Digital Commons Network^™

Neutron Imaging Of Al6061 Prepared By Solid-State Friction Stir Additive Manufacturing, Saber Nemati, Leslie G. Butler, Kyungmin Ham, Gerald L. Knapp, Congyuan Zeng, Selami Emanet, Hamed Ghadimi, Shengmin Guo, Yuxuan Zhang, Hassina Bilheux

Faculty Publications

Solid-state Friction Stir Additive Manufacturing has recently gained attention as a result of its capacity to fabricate large-scale parts while preserving the mechanical properties of the feedstock material. However, the correlation between the quality of layer-by-layer bonding of the deposited metal and processing parameters has remained unknown. Neutron imaging techniques, with 90% total transmission per cm, are employed for Al6061 parts fabricated by MELD® Technology as a non-destructive evaluation approach for the first time to investigate the layer-by-layer structure of a stadium-shaped ingot in different sections. The post-processed results show the fabricated parts with an optimized set of processing parameters …

Correction: Design Of Crack-Free Laser Additive Manufactured Inconel 939 Alloy Driven By Computational Thermodynamics Method (Mrs Communications, (2022), 12, 5, (844-849), 10.1557/S43579-022-00253-X), Congyuan Zeng, Huan Ding, Uttam Bhandari, S. M. Guo

Faculty Publications

The article Design of crack-free laser additive manufactured Inconel 939 alloy driven by computational thermodynamics method, written by Congyuan Zeng, Huan Ding, Uttam Bhandari, S. M. Guo, was originally published electronically on the publisher’s internet portal on 9 September 2022 without open access. With the author(s)’ decision to opt for Open Choice the copyright of the article changed on 20 December 2022 to © The Author(s) 2022 and the article is forthwith distributed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate …

Wind Loads On Overhead Sign Structures: A Comparative Study, Aly Mousaad Aly, James Benson

Faculty Publications

Road signs are prone to extreme winds that cause significant damage. Overhead sign structures can disrupt traffic and cause harm to the traveling public if a failure occurs under extreme wind conditions. In this paper, we employ Computational Fluid Dynamics (CFD) in a comparative study to understand the aerodynamics of standard, porous, and curved signs. The study shows the viability of porous and curved overhead boards for lessening aerodynamic loads, which can mini-mize damage and enhance safety on roadways. Porous overhead signs can decrease the drag forces; however, the size of the openings is a vital parameter in reducing wind …

Sediment Transport And Geomorphological Evolution In The Northern Gulf Of Mexico, Kelli Moran

LSU Doctoral Dissertations

This dissertation explores the mechanisms driving sediment transport and deposition on the continental shelf and within the bays of the northern Gulf of Mexico via a suite of geophysical methods and sediment cores on a variety of timescales. This dissertation is comprised of three main chapters, each focusing on a different location, environment, and process but tied together using geophysical survey, a thematic focus on geomorphic change and sediment transport within the deltaic cycle and deltaic plain environments, and the implications this change poses for both past and future sediment transport and environmental change in response to sea level change. …

Publisher Correction: A Very Luminous Jet From The Disruption Of A Star By A Massive Black Hole (Nature, (2022), 612, 7940, (430-434), 10.1038/S41586-022-05465-8), Igor Andreoni, Michael W. Coughlin, Daniel A. Perley, Yuhan Yao, Wenbin Lu, S. Bradley Cenko, Harsh Kumar, Shreya Anand, Anna Y.Q. Ho, Mansi M. Kasliwal, Antonio De Ugarte Postigo, Ana Sagués-Carracedo, Steve Schulze, D. Alexander Kann, S. R. Kulkarni, Jesper Sollerman, Nial Tanvir, Armin Rest, Luca Izzo, Jean J. Somalwar, David L. Kaplan, Tomás Ahumada, G. C. Anupama, Katie Auchettl, Sudhanshu Barway, Eric C. Bellm, Varun Bhalerao, Joshua S. Bloom, Michael Bremer, Mattia Bulla, Eric Burns, Sergio Campana, Poonam Chandra

Faculty Publications

In the version of this article initially published, there was in an error in the third-to-last sentence of the abstract, now reading, in part, “we calculate a rate of 0.02–0.01 +0.04 Gpc–3 yr–1”, where Gpc was spelled out as gigapascals, not gigaparsecs. Also, the scale label (2″) was missing in the lower-left corner of Fig. 1b. The errors have been corrected in the HTML and PDF versions of the article.

An Exploration Of Black Women Faculty Members' Faculty Development And Career Advancement Experiences Within A Pwi, Monica N. Guient

LSU Doctoral Dissertations

At a large, research-intensive, predominantly White university, in this qualitative case study, Black women faculty members’ experiences with and perceptions of institutionally sponsored faculty development activities in relation to career advancement was explored. The career advancement of faculty members from underrepresented and minoritized populations—particularly Black women—is ultimately impacted by the racialized and gendered disparities among tenure-track and tenured professors in research, service, and teaching. Unique to this study is the exploration of how Black women faculty members experience the human resource development practice of faculty development while also gathering information from the institutional leaders who oversee and guide institutionally sponsored …

First-Principles Molecular Dynamics Study Of Liquid Iron-Rich Alloys Under Conditions Of The Earth’S Core, Dipendra Banjara

LSU Doctoral Dissertations

In this dissertation, we report the results of the first-principles molecular dynamics (FPMD) simulations and data analysis on the thermodynamic, structural, and transport properties of iron-rich metallic liquids considering several light and heavy elements under wide ranges of pressure and temperature that are relevant to the earth’s core. Our simulations of pure liquid iron cover the pressure range from 0 GPa at 2000 K to 380 GPa at 7000 K perhaps representing the most extensive computational study to date. We studied four molten iron-rich alloys corresponding to 2.67 atom% of Ni, Co, Mo, and W at pressures up to 380 …

Chiral Uncertainties In Ab Initio Elastic Nucleon-Nucleus Scattering, Robert B. Baker, Matthew Burrows, Charlotte Elster, Kristina D. Launey, Pieter Maris, Gabriela Popa, Stephen P. Weppner

Faculty Publications

The effective interaction between a nucleon and a nucleus is one of the most important ingredients for reaction theories. Theoretical formulations were introduced early by Feshbach and Watson, and efforts of deriving and computing those ‘optical potentials’ in a microscopic fashion have a long tradition. However, only recently the leading order term in the Watson multiple scattering approach could be calculated fully ab initio, meaning that the same nucleon-nucleon (NN) interaction enters both the structure as well as the reaction pieces on equal footing. This allows the uncertainties from the underlying chiral effective NN interaction to be systematically explored in …

Development Of A Peptide-Based Protac Incorporating A Β-Hairpin Sequence, Hannah Catherine Hymel

LSU Doctoral Dissertations

The ubiquitin-proteasome system (UPS) is a biochemical pathway primarily responsible for the degradation of damaged proteins. The UPS is regulated by E3 ubiquitin ligases, which recognize specific degradation sequences, or degrons, on a protein leading to protein ubiquitination and subsequent degradation by the proteasome. Proteolysis targeting chimeras (PROTACs) have emerged as a novel therapeutic agent to selectively degrade ‘undruggable’ targets; however, many peptide-based PROTACs suffer low cell permeability and high protease susceptibility. The goal of this work is to utilize degron-based substrates that function as cell penetrating peptides (CPPs) in a PROTAC to selectively degrade a target. The first part …

Anaerobic Toluene Biodegradation Potential At A Superfund Site Where Toluene Biosynthesis Was Observed, George Carson

LSU Master's Theses

At a Superfund site near Baton Rouge, LA, the subsurface injection of molasses has been used to stimulate anerobic reductive dechlorination of halogenated organic compounds (e.g., 1,2-dichloroethane and vinyl chloride) present in the groundwater. Following some molasses injections, temporary accumulation of toluene and p-cresol was observed in the groundwater. Accumulation of these aromatic hydrocarbons, which were not detected in the molasses, has been attributed to anaerobic biotransformation of the amino acids phenylalanine and tyrosine. Experiments reported here were conducted in support of an effort to determine if toluene biodegrading bacteria were present in the area where anaerobic toluene accumulation was …

A Forestry Trade Data Discrepancy Analysis, Morgan Alyce Daigle

LSU Master's Theses

Trade data across multiple databases experience unavailability across some countries/forestry products, inconsistency, and unreliability; and these qualities manifest as discrepancies in the data. Literature provides evidence of discrepancies and inconsistencies within international trade statistics, including documented cases in which they are present within agriculture sector trade.

While researchers have worked to pinpoint factors to explain discrepancies, studies on the forestry trade databases are not as prevalent. Therefore, more research needs to be conducted to identify discrepancies within forest sector products trade data to understand the nature of discrepancies found between different bilateral trading partners.

The goal of this thesis is …

Media Literacy In Public Education: A Mixed-Method Exploration, Jessica Wyers

LSU Doctoral Dissertations

You have to know where you are to know where you’re going. This is the approach I attempt to take to understand next steps in media literacy education and policy. Little research has been done to understand the current state of media literacy education, what is actually happening in the classrooms and education system, to better judge more intentional interventions in the future.

This dissertation explores the current issues in media literacy education in our public schools. I combine the strengths of a qualitative investigation of published public school media literacy curricula with survey data measuring the perceptions of students’ …

Computational Study Of C-C Coupling Reactions On Heterogeneous Catalysts, Md Saeedur Rahman

LSU Doctoral Dissertations

The utilization of carbon dioxide (CO₂) in chemical production has attracted global research interest. Reacting CO₂ with methane (CH₄) removes these greenhouse gases from the atmosphere and turns both compounds into building blocks for organic compound synthesis. A commonly explored pathway involves dry reforming of methane (DRM), which reacts CH₄ and CO₂ to form syngas, a mixture of H₂ and CO. Syngas is a widely used feedstock for synthesizing chemicals ranging from methanol to fuels via the Fischer-Tropsch (FT) process. However, DRM has a large positive ΔGº, which requires the …

Sexual Dimorphism In Corallite Size And Modularity Of A Broadcast Spawning Coral, Porites Lobata, Ricardo M. Pedraza-Pohlenz, Eduardo F. Balart, J. J.Adolfo Tortolero-Langarica, Alma Paola Rodríguez-Troncoso, Michael E. Hellberg, Orión Norzagaray-López, Rafael A. Cabral-Tena, Amílcar Leví Cupul-Magaña, David A. Paz-García

Faculty Publications

Differences in selective pressures and the energetic cost of gametes in gonochoristic corals should vary with the sex of the colony, which may lead to sexual dimorphism. Coral colonies are composed of subunits (corallites) that create a complex morphological architecture. If corallite features are distinct between sexes, then the degree of coordinated change among these subunits may also vary (phenotypic modularity). This study tested for sexual dimorphism in the corallites of the reef-building coral Porites lobata, a gonochoric broadcast spawner, and compared this with previously demonstrated sexual dimorphism in its congener P. panamensis, a gonochoric brooder. Corallite area in P. …

Flood Risk Assessment For Residences At The Neighborhood Scale By Owner/Occupant Type And First-Floor Height, Ayat Al Assi, Rubayet Bin Mostafiz, Carol J. Friedland, Md Adilur Rahim, Robert V. Rohli

Faculty Publications

Evaluating flood risk is an essential component of understanding and increasing community resilience. A robust approach for quantifying flood risk in terms of average annual loss (AAL) in dollars across multiple homes is needed to provide valuable information for stakeholder decision-making. This research develops a computational framework to evaluate AAL at the neighborhood level by owner/occupant type (i.e., homeowner, landlord, and tenant) for increasing first-floor height (FFH). The AAL values were calculated here by numerically integrating loss-exceedance probability distributions to represent economic annual flood risk to the building, contents, and use. A simple case study for a census block in …

Measurement Of Near-Threshold Proton Branching Ratios In 31s Important For Novae, Sudarsan Balakrishnan

LSU Doctoral Dissertations

Classical novae are stellar explosions that contribute to the nucleosynthesis of isotopes on the proton-rich side of the valley of stability up to ⁴⁰Ca. In ONe novae, the incompletely understood reaction rate of ³⁰P(p,γ)³¹S is known to strongly influence the production rate of several stable isotopes such as ³⁰Si, ³¹P, and ^32,33,34S. A precise measurement of this reaction rate has several potential implications towards matching astrophysical observables to the physical composition of the nova site -- the observed elemental abundance ratios of O/S and S/Al have been suggested as useful `thermometers' to gauge …

Drivers Of Diatom Production And The Legacy Of Eutrophication In Two River Plume Regions Of The Northern Gulf Of Mexico, Jeffrey W. Krause, Adam D. Boyette, Israel A. Marquez, Rebecca A. Pickering, Kanchan Maiti

Faculty Publications

In the northern Gulf of Mexico (nGoM), the Louisiana Shelf (LS) and Mississippi Bight (MB) subregions are influenced by eutrophication to varying degrees. Despite recognition that dissolved silicon may regulate diatom productivity in the nGoM, there is only one published data set reporting biogenic silica (bSiO2) production rates for each subregion. We report that bSiO2 production rates on the LS and MB are high and appear to be controlled by different nutrients among seasons. Despite exceptional upper trophic level biomass regionally, which suggests significant primary production by diatoms (as in other systems), gross euphotic-zone integrated bSiO2 production rates are lower …

Dissolved Organic Carbon Dynamics And Fluxes In Mississippi-Atchafalaya Deltaic System Impacted By An Extreme Flood Event And Hurricanes: A Multi-Satellite Approach Using Sentinel-2/3 And Landsat-8/9 Data, Bingqing Liu, Eurico J. D’Sa, Francesca Messina, Melissa M. Baustian, Kanchan Maiti, Victor H. Rivera-Monroy, Wei Huang, Ioannis Y. Georgiou

Faculty Publications

Transport of riverine and wetland-derived dissolved organic carbon (DOC) spanning tidal wetlands, estuaries, and continental shelf waters functionally connects terrestrial and aquatic carbon reservoirs, yet the magnitude and ecological significance of this variable and its spatiotemporal linkage remains uncertain for coastal deltaic regions, such as Mississippi River Delta Plain, which includes Mississippi (MR) and Atchafalaya (AR) rivers and estuaries with vast expanses of wetlands and coastal forests. We examined DOC dynamics and fluxes in this large river-dominated wetland-estuarine system for the period between 2019 and 2021 that included an extreme river flood event in 2019, two major hurricanes (Barry in …

Global Sea Surface Cyclogeostrophic Currents Derived From Satellite Altimetry Data, Yuhan Cao, Changming Dong, Alexandre Stegner, Brandon J. Bethel, Chunyan Li, Jihai Dong, L. Haibin, Jingsong Yang

Faculty Publications

Sea surface currents (SSC) derived from the sea surface height anomalies (SSHA) as measured by multi-satellite altimeters are widely used for various applications including studies on ocean dynamics, marine ecology, and climate change. However, present SSC products estimated on the assumption of an idealized geostrophic balance is biased. To overcome this idealization, this study considers flow curvature in the estimation of sea surface velocities in the global ocean, with the computation scheme validated using numerical model results. It is demonstrated that the inclusion of curvature into SSC estimations significantly changes SSC dynamic features in terms of kinetic energy, enstrophy (the …

Design And Field-Scale Demonstration Of The Buoyant-Kill Process For Restoring Integrity Of Wells With Sustained Casing Pressure, Efecan Demirci, Andrew Wojtanowicz

Faculty Publications

Sustained Casing Pressure (SCP) is the persistent casinghead pressure resulting from the well’s annular integrity loss and migration of gas above the leaking cement sheath. Downhole—intervention methods for SCP removal employ workover rigs to access and plug off the leaking annulus at depth from within the well. The inexpensive rig-less method of Buoyant Kill involves surface injection of immiscible heavy fluid at the casinghead into the well’s annulus to replace the annular fluid column above the gas-leaking cement and stop gas migration. Laboratory and pilot-size testing have shown feasibility of the method. Presented here, is a field-scale demonstration experiment conducted …

Visual Literacy Unframed: Planning An Oer To Improve College-Level Visual Analysis Skills, Marty Miller

Faculty Publications

No abstract provided.

A Community-Engaged Oral History Study As A Tool For Understanding Environmental Justice Aspects Of Human Exposures To Hazardous Waste Thermal Treatment Emissions In Colfax, La, Matilda Odera, Blair Kelley, Louie Rivers, Alyanna Wilson, Jessica Tran, Khushi Patel, Brenda Vallee, Wilma Subra, Jennifer A. Cramer, Jennifer K. Irving, Margaret Reams, Jennifer Richmond-Bryant

Faculty Publications

This study investigates environmental justice (EJ) themes related to siting a hazardous waste thermal treatment facility near a low-income community of color. We investigated effects of living near a hazardous waste thermal treatment facility through three EJ aspects: recognitional, procedural, and distributive justice. The study involved the collection of oral history interviews from residents of Colfax, a town in Grant Parish, Louisiana, that hosts an open burn/open detonation hazardous waste thermal treatment facility. The facility processes materials such as munitions, theme park waste, and contaminated soils from Superfund sites, and it increased its volume drastically in 2014. Residents reported adverse …

The Role Of Fmri In Drug Development: An Update, Owen Carmichael

Clinical Research Faculty Publications

Functional magnetic resonance imaging (fMRI) of the brain is a technology that holds great potential for increasing the efficiency of drug development for the central nervous system (CNS). In preclinical studies and both early- and late-phase human trials, fMRI has the potential to improve cross-species translation of drug effects, help to de-risk compounds early in development, and contribute to the portfolio of evidence for a compound’s efficacy and mechanism of action. However, to date, the utilization of fMRI in the CNS drug development process has been limited. The purpose of this chapter is to explore this mismatch between potential and …

Joint Estimation Of Neural Events And Hemodynamic Response Functions From Task Fmri Via Convolutional Neural Networks, Kai Cheng Chuang, Sreekrishna Ramakrishnapillai, Krystal Kirby, Arend W.A. Van Gemmert, Lydia Bazzano, Owen T. Carmichael

Clinical Research Faculty Publications

Joint decomposition of functional magnetic resonance imaging (fMRI) time series into time courses of neural activity events and hemodynamic response functions (HRF) can enable new insights into functional connectivity, task activation, and neurovascular coupling in health and disease. Current methods for this problem handle time series of either temporally isolated events or extended blocks of continuous events but not both; and they constrain the HRF to one specific functional form. We propose to use an autoencoder and a convolutional neural network (CNN) to overcome these challenges. The autoencoder uses convolutional neural networks to reconstruct the fMRI time series while estimating …

S.W. Griffith: A Suitable Case For Indictment?, Mark Finnane, Jonathan Richards

Faculty Publications

In his 2021 book ‘Truth-Telling: History, Sovereignty and the Uluru Statement’, Henry Reynolds called for an inquiry into the historical record of Samuel Walker Griffith, Federation ‘father’ and first Chief Justice of the High Court of Australia. Reynolds’ iconoclasm targeted a historical figure whose name is memorialised in a Riverina town, a Canberra suburb and a Queensland university. Reynolds charged that Griffith was morally and politically responsible for the violence carried out by an agency of the Queensland government, the Native Police. This historically grounded allegation relates to Griffith's pre-Federation Queensland political career, 1874–93, when he served intermittently as Premier, …

Challenges In The Combination Of Radiotherapy And Immunotherapy For Breast Cancer, Rui Zhang, Samantha D. Clark, Beibei Guo, Tianyi Zhang, Duane Jeansonne, Samithamby J. Jeyaseelan, Joseph Francis, Weishan Huang

Faculty Publications

Introduction: Immunotherapy (IT) is showing promise in the treatment of breast cancer, but IT alone only benefits a minority of patients. Radiotherapy (RT) is usually included in the standard of care for breast cancer patients and is traditionally considered as a local form of treatment. The emerging knowledge of RT-induced systemic immune response, and the observation that the rare abscopal effect of RT on distant cancer metastases can be augmented by IT, have increased the enthusiasm for combinatorial immunoradiotherapy (IRT) for breast cancer patients. However, IRT largely follows the traditional sole RT and IT protocols and does not consider patient …

A Bayesian Phase I/Ii Design To Determine Subgroup-Specific Optimal Dose For Immunotherapy Sequentially Combined With Radiotherapy, Beibei Guo, Yong Zang, Li Hsiang Lin, Rui Zhang

Faculty Publications

Sequential administration of immunotherapy following radiotherapy (immunoRT) has attracted much attention in cancer research. Due to its unique feature that radiotherapy upregulates the expression of a predictive biomarker for immunotherapy, novel clinical trial designs are needed for immunoRT to identify patient subgroups and the optimal dose for each subgroup. In this article, we propose a Bayesian phase I/II design for immunotherapy administered after standard-dose radiotherapy for this purpose. We construct a latent subgroup membership variable and model it as a function of the baseline and pre-post radiotherapy change in the predictive biomarker measurements. Conditional on the latent subgroup membership of …

A Man Of Bad Reputation: The Murder Of John Stephens And The Contested Landscape Of North Carolina Reconstruction, Evan Rothera

Civil War Book Review

A Man of Bad Reputation opens with John G. Lea’s confession that he had assassinated North Carolina State Senator John Walter Stephens in 1870. Lea gave his confession in 1919, nearly half a century after the murder. Stephens’s death, Drew A. Swanson contends, had profound repercussions. On the one hand, it “featured prominently in the US Congress’s investigation of Klan activities in the South,” which eventually led for the Enforcements Acts and the end of the first Ku Klux Klan. On the other hand, it sparked the Kirk-Holden War, which led to the impeachment of Governor William Woods Holden, his …

Targeting The Aspergillus Flavus P2c Gene Through Host-Induced Gene Silencing Reduces A. Flavus Infection And Aflatoxin Contamination In Transgenic Maize, Yenjit Raruang, Olanike Omolehin, Dongfang Hu, Qijian Wei, Surassawadee Promyou, Lidiya J. Parekattil, Kanniah Rajasekaran, Jeffrey W. Cary, Kan Wang, Zhi Yuan Chen

Faculty Publications

Aspergillus flavus is an opportunistic fungal pathogen that infects maize and produces aflatoxins. Using biocontrol or developing resistant cultivars to reduce aflatoxin contamination has only achieved limited success. Here, the A. flavus polygalacturonase gene (p2c) was targeted for suppression through host-induced gene silencing (HIGS) to reduce aflatoxin contamination in maize. An RNAi vector carrying a portion of the p2c gene was constructed and transformed into maize B104. Thirteen out of fifteen independent transformation events were confirmed to contain p2c. The T2 generation kernels containing the p2c transgene had less aflatoxin than those without the transgene in six out of eleven …

The Nitrogen-Dependent Gaba Pathway Of Tomato Provides Resistance To A Globally Invasive Fruit Fly, Hao Li, Yuan Zhang, Hu Li, Gadi V. P. Reddy, Zhihong Li, Fajun Chen, Yucheng Sun, Zihua Zhao

Faculty Publications

Introduction: The primary metabolism of plants, which is mediated by nitrogen, is closely related to the defense response to insect herbivores. Methods: An experimental system was established to examine how nitrogen mediated tomato resistance to an insect herbivore, the oriental fruit fly (Bactrocera dorsalis). All tomatoes were randomly assigned to the suitable nitrogen (control, CK) treatment, nitrogen excess (NE) treatment and nitrogen deficiency (ND) treatment. Results: We found that nitrogen excess significantly increased the aboveground biomass of tomato and increased the pupal biomass of B. dorsalis. Metabolome analysis showed that nitrogen excess promoted the biosynthesis of amino acids in healthy …