Digital Commons Network^™

Droplet-Based Fuel Property Measurements, Wanjun Dang

LSU Doctoral Dissertations

Ongoing work to find renewable biofuels to function as drop-in replacements or blending components with gasoline has identified a large number of fuel candidates. Given the vast number of potential biomass-derived fuel molecules and limited sample sizes, screening tools are required to down-select candidate fuels having desired physical properties to ensure good engine performance. This work investigates approaches for rapid screening of candidate fuels using micro-liter sample sizes targeting four properties -- surface tension, viscosity, heat of vaporization (HOV), and vapor pressure. Measurement techniques for fuel properties are developed based on unit phenomena for liquid fuel droplets including droplet oscillation …

Reaction Pathways Of Molecular Growth For Bay-Region Methyl-Substituted Polycyclic Aromatic Hydrocarbons During Supercritical Pyrolysis Of N-Decane, Venkata Sai Krishna Karthik Vutukuru

LSU Doctoral Dissertations

Prior to its combustion, fuel for future-highspeed aircraft will experience supercritical conditions, causing the fuel to undergo pyrolytic reactions that lead to the formation of polycyclic aromatic hydrocarbons (PAH), precursors to fuel-line solids that hinder aircraft’s safe operation. Therefore, understanding the formation pathways of PAH under supercritical conditions is important to preventing formation of these solids.

Previous work from our group has shown that n-alkanes are particularly problematic regarding solids formation and that the model fuel n-decane produces an abundance of aliphatics and one- to nine-ring aromatics—many of which are methyl-substituted. Some of these methyl-substituted PAH have their …

Asynchronous, Distributed Optical Mutual Exclusion And Applications, Ahmed Bahaael Mansour

LSU Doctoral Dissertations

Silicon photonics have drawn much recent interest in the setting of intra-chip andmodule communication. In this dissertation, we address a fundamental computationalproblem, mutual exclusion, in the setting of optical interconnects. As a main result, wepropose an optical network and an algorithm for it to distribute a token (shared resource)mutually exclusively among a set ofnprocessing elements. Following a request, the tokenis granted in constant amortized time andO(n) worst case time; this assumes constantpropagation time for light within the chip. Additionally, the distribution of tokens is fair,ensuring that no token request is denied more thann−1 times in succession; this is thebest possible. …

Numerical Investigation Of The Impact Of Distortion On The Hydrodynamics In The Lower Mississippi River Physical Model (Lmrpm), Ali Heidarizhaleh

LSU Doctoral Dissertations

The Lower Mississippi River Physical Model (LMRPM) is a distorted-scale, 1:6000 horizontal and 1:400 vertical, movable-bed model that is being used to complement ongoing numerical and field studies directed at studying how non-cohesive sediment transport will be impacted by future changes in relative sea level rise and river discharges, as well various management strategies, such as river sediment diversions, in the lower ~190 miles of the Mississippi River The LMRPM was designed using Froude number (Fr) similarity between the prototype and the model, while the flow Reynolds number is relaxed, but determined to be high enough to ensure rough turbulent …

Application Of Gas-Assisted Gravity Drainage (Gagd) Process For Enhancing Recovery From Unconventional Resources, Muzher Al Musabeh

LSU Doctoral Dissertations

The oil recovery with hydraulic fracturing has played an important role in hydrocarbon production and energy support last decade from unconventional resources. Characteristically, the significant production decline and low recovery factors from these reservoirs triggered the need for new EOR techniques to compensate for the decline and help sustain the production. In this study, an experimental investigation of the Gas-Assisted Gravity Drainage (GAGD) process in the presence of fractures as EOR process was conducted using Nitrogen (N2) and Carbon Dioxide (CO2) in Berea Sandstone (BSS) and Tuscaloosa Marine Shale (TMS). Core flooding and EOR experiments were used to determine the …

Engineering The Surface Of Fe3o4 Nanoparticles For Catalytic And Magnetic Applications, Natalia Da Silva Moura

LSU Doctoral Dissertations

With the rapid depletion of the U.S. energy resources coupled with population growth, heat management technologies must be improved to sustain our quality of life. Precisely, in catalysis, it is estimated that only ~50% of the energy supplied to the reactor is used for product conversion due to dissipation losses. Among the emerging technologies with a promising reduction in heat losses is induction heating, offering targeted heat delivery with magnetic nanoparticles. Under alternating magnetic fields (AMF), these nanoparticles can absorb the energy from Radio-Frequency (RF) fields and dissipate it as heat on the nanoparticle surface. This in situ heat generation …

Communications, Decision-Making, And Interactions Of A Multi-Agent Autonomous Vehicle System, Daniel Davis Smith

LSU Doctoral Dissertations

Autonomous vehicles are becoming ever more common and offer many attractive benefits to society. They can operate for long periods of time unattended, operate in environments that may be dangerous to humans, perform time consuming or repetitive tasks and all with greater efficiency and lower costs than humans. For these vehicles to be able to do these things, algorithms need to be designed and optimized that allow them to interact with the real-world environment in safe, effective, and efficient ways.

We designed and built a set of three homogeneous water-based autonomous surface vehicles equipped with appropriate sensors and communications ability …

Laser Surface Treatment And Laser Powder Bed Fusion Additive Manufacturing Study Using Custom Designed 3d Printer And The Application Of Machine Learning In Materials Science, Hao Wen

LSU Doctoral Dissertations

Selective Laser Melting (SLM) is a laser powder bed fusion (L-PBF) based additive manufacturing (AM) method, which uses a laser beam to melt the selected areas of the metal powder bed. A customized SLM 3D printer that can handle a small quantity of metal powders was built in the lab to achieve versatile research purposes. The hardware design, electrical diagrams, and software functions are introduced in Chapter 2. Several laser surface engineering and SLM experiments were conducted using this customized machine which showed the functionality of the machine and some prospective fields that this machine can be utilized. Chapter 3 …

Characterization Of Application-Driven Sol-Gel Coated Meshes And Composites, Armaghan Naderi

LSU Doctoral Dissertations

Surface engineering is a multi-disciplinary research area that encompasses disciplines such as materials science, chemistry, mechanical engineering, and electrical engineering. Coating is a surface modification technique in surface engineering, applied on the surface of a substrate (i.e., bulk material), to cover/protect it from environmental degradation or to modify/improve surface properties for specific applications. This PhD research presents an in-depth investigation of sol-gel ceramic coatings to modify surface characteristics of bulk materials for two specific applications: 1) antistatic/antidust applications, and 2) biomaterial implant applications.

First, zirconia antistatic thin films on glass substrates, and their application to polymer-based composites, was studied. Zirconia …

Direct Activation Of Light Alkanes To Value-Added Chemicals Using Supported Metal Oxide Catalysts, Md Ashraful Abedin

LSU Doctoral Dissertations

One of the most challenging aspects of modern-day catalysis is the conversion of methane. Direct conversion of methane via dehydroaromatization (MDHA) is a well-known process which can produce valuable hydrocarbons. Mo oxide supported on ZSM-5/MCM-22 has been studied extensively in recent years for MDHA. Mo carbides are responsible for activating methane by forming CHx species. These are dimerized into C2Hy and oligomerized on ZSM-5/MCM-22 Brønsted acid sites to form aromatics. Sulfated zirconia (SZ) supported Mo catalyst contains the acid sites necessary to produce benzene in MDHA. Here, sulfated hafnia (SH), a homologous oxide like SZ, has been proposed to provide …

An Improved Earned Value Management Method Integrating Quality And Safety, Brian Briggs

LSU Doctoral Dissertations

The construction industry invests significant time and money to improve quality and safety while reducing cost and schedule impacts. The industry has a sincere desire to improve construction project management methods to improve efficiency. Historically, quality and safety underperformances result from undermanaged quality control and safety activities. The cost and schedule impacts associated with poor quality work have always had an impact on construction operations. The unprecedented challenges and uncertainties of COVID-19 highlighted the need to improve the Earned Value Management (EVM) method within construction to reflect these quality and safety activities. The central goal of this dissertation is to …

Impact Of Personality Traits And Team Criteria On Construction Team Performance, Arlys Silva Payne

LSU Doctoral Dissertations

This dissertation investigated how personality traits and team criteria influence team performance in real construction projects. Though personality influence on team performance has been significantly investigated in other business sectors, the literature revealed that the construction industry lacks investigations regarding personality influencing team performance. The existing literature revealed that the Big Five Factors (BFF) was the most popular assessment tool for personality. Thus, this dissertation adopted the 50-Item Personality questionnaire developed by Goldberg, which consited of extraversion, aggreeableness, conscientiousness, neuroticism, and openness to experience. The literature also revealed several common team criteria to evaluate team performance: team member satisfaction, shared …

Single-Family Residential Flood Loss Reduction Through Freeboard, Ehab Said Gnan

LSU Doctoral Dissertations

The lack of flood loss estimation methods conducted on a micro-scale level that consider the full loss‐exceedance probabilities curve poses a significant problem in flood risk assessment. Also, the lack of robust benefit-cost analysis (BCA) that quantifies benefits at the micro-scale level leads to sub-optimal results, and therefore sub-optimal decisions when determining the optimal freeboard. Further, flood loss assessments focus on owner-occupied housing and neglect rental housing. These loss assessment deficiencies underscore the need for a robust assessment that quantifies the life-cycle benefits for all stakeholders and provides actionable information to enable informed decisions.

This research presents a comprehensive methodology …

Advanced Methods For Steady-State And Stability Analyses Of Hybrid Power Systems, Mohammad Mehdi Rezvani

LSU Doctoral Dissertations

The term hybrid power grids refer to the combination of two power systems with different intrinsic characteristic. For instance, ac-dc grids and transmission-distribution systems are kinds of hybrid power grids. Challenges in analyzing the hybrid power grids arise since two sets of equations should be solved either simultaneously or sequentially. In the simultaneous (unified) methods, the ac and dc system of equations are solved simultaneously, while, in the sequential approaches, these equations are solved in an error loop. In this dissertation, a unified method is proposed for steady-state and fault analyses of hybrid ac-dc power grids, while a sequential approach …

Vertical Feature Delineation For Flood Hazard Assessments At The Coastal Land Margin, Shu Gao

LSU Doctoral Dissertations

Coastal and riverine flooding constitutes a major environmental hazard that affect millions of people residing along the world’s coastline. Improved understanding of the driving mechanisms that can cause flooding within coastal watersheds requires advanced hydrologic and coastal storm surge simulation. Such advanced simulation is dependent upon an accurate digital elevation model (DEM) for the optimal topographical representation of the true domain in the discretized model grid (mesh). However, it is not possible to afford mesh resolution as fine as contemporary DEMs, resolved at sub-10 meters, due to the impractical computational expense. Therefore, significant elevation barriers such as roadbeds, levees, railroads, …

Studying Complex Aquifer Systems From Large-Scale Stratigraphy Development To Local Aquifer Storage And Recovery, Hamid Vahdat Aboueshagh

LSU Doctoral Dissertations

Hydrostratigraphy model is an essential component of building valid groundwater models. Many challenges are associated with constructing hydrostratigraphy models which include geological complexities such as faults, domes, and angular unconformities. Developing a method with an emphasis on capturing big data to thoroughly inform large-scale models is one of the challenges addressed in the first part of this study. The method is predicated upon discretization of the study domain into tiles based on the geological dip direction and faults. The application of the method in the state of Louisiana with the utilization of more than 114000 well logs demonstrates promising results …

Simulation Of Compound Flood Events In Low-Gradient Coastal Watershed, Felix Luis Santiago-Collazo

LSU Doctoral Dissertations

Low-gradient coastal watersheds are susceptible to flooding caused by various flows such as rainfall, tides, and storm surge. Compound flooding occurs when at least two of these mechanisms happen simultaneously or in close succession. Different inundation models, observed data, and/or a combination of these are coupled through varying techniques involving one-way, loosely, tightly, or fully coupled approaches to assess compound flooding. This study presents a one-dimensional (1-D), fully coupled compound inundation model based on the Shallow Water equations. This model approach simultaneously simulates the free water surface variations in the ocean domain (i.e., tide and storm surge modeling), rainfall-runoff in …

Atomistic Thermo-Mechanical Description Of The Deformation Behavior, Scaling Laws, And Constitutive Modeling Of Nanoporous Gold, Mohammed Hassan Yousef Saffarini

LSU Doctoral Dissertations

Metallic foams, or nanoporous (NP) metals as it is widely referred to in literature, with ligament sizes up to a few tens of nm show exceptional mechanical properties such as high strength and stiffness per weight ratio under different loading scenarios due to their high surface area to solid volume ratio. Therefore, they can be utilized in a wide range of applications making them of great interest to researchers. While their elasticity and yield strength have been the subject of several studies, very limited attention was given to the effect of size, strain rate, and temperature on the material plastic …

Fatigue Monitoring Through Wearable Sensors For Construction Workers, Srikanth Sagar Bangaru

LSU Doctoral Dissertations

About 40% of the US construction workforce experiences high-level fatigue, which leads to poor judgment, increased risk of injuries, a decrease in productivity, and a lower quality of work. Excessive fatigue from working in unpleasant working conditions, long working hours, or heavy workloads can aggravate fatigue's adverse effects, leading to work-related musculoskeletal disorders (WMSDs) and productivity loss. Therefore, it is essential to monitor fatigue to reduce the adverse effects and preventing long-term health problems. However, since fatigue demonstrates itself in several complex processes, there is no single standard measurement method for fatigue detection. This research aims to develop a system …

Semantics-Guided Human Motion Modeling In Virtual Reality Environment, Matthew Korban

LSU Doctoral Dissertations

Human Motion Modeling is essential in Computer Animation and Human-Computer Interaction. This dissertation studies how to enhance the speed and robustness of Human Motion Modeling in Virtual Reality (VR) environments. Specifically, we aim to design a pipeline to effectively capture and use semantic action information to guide the motion capturing from users in physical worlds and its transfer onto digital avatars in VR environments. To recognize the user's action, we first proposed a new Dynamic Directed Graph Convolutional Network (DDGCN) to model spatial and temporal features from users' skeletal representations. The DDGCN consists of several dynamic feature modeling modules to …

Error Prevention In Sensors And Sensor Systems, Pedro J. Chacon Dominguez

LSU Doctoral Dissertations

Achievements in all fields of engineering and fabrication methods have led towards optimization and integration of multiple sensing devices into a concise system. These advances have caused significant innovation in various commercial, industrial, and research efforts. Integrations of subsystems have important applications for sensor systems in particular. The need for reporting and real time awareness of a device’s condition and surroundings have led to sensor systems being implemented in a wide variety of fields. From environmental sensors for agriculture, to object characterization and biomedical sensing, the application for sensor systems has impacted all modern facets of innovation. With these innovations, …

A Comprehensive Study On Printed Circuit Board Backdoor Coupling In High Intensity Radiated Fields Environments, Ryan Patrick Tortorich

LSU Doctoral Dissertations

Due to the prevalence of unintentional electromagnetic interference (EMI) and the growth of intentional electromagnetic interference (IEMI) or high power microwave (HPM) sources, it is now more important than ever to understand how electronic systems are affected by high intensity radiated fields (HIRF) environments. Both historic events and experimental testing have demonstrated that HIRF environments are capable of disrupting and potentially damaging critical systems including but not limited to civil and military aircraft, industrial control systems (ICS), and internet of things (IoT) devices. However, there is limited understanding on the complex electromagnetic interactions that lead to such effects. This study …

Modeling Hydraulic Fracturing Initiation And Propagation In Porous Rock Formationsl, Chang Huang

LSU Doctoral Dissertations

Hydraulic fracturing has long been introduced to the oil and gas industry since the early nineteenth century for both reservoir characterization and reservoir stimulation. Despite the progress made in the last two decades, many challenges still have not been tackled regarding not only the propagation problem but also the initiation problem due to its complexity. The dissertation is divided into two stages, i.e., before and after fracture initiation. The first stage of the research aimed at improving the accuracy in solving the poro-mechanical response of wellbore during fluid injection before a tensile fracture occurs, which is crucial to determine the …

An Investigation Of The Effects Of Variable Magnetic Field Gradients On Soot And Co Emissions From Non-Premixed Hydrocarbon Flames, Edison Ekperechukwu Chukwuemeka

LSU Doctoral Dissertations

The interaction of the paramagnetic species in a combustion process with the mag- netic field placed in the vicinity of non-premixed flames affects the characteristics of the non-premixed flames - flame height and flame lift-off height. However, the effect of this magnetic interaction on the pollutants generated by the flame is unknown.

In general, pollutant formation is promoted in most combustion systems due to in- complete combustion of the hydrocarbon due to improper mixing. Since paramagnetic combustion species such as O2, O, OH, etc interacts with magnetic fields and possess a preferential motion direction, imposing magnetic field on non-premixed flames …

High Temperature Polymer Electrolytes For Hydrogen Fuel Cells And Electrochemical Pumps, Gokul Venugopalan

LSU Doctoral Dissertations

Hydrogen fuel cell and separation technologies such as proton exchange membrane fuel cells (PEMFCs) and electrochemical hydrogen pump (ECHP) offer a profound advantage in the transition to a low-carbon economy. An imperative hitch in hydrogen fuel cells and ECHP technology has been the electrocatalyst poisoning by carbon monoxide (CO) and other contaminants in the reactant mixture. By operating, hydrogen fuel cells and ECHPs at high temperatures (>200 °C), the effect of CO adsorption on the electrocatalyst surface could be curtailed. The high-temperature operation of devices necessitates a proton exchange membrane (PEM) to operate under anhydrous conditions.

In this work, …

Development Of Cracking Resistance Prediction Model Of Long-Term Aged Asphalt Mixtures, Peyman Barghabany

LSU Doctoral Dissertations

With the increasing complexity of asphalt mixture composition, the current volumetric-based Superpave mixture design would not be sufficient to address durability concerns. To address this limitation, performance-based testing is introduced to supplement conventional volumetric mixture design in assessing the cracking resistance of asphalt mixtures. To perform cracking tests, samples need to be aged to represent the most embrittlement case. The current AASHTO standard for asphalt mixture long-term aging (LTA) is a 5-day oven-aging at 85°C. Quality control/assurance practices require samples to be long-term aged prior to a cracking test which is a time-consuming process. Therefore, it would be beneficial to …

Adsorption And Transport Of Colloids At Interface And In Bulk, Jingyun Lee

LSU Doctoral Dissertations

Colloids are suspensions of microscopic insoluble particles dispersed in a continuum phase such as liquid or gas. Colloids are found in our everyday life from food and cosmetic industries to pharmaceutical and biomedical applications. Depending on a global minimum of the free-energy landscape, colloidal suspensions can be classified as two major classes: equilibrium or active colloidal system. This Ph.D dissertation presents strategies to engineer equilibrium self-assembled structures and out-of-equilibrium active matter using various interparticle forces.

First, we introduce the means to promote the equilibrium self-assembled structures driven by adsorption of colloids at interface. Typically, adsorption of colloids at interface is …

Gold-Semiconductor Photocatalysts For Water Treatment Under Visible And Ultraviolet Light, Daniel Willis

LSU Doctoral Dissertations

Water scarcity threatens the lives of millions of people worldwide. It is imperative to improve the energy efficiency and affordability of water treatment methods to avoid a looming water-energy crisis. To meet this challenge, I have pursued research on the use of sunlight—our most reliable and abundant source of energy—to drive water treatment through photocatalysis. I explored the literature and found gold-semiconductor materials to hold promise for harvesting sunlight and catalyzing the breakdown of waterborne contaminants. Initially, I designed a novel optical cavity with gold (Au) nanoparticles on a zinc oxide / titania (TiO₂) / aluminum film stack …

Led-Based Optical Sensing Platforms For Multi-Analyte Detection, Youngho Shin

LSU Doctoral Dissertations

Real-time monitoring of phytoplankton groups provides important information about aquatic ecological states, nutrient abundance, and water pollution. A rapid and accurate method for monitoring phytoplankton in water is commonly performed by detecting fluorescence emission from the plankton; however, commercially available portable fluorescence sensors are still expensive, bulky, and limited in functions, such as lacking the capability of selectively detecting multiple phytoplankton groups. In this regard, a low-cost and portable fluorometer platform for phytoplankton detection was developed in order to address the issues that current portable fluorometers have.

This dissertation has four main goals: (1) perform a study on fluorescence measurement …

Non-Newtonian Model Development For Post-Wildfire Flood Risk Management, Ian Eli Floyd

LSU Doctoral Dissertations

Wildfire effected regions of the western U.S. frequently produce non-Newtonian floods (or floods that have a non-linear relationship between stress and deformation) in response to moderate to severe precipitation events. This research presents the development, evaluation, and demonstration of a post-wildfire hydrodynamic one-dimensional and two-dimensional diffusive wave and shallow-water numerical modeling approach that can be used to predict post-wildfire downstream runout of debris flows and floodplain inundation conditions. While researchers have developed a variety of Non-Newtonian approaches to simulate debris flows and mudflows, there has been very limited application to post-wildfire flooding. This can make it difficult to understand the …