Engineering Commons^™

Enhancing Optical And Thermal Properties Of Nanofibrous Films Inspired By The White Beetle Scale, Bokyung Park

Nanoscience and Microsystems ETDs

The Cyphochilus white beetle has received significant attention recently for its exceptional visible-light-scattering properties, owing to the beetle scale's anisotropic nano-fibrillar network structure. Inspiration from the remarkable optical properties of these biological species has directed research efforts to fabricating biomimetic nano-fibrillar structures with polymer materials. In this work, electrospun silk fibroin polymer films reproduce the white beetle scale's anisotropic nature to draw on its optical scattering properties and further improve the radiative-cooling capabilities of silk fabrics. An anisotropically restructured silk film with a mean fiber diameter of a few hundred nanometers substantially increases optical scattering strength in the visible spectrum …

Examination Of Ionization In Cesium Diode Pumped Alkali Lasers With An Ion Chamber Diagnostic, Benjamin Oliker

Optical Science and Engineering ETDs

Diode pumped alkali lasers (DPALs) are leading candidates for future high power applications, with many potential utilities for the military, aerospace, communications, and scientific diagnostics. A critical step in their development is measurement and understanding of unwanted ionization processes that occur inside the laser, which decrease efficiency, reduce the usable alkali population, and increase heat load. In this dissertation, direct measurement of the ionization rate of a cesium DPAL gain medium are made for the first time, via application of an ion chamber diagnostic. Results will demonstrate that the rate of ionization is slow compared to pump absorption, with a …

Multi-Scale Modeling Of Dislocation Motion And Interaction: Theory, Plastic Properties, And Boundary Conditions, Abu Bakar Siddique

Mechanical Engineering ETDs

Dislocation theory is the fundamental tool for explaining plasticity in the material. The elastic field of a material is always influenced by the presence of dislocations and other defects independent of the loading configurations. Scientists and researchers have minimal success in solving plasticity problems analytically. And for this reason, the capturing of dislocation dynamics is highly dependent on numerical modeling, which is always a challenge for its inherent multi-scale nature. Current research investigates and develops self-consistent numerical models for different plasticity problems based on the distributed-dislocation technique and the collocation-point method. Numerical methods are developed for different boundary conditions in …

Ailbot: A Respiratory-Focused Symptom Checker Chatbot For Children, Gabrielle Mae V. Arco, Ken Ivan T. Cheng, Pamela S. Chong, Chico Andre G. Olaguer

DLSU Senior High School Research Congress

Inadequate access to healthcare, accompanied by the spread of COVID-19 has significantly affected most Filipinos. The prolonged quarantine period in the Philippines due to this virus restricts the movement and lifestyle of people. Thus, it makes medical appointments difficult to arrange. The ever-growing number of healthcare chatbots can provide access to healthcare check-ups quickly. These systems are still in their infancy stages, with the majority focusing on the mental and emotional well-being of people and catering to the general public. This study aims to develop a chatbot geared toward the respiratory health of Filipino children. Through the use of Chatfuel, …

An Analysis On The Usability Of A Mental Health Assessment Chatbot For Teenagers, Amanda Maria R. Sablay, Fiona Amaia M. Tano, Jazmin Abigail R. Zulueta

DLSU Senior High School Research Congress

Globally, people are faced with barriers to mental intervention due to a lack of resources, especially in low-income countries. Mental health chatbots have gained popularity due to their accessibility. However, the usability of a mental health chatbot designed to assess the mental well-being of Filipino teenagers is yet to be quantified. This paper aims to determine the acceptance of Filipino teenagers towards a chatbot as a medium to assess their mental well-being. This study presents a design for a conversation flow based on the Pediatric Symptom Checklist to create a text-based chatbot application verified by end-users and a psychologist. From …

A Microfluidic Assay For Single Cell Bacterial Adhesion Studies Under Shear Stress, Amanda Trusiak

Electronic Theses and Dissertations

The study of bacterial adhesion to host cells is important in understanding bacterial pathogenesis and developing new therapeutic approaches. Here, we studied bacterial adhesion under shear stress using a novel microfluidic method. Specifically, the adhesion of a uropathogenic E. coli strain (FimHOn, ATCC 700928/CFT073) to mannose-modified substrates was studied under flow conditions. The FimHOn E. coli strain expresses FimH which is a mannose-specific adhesin found on the fimbriae that binds to glycoproteins on the epithelium. We developed a microfluidic method that mimics bacterial adhesion to urothelial cells. First, the microfluidic channels were modified by sequentially adsorbing BSA-mannose and BSA onto …

Direct Simulation And Reduced-Order Modeling Of Premixed Flame Response To Acoustic Modulation, Zheng Qiao

Theses and Dissertations

This dissertation introduces a general, predictive and cost-efficient reduced-order modeling (ROM) technique for characterization of flame response under acoustic modulation. The model is built upon the kinematic flame model–G-equation to describe the flame topology and dynamics, and the novelties of the ROM lie in i) a procedure to create the compatible base flow that can reproduce the correct flame geometry and ii) the use of a physically-consistent acoustic modulation field for the characterization of flame response. This ROM addresses the significant limitations of the classical kinematic model, which is only applicable to simple flame configurations and relies on ad-hoc models …

The Effects Of Ecological Simulation For Ground Vehicle Mobility Forecasting, Christopher R. Hudson

Theses and Dissertations

Unmanned ground vehicles (UGV) are being explored for use in military domains. Military UGVs operate in complex off-road environments. Vehicle mobility forecasting plays an important role in understanding how and where a vehicle can operate. Traditional mobility forecasting has been done using an analytical model known as the NATO Reference Mobility Model (NRMM). There has been a push to extend the forecasting capabilities of NRMM by integrating more simulation methods. Simulation enables the repeated testing of UGVs in scenarios that would be difficult or dangerous to study in real world testing. To accurately capture UGV performance in simulation, the operating …

A Comparative Study On The Functionality Of Porcine Dura As A Tissue-Engineered Dura Mater Graft For Clinical Applications, Ashma Sharma

Theses and Dissertations

Damage to dura mater may occur during intracranial or spinal surgeries, which can result in cerebrospinal fluid leakage as well as other potentially fatal physiological changes. As a result, biological scaffolds derived from xenogeneic materials are typically used to repair and regenerate dura mater post intracranial or spinal surgeries. In this study we explore the mechanics, structure, and immunological capacity of xenogeneic dura mater to be considered as a replacement for human dura. A comparative analysis is done between native porcine dura and a commercially available bovine collagen-based dura graft. Native porcine dura mater was decellularized and subjected to mechanical …

Investigating The Effect Of Dissolved Oxygen-Assisted Corneal Cross-Linking (Cxl) On Porcine Corneas, Julianni Dar

Electronic Theses and Dissertations

Corneal cross-linking is a clinical procedure that is known to stop the progression of keratoconus, an eye disease that affects the cornea’s structure, ultimately leading to vision loss in its advanced stages. The typical treatment plan includes riboflavin and UV-A exposure in the hope to increase the mechanical properties of the cornea. There are two types of CXL pathways, with Type-II CXL requiring oxygen. Naturally, the dissolved oxygen is limited in the cornea; therefore, limiting the effect of Type-II CXL. This study proposes to improve the Type-II CXL contribution by integrating dissolved oxygen during the standard CXL treatment used in …

Scalable Deeper Graph Neural Networks For High-Performance Materials Property Prediction, Sadman Sadeed Omee, Steph-Yves Louis, Nihang Fu, Lai Wei, Sourin Dey, Rongzhi Dong, Qinyang Li, Jianjun Hu

Faculty Publications

Machine-learning-based materials property prediction models have emerged as a promising approach for new materials discovery, among which the graph neural networks (GNNs) have shown the best performance due to their capability to learn high-level features from crystal structures. However, existing GNN models suffer from their lack of scalability, high hyperparameter tuning complexity, and constrained performance due to over-smoothing. We propose a scalable global graph attention neural network model DeeperGATGNN with differentiable group normalization (DGN) and skip connections for high-performance materials property prediction. Our systematic benchmark studies show that our model achieves the state-of-the-art prediction results on five out of six …

Supplier Performance Scorecard Utilization In The Medical Device Manufacturing Healthcare Supply Chain, Justin Cardisco

Theses and Dissertations

The medical device manufacturing industry has a deficiency in determining how to improve supplier performance for the components and systems they purchase. Many complex medical devices require components from superb suppliers. But how does a medical device manufacturer (MDM) impartially assess supplier performance to know which suppliers to continuing with (or even boost purchase volumes) and which suppliers they should exit? This study describes which supplier-specific metrics are most important to medical device manufacturers (MDMs) so they can utilize this supplier performance scorecard backed by real-world inputs. This research will focus on five categories to measure MDM supplier performance (Quality, …

Automotive Sensor Fusion Systems For Traffic Aware Adaptive Cruise Control, Jonah T. Gandy

Theses and Dissertations

The autonomous driving (AD) industry is advancing at a rapid pace. New sensing technology for tracking vehicles, controlling vehicle behavior, and communicating with infrastructure are being added to commercial vehicles. These new automotive technologies reduce on road fatalities, improve ride quality, and improve vehicle fuel economy. This research explores two types of automotive sensor fusion systems: a novel radar/camera sensor fusion system using a long shortterm memory (LSTM) neural network (NN) to perform data fusion improving tracking capabilities in a simulated environment and a traditional radar/camera sensor fusion system that is deployed in Mississippi State’s entry in the EcoCAR Mobility …

A Drift-Flux Model For Upward Two-Phase In Pipes With High Velocity Flows, Woochan Lee

LSU Doctoral Dissertations

This study proposes the evaluation and development of a drift-flux model for upward two-phase high-velocity flow in large diameter pipes. A case where the proposed model is applicable is WCD (Worst-Case-Discharge) calculations for offshore wells. WCD assumes relatively larger pipe diameters and higher flow rates than the flow experiments at laboratory conditions utilized to validate and develop most of the flow models available in the literature.

Most of the two-phase flow models describe flow regime transitions as discrete processes by assigning the required void fraction or velocity for each flow regime transition. Therefore, for each flow regime, flow-regime-dependent correlations or …

Transformer Fault Event Detection And Classification Using Pmus, Yadunandan Paudel

Theses and Dissertations

Transformer is one of the most reliable components in an electric power system, however its failure has huge opportunity costs for an electric utility. In this work, we detect transformer electrical faults promptly and accurately classify the fault types using voltage/current data from Phasor Measurement Units. Our work can also eliminate uncertainties which are inherent in traditional transformer fault diagnostic techniques like dissolved gas analysis. In this thesis, first, possible causes of transformer failures are discussed, and four common transformer electrical faults are identified. Second, a comprehensive simulation model for electrical faults is developed. Third, fast and efficient abrupt change …

Structural Sizing Of Post-Buckled Thermally Stressed Stiffened Panels, Walid Arsalane

Theses and Dissertations

Design of thermoelastic structures can be highly counterintuitive due to design-dependent loading and impact of geometric nonlinearity on the structural response. Thermal loading generates in-plane stresses in a restrained panel, but the presence of geometric nonlinearity creates an extension-bending coupling that results in considerable transverse displacement and variation in stiffness characteristics, and these affects are enhanced in post-bucking regimes. Herein a methodology for structural sizing of thermally stressed post-buckled stiffened panels is proposed and applied for optimization of the blade and hat stiffeners using a gradient-based optimizer. The stiffened panels are subjected to uniform thermal loading and optimized for minimum …

Mechanical Property Relationships Of Cement Or Lime Stabilized Soils Throughout A Pavement's Life, Leigh E.W. Ayers

Theses and Dissertations

Soil-cement is an integral part of pavement design, especially in areas that are aggregate deprived, such as Mississippi. Current designs are reliant on the relationship of unconfined compressive strength (UCS) to other mechanical properties. The other properties discussed in this dissertation are Modulus of Elasticity (E), Indirect Tensile Strength (St), and Modulus of Rupture (MOR). This dissertation includes a comprehensive review of past design methods and mechanical property relationships. While some mechanical property relationships were shown to be well understood (i.e. St to UCS), others were not as accurate, especially for the later life mechanical properties (i.e. MOR to UCS …

Analysis And Implementation Of Low Fidelity Radar-Based Remote Sensing For Unmanned Aircraft Systems, Matthew Duck

Theses and Dissertations

Radar-based remote sensing is consistently growing, and new technologies and subsequent techniques for characterization are changing the feasibility of understanding the environment. The emergence of easily accessible unmanned aircraft system (UAS) has broadened the scope of possibilities for efficiently surveying the world. The continued development of low-cost sensing systems has greatly increased the accessibility to characterize physical phenomena. In this thesis, we explore the viability and implementation of using UAS as a means of radar-based remote sensing for ground penetrating radar (GPR) and polarimetric scatterometry. Additionally, in this thesis, we investigate the capabilities and implementations of low-cost microwave technologies for …

Recognizing Traffic Signaling Gestures Through Automotive Sensors., Benjamin James Bartlett

Theses and Dissertations

As technology advances with each new day, so do the applications and uses of the different modalities of technology, including transportation, particularly in ADAS vehicles. These systems allow the vehicle to avoid collisions, change lanes, adjust the vehicle’s speed, and more without the need of driver input. However, each sensor type has a weakness, and most advanced driver- assisted system (ADAS) vehicles rely heavily on sensors, such as RGB cameras, radars, and LiDAR sensors. These visual-based sensors may collect very noisy data in cloudy, raining, foggy, or other obscuring phenomena. Radar, on the other hand, does not rely on visual …

Photocatalytic Degradation Of Organic Contaminants By Titania Particles Produced By Flame Spray Pyrolysis, Noah Babik

Theses and Dissertations

Advanced oxidation of organic pollutants with TiO2 photocatalysts is limited due to the wide bandgap of TiO2, 3.2 eV, which requires ultraviolet (UV) radiation. When nanosized TiO2 is modified by carbon doping, charge recombination is inhibited and the bandgap is narrowed, allowing for efficient photodegradation under visible light. Here, we propose a flame spray pyrolysis (FSP) technique to create TiO2. The facile process of FSP has been successful in preparing highly crystalline TiO2 nanoparticles. Using the same procedure to deposit TiO2 onto biochar, the photocatalyst was doped by the carbonaceous material. The morphology, crystalline and electronic structure of the FSP …

Assessment Of Mechanical Engineering Skills: A Synthesis Of Industry And Academic Graduate Level Curriculum Requirements, Francie Baker

Theses and Dissertations

Students who graduate with an advanced degree in mechanical engineering are a diverse group in their path to post-baccalaureate degree attainment. Some students choose to obtain their master’s or Ph.D. post bachelors, but before they enter the workplace. Others enter the workforce and return as full-time students or progress on their advanced degrees while maintaining part- or full-time employment. Current accreditation standards for undergraduate degree programs are part of a changing landscape of standards and professional requirements that have adapted and continue to adapt as programs prepare students to work in professional engineering fields. Advanced degrees do not have the …

Design, Construction, And Characterization Of A Test Stand Used To Test Filter Media, Adam W. Parsons

Theses and Dissertations

Air filters are routinely used to remove various aerosols ranging from radioactive particles to airborne viruses. The overall performance of a filter may be simplified to consider only two main performance characteristics: 1) the efficiency at which particles are removed by the filter, and 2) the filter’s resistance to air flow. Per the DOE Nuclear Air Cleaning Handbook, HEPA filters require a minimum filter efficiency of 99.97% for particles 0.3 micrometers in diameter. Understanding how filters will perform with respect to time and mass loading is essential towards building more robust filters that operate more efficiently and safely. Analyzing the …

Spatial-Spectral Analysis In Dimensionality Reduction For Hyperspectral Image Classification, Chiranjibi Shah

Theses and Dissertations

This dissertation develops new algorithms with different techniques in utilizing spatial and spectral information for hyperspectral image classification. It is necessary to perform spatial and spectral analysis and conduct dimensionality reduction (DR) for effective feature extraction, because hyperspectral imagery consists of a large number of spatial pixels along with hundreds of spectral dimensions.

In the first proposed method, it employs spatial-aware collaboration-competition preserving graph embedding by imposing a spatial regularization term along with Tikhonov regularization in the objective function for DR of hyperspectral imagery. Moreover, Collaboration representation (CR) is an efficient classifier but without using spatial information. Thus, structure-aware collaborative …

Modeling Multi-Criteria Decision-Making Problems With Applications In Last Mile Delivery And School Safety Assessment, Ayat Alrahahleh

Theses and Dissertations

The last-mile delivery option has become a focal point of academic research and industrial development in recent years. Multiple factors such as increased demands on delivery flexibility, customer requirements, delivery urgency, and many others are enforcing to adopt this option. For fulfilling this paradigm shift in delivery and providing additional flexibility, drones can be considered as a viable option to use for last-mile delivery cases. Numerous drones are available in the market with varying capacities and functionalities, posing a significant challenge for decision-makers to select the most appropriate drone type for a specific application. For this purpose, this study proposes …

A Novel Method For Sensitivity Analysis Of Time-Averaged Chaotic System Solutions, Christian A. Spencer-Coker

Theses and Dissertations

The direct and adjoint methods are to linearize the time-averaged solution of bounded dynamical systems about one or more design parameters. Hence, such methods are one way to obtain the gradient necessary in locally optimizing a dynamical system’s time-averaged behavior over those design parameters. However, when analyzing nonlinear systems whose solutions exhibit chaos, standard direct and adjoint sensitivity methods yield meaningless results due to time-local instability of the system. The present work proposes a new method of solving the direct and adjoint linear systems in time, then tests that method’s ability to solve instances of the Lorenz system that exhibit …

A Modular Synthesis Of Processable And Thermally Stable Semi-Fluorinated Aryl Ether Polymers Via Step-Growth Polymerization Of Fluoroalkenes, Ketki Eknath Shelar

Theses and Dissertations

Tailored fluoropolymers remain the leading choice for a wide variety of advanced high-performance applications, including electronic/optical and energy conversion, owing to their unique blend of complementary high-performance properties. Amorphous semi-fluorinated polymers exhibit improved solubility and melt processability when compared to traditional perfluoropolymers. A leading class of semi-fluorinated aryl ether polymers includes perfluorocyclobutyl (PFCB), perfluorocycloalkenyl (PFCA), and fluoroarylene vinylene ether (FAVE) polymers. Monomers containing aromatic trifluorovinyl ethers (TFVE) are used to synthesize PFCB polymers via radical-mediated [2+2] cyclodimerization. On the other hand, FAVE and PFCA polymers are polymerized via base-mediated nucleophilic addition/elimination of bisphenols with TFVE monomers and decafluorocyclohexene respectively. The …

Impact Of Climate Oscillations/Indices On Hydrological Variables In The Mississippi River Valley Alluvial Aquifer., Meena Raju

Theses and Dissertations

The Mississippi River Valley Alluvial Aquifer (MRVAA) is one of the most productive agricultural regions in the United States. The main objectives of this research are to identify long term trends and change points in hydrological variables (streamflow and rainfall), to assess the relationship between hydrological variables, and to evaluate the influence of global climate indices on hydrological variables. Non-parametric tests, MMK and Pettitt’s tests were used to analyze trend and change points. PCC and Streamflow elasticity analysis were used to analyze the relationship between streamflow and rainfall and the sensitivity of streamflow to rainfall changes. PCC and MLR analysis …

A Harmonic Radar System For Honey Bee Tracking To Better Understand Colony Collapse Disorder, William B. Woo

Theses and Dissertations

Honey bees are some of the most important pollinators for agriculture in the world and are pivotal to the health of worldwide ecosystems. Like all insects, bees struggle with exposure to parasites, diseases, and other environmental factors that can negatively affect the overall health of the colony. Recently, a new unexplainable phenomenon called Colony Collapse Disorder (CCD) has been wreaking havoc on bee populations worldwide. As a result, a system capable of tracking bees is required to understand the different contributions of chemicals, parasites, etc. to CCD. This research seeks to show data supporting the development of systems for an …

Phase-Field Simulations Of The Precipitation Kinetics And Microstructure Development In Nickel-Based Superalloys, Caleb O. Yenusah

Theses and Dissertations

The continual research and development of nickel-based superalloys is driven by the global demand to improve efficiency and reduce emissions in the aerospace and power generation industries. Integrated Computational Material Engineering (ICME) is a valuable tool for reducing the cost, time, and resources necessary for the development and optimization of the mechanical properties of materials. In this work, an ICME approach for understanding the microstructure development and optimizing the mechanical properties in nickel-based superalloys is employed. Most nickel-based superalloys are precipitate strengthened by either the γ’ phase, γ” phase, or both. Therefore, understanding the precipitation kinetics and morphological evolution of …

Development And Evaluation Of Seasonal, Continental-Scale Streamflow Forecasts, Elissa Marie Yeates

Theses and Dissertations

Methods of forecasting streamflow using atmospheric ensembles and hydrologic routing have greatly improved over the past decades. These forecasts anticipate the timing and magnitude of streamflow peaks, enabling early warning of floods. Recent advances in atmospheric modeling have enabled production of forecasts months ahead, which are less precise but give a useful sense of trends.

The purpose of this study is to produce and evaluate a seasonal streamflow forecast model using a Muskingum routing hydrologic model coupled with runoff from a land surface model, and atmospheric input from a medium-term atmospheric and precipitation model. To evaluate the skill of the …