Digital Commons Network^™

Research Incentive Programs For Closures Of Public And Private Grade Crossings, Julius Codjoe

Publications

Vehicle-train crashes that occur at highway-rail crossings result in injuries, fatalities, and damage to equipment. In order to reduce the number of vehicle-train crashes, Federal Railroad Administration requires states which have challenges with crossing safety, including Louisiana, to develop a State Action Plan to improve grade crossing safety. Consequently, identification of specific solutions for improving safety at crossings was included in the 2015 Louisiana Transportation Plan as one of its objectives. This study seeks to identify and evaluate current and new incentive programs that encourage closure of at-grade railroad crossings to reduce the number of potential vehicle-train collision points, and …

High-Throughput Assessment Of A Novel, Thiol-Acrylate Hydrogel For Tumor Spheroid Synthesis In A Microfluidic Device, Nathan Daniel Kersker

LSU Master's Theses

The extracellular environment plays an important role in regulating cell behavior. The mechanical, structural, and compositional properties of the extracellular matrix can determine the fate of the growing cells. Standard two-dimensional culturing in a flask fails to represent a native cellular environment. To create the native environment suitable for cells, hydrogels were previously studied. One of the most extensively studied synthetic hydrogels was a poly(ethylene glycol diacrylate) (PEGDA) hydrogel. However, the need for UV polymerization may introduce unwanted changes in cell morphology and viability. The hydrogel being proposed was a form of a thiol-acrylate hydrogel that can eliminate this problem …

Systematic Quantum Cluster Typical Medium Method For The Study Of Localization In Strongly Disordered Electronic Systems, Hanna Terletska, Yi Zhang, Ka Ming Tam, Tom Berlijn, Liviu Chioncel, N. S. Vidhyadhiraja, Mark Jarrell

Faculty Publications

Great progress has been made in recent years towards understanding the properties of disordered electronic systems. In part, this is made possible by recent advances in quantum effective medium methods which enable the study of disorder and electron-electronic interactions on equal footing. They include dynamical mean-field theory and the Coherent Potential Approximation, and their cluster extension, the dynamical cluster approximation. Despite their successes, these methods do not enable the first-principles study of the strongly disordered regime, including the effects of electronic localization. The main focus of this review is the recently developed typical medium dynamical cluster approximation for disordered electronic …

Emergent Clustering Phenomena In The Framework Of The Ab Initio Symmetry-Adapted No-Core Shell Model, K. D. Launey, A. Mercenne, G. H. Sargsyan, H. Shows, R. B. Baker, M. E. Miora, T. Dytrych, J. P. Draayer

Faculty Publications

This article discusses the emergence - from first principles - of collectivity and clustering in light and intermediate-mass nuclei, up to the calcium region, with implications for reproducing enhanced E2 transitions in deformed nuclei, and for further understanding the formation of alpha clustering. Structure calculations use nucleon-nucleon chiral potentials and are based on the ab initio symmetry-adapted no-core shell model (SA-NCSM) that expands the reach of the no-core shell-model theory to heavier nuclei and enables the description of spatially enhanced nuclear configurations. This is achieved by using a physically relevant symmetry-adapted basis, which exploits approximate symmetries that, we find, dominate …

Speciation And Hybridization In Jamaican-Endemic Streamertail Hummingbirds (Trochilus Polytmus And T. Scitulus), Caroline D. Judy

LSU Doctoral Dissertations

Streamertails hummingbirds (Trochilus polytmus and T. scitulus) are recently diverged sister taxa that appear to have speciated in situ on the island of Jamaica. They are distinguished by male bill color, a secondary sexual trait that is coral red in T. polytmus and jet black in T. scitulus. They hybridize in a narrow zone where their ranges meet in eastern Jamaica. In Chapter 2, I performed a formal population survey of T. scitulus to determine the size of the population, which was unknown. I determined that the total population contains well over 100,000 individuals despite its limited …

Toward Building Resilient, Sustainable, And Smart Infrastructure In The 21st Century, Aly Mousaad Aly

Faculty Publications

In recent years, as a result of significant climate change, stringent windstorms are becoming more frequent than before. Given the threat that windstorms bring to people and property, wind/structural engineering research is imperative to improve the resilience of existing and new infrastructure, for community safety and assets protection. The Windstorm Impact, Science and Engineering (WISE) research program at Louisiana State University (LSU) focuses on creating new knowledge applicable to the mitigation of existing and new infrastructure, to survive and perform optimally under natural hazards. To achieve our research goals, we address two imperious challenges: (i) characterization of realistic wind forces …

Finite Time Estimation Through A Continuous-Discrete Observer, Frédéric Mazenc, Saeed Ahmed, Michael Malisoff

Faculty Publications

We study two broad classes of nonlinear time-varying continuous-time systems with outputs. For the first class, we build an observer in the case where a state dependent disturbance affects the linear approximation. When the disturbances are the zero functions, our observer provides exact values of the state at all times larger than a suitable finite time, and it provides an approximate estimate when there are nonzero disturbances, so our observers are called finite time observers. We use this construction, which is of interest for its own sake, to design a globally exponentially stabilizing dynamic output feedback for a family of …

The Effects Of Pressure And Magnetic Field On Phase Transitions And Related Physical Properties In Solid State Caloric Materials, Ahmad Ikhwan Us Saleheen

LSU Doctoral Dissertations

Solid-state caloric effects, such as the magnetocaloric (MCE) and barocaloric (BCE) effects, may be utilized in future cooling technologies that are more efficient and environment-friendly. Large caloric effects often occur near phase transitions, especially near coupled first-order magnetostructural transitions (MST), and are initiated by external parameters, such as magnetic field or hydrostatic pressure. In this dissertation, the effects of pressure, temperature, and magnetic field on the phase transitions in three material systems are studied in order to elucidate how the respective caloric effects are affected.

In the first study, the realization of a coupled MST in a MnNiSi-based system through …

Origin Of Localization In Ti-Doped Si, Yi Zhang, R. Nelson, K. M. Tam, W. Ku, U. Yu, N. S. Vidhyadhiraja, H. Terletska, J. Moreno, M. Jarrell, T. Berlijn

Faculty Publications

Intermediate band semiconductors hold the promise to significantly improve the efficiency of solar cells but only if the intermediate impurity band is metallic. We apply a recently developed first principles method to investigate the origin of electron localization in Ti doped Si, a promising candidate for intermediate band solar cells. We compute the critical Ti concentration and compare it against the available experimental data. Although Anderson localization is often overlooked in the context of intermediate band solar cells, our results show that in Ti doped Si it plays a more important role in the metal insulator transition than Mott localization. …

Identifying Structural Changes With Unsupervised Machine Learning Methods, Nicholas Walker, Ka Ming Tam, Brian Novak, M. Jarrell

Faculty Publications

Unsupervised machine learning methods are used to identify structural changes using the melting point transition in classical molecular dynamics simulations as an example application of the approach. Dimensionality reduction and clustering methods are applied to instantaneous radial distributions of atomic configurations from classical molecular dynamics simulations of metallic systems over a large temperature range. Principal component analysis is used to dramatically reduce the dimensionality of the feature space across the samples using an orthogonal linear transformation that preserves the statistical variance of the data under the condition that the new feature space is linearly independent. From there, k-means clustering is …

High Energy Grating Techniques, Leslie G. Butler, Kyungmin Ham, Warren W. Johnson

College of Science Patents

Imaging techniques that may be used in applications such as differential phase contrast imaging are disclosed that include, for example, configuring a beam source and a beam detector such that a beam connects the two, positioning an object, a phase grating and an analyzer grating in the beam path, producing multiple data sets based on various analyzer grating positions, and conducting a regression analysis using a predetermined function having a set of fitting coefficients to establish those fitting coefficients. In those techniques, the fitting coefficients may be used to characterize a set of interference properties associated with the object.

Disappearance Of Phragmites In Louisiana And Nipponaclerda Biwakoensis, Rachel Tugger

Honors Capstones

No abstract provided.

A Discrete Element Method Study Of Granular Self-Organization In An Orbital-Driven Sphere And Computational Fluid Dynamics Simulations Of Slurry Flow In A Single-Loop Loop Reactor, Spencer Blum

Honors Capstones

No abstract provided.

Stress Fluctuation, Crack Renucleation And Toughening In Layered Materials, C. J. Hsueh, L. Avellar, B. Bourdin, G. Ravichandran, K. Bhattacharya

Faculty Publications

It has been established that contrast in the elastic properties can lead to enhancement of fracture toughness in heterogeneous materials. Focussing on layered materials as a model system, we show that this enhancement is a result of two distinct phenomena – first, fluctuations in stress leading to regions where the stress intensity at the crack is considerably smaller than that of the macroscopically applied value; and second, the lack of stress intensity when a crack is at a compliant to stiff interface thereby requiring renucleation. Using theoretical, computational and experimental methods, we study two geometries – a layered material and …

A Robust Solver For A Mixed Finite Element Method For The Cahn–Hilliard Equation, Susanne C. Brenner, Amanda E. Diegel, Li Yeng Sung

Faculty Publications

We develop a robust solver for a mixed finite element convex splitting scheme for the Cahn–Hilliard equation. The key ingredient of the solver is a preconditioned minimal residual algorithm (with a multigrid preconditioner) whose performance is independent of the spacial mesh size and the time step size for a given interfacial width parameter. The dependence on the interfacial width parameter is also mild.

Molecular Level Interactions And Transformations Of Natural Organic Matter Within The Environment, Benjamin J. Haywood

LSU Doctoral Dissertations

This work was done in order to deepen the understanding of interactions occurring during sorption of anthropogenic organic compounds and dissolved organic matter (DOM) onto soil. As well as the transformation DOM undergoes during the sorption process and the overall transformation OM undergoes in the environment. This was achieved through the use of a “bottom-up” synthetic investigation, “top-down” natural system study, and a combination of these approaches.

The “bottom-up” approach, discussed in Chapter 2, involved the synthesis of a modular multi-tiered engineered soil surrogate (ESS) designed to mimic OM and general trends identified in the literature that impacts sorption behavior. …

An Evaluation Of Modified Bed Load Sediment Transport Equations For Enhanced Sediment Transport Quantification In Steep Mountain Streams – Case Study Little Fountain Creek, Colorado Springs, Co., James Emerson Smith Iv

LSU Master's Theses

In mountainous regions, extreme floods occur every year, placing societies and infrastructures at risk. Communities rely on local, state, and federal agencies to emplace flood structures, perform flood risk assessments, and simulate catastrophic events. While, our ability to quantify and predict the movement of sediment in streams with low gradients is well developed (Bathurst, 1987), our ability to quantify and predict the movement of sediment along steep mountain streams (SMS) has not been developed to a similar degree (Yager, 2012; Schneider, 2016). To most effectively manage mountainous watersheds and understand the risk associated with flood events, scientists must better understand …

Current Caco3 Dissolution At The Seafloor Caused By Anthropogenic Co2, David Trossman

Faculty Publications

No abstract provided.

Analysis Of Fluvial Scroll Bar Development With Surface Wave Inversion: False River, Louisiana, Blake Odom

LSU Master's Theses

The development of ridge-and-swale scroll bar topography of meandering river point bars is not well understood. We hypothesize that scroll bars formed during lateral accretion by the landward migration of transverse bars. To explore this, we relate the scroll bar topography to the internal sedimentary structure. We acquire, invert, and interpolate three pseudo-2D shear wave velocity profiles in two regions of the False River point bar, a Mississippi river oxbow lake in Pointe Coupee Parish Louisiana. Prior studies provide electrical conductivity well logs and cores as well as SH seismic reflection images along the same seismic surveys. LiDAR elevation data …

From The River To The Gulf: An Investigation Of Biogeochemical Cycling In Wetland Soils And Coastal Shelf Sediments, Katie Bowes

LSU Master's Theses

Louisiana is home to 40% of the coastal wetlands in the lower 48 states, yet accounts for 80% of the coastal wetland loss in this region. This loss is attributed to decreased sediment supply, levee alteration, sea level rise, channelization, and subsidence. The levee system in Louisiana disconnected coastal wetlands from the main stem of the Mississippi River (MSR), reducing the amount of land-building sediment that reaches coastal wetlands. This disconnection also allows a greater percentage of river discharge, including agricultural contaminants and runoff, to flow into the northern Gulf of Mexico (NGOM).

The 2012 Coastal Master Plan proposed eight …

Search For Cp Violation In Neutrino And Antineutrino Oscillations By The T2k Experiment With 2.2×1021 Protons On Target, K. Abe, R. Akutsu, A. Ali, J. Amey, C. Andreopoulos, L. Anthony, M. Antonova, S. Aoki, A. Ariga, Y. Ashida, Y. Azuma, S. Ban, M. Barbi, G. J. Barker, G. Barr, C. Barry, M. Batkiewicz, 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

The T2K experiment measures muon neutrino disappearance and electron neutrino appearance in accelerator-produced neutrino and antineutrino beams. With an exposure of 14.7(7.6)×1020 protons on target in the neutrino (antineutrino) mode, 89 νe candidates and seven anti-νe candidates are observed, while 67.5 and 9.0 are expected for δCP=0 and normal mass ordering. The obtained 2σ confidence interval for the CP-violating phase, δCP, does not include the CP-conserving cases (δCP=0, π). The best-fit values of other parameters are sin2θ23=0.526-0.036+0.032 and Δm322=2.463-0.070+0.071×10-3 eV2/c4.

Economic Impacts Of Groundwater Salinity In Louisiana, Rajan Dhakal

LSU Master's Theses

In the United States, nearly 60 million acres of land is affected by water and soil salinity problems that pose a serious threat to the long-term economic and environmental viability of the agricultural sector. Understanding the economic impacts of soil salinity in agricultural lands is essential for planning farming practices in several salinity affected regions. This study presents a two-stage approach to assess the damage from salinity in two major aquifers in Louisiana. In the first stage, looking at the trend of rise in salt content within these aquifers, I predict the future level of salinity by assuming three different …

Hyperspectral Imaging For Characterizing Single Plasmonic Nanostructure And Single-Cell Analysis, Nishir Sanatkumar Mehta

LSU Master's Theses

Orientation of plasmonic nanostructures is an important feature in many nanoscale applications such as photovoltaics, catalyst, biosensors DNA interactions, protein detections, hotspot of surface-enhanced Raman spectroscopy (SERS), and fluorescence resonant energy transfer (FRET) experiments. Silver nanocubes with significant spectral signatures between 400-700 nm are observed in this experimental research. Whereas study of single cells will enable the analysis of cell-to-cell variations within a heterogeneous population. These variations are important for further analysis and understanding of disease propagation, drug development, stem cell differentiation, embryos development, and how cells respond to each other and their environment. Adipose-derived mesenchymal stem cells possess the …

Longitudinal Study Of The Attitudes And Behaviors Of Environmental Education Program Participants., Kasie R. Dugas

LSU Master's Theses

The goal of this longitudinal study was to measure the attitudes and behaviors of participants of the Marsh Maneuvers program over the course of the last 25 years. The goal of the Marsh Maneuvers program is to educate students into becoming environmentally literate adults. Environmental literacy is considered herein to be people possessing knowledge about and positive attitudes and behaviors towards the environment. Although students learn basic science and environmental knowledge in the classroom, true environmental literacy is believed to require more hands-on understanding of the material. To evaluate the effectiveness of the program, the following three objectives were completed. …

New Borehole Breakout Derived Stress Constraints And Their Implications For Stress Heterogeneity Near High Risk Fault Systems In The Santa Barbara Channel, Southern California, Edward Harris Pritchard

LSU Master's Theses

The Santa Barbara Channel represents the offshore portion of the Ventura Basin in Southern California. Ongoing transpression related to a regional left step in the San Andreas Fault has led to the formation of E-W trending en-echelon fault systems, with both north and south dips, which accommodate varying rates of localized shortening across the basin. Recent studies have suggested that faults within the northern region of the channel could be capable of a multisegment rupture and producing a M_w 7.7–8.1 tsunamigenic earthquake. However, dynamic rupture models producing these results have not accounted for stress heterogeneity, which is …

Purposeful Planning And Intentional Practice In Literacy Leadership: The Making Of An Urban Principal, Nakia Claudette Jackson Perkins

LSU Doctoral Dissertations

ABSTRACT

Audubon Elementary is an urban elementary school that is the setting for this proposed study. It is a high-achieving, high-performing school where achievement goals are always centered on literacy learning, especially within the context of accountability wherein faculty and school leadership acknowledge the importance that the school district has placed on standardized testing. Pre-K through fifth grades are housed at the school. In 2018, there are approximately 554 students who are guided by 65 faculty and staff members.

Participants were purposely selected based on both convenience and criteria sampling (Collins, Onwuegbuzie, & Jiao, 2007). Initially, six participants, or classroom …

Citizen Science In 4-H: Youth Volunteer Motivations, Participation, Retention And Scientific Literacy, Veronica Del Bianco

LSU Doctoral Dissertations

The primary purpose of this study was to examine the influence of volunteer motivation, participation, and citizen science project type on the retention and scientific literacy of 4-H youth volunteers ages 8-19 years participating in science projects. The conceptual model of participation in organized activities (OA) proposed by Bohnert, Fredericks and Randall (2010) was used as a framework for the variables included in the study categorizing them as predictors of participation, participation, program characteristics, or outcomes. A systematic review of volunteer motivations, retention, and scientific literacy in citizen science projects exposed that the literature contains silos of information published in …

Beam Theory For Classical And Quantum Nonlinear Optics---Exposing Classical And Quantum Correlations Of Transverse-Spatial Modes, Robert Nicholas Lanning

LSU Doctoral Dissertations

Optics is arguably the most important branch of physics that has ever been studied. It is not only an essential ingredient of many other branches of physics that we study, it governs how we see, how we measure, and how we communicate in the modern world. And as the world continues to change, so do our tools and resources. In a relatively short amount of time, we have progressed from rudimentary tools that shape the world around us, to tools that harness the fundamental laws of nature. Unsurprisingly, the laws of nature governing optics remain paramount. This is because many …

Unpacking The Double Bind: Exploring How The Intersection Of Race And Gender Shape The Undergraduate Experiences Of African American Women In Engineering, Anissa Guerin

LSU Doctoral Dissertations

This three-part qualitative study explored the factors that contribute to the success of African American female students’ persistence in engineering majors. This study also addressed obstacles African American female students face and overcome to persist in engineering majors. Examining African American women in engineering who persist would be an effective method to provide academic support and increase participation amongst this underrepresented group. In addition to exploring the challenges and barriers faced by African American women, this study also acknowledged the skills, perspectives and resources African American women bring to engineering and engineering education. Highlighting their distinctive contributions and attributes would …

Calculation Guided Rational Design And Synthesis Of Novel Cationic Fluorescent Meso–Pyridinium Bodipys For Bio-Imaging, Daniel J. Lamaster

LSU Doctoral Dissertations

Chapter 1 contains a brief overview of the history, synthesis, and properties of BODIPY dyes as well as that of the biomedical applications of bio-imaging and photodynamic therapy. Additionally, an overview of the theoretical framework of density functional theory and its time-dependent variant are provided. In Chapter 2, the effects of structural modification on the electronic structure and electron dynamics of cationic meso-(4-pyridyl)-BODIPYs were investigated. A library of 2,6-difunctionalized meso-(4-pyridyl)-BODIPYs bearing various electron-withdrawing substituents was designed and DFT calculations were used to model the redox properties, while TDDFT was used to determine the effects of functionalization on the excited …