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A Numerical Investigation Of Sediment Dynamics In The Northern Gulf Of Mexico In Connection With Hurricanes, Fluid Mud, Climate Change, And Biogeochemical Cycling, Zhengchen Zang

LSU Doctoral Dissertations

Sediment transport and deposition in marginal seas is jointly controlled by many factors including hydrodynamics, fluvial inputs, and the characteristics of sediment particles. This dissertation study employs the coupled ocean-atmosphere-wave-and-sediment transport modeling system (COAWST) to investigate the mechanism of sediment transport in the northern Gulf of Mexico (nGoM) on different temporal scales, as well as its interaction with biogeochemical processes.

First of all, a three-way coupled (atmosphere-wave-ocean) hurricane model reproduced the hydro- and sediment dynamics during hurricane Gustav (2008). Intensive alongshore and offshore currents were simulated on the eastern/western sectors of hurricane track, respectively. High suspended sediment concentration (SSC) was …

Silica And Siloxane Model Systems, Bruno Jakobi

LSU Doctoral Dissertations

This dissertation focuses on the development and synthesis of model system for the investigation of the morphology, interactions, and dynamics in linear and branched polymers and polymer nanocomposites. The materials are designed to reduce the number of uncontrolled parameters and to be ideally suitable for neutron scattering studies. Hereby, two main objectives are defined:

The first project is to develop model nanocomposites based on the grafting of poly(dimethylsiloxane) (PDMS) to primary particles and well-defined aggregates. For that purpose, the functionalization of silica nanoparticles with a chlorosilane and the influence of moisture on the reaction was studied. Higher grafting densities than …

Pyrenylpyridines: Sky-Blue Emitters For Organic Light-Emitting Diodes, Thenahandi Prasanthi Deepthika De Silva, Sang Gill Youm, Isiah M. Warner

Faculty Publications

A novel sky-blue-emitting tripyrenylpyridine derivative, 2,4,6-tri(1-pyrenyl)-pyridine (2,4,6-TPP), has been synthesized using a Suzuki coupling reaction and compared with three previously reported isomeric dipyrenylpyridine (DPP) analogues (2,4-di(1 pyrenyl)pyridine (2,4-DPP), 2,6-di(1-pyrenyl)pyridine (2,6-DPP), and 3,5-di(1-pyrenyl)-pyridine (3,5-DPP)). 0 revealed by single-crystal X-ray analysis and computational simulations, all compounds possess highly twisted conformations in the solid state with interpyrene torsional angles of 42.3 degrees-57.2 degrees. These solid-state conformations and packing variations of pyrenylpyridines could be correlated to observed variations in physical characteristics such as photo/thermal stability and spectral properties, but showed only marginal influence on electrochemical properties. The novel derivative, 2,4,6-TPP, exhibited the lowest degree …

Short- And Intermediate-Range Structure And Dynamics Of Fe-Ni-C Liquid Under Compression, Jianwei Wang

Faculty Publications

Properties of liquid Fe alloys under high-pressure conditions are crucial for understanding the composition, thermal state, and dynamics of Earth's core. Experiments on such liquids, however, are often performed under pressures far below those of the outer core, necessitating long extrapolations of experimental results to core conditions. Such estimates can be complicated by light elements possibly forming pressure-dependent molecular clusters that can significantly affect the physical properties of liquids as core conditions are approached. First-principles molecular dynamics simulations were employed to compute the properties of an Fe-Ni-C liquid with a composition of Fe3.7Ni0.37C at 1673 K and pressures from 0 …

Short- And Intermediate-Range Structure And Dynamics Of Fe-Ni-C Liquid Under Compression, Jianwei Wang

Faculty Publications

Properties of liquid Fe alloys under high-pressure conditions are crucial for understanding the composition, thermal state, and dynamics of Earth's core. Experiments on such liquids, however, are often performed under pressures far below those of the outer core, necessitating long extrapolations of experimental results to core conditions. Such estimates can be complicated by light elements possibly forming pressure-dependent molecular clusters that can significantly affect the physical properties of liquids as core conditions are approached. First-principles molecular dynamics simulations were employed to compute the properties of an Fe-Ni-C liquid with a composition of Fe3.7Ni0.37C at 1673 K and pressures from 0 …

Turn-On Near-Infrared Fluorescent Sensors For Selective Monitoring Of Kinase Activity, Gerard Thomas Ducharme

LSU Doctoral Dissertations

Reliable and selective detection of specific biopolymers is critical in a broad range of biomedical and technological areas, including availability of simple and efficient point-of-care-compatible systems for the detection of prognostic, pharmacodynamic and predictive biomarkers. Monitoring epidermal growth factor receptor (EGFR) tyrosine kinase is of major significance due to its link to many epithelial cancers. This task is complicated by the high rate of mutation occurring in patients treated with kinase inhibitors. This dissertation describes a conceptually novel design and synthesis of turn-on near-infrared fluorescent sensors for selective and sensitive detection of EGFR. The fluorescent signal generation mechanism is based …

Age And Growth Of Hardhead Catfish And Gafftopsail Catfish In Coastal Louisiana, Usa, Shane Flinn, Stephen Midway

Faculty Publications

The Hardhead Catfish Ariopsis felis and Gafftopsail Catfish Bagre marinus are marine catfishes that have low recreational and commercial landings in U.S. waters, although they are among the most abundant species in coastal waters of the Gulf of Mexico. Few biological studies exist on marine catfishes, with most studies focusing on their unique reproductive biology. This study evaluated weight-length relationships for Gafftopsail Catfish (n = 264) and Hardhead Catfish (n = 823) sampled from across coastal Louisiana, USA, during 2016-2018; subsamples (93 and 266, respectively) were aged using lapilli for age and growth analyses. Hardhead Catfish showed a small but …

Lsu Research Fall 2019, Louisiana State University And Agricultural And Mechanical College

Research Magazine

LSU Research is published annually by the Office of Research & Economic Development, Louisiana State University.

Fecundity Of The Parental And Fitness Of The F1 Populations Of Corn Earworm From Refuge Ears Of Seed Blend Plantings With Genuity® Smartstax™ Maize, Jianguo Guo, Fei Yang, Sebe Brown, David Kern, Graham P. Head, Paula A. Price, Ying Niu, Fangneng Huang

Faculty Publications

Seed blend, also called ‘refuge-in-the-bag (RIB)’, has been used as a refuge strategy to generate susceptible insect populations for Bt maize resistance management in the U.S. Corn Belt. A major concern related to the use of RIB is the cross-pollination of maize plants that cause Bt protein expression in the kernels of refuge ears. Bt protein expression in the refuge ears can negatively affect the insect populations on refuge plants, especially for ear feeders such as the corn earworm, Helicoverpa zea (Boddie). The current study investigated the reproduction of three populations of H. zea collected from a pure stand of …

Nature Of The Crust In The Northern Gulf Of California And Salton Trough, Patricia Persaud

Faculty Publications

In the southern Gulf of California, the generation of new oceanic crust has resulted in linear magnetic anomalies and seafloor bathymetry that are characteristic of active seafloor-spreading systems. In the northern Gulf of California and the onshore (southeastern California, USA) Salton Trough region, a thick sedimentary package overlies the crystalline crust, masking its nature, and linear magnetic anomalies are absent. We use potential-field data and a geotherm analysis to constrain the composition of the crust (oceanic or continental) and develop a conceptual model for rifting. Gravity anomalies in the northern Gulf of California and Salton Trough are best fit with …

A Geometric Analogue Of A Conjecture Of Gross And Reeder, Masoud Kamgarpour, Daniel S. Sage

Faculty Publications

Let G be a simple complex algebraic group. We prove that the irregularity of the adjoint connection of an irregular flat G-bundle on the formal punctured disk is always greater than or equal to the rank of G. This can be considered as a geometric analogue of a conjecture of Gross and Reeder. We will also show that the irregular connections with minimum adjoint irregularity are precisely the (formal) Frenkel-Gross connections. As a corollary, we establish the de Rham analogue of a conjecture of Heinloth, Nĝo, and Yun for G = SLn.

Higher Gauss Sums Of Modular Categories, Siu Hung Ng, Andrew Schopieray, Yilong Wang

Faculty Publications

The definitions of the nth Gauss sum and the associated nth central charge are introduced for premodular categories C and n∈ Z. We first derive an expression of the nth Gauss sum of a modular category C, for any integer n coprime to the order of the T-matrix of C, in terms of the first Gauss sum, the global dimension, the twist and their Galois conjugates. As a consequence, we show for these n, the higher Gauss sums are d-numbers and the associated central charges are roots of unity. In particular, if C is the Drinfeld center of a spherical …

Overview: Additive Manufacturing Enabled Accelerated Design Of Ni-Based Alloys For Improved Fatigue Life, S. Shao, M. M. Khonsari, S. Guo, W. J. Meng, N. Li

Faculty Publications

An in-depth overview on an emerging area of the additive-manufacturing-enabled, accelerated design of Ni-based alloys for improved high-cycle and very-high-cycle fatigue life is presented. Existing literature on the subject is critically reviewed, and key knowledge gaps are identified. An efficient life-cycle approach, integrating the model-make-measure-verify strategy in the design of these alloys is introduced and discussed.

Measurement Of The Muon Neutrino Charged-Current Cross Sections On Water, Hydrocarbon And Iron, And Their Ratios, With The T2k On-Axis Detectors, K. Abe, R. Akutsu, A. Ali, C. Andreopoulos, L. Anthony, M. Antonova, S. Aoki, A. Ariga, Y. Ashida, Y. Awataguchi, Y. Azuma, S. Ban, M. Barbi, G. J. Barker, G. Barr, C. Barry, M. Batkiewicz-Kwasniak, F. Bench, V. Berardi, S. Berkman, R. M. Berner, L. Berns, S. Bhadra, S. Bienstock, A. Blondel, S. Bolognesi, B. Bourguille, S. B. Boyd

Faculty Publications

We report a measurement of the flux-integrated νμ charged-current cross sections on water, hydrocarbon, and iron in the T2K on-axis neutrino beam with a mean neutrino energy of 1.5 GeV. The measured cross sections on water, hydrocarbon, and iron are σH2oCC = (0.840±0.010(stat.)+0.10-0.08(syst.)) ×10-38 cm2/nucleon, σCHCC = (0.817±0.007(stat.)+0.11-0.08(syst.)) × 10-38 cm2/nucleon, and σFeCC = (0.859±0.003(stat.)^+0.12-0.10(syst.)) ×10-38 cm2/nucleon, respectively, for a restricted phase space of induced muons: θμ < 45° and pμ > 0.4 GeV/c in the laboratory frame. The measured cross section ratios are σH2oCC/σCHCC = 1.028±0.016(stat.)±0.053(syst.), σFeCC/σH2oCC = 1.023±0.012(stat.)±0.058(syst.), and σFeCC/σCHCC = 1.049±0.010(stat.)±0.043(syst.). These results, with an unprecedented precision for the measurements of neutrino …

Coupled Landscape And Channel Dynamics Across The Ganges-Brahmaputra Tidal-Fluvial Continuum, Southwest Bangladesh, Edwin Jefferson Bomer Iv

LSU Doctoral Dissertations

The Ganges-Brahmaputra (G-B) Delta of Bangladesh and India is widely considered to be one of the most vulnerable coastal systems in the world, owing to locally-accelerated sea level rise and landscape modification by human activities. Recent research efforts have identified pronounced elevation differences between natural and embanked areas in the G-B tidal delta plain, suggesting that natural landscapes are keeping pace with sea-level rise while anthropogenic locations are actively subsiding. However, this observation represents a singular point in time, and longitudinal trends of surface elevation in these regions are presently unknown. For communities residing in upstream regions of G-B delta …

Modeling Agrilus Planipennis F. (Coleoptera: Buprestidae) Spread In New Jersey, Erik Lyttek, Pankaj Lal, Garrett Nieddu, Eric Forgoston, Taylor Wieczerak, Timothy Schowalter

Faculty Publications

Pests and disease have become an increasingly common issue as globalized trade brings non-native species into unfamiliar systems. Emerald ash borer (Agrilus planipennis), is an Asiatic species of boring beetle currently devastating the native population of ash (Fraxinus) trees in the northern forests of the United States, with 85 million trees having already succumbed across much of the Midwest. We have developed a reaction-diffusion partial differential equation model to predict the spread of emerald ash borer over a heterogeneous 2-D landscape, with the initial ash tree distribution given by data from the Forest Inventory and Analysis. As expected, the model …

Deprogramming Deficit: A Narrative Of A Developing Black Critical Stem Education Researcher, Monica L. Ridgeway

Taboo: The Journal of Culture and Education

No abstract provided.

So, You Want To Attract And Retain Diverse Faculty???: An Autoethnography, Melva R. Grant

Taboo: The Journal of Culture and Education

No abstract provided.

Don’T Wanna Teach No White Children: The Journey Into My Pedagogy, Fran Bates Oates

Taboo: The Journal of Culture and Education

No abstract provided.

Overcoming Imposter Syndrome And Stereotype Threat: Reconceptualizing The Definition Of A Scholar, Callie Womble Edwards

Taboo: The Journal of Culture and Education

No abstract provided.

Supercritical Co2 Foam Enhanced Oil Recovery: From Mechanistic Model Fit To Lab Experiments To Field-Scale Evaluation, Mohammad Izadi

LSU Doctoral Dissertations

This study investigates how a mechanistic foam modeling approach based on bubble population balance is applied to a series of laboratory experimental data of a supercritical CO₂ foam in reservoir conditions to extract model parameters (topic 1). The model with model parameters determined from the fit is then used to estimate how far fine-textured strong foam can propagate into the reservoir, before turning into coarse-textured weak foam and before being segregated by gravity (topic 2). With the help of mechanistic model, a possible range of gas mobility for supercritical CO₂ foam is calculated and the resulting gas-phase mobility …

Genericness Of Pre-Inflationary Dynamics And Probability Of The Desired Slow-Roll Inflation In Modified Loop Quantum Cosmologies, Bao Fei Li, Parampreet Singh, Anzhong Wang

Faculty Publications

We study the evolution of a spatially flat Friedmann-Lemaître-Robertson-Walker universe for chaotic and Starobinsky potentials in the framework of modified loop quantum cosmologies. These models result in a nonsingular bounce as in loop quantum cosmology, but with far more complex modified Friedmann dynamics with higher order than quadratic terms in the energy density. For the kinetic-energy-dominated bounce, we obtain analytical solutions using different approximations and compare with numerical evolution for various physical variables. The relative error turns out to be less than 0.3% in the bounce regime for both of the potentials. The generic features of the dynamics - shared …

Search For Heavy Neutrinos With The T2k Near Detector Nd280, K. Abe, R. Akutsu, A. Ali, C. Andreopoulos, L. Anthony, M. Antonova, S. Aoki, A. Ariga, Y. Ashida, Y. Awataguchi, Y. Azuma, S. Ban, M. Barbi, G. J. Barker, G. Barr, C. Barry, M. Batkiewicz-Kwasniak, F. Bench, V. Berardi, S. Berkman, R. M. Berner, L. Berns, S. Bhadra, S. Bienstock, A. Blondel, S. Bolognesi, B. Bourguille, S. B. Boyd

Faculty Publications

This paper reports on the search for heavy neutrinos with masses in the range 140

Quantum Rebound Capacity, Siddhartha Das, Mark M. Wilde

Faculty Publications

Inspired by the power of abstraction in information theory, we consider quantum rebound protocols as a way of providing a unifying perspective to deal with several information-processing tasks related to and extending quantum channel discrimination to the Shannon-theoretic regime. Such protocols, defined in the most general quantum-physical way possible, have been considered in the physical context of the Das-Wilde (DW) model of quantum reading [arXiv:1703.03706]. In [arXiv:1901.05895], it was discussed how such protocols apply in the different physical context of round-trip communication from one party to another and back. The common point for all quantum rebound tasks is that the …

Sequence-Defined Ionic Peptoid Block Copolymers: Synthesis And Solution Self-Assembly, Garrett Leigh Sternhagen

LSU Doctoral Dissertations

This work covers efforts to develop a peptoid-based model system for systematically studying the role of ionic functional groups in determining the structure of ionic block copolymer (BCP) self-assemblies in water. A key challenge in the study of polyelectrolytes is the lack of synthetic control over the location of ionic monomers along a polymer chain. We developed a model system based on sequence-defined ionic peptoid BCPs having discrete chain length and precisely positioned ionic monomers along the chain to specifically address this issue. In Chapter 1, synthetic strategies to access well-defined polypeptoids and their application in BCP synthesis are reviewed. …

Search For The Isotropic Stochastic Background Using Data From Advanced Ligo's Second Observing Run, B. P. Abbott, R. Abbott, T. D. Abbott, S. Abraham, F. Acernese, K. Ackley, C. Adams, V. B. Adya, C. Affeldt, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, G. Allen, A. Allocca, M. A. Aloy, P. A. Altin, A. Amato, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. V. Angelova, S. Antier, S. Appert, K. Arai, M. C. Araya, J. S. Areeda, M. Arène, N. Arnaud, K. G. Arun

Faculty Publications

The stochastic gravitational-wave background is a superposition of sources that are either too weak or too numerous to detect individually. In this study, we present the results from a cross-correlation analysis on data from Advanced LIGO's second observing run (O2), which we combine with the results of the first observing run (O1). We do not find evidence for a stochastic background, so we place upper limits on the normalized energy density in gravitational waves at the 95% credible level of ωGW<6.0×10-8 for a frequency-independent (flat) background and ωGW<4.8×10-8 at 25 Hz for a background of compact binary coalescences. The upper limit improves over the O1 result by a factor of 2.8. Additionally, we place upper limits on the energy density in an isotropic background of scalar- and vector-polarized gravitational waves, and we discuss the implication of these results for models of compact binaries and cosmic string backgrounds. Finally, we present a conservative estimate of the correlated broadband noise due to the magnetic Schumann resonances in O2, based on magnetometer measurements at both the LIGO Hanford and LIGO Livingston observatories. We find that correlated noise is well below the O2 sensitivity.

Effect Of Surfactant, Oil:Water Ratio And Temperature On The Rheology Of Emulsion-Suspension Complex Fluids: Implications For Oil-Based Drilling Fluids, Gilles Landry Numkam

LSU Doctoral Dissertations

Drilling fluids are non-Newtonian mixtures that play a critical role in the timely and successful completion of oil and gas wells. In the particular case of offshore operations, proper design of drilling fluids is of paramount importance in the constant quest to lower break-even prices. Most downhole problems are directly or in-directly related to the rheological and physical properties of drilling fluids, thereby calling for a better understanding of the underlying changes of these properties with respect to drilling fluid composition and external conditions.

The current stance in the design of drilling fluids involves the selection of components and their …

Symmetries And Canonical Transformations In Nuclei, David Kekejian, Jerry P. Draayer, Kristina D. Launey

Faculty Publications

We begin with a brief historical overview of the importance of special symmetries in atomic nuclei, especially the symplectic symmetry. We then show how deforming the symplectic algebra through canonical transformations that are unitary can be used to describe the same physics that in a non-deformed picture requires huge model spaces in far smaller deformed spaces, a simplification that should proportionally reduce the complexity of using the symplectic symmetry in applications. The overarching objective is to exploit this strategy to probe more deeply into the (ab initio) structure of nuclei, short cutting a need to await the development of evermore …

Intelligent Identification For Rock-Mineral Microscopic Images Using Ensemble Machine Learning Algorithms, Jonathan Shi

Faculty Publications

It is significant to identify rock-mineral microscopic images in geological engineering. The task of microscopic mineral image identification, which is often conducted in the lab, is tedious and time-consuming. Deep learning and convolutional neural networks (CNNs) provide a method to analyze mineral microscopic images efficiently and smartly. In this research, the transfer learning model of mineral microscopic images is established based on Inception-v3 architecture. The four mineral image features, including K-feldspar (Kf), perthite (Pe), plagioclase (Pl), and quartz (Qz or Q), are extracted using Inception-v3. Based on the features, the machine learning methods, logistic regression (LR), support vector machine (SVM), …

The Tensile Root Strength Of Spartina Patens Varies With Soil Texture And Atrazine Concentration, Lauris O. Hollis, R. Eugene Turner

Faculty Publications

The widely used agricultural herbicide atrazine enters wetlands and may potentially affect wetland plants that provide critical reinforcement of soil strength and contribute to ecosystem stability in ways that may vary among soil types. We conducted greenhouse experiments using four levels of atrazine doses and three different soil textures to test for differences between control and experimental treatments and interactive effects of soil texture and atrazine exposure by using the tensile root strength of the coastal wetland emergent macrophyte Spartina patens as the response variable. The tensile root strength of S. patens was not affected after 50days of atrazine exposure …