation waves (400 ≤ Up ≤ 800 m/s). A number …

The Impact Of A Freshmen-Year Seminar On Students' Second-Year Retention, Lori Henry Richard

LSU Doctoral Dissertations

This study investigated the impact a freshman-year seminar course, UNIV 101, had on students’ second-year retention. Retention was determined based on a student’s subsequent enrollment at the university, one year after their initial semester. In addition, this study explored the relationship between selected independent variables found in literature and second-year retention. Finally, the study sought to determine if selected variables, completion of UNIV 101, and final letter grade earned by students in UNIV 101 was able to predict the probability of retention. The target population for this study was all first-time freshmen enrolled in a small, public, regional institution in …

Spectrum Sensing, Spectrum Monitoring, And Security In Cognitive Radios, Erfan Soltanmohammadi

LSU Doctoral Dissertations

Spectrum sensing is a key function of cognitive radios and is used to determine whether a primary user is present in the channel or not. In this dissertation, we formulate and solve the generalized likelihood ratio test (GLRT) for spectrum sensing when both primary user transmitter and the secondary user receiver are equipped with multiple antennas. We do not assume any prior information about the channel statistics or the primary user’s signal structure. Two cases are considered when the secondary user is aware of the energy of the noise and when it is not. The final test statistics derived from …

Methods For The Characterization Of Deep-Sea Benthic Megafauna In The Vicinity Of The Deepwater Horizon Macondo Well, Stephanie Marie Sharuga

LSU Doctoral Dissertations

Soft-sediment benthic environments are amongst the largest marine ecosystems in the world and play important roles in many ecosystem functions. In recent years, exploitation of resources and unintentional impacts on deep-sea benthic environments has increased. The Deepwater Horizon oil spill of 2010 in the northern Gulf of Mexico (GoM) represented a prime example of this. The oil spill not only highlighted deficiencies of data and information on baseline conditions, but also represented an opportunity to learn more and develop better methods for the future. Deep-sea imaging platforms such as autonomous underwater vehicles (AUVs) and remotely operated vehicles (ROVs) have been …

Synthesis, Characterization, And Investigation Of The Catalytic Activity Of Nio, Cuo, And Nio-Cuo Nanoparticles On Silica As Surrogates Of Combustion-Generated Nanoparticles, Nuwan Nilanka Balapitiya Liyanage

LSU Doctoral Dissertations

Transition metal oxide nanoparticles contained in fly ash are known to catalyze the formation of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) during the waste incineration process. The potential catalytic activity of silica-supported NiO, CuO, and NiO-CuO nanoparticles for the formation of PCDD/Fs will be discussed in this dissertation. The successful synthesis of silica-supported NiO, CuO, and NiO-CuO nanoparticles as surrogates of combustion-generated nanoparticles was important to this study. The synthesis was followed by the characterization of the nanoparticle surrogates by X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDS). Finally, the catalytic …

Phytoplankton Response To South Louisiana Crude Oil Exposure: Determining Impacts At Individual, Community, Toxin Production, Enzymatic-Activity And Gene-Expression Levels, Koray Ozhan

LSU Doctoral Dissertations

The Deepwater Horizon oil spill in the Gulf of Mexico (GoM) raised an important question. What is the ecological impact of the oil, the dispersant, and the dispersed oil to the GoM ecosystem? Significant and varying research efforts have contributed answers to this question. However, to better understand the complete ecological consequences of the spill in the GoM, the impact of the spill at the base of marine food web should be examined. This research aims to understand impact of the spilled oil, South Louisiana crude oil (LSC), the chemical dispersant, Corexit® EC9500A, and the dispersed oil on phytoplankton communities …

Vocal Fold Analysis From High Speed Videoendoscopic Data, Jing Chen

LSU Doctoral Dissertations

High speed videoendoscopy (HSV) of the larynx far surpasses the limits of videostroboscopy in evaluating the vocal fold vibratory behavior by providing much higher frame rate. HSV enables the visualization of vocal fold vibratory pattern within an actual glottic cycle. This very detailed infor-mation on vocal fold vibratory characteristics could provide valuable information for the assessment of vocal fold vibratory function in disordered voices and the treatments effects of the behavioral, medical and surgical treatment procedures. In this work, we aim at addressing the problem of classi-fying voice disorders with varying etiology by following four steps described shortly. Our method-ology …