Digital Commons Network^™

Toward A Comparative Framework For Studies Of Altitudinal Migration, David Vander Pluym, Nicholas A. Mason

Faculty Publications

The study and importance of altitudinal migration has attracted increasing interest among zoologists. Altitudinal migrants are taxonomically widespread and move across altitudinal gradients as partial or complete migrants, subjecting them to a wide array of environments and ecological interactions. Here, we present a brief synthesis of recent developments in the field and suggest future directions toward a more taxonomically inclusive comparative framework for the study of altitudinal migration. Our framework centers on a working definition of altitudinal migration that hinges on its biological relevance, which is scale-dependent and related to fitness outcomes. We discuss linguistic nuances of altitudinal movements and …

Temporal Scales Of Mass Wasting Sedimentation Across The Mississippi River Delta Front Delineated By 210pb/137cs Geochronology, Jeffrey Duxbury, Samuel J. Bentley, Kehui Xu, Navid H. Jafari

Faculty Publications

The Mississippi River Delta Front (MRDF) is a subaqueous apron of rapidly deposited and weakly consolidated sediment extending from the subaerial portions of the Birdsfoot Delta of the Mississippi River, long characterized by mass-wasting sediment transport. Four (4) depositional environments dominate regionally (an undisturbed topset apron, mudflow gully, mudflow lobe, and prodelta), centering around mudflow distribution initiated by a variety of factors (hurricanes, storms, and fluid pressure). To better understand the spatiotemporal scales of the events as well as the controlling processes, eight cores (5.8–8.0 m long) taken offshore from the South Pass (SP) and the Southwest Pass (SWP) were …

Application Of Surge Arrester In Limiting Voltage Stress At Direct Current Breaker, Mohammadamin Moghbeli, Shahab Mehraeen, Sudipta Sen

Faculty Publications

Hybrid DC circuit breakers combine mechanical switches with a redirecting current path, typically controlled by power electronic devices, to prevent arcing during switch contact separation. The authors’ past work includes a bipolar hybrid DC circuit breaker that effectively redirects the fault current and returns it to the source. This reduces arcing between the mechanical breaker’s contacts and prevents large voltage overshoots across them. However, the breaker’s performance declines as the upstream line inductance increases, causing overvoltage. This work introduces a modification to the originally proposed hybrid DC breaker to make it suitable to use anywhere along DC grid lines. By …

Insights From Augmented Data Integration And Strong Regularization In Drug Synergy Prediction With Synergnet, Mengmeng Liu, Gopal Srivastava, J. Ramanujam, Michal Brylinski

Faculty Publications

SynerGNet is a novel approach to predicting drug synergy against cancer cell lines. In this study, we discuss in detail the construction process of SynerGNet, emphasizing its comprehensive design tailored to handle complex data patterns. Additionally, we investigate a counterintuitive phenomenon when integrating more augmented data into the training set results in an increase in testing loss alongside improved predictive accuracy. This sheds light on the nuanced dynamics of model learning. Further, we demonstrate the effectiveness of strong regularization techniques in mitigating overfitting, ensuring the robustness and generalization ability of SynerGNet. Finally, the continuous performance enhancements achieved through the integration …

Advancing Hydrogen Gas Utilization In Industrial Boilers: Impacts On Critical Boiler Components, Mitigation Measures, And Future Perspectives, Edem Honu, Shengmin Guo, Shafiqur Rahman, Congyuan Zeng, Patrick Mensah

Faculty Publications

This review sets out to investigate the detrimental impacts of hydrogen gas (H2) on critical boiler components and provide appropriate state-of-the-art mitigation measures and future research directions to advance its use in industrial boiler operations. Specifically, the study focused on hydrogen embrittlement (HE) and high-temperature hydrogen attack (HTHA) and their effects on boiler components. The study provided a fundamental understanding of the evolution of these damage mechanisms in materials and their potential impact on critical boiler components in different operational contexts. Subsequently, the review highlighted general and specific mitigation measures, hydrogen-compatible materials (such as single-crystal PWA 1480E, Inconel 625, and …

Peak Microhardness Recovery Via T6 Heat Treatment With Extremely Soft Annealed Al7075 Feedstock In Additive Friction Stir Deposition, Huan Ding, Uttam Bhandari, Pengcheng Zhu, Ehsan Bagheri, Saeid Zavari, Yehong Chen, Yang Mu, Yongqiang Wang, Shengmin Guo

Faculty Publications

With standard T6 heat treatments, precipitate-hardened alloys such as Al7075 and Al6061 fabricated using Additive Friction Stir Deposition (AFSD) method restore to noticeablely different peak mechanical properties. Previous research observed similar results but did not provide a viable solution. This study proposes a new processing strategy, namely enhanced plastic deformation by subjecting the Al7075 feedstock to annealed softening treatments. Specifically, by annealing the standard T651-Al7075 feedstock and deposition substrate (179 HV), their Microhardness were first degraded to its lowest state (80 HV), which is called a Soft-to-Soft system. For the Soft-to-Soft system subjected to AFSD, after undergoing appropriate T6 heat …

A Review Of Agrivoltaic Systems: Addressing Challenges And Enhancing Sustainability, Amro A. Zahrawi, Aly Mousaad Aly

Faculty Publications

Agrivoltaics is a relatively new term used originally for integrating photovoltaic (PV) systems into the agricultural landscape and expanded to applications such as animal farms, greenhouses, and recreational parks. The dual use of land offers multiple solutions for the renewable energy sector worldwide, provided it can be implemented without negatively impacting agricultural production. However, agrivoltaics represent a relatively new technology, facing challenges including economic viability, vulnerability to wind loads, and interference with growing crops. This paper reviews the recent research on integrating agrivoltaics with farming applications, focusing on challenges, wind impact on agrivoltaics, and economic solutions. The effect of agrivoltaics …

An Intelligent Impulsive Noise Mitigation With Deep Learning Method, Guo Yang, Yuwen Qian, Zikun Wang, Xiangwei Zhou, Wen Wu

Faculty Publications

To enable message transmission among sensors and equipment, power line communication (PLC) is a widely adopted smart grid. However, due to the occurrence of impulsive noise (IN), reliable transmissions over PLC channels in the smart grid are challenging. Therefore, in this paper, we propose an adaptive noise mitigation scheme to clip the IN with the sliding window-based method, where the altitude of the received signal in the current time slots is obtained by computing the average altitude of signals in the previous and next time slots. To detect the states of IN and dynamically estimate the power threshold of signals …

A Hermetic Package Technique For Multi-Functional Fiber Sensors Through Pressure Boundary Of Energy Systems Based On Glass Sealants, Zhichun Fan, Shuda Zhong, Kehao Zhao, Qirui Wang, Yuqi Li, Guangyin Zhang, Guangqun Ma, Jieru Zhao, He Yan, Zhiyong Huang, Jyotsna Sharma, Kevin P. Chen

Faculty Publications

This paper presents a hermitic fiber sensor packaging technique that enables fiber sensors to be embedded in energy systems for performing multi-parameter measurements in high-temperature and strong radiation environments. A high-temperature stable Intrinsic Fabry–Perot interferometer (IFPI) array, inscribed by a femtosecond laser direct writing scheme, is used to measure both temperature and pressure induced strain changes. To address the large disparity in thermo-expansion coefficients (TECs) between silica fibers and metal parts, glass sealants with TEC between silica optical fibers and metals were used to hermetically seal optical fiber sensors inside stainless steel metal tubes. The hermetically sealed package is validated …

Geothermo-Mechanical Alterations Due To Heat Energy Extraction In Enhanced Geothermal Systems: Overview And Prospective Directions, Mary C. Ngoma, Oladoyin Kolawole, Olufemi Olorode

Faculty Publications

Geothermal energy from deep underground (or geological) formations, with or without its combination with carbon capture and storage (CCS), can be a key technology to mitigate anthropogenic greenhouse gas emissions and meet the 2050 net-zero carbon emission target. Geothermal resources in low-permeability and medium- and high-temperature reservoirs in sedimentary sequence require hydraulic stimulation for enhanced geothermal systems (EGS). However, fluid migration for geothermal energy in EGS or with potential CO2 storage in a CO2-EGS are both dependent on the in situ flow pathway network created by induced fluid injection. These thermo-mechanical interactions can be complex and induce varying alterations in …

Vibrational Study Of Co, O2, And H2 Adsorbed On The Cocrfeni (110) High Entropy Alloy Surface, Frank Mckay, Andrew N. Okafor, David P. Young, Ye Xu, Phillip T. Sprunger

Faculty Publications

The vibrational properties of CO, O2, and H2 molecularly or dissociatively adsorbed on a CoCrFeNi(110) surface have been probed using high-resolution energy loss spectroscopy (HREELS) and modeled using density functional theory (DFT) calculations. Large (∼20 mm3) single-crystal, quaternary face-centered cubic CoCrFeNi was synthesized via a modified Czochralski technique. We show strong evidence that CO adsorbs primarily on bridge and on-top sites in compositionally varied local environments, which reflect the random, multielemental surface composition inherent in a high entropy alloy. A variation of adsorption sites is also found with oxygen, which exhibits two broad groups of modes. Comparison to previous photoemission …

Detecting Sand Ingress And Migration Using Fiber Optic Distributed Acoustic Sensing Technology And Computational Fluid Dynamics During Oil And Gas Production, Rishikesh Shetty

LSU Doctoral Dissertations

Sand production in oil and gas operations presents significant challenges, leading to equipment damage, reduced production efficiency, and costly well interventions. Conventional sand detection techniques, primarily surface-based acoustic sensors, fail to provide real-time insights into sand ingress and migration within the wellbore. This dissertation explores the use of distributed fiber optic sensing technology for monitoring sand transport in pipelines and wellbores.

This research is divided into two experimental phases: a surface flow loop and a wellbore setup. The surface flow loop experiment involves a 40-ft-long, 2-in. diameter PVC pipe to simulate sand transport in horizontal pipelines. Sand slurry, with varying …

Sources And Transport Of Dissolved Organic Carbon In Barataria Basin, Louisiana, Mukseet Mahmood

LSU Master's Theses

The fate of soil organic carbon loss from eroding coastal wetlands is of great importance, given its potential impact on atmospheric CO2 concentration. A large fraction of this soil organic carbon upon coastal erosion is released as dissolved organic and inorganic carbon (DOC and DIC) to adjacent water bodies.

In this study, we investigate the seasonal distribution and transport of DOC and DIC in Barataria basin in Louisiana, USA, bordering northern Gulf of Mexico. This region is currently undergoing one of the highest land-loss in the USA. Seasonal measurements of DOC, DIC and colored dissolved organic matter (CDOM) were carried …

Coastal Sedimentary Records Of Extreme Events And Human Activity: Examples From Hurricanes And Microplastics, Nicholas T. Culligan

LSU Doctoral Dissertations

Coastal regions are uniquely vulnerable to a myriad of natural and anthropogenically caused stresses such as hurricane strikes and chronic microplastic pollution. Both hurricanes and microplastics have major negative effects on global coastlines and are forecast to become more damaging in the future. However, current model trends are based on limited modern data and may not provide an accurate or comprehensive view of the future. Therefore, this dissertation investigates coastal stratigraphic records to determine long-term past trends of these presses and pulses so that researchers, stakeholders, and policy makers can use them to enact strategies to mitigate damages from worsening …

Analysis Of Traffic Operation And Safety At Cloverleaf And Diamond Interchanges With And Without Connected And Autonomous Vehicles, Nischal Khadka

LSU Master's Theses

Even though diamond and cloverleaf interchanges are commonly used in road networks, comparative studies on their operational safety and efficiency remain limited. Also, previous studies have explored the impact of Connected and Autonomous Vehicles (CAVs) at diamond interchanges, but the effects on cloverleaf interchanges are not yet thoroughly investigated. This study addresses these gaps by evaluating the traffic operation and safety performance of cloverleaf interchanges compared to diamond interchanges. It also assesses the influence of various Market Penetration Rates (MPRs) of CAVs on travel time, queue lengths, and conflict points at cloverleaf interchanges, considering different weaving lengths.

Data on peak-hour …

Creating A Wholistic Manufacturing Score To Highlight The Effects Of Hidden Inefficiencies In Automated Manufacturing Caused By Soft Dedication And Preventative Maintenance Failures, Oded Tal

LSU Doctoral Dissertations

The semiconductor industry is one of the most advanced manufacturing sectors, operating at an unparalleled scale and complexity. A new manufacturing facility costs between $500 million and $15 billion, and the industry's investment in automation is unmatched. However, the intricate and cyclical nature of semiconductor manufacturing creates very complex manufacturing facilities where the boundaries between planning and real-time operations often blur.

For the industry to keep improving, there is a need to create a new method that allows comparison among different manufacturing environments to uncover hidden losses that may be obscured by automation.

To better understand these hidden losses, the …

Trends In Hot Carrier Distribution For Disordered Noble-Transition Metal Alloys, Eklavya Thareja, Kevin M. Mcpeak, Phillip T. Sprunger, Ilya Vekhter, William A. Shelton

Faculty Publications

We developed and tested an approach for predicting trends for efficient hot carrier generation among disordered metal alloys. We provide a simple argument for the importance of indirect transitions in the presence of disorder, thus justifying the use of joint density of states (JDOS)-like quantities for exploring these trends. We introduce a new JDOS-like quantity, JDOSK , which heuristically accounts for longer lifetimes of quasiparticles close to the Fermi energy. To demonstrate the efficacy of this new quantity, we apply it to the study of Cu50X50 where X = Ag, Au, Pd and Y50Pd50 where Y = Au, Ni. We …

Photoactivated Cyclic Polyphthalaldehyde Microcapsules For Payload Delivery, Youngsu Shin, Jared M. Schwartz, Anthony C. Engler, Brad Jones, Oleg Davydovich, Paul A. Kohl

Faculty Publications

Microcapsules with a cyclic polyphthalaldehyde (cPPA) shell and oil core were fabricated by an emulsification process. The low ceiling temperature cPPA shell was made phototriggerable by incorporating a photoacid generator (PAG). Photoactivation of the PAG created a strong acid which catalyzed cPPA depolymerization, resulting in the release of the core payload, as quantified by 1H NMR. The high molecular weight cPPA (197 kDa) yielded uniform spherical microcapsules. The core diameter was 24.8 times greater than the cPPA shell thickness (2.4 to 21.6 μm). Nonionic bis(cyclohexylsulfonyl)diazomethane (BCSD) and N-hydroxynaphthalimide triflate (HNT) PAGs were used as the PAG in the microcapsule shells. …

A Coarse-Grained Molecular Dynamics Study Of Gas Hydrate Formation And Dissociation, Meisam Adibifard

LSU Doctoral Dissertations

The study of gas hydrates has increased significantly over the last two decades because of their potential application in energy storage, production and transportation, water desalination, refrigeration, gas separation, etc. There is a significant interest in commercially developing natural gas hydrates because the energy content of methane hydrate reservoirs (MHRs) is at least twice that of all conventional fossil fuels combined. Additionally, due to the higher storage capacity of hydrates, it is proposed to sequester CO₂ in the form of CO₂ hydrate, thereby reducing the amount of greenhouse gases. Hence, hydrates offer a dual solution to two of …

Engineering Electronic Properties Of Random Alloys For Catalytic Applications, Andrew N. Okafor

LSU Doctoral Dissertations

Engineering catalytic materials is a key endeavor in the catalysis science to improve the catalytic activity of existing catalysts for specific applications and reduce the dependence on rare metals and minerals. While alloying, or mixing of metals, has been extensively studied, the focus has conventionally been placed on intermetallic phases or nanostructures such as core-shell particles, which are conceptually described by simple lattice models. This research focuses on understanding the catalytic properties of structurally ordered but compositionally disordered (or random) alloys, which have remained under-explored due to complexity at the atomic scale. Existing research focuses on synthesizing multicomponent alloys and …

A Comparison Of Diploid And Triploid Eastern Oysters For Aquaculture Production Under Extreme Temperatures And Salinities, Joshua H. Kim

LSU Master's Theses

Off-bottom aquaculture of Eastern oysters (Crassostrea virginica) is a nascent industry that is increasingly supported by the use of triploid oysters, which grow faster than diploids. Despite their growth advantage, elevated triploid mortality compared to diploids under high temperature, low salinity, or a combination of these conditions challenge consistent triploid production. Identifying the environmental thresholds at which differential triploid mortality occurs and predicting its economic impact are important to informing decision-making in oyster aquaculture. The goal of this thesis was to compare the biological and economic performance of diploid and triploid oysters under high temperature and low salinity conditions. …

Catalytic Upcycling Of Waste Plastics By Induction Heating, Bernard Whajah

LSU Doctoral Dissertations

The development of plastics over the past half century has led to rapid technological advances; however, the long-term negative environmental impacts of these materials compel new depolymerization and upcycling strategies. Plastics are indispensable due to their unique physical and chemical properties and affordability, leading to a significant increase in production rates. However, their recycling rates lag far behind their production rates. Polyolefins like LDPE and HDPE, which are common plastics, decompose very slowly in the environment. Converting these plastics into useful products often requires high-temperature pyrolysis, resulting in undesired distributions of products.

To address this challenge, this study focuses on …

Building A Simplistic Automatic Extruder: Instrument Development Opportunities For The Laboratory, Stefanie Klisch, Dylan Gilbert, Emma Breaux, Aliyah Dalier, Sudipta Gupta, Bruno Jakobi, Gerald J. Schneider

Faculty Publications

This work presents an automatic extruder as a research experience for undergraduate students. The system offers a user-friendly approach to preparing vesicles, such as liposomes or polymersomes, with a defined size and polydispersity─properties crucial for research in biology and macromolecules. It comprises two syringe pumps connected by a membrane filter. The setup is controlled by software. Compared to manual extrusion, this automated system provides advantages, such as precisely controlled variables. The project describes a tool to enhance undergraduate learning in science and engineering laboratories. Building an automatic extruder serves as a simplified model of a complex industrial process. It offers …

Bernoulli Convolution Of The Depth Of Nodes In Recursive Trees With General Affinities, Toshio Nakata, Hosam Mahmoud

Journal of Stochastic Analysis

No abstract provided.

Why Are There So Many Definitions Of Eutrophication?, Alexandrine Pannard, Philippe Souchu, Christian Chauvin, Monique Delabuis, Chantal Gascuel-Odoux, Erik Jeppesen, Morgane Le Moal, Alain Ménesguen, Gilles Pinay, Nancy N. Rabalais, Yves Souchon, Elisabeth M. Gross

Faculty Publications

Because of the first observations in the 1900s of the oligotrophic and eutrophic states of lakes, researchers have been interested in the process that makes lakes become turbid because of high phytoplankton biomass. Definitions of eutrophication have multiplied and diversified since the mid-20th century, more than for any other ecological process. Reasons for the high number of definitions might be that the former ones did not sufficiently describe their causes and/or consequences. Global change is bringing eutrophication more into the spotlight than ever, highlighting the need to find consensus on a common definition, or at least to explain and clarify …

Using Loss-On-Ignition To Estimate Total Nitrogen Content Of Mangrove Soils, Havalend E. Steinmuller, Joshua L. Breithaupt, André S. Rovai, Kevin M. Engelbert, Joseph M. Smoak, Lisa G. Chambers, Kara R. Radabaugh, Ryan P. Moyer, Amanda Chappel, Derrick R. Vaughn, Thomas S. Bianchi, Robert R. Twilley, Paulo R. Pagliosa, Miguel Cifuentes-Jara, Danilo Torres

Faculty Publications

Loss-on-ignition (LOI) has been widely used to estimate soil organic carbon (OC) content for coastal wetland soils, owing to recent interest in ‘blue carbon’ systems. Comparatively less attention has been paid to soil nutrient retention, specifically total nitrogen (TN), despite being a historically limited resource that influences C cycling and aquatic ecosystem health. A single conversion equation is available to estimate soil TN content from LOI, derived from salt marshes. This study investigated the utility of creating TN conversion equations from LOI data for application in mangrove soils to improve global understanding of their role in TN interception and sequestration. …

Solubilization Of Paclitaxel With Natural Compound Rubusoside Toward Improving Oral Bioavailability In A Rodent Model, Jian Zhang, Jicheng Shu, Rhett W. Stout, Paul S. Russo, Zhijun Liu

Faculty Publications

Paclitaxel, which features low water solubility and permeability, is an efflux pump substrate. The current paclitaxel drugs are given intravenously after resolving the solubility issue. Yet, oral delivery to achieve therapeutic bioavailability is not effective due to low absorption. This study evaluated a natural compound, rubusoside, to improve oral bioavailability in an animal model. Free paclitaxel molecules were processed into nano-micelles formed in water with rubusoside. The particle size of the nano-micelles in water was determined using dynamic light scattering. The oral bioavailability of paclitaxel in nano-micelles was determined against Cremophor/alcohol-solubilized Taxol after oral and intravenous administration to pre-cannulated Sprague …

The Evolution Of Science And Regulation Of Dietary Supplements: Past, Present, And Future, Paul M. Coates, Regan L. Bailey, Jeffrey B. Blumberg, Ahmed El-Sohemy, Elizabeth Floyd, Joshua Z. Goldenberg, Aimée Gould Shunney, Hannah D. Holscher, Yasmeen Nkrumah-Elie, Deshanie Rai, Barry W. Ritz, Wendy J. Weber

Division of Basic Science Faculty Publications

Dietary supplement use in the United States is widespread and increasing, especially among certain population groups, such as older Americans. The science surrounding dietary supplements has evolved substantially over the last few decades since their formal regulation in 1994. Much has been learned about the mechanisms of action of many dietary supplement ingredients, but the evidence on their health effects is still building. As is true of much nutrition research, there are many studies that point to health effects, but not all are at the level of scientific evidence (e.g., randomized controlled interventions), rigor, or quality needed for definitive statements …

The Impact Of Obesity On Reproductive Health And Metabolism In Reproductive-Age Females, Samantha B. Schon, Hannah E. Cabre, Leanne M. Redman

Clinical Research Faculty Publications

Obesity is a highly prevalent chronic disease that impacts >40% of reproductive-aged females. The pathophysiology of obesity is complex and can be understood simply as a chronic energy imbalance whereby caloric intake exceeds caloric expenditure with an energy surplus stored in adipose tissue. Obesity may be categorized into degrees of severity as well as different phenotypes on the basis of metabolic health and underlying pathophysiology. Obesity and excess adiposity have a significant impact on fertility and reproductive health, with direct effects on the hypothalamic-pituitary-ovarian axis, the ovary and oocyte, and the endometrium. There are significant adverse pregnancy outcomes related to …

Effects Of E-Cigarettes On The Lung And Systemic Metabolome In People With Hiv, Aline Zaparte, Courtney J. Christopher, Connie Arnold, Lauren Richey, Adairre Castille, Kyle Mistretta, Christopher M. Taylor, Huiyi Lin, Steve Nelson, John P. Kirwan, John W. Apolzan, Shawn R. Campagna, David A. Welsh

Division of Basic Science Faculty Publications

The popularity of e-cigarettes (vaping) has soared, creating a public health crisis among teens and young adults. Chronic vaping can induce gut inflammation and reduce intestinal barrier function through the production of the proinflammatory molecule hydrogen sulfide (H2S). This is particularly concerning for people with HIV (PWH) as they already face impaired immune function and are at a higher risk for metabolic dysregulation, diabetes, and chronic liver disease. Furthermore, PWH experience unhealthy behaviors, making it crucial to understand the systemic metabolic dysregulation and pathophysiological mechanisms associated with vaping in this population. Here, we employed liquid chromatography–mass spectrometry (LC-MS)-based metabolomics to …