Digital Commons Network^™

Optimized Multilayer Structures With Ultrabroadband Near-Perfect Absorption, Chenglong You, Corey T. Matyas, Yin Huang, Jonathan P. Dowling, Georgios Veronis

Faculty Publications

We present aperiodic multilayer structures with ultrabroadband near-perfect absorption in the visible and near-infrared wavelength range. We use a hybrid optimization algorithm coupled with the transfer-matrix method, to optimize both the material composition and the layer thicknesses of the aperiodic multilayer structures that are composed of infinite slabs of material above a semi-infinite substrate. In order to achieve ultrabroadband near-perfect absorption, we consider a broad range of materials including dielectrics, metals, and semiconductors. The optimization algorithms previously used to design ultrabroadband near-perfect absorbers only optimized the layer thicknesses of structures with fixed material composition. In contrast, we find that our …

Influence Of Metal Nuclearity And Physicochemical Properties Of Ceria On The Oxidation Of Carbon Monoxide, Linxi Wang, Shyam Deo, Kerry Dooley, Michael J. Janik, Robert M. Rioux

Faculty Publications

The redox properties of ceria make it suitable as a catalyst or support in oxidation reactions. Ceria-supported transition metal nanoparticles or isolated single atoms provide a metal-support interface that reduces the energy cost to remove interfacial oxygen atoms, providing active oxygen species that can participate in Mars van Krevelen oxidation processes. CO oxidation is a key probe reaction to test the reducibility of ceria-supported catalysts and is also practically important in the elimination of CO at relatively low temperatures in various applications. Preferential oxidation of CO (PROX) in excess H2 controls the CO concentration to ultra-low levels to prevent poisoning …

First & Second Cycles Final Report For: Educational And Workforce Development Through Creation Of Programs In Transportation To Generate Future Careers For Our Students In Navajo Nation Region, Gholam Ehteshami

Publications

Navajo Technical University (NTU) in New Mexico, has made a partnership with the Tran-SET regional center at Louisiana State University, LSU. We have provided learning and training the Native American students in transportation-related Industries to some of STEM students at NTU through these partnerships opportunities. The program was designed and supported by Native American students from high school to STEM undergraduate students. The program was implemented accordingly with four main components: (1). Selected eligible and interested Native American student to paid summer internships to the field and facilities of transportations industries and participate in research summer at LSU. (2). Directed …

Estuarine And Coastal Natural Hazards: An Introduction And Synthesis, Jay Veeramony, Chunyan Li, Alex Sheremet, Edward P. Myers, Meng Xia, Steve Mitchell

Faculty Publications

Two sessions were organized during the 2018 Fall AGU Meeting entitled, (1) Coastal Response to Extreme Events: Fidelity of Model Predictions of Surge, Inundation, and Morphodynamics and (2) Improved Observational and Modeling Skills to Understand the Hurricane and Winter Storm Induced Surge and Meteotsunami. The focus of these sessions was on examining the impact of natural disasters on estuarine and coastal regions worldwide, including the islands and mainland in the northwestern Atlantic and the northwestern Pacific. The key research interests are the investigations on the regional dynamics of storm surges, coastal inundations, waves, tides, currents, sea surface temperatures, storm inundations …

Towards Optimizing Quality Assurance Outcomes Of Knowledge-Based Radiation Therapy Treatment Plans Using Machine Learning, Phillip Douglas Hardenbergh Wall

LSU Doctoral Dissertations

Knowledge-based planning (KBP) techniques have been shown to provide improvements in plan quality, consistency, and efficiency for advanced radiation therapies such as volumetric modulated arc therapy (VMAT). While the potential clinical benefits of KBP methods are generally well known, comparatively less is understood regarding the impact of using these systems on resulting plan complexity and pre-treatment quality assurance (QA) measurements, especially for in-house KBP systems. Therefore, the overarching purpose of this work was to assess QA implications with using an in-house KBP system and explore data-driven methods for mitigating increased plan complexity and QA error rates without compromising dosimetric plan …

Impact Of Direct Fine Motor Intervention On Handwriting, Carlye Breuhl

LSU Master's Theses

Structured fine motor lessons consisting of regulated fine motor materials and feedback is documented in the literature as a strategy for strengthening fine motor skills (Hamilton & Liu, 2017). The purpose of the present study was to determine (1) the mean duration of child engagement with fine motor materials within the classroom during free play, and (2) if direct intervention with fine motor materials, which promote pinch and grip strength, would impact handwriting performance. Children were observed during free play, interacting with materials. The hypothesis suggested interacting with fine motor materials, specifically promoting pinch and grip strength, would result in …

Spontaneous Creation Of Circularly Polarized Photons In Chiral Astrophysical Systems, Adrian Del Rio, Nicolas Sanchis-Gual, Vassilios Mewes, Ivan Agullo, José A. Font, Jose Navarro-Salas

Faculty Publications

This work establishes a relation between chiral anomalies in curved spacetimes and the radiative content of the gravitational field. In particular, we show that a flux of circularly polarized gravitational waves triggers the spontaneous creation of photons with net circular polarization from the quantum vacuum. Using waveform catalogs, we identify precessing binary black holes as astrophysical configurations that emit such gravitational radiation and then solve the fully nonlinear Einstein's equations with numerical relativity to evaluate the net effect. The quantum amplitude for a merger is comparable to the Hawking emission rate of the final black hole and small to be …

Benthic Nitrogen Dynamics In Response To Deltaic Succession, Anthropogenic Fertilization And Hurricane Events In An Emerging Coastal Deltaic Floodplain Within The Mississippi River Delta Plain, Song Li

LSU Doctoral Dissertations

Increasing concentrations of nitrogenous fertilizer (NO₃^-) in rivers have potentially altered benthic nitrogen (N) cycling in coastal deltaic floodplains at the continental margins of major rivers. Here I evaluated the N removal capacity of a newly emergent coastal deltaic floodplain [Wax Lake Delta (WLD)] within the Mississippi River Delta Plain using continuous flow-through incubations. I investigated the response of benthic N dynamics in WLD to deltaic succession, anthropogenic fertilization and hurricane events. The estimated annual NO₃^- removal of 896 Mg N yr^-1 in WLD accounts for 10 to 27% of total NO₃^{- …}

Pyrene Pyrimidine Derivatives: Synthesis, Characterization And Applications, John Kihara Mathaga

LSU Master's Theses

In this thesis, development of new materials to the field of optoelectronics were studied. Optoelectronic devices based on organic semiconductors in order to replace their inorganic counterparts have been an increasing focus of research in recent decades. Organic light-emitting diodes (OLEDs) have gained commercial acceptance for their potential use in high-resolution displays and solid-state lighting. This general acceptance is despite the fact that organic electronic concepts (solar cells, transistors and detectors) are still in an early stage of development. OLEDs materials intrinsic advantages, like low power consumption as compared to LED counterparts, a tunable color range, ease of manufacturing, and …

Temporal And Spatial Trends Of Dead Copepods In The Northern Gulf Of Mexico In Relation To The Deepwater Horizon Oil Spill, Jessica L. Tolan

LSU Master's Theses

Zooplankton are a critical link between primary producers and higher trophic levels in the marine environment. They play a critical role in carbon cycling, are an important food source for commercially important species, and are excellent indicator genera for environmental changes that take place in marine ecosystems. This research quantified temporal and spatial patterns of dead copepods in response to the Deepwater Horizon Oil Spill (DWH) site using ZooSCAN imaging technologies. Research showed that the proportion of dead copepods (showed evidence of decay but no physical damage due to predation) increased with depth, and at time periods closest to the …

Effects Of And Preference For Fixed Ratio And Time-Based Exchange Production Schedules In A Token System, Sarah Christian Holmes

LSU Master's Theses

Token systems have been implemented to change behavior across species and settings. Token systems involve token-production, exchange-production, and token-exchange schedules. In the current study, we evaluated the effects of fixed-ratio and yoked time exchange-production schedules on 4 preschoolers’ rate of responding on a marble spooning task, mean pause duration between responses, and percentage of session spent engaging in the target task. Following an initial reversal demonstrating a primary reinforcement effect, we used a multielement design to compare exchange-production schedule conditions and a control condition in which participants earned tokens that were not exchangeable. Following the exchange-production schedule comparison, we examined …

Exploring Effects Of Background Music In A Serious Game On Attention By Means Of Eeg Signals In Children, Fettah Kiran

LSU Master's Theses

Music and Serious Games are separately useful alternative therapy methods for helping people with a cognitive disorder, including Attention Deficit Hyperactivity Disorder (ADHD). The goal of this thesis is to explore the effect of background music on children with and without ADHD. In this study, a simple Tetris game is designed with Beethoven, Mozart music, and no-music. There are different brainwave techniques for recording; among others, the electroencephalography (EEG) allows for the most efficient use of BCI. We recorded the EEG brain signals of the regular and ADHD subjects who played the Tetris we designed according to our protocol that …

Homeward Bound, Kyle Peruch

LSU Master's Theses

This paper explores agency and opposition as the underlining themes in the artworks of Homeward Bound. Both doctrines are important religious teachings that I have used to explore artistic ideas such as tension, balance and perspective. Each artwork displays a point of view on how I have confronted opposition in my lifetime. The sculptures are also meant to offer a sense of encouragement and hope to the viewer as they analyze each piece of art.

Reliability Analysis Of Concrete Gravity Dams Under Earthquake Loads, Anu Abraham

LSU Master's Theses

Dams are infrastructure assets of extreme importance; the failure of which can have catastrophic consequences on adjacent communities. Therefore, it is prudent for authorities to evaluate the safety of existing dams in seismically active regions. This thesis focuses on carrying out a reliability analysis of concrete gravity dams under earthquake loads using an enhanced finite element model. For many years, reliability studies on concrete gravity dams were performed using a finite element model that considered a massless foundation and assumed that water is incompressible. Moreover, the design ground motion was applied without any modification either at the bottom fixed boundary …

Study Of The Effect Of Heating - Cooling Cycles On The Clay - Concrete Pile Interface Characteristics, Abedalqader Ahmad Idries

LSU Master's Theses

This study aimed at investigating the effect of heating-cooling cycles on the interface strength parameters of clay soil-concrete for potential applications to improve the side capacity of piles driven in clayey soil by the heating process, and also to assess the behavior of geothermal piles regarding interface shear strength parameters. A modified large-size direct shear test device with the dimensions 12” x 12” x 8”, was used in this study. A concrete block (12” x 12” x 4”) of similar texture and smoothness to the concrete piles was used to simulate the pile interface. The tested clays are low plasticity …

An Investigation Of Athletic Buoyancy In Adult Recreational And Sport Club Athletes, Jackie Rae Victoriano Calhoun

LSU Doctoral Dissertations

Athletic buoyancy is the ability of an athlete to effectively handle the daily setbacks and challenges they face during training and competition. Although buoyancy has received ample research in the academic domain, a dearth of information exists regarding buoyancy in the athletic domain. Therefore, the overall purpose of this dissertation was to investigate athletic buoyancy’s independent contribution to sport psychology while also exploring antecedents and outcomes in adult athletes.

Study 1 compared athletic buoyancy to other cognate constructs, or similar constructs, to determine their conceptual boundaries. A one-time, online questionnaire was distributed to 294 recreational athletes (M age = …

Body Temperature And Cardiovascular Control During Exercise In The Heat: Implications For Special Populations And Athletic Performance, Haoyan Wang

LSU Doctoral Dissertations

Exercise in the heat increases the risk of dehydration and hyperthermia, subsequently impaired cardiovascular function and increased thermal stress. The purpose of this dissertation is to determine the fluid balance, cardiovascular function, thermoregulation, and cooling intervention during exercise in the heat. Four novel studies were conducted in this dissertation.

The first and second studies investigated the fluid balance during exercise in the heat across different sports with their special concerns. The first study conducted in female soccer, suggesting most players were in a hypohydration state after practice, and various fluid needs were exhibited by different positions, possibly associated with on-field …

Identification Of Top-Down, Bottom-Up, And Cement-Treated Reflective Cracks Using Convolutional Neural Network And Artificial Neural Network, Nirmal Dhakal

LSU Doctoral Dissertations

The objective of this study was to formulate a Convolutional Neural Networks (CNN) model and to develop a decision-making tool using Artificial Neural Networks (ANN) to identify top-down, bottom-up, and cement treated (CT) reflective cracking in in-service flexible pavements. The CNN’s architecture consisted of five convolutional layers with three max-pooling layers and three fully connected layers. Input variables for the ANN model were pavement age, asphalt concrete (AC) thickness, annual average daily traffic (AADT), type of base, crack orientation, and crack location. The ANN network architecture consisted of an input layer of six neurons, a hidden layer of ten neurons, …

Spatial Synchrony Is Related To Environmental Change In Finnish Moth Communities: Synchrony And Environmental Change, Tad A. Dallas, Laura H. Antão, Juha Pöyry, Reima Leinonen, Otso Ovaskainen

Faculty Publications

© 2020 The Author(s). Spatially distinct pairs of sites may have similarly fluctuating population dynamics across large geographical distances, a phenomenon called spatial synchrony. However, species rarely exist in isolation, but rather as members of interactive communities, linked with other communities through dispersal (i.e. a metacommunity). Using data on Finnish moth communities sampled across 65 sites for 20 years, we examine the complex synchronous/anti-synchronous relationships among sites using the geography of synchrony framework. We relate site-level synchrony to mean and temporal variation in climatic data, finding that colder and drier sites-and those with the most drastic temperature increases-are important for …

Effects Of Menu Labeling Policies On Transnational Restaurant Chains To Promote A Healthy Diet: A Scoping Review To Inform Policy And Research, Sofía Rincón-Gallardo Patiño, Mi Zhou, Fabio Da Silva Gomes, Robin Lemaire, Valisa Hedrick, Elena Serrano, Vivica I. Kraak

Faculty Publications

No abstract provided.

Understanding Air Pollutants And Meteorology Interactions Using Chemical Transport Models, Pengfei Wang

LSU Doctoral Dissertations

Air pollution is a worldwide threat to human health and ecosystems, especially in developing countries. After being emitted to the atmosphere, air pollutant concentrations are determined by chemical and physical processes including transport, transformation, and deposition, which are largely affected by meteorological variations. In turn, pollutants such as fine particulate matter (PM_2.5) affect meteorology by impacting solar radiation and cloud condensation processes. Thus, it is important and necessary to understand the interactions between air pollutants and meteorology for better designing effective air pollution control strategies and forecasting weather. In this study, two chemical transport models (CTMs) are applied …

Video-Based Interventions: Teaching Adults And Preschoolers, Philip Ross Richard Iii

LSU Doctoral Dissertations

Long gone are the days in which technology is looked upon as a trivial novelty. Whether evoking positive or negative reactions, advancements in technology continue to alter our daily environments. One such example is Video Based Interventions (VBI). VBI utilize video recording to facilitate the acquisition of various skills and behaviors (Rayner, Denholm, & Sigafoos, 2009). While it may sound like a simple intervention at first, many procedural variations of have been examined in research and practice. The two experiments comprising the current study examined the effectiveness of video models when used in conjunction with other instructional methods. Experiment I …

Evolution Of Computational Thinking Contextualized In A Teacher-Student Collaborative Learning Environment., John Arthur Underwood

LSU Doctoral Dissertations

The discussion of Computational Thinking as a pedagogical concept is now essential as it has found itself integrated into the core science disciplines with its inclusion in all of the Next Generation Science Standards (NGSS, 2018). The need for a practical and functional definition for teacher practitioners is a driving point for many recent research endeavors. Across the United States school systems are currently seeking new methods for expanding their students’ ability to analytically think and to employee real-world problem-solving strategies (Hopson, Simms, and Knezek, 2001). The need for STEM trained individuals crosses both the vocational certified and college degreed …

A Chance For Success: Understanding How Latinx Students Make Meaning Of Federal Work-Study Employment, Raylea Danelle Rideau

LSU Doctoral Dissertations

Many students engage in Federal Work-Study as a means of additional income and part-time employment. However, few studies detail the program’s overall effectiveness and impact, especially from the perspectives of students of color. This qualitative study described, by way of multiple case study design, how Latinx students employed in at least one semester of an on-campus Federal Work-Study position make meaning of their employment experience. The researcher explored the varied experiences of six undergraduate Latina women employed through work-study through the theoretical lenses of happenstance, self-authorship, and career construction. Sources of evidence used for this study included interviews, documentation, written …

Exploring The Role Of Engagement Among Sport Volunteers At College Football Bowl Games, Marcella Otto

LSU Doctoral Dissertations

Recent scholars noted the need for an engaged workforce to achieve optimal performance in various institutional fields. Within the sports industry, organizations often rely heavily on volunteers as a vital resource to accomplish goals and missions (Cuskelly, 2004; Doherty, 2009). The sport volunteer literature demonstrates the broadness of the field but also shows the increased demand for volunteers to aid staging events, even as the recruitment pool of volunteers is generally decreasing. Relatedly, it is in the best interest of organizations to maintain and manage volunteers to stay efficient (Chelladurai, 2006) because the need for this human resource continues to …

Engineering Dopant Position In Structure-Controlled Ceo2-Zro2 Catalysts, Behnam Safavinia

LSU Master's Theses

CeO₂-ZrO₂ (CZO) nanoparticles (NPs) have application in many catalytic reactions, such as methane reformation, due to their oxygen cycling ability. Ni doping has been shown to improve the catalytic activity and acts as an active site for the decomposition of methane. In this work, Ni:CZO NPs were synthesized via a two-step co-precipitation/molten salt synthesis to compare Ni distribution, oxygen vacancy concentration, and catalytic activity relative to a reference state-of-the-art catalyst. To better understand the effects of Ni position and dispersion, and oxygen vacancy formation in these materials, the Ni concentration, reaction time, and deposition methods were varied. …

Attosecond Time-Domain Measurement Of Core-Level-Exciton Decay In Magnesium Oxide, Romain Géneaux, Christopher J. Kaplan, Lun Yue, Andrew D. Ross, Jens E. Bækhøj, Peter M. Kraus, Hung Tzu Chang, Alexander Guggenmos, Mi Ying Huang, Michael Zürch, Kenneth J. Schafer, Daniel M. Neumark, Mette B. Gaarde, Stephen R. Leone

Faculty Publications

Excitation of ionic solids with extreme ultraviolet pulses creates localized core-level excitons, which in some cases couple strongly to the lattice. Here, core-level-exciton states of magnesium oxide are studied in the time domain at the Mg L2,3 edge with attosecond transient reflectivity spectroscopy. Attosecond pulses trigger the excitation of these short-lived quasiparticles, whose decay is perturbed by time-delayed near-infrared pulses. Combined with a few-state theoretical model, this reveals that the infrared pulse shifts the energy of bright (dipole-allowed) core-level-exciton states as well as induces features arising from dark core-level excitons. We report coherence lifetimes for the two lowest core-level excitons …

The Evolution Of Bivalve Shell Matrix Proteins, Mark Ira Duhon Ii

LSU Doctoral Dissertations

This dissertation focuses on the molecular underpinnings surrounding the evolution of the biomineralized shells of marine bivalves. Bivalve molluscs synthesize remarkably complex shells from calcium carbonate and an organic matrix of proteins secreted from the dorsal edge of the mantle. Molecular analyses of shell matrix proteins (SMPs) have suggested high rates of gene turnover despite the conserved nature of the shell itself. Here, I used proteomic and transcriptomic data to identify the SMPs and other biomineralization proteins from seven bivalve species that diverged 3-513 Mya. Contrary to previous studies that identified only a few shared biomineralization transcripts across the Bivalvia, …

Valuing Voices: Construction Of Meaning Through Discursive Interactions During A Critical Service-Learning Partnership, Jane Helen Noble

LSU Doctoral Dissertations

As teacher educators strive to prepare preservice teachers for careers as literacy instructors and advocates of social justice in education, critical service-learning pedagogy has been considered as an approach for teacher education programs. Tenets of academic study, reflective practice, social change, and the development of authentic relationships between universities and communities outline the structure for critical-based field experiences. What are preservice teachers learning in these spaces? How do they grow as part of critical service- learning courses? How do community organizations and members interpret experiences in the partnership, and how do they describe their roles?

This study highlights the voices …

Temporal Decomposition For Multi-Interval Optimization In Power Systems, Farnaz Safdarian

LSU Doctoral Dissertations

Large optimization problems are frequently solved for power systems operation and analysis of electricity markets. Many of these problems are multi-interval optimization with intertemporal constraints. The size of optimization problems depends on the size of the system and the length of the considered scheduling horizon. Growing the length of the scheduling horizon increases the computational burden significantly and might make solving the problem in a required time span impossible. Many simplifications and approximation techniques are applied to reduce the computational complexity of multi-interval scheduling problems and make them solvable in a reasonable time span. Geographical decomposition is presented in the …