Materials Science and Engineering Commons^™

Improvement Of Gravelly Laterite And Cement Stable Disposal In West Africa, Jin Haibing, Yi Zicheng, Zhuo Rong

Journal of China & Foreign Highway

Owing to poor gradation and high liquid limit and plasticity index，the application of gravel laterite on road paving is limited in West Africa.To overcome this issue，laterite granule combined with sand at different content was explored.The performance including the particle composition，limit water content and CBR value was investigated.The results indicate that sand treatment can improve the gradation，enhance the compactness，and reduce the plasticity index.The improved gravel laterite can meet the requirements of subbase，cushion，and base courses.Cement treatment can improve the mechanical properties of laterite grains.Cement and sand content affect the unconfined compressive strength significantly，with an optimal sand content range identified.Specifically，laterite granules mixed with …

Review Of Cyclic Voltammetry Measurements For Uranium In Flinak Molten Salt, Jackson Ivory

Reviews, Analyses, and Instructional Studies in Electrochemistry (RAISE)

The electrochemical behavior of uranium FLiNaK molten salts is explored, focusing on cyclic voltammetry (CV) as a powerful tool for redox characterization and diffusion studies. Through a comprehensive review of recent research, the study highlights the significance of CV in understanding electrode kinetics, material compatibility, and process optimization in molten salt environments. The findings underscore the potential of FLiNaK molten salt reactors in advancing nuclear energy technologies, fuel processing, and waste management strategies. Collaborative interdisciplinary efforts are emphasized to address challenges and accelerate innovation in electrochemical methods for nuclear applications.

An Overview Of How To Measure The Kinetic Properties Of An Anode Material For The Chlorine Evolution Reaction, Cameron Vann

Reviews, Analyses, and Instructional Studies in Electrochemistry (RAISE)

The process of generating chlorine gas using electrolysis in aqueous systems is well established. However, a new process requires chlorine to be generated at high temperatures using molten salt. This harsh environment requires a new study of anode materials for the chlorine evolution reaction. Anode materials can be compared by their kinetic parameters, the transfer coefficient α and the exchange current i0. The basic theory of these properties as they relate to the chlorine evolution reaction has been detailed and an analysis method for finding these effective parameters has been shown and demonstrated.

Investigating The Impact Of Secondary Activation Time On The Adsorption Properties Of Activated Biochar For Arsenic Removal From Wastewater, Achyuth Bharadwaj Rayarao

Graduate Theses and Dissertations (2019 - present)

Biochar, a naturally occurring and renewable carbon material, becomes porous through activation. Activated biochar is an ideal candidate for use as an adsorbent. The objective of this study is to investigate whether activated biochar derived from Colorado soft pine serves as a better adsorbent and demonstrates enhanced adsorption capabilities after undergoing secondary physical activation at various activation times. The effect of secondary action time on physical adsorption properties drawn from the analysis of isotherm plots, surface areas and pore size patterns were examined by using a physisorption analyzer. Chemical structures were identified using both ultimate and proximate analyses, while porosity …

A Comprehensive Investigation Of The Influence Of Geometric Structure On The Shape Memory Performance Of Nafion, Jade Thomas

Physics Undergraduate Honors Theses

While perfluorosulfonic acid (PFSA) membranes have primarily been used in fuel cells due to their chemical, thermal, and mechanical stability, one PFSA, Nafion, boasts two unique characteristics: a broad glass transition (~55 °C to 130 °C) and a temperature-persistent electrostatic network. The combination of these two characteristics endows Nafion with exceptional shape memory properties – the ability of a material to morph and transform into pre-programmed shapes when exposed to an external stimulus – with enhanced permanent shape memorization, and a potentially near-infinite number of temporary shape memorization. This study focused on expanding the base of knowledge surrounding Nafion’s shape …

The Analysis Of Mechanical Exfoliation Of Graphene For Various Fabrication And Automation Techniques, Lance Yarbrough

Physics Undergraduate Honors Theses

Mechanical Exfoliation

A Comprehensive Investigation Of The Influence Of Geometric Structure On The Shape Memory Performance Of Nafion, Jade Thomas

Mechanical Engineering Undergraduate Honors Theses

While perfluorosulfonic acid (PFSA) membranes have primarily been used in fuel cells due to their chemical, thermal, and mechanical stability, one PFSA, Nafion, boasts two unique characteristics: a broad glass transition (~55 °C to 130 °C) and a temperature-persistent electrostatic network. The combination of these two characteristics endows Nafion with exceptional shape memory properties – the ability of a material to morph and transform into pre-programmed shapes when exposed to an external stimulus – with enhanced permanent shape memorization, and a potentially near-infinite number of temporary shape memorization. This study focused on expanding the base of knowledge surrounding Nafion’s shape …

Free And Forced Vibrations Of Elastically Restrained Cantilever With Lumped Oscillator, Alireza Babaei, Johné Parker, Paria Moshaver

Earth and Environmental Sciences Faculty Publications

The efficiency assessment of cantilever-based energy harvesters relies on vibrational analysis, which necessitates modi- fications aimed at enhancing efficiency. These modifications involve manipulating the fundamental frequency to lower values and encompassing a wider range of resonances within a specified bandwidth. Consequently, this paper introduces an original analytical-numerical exploration into the vibratory response of a cantilever with a novel boundary condi- tion involving an elastically restrained oscillator-spring arrangement. At the microbeam’s tip, an oscillator is elastically confined by a linear spring, resulting in a novel set of coupled governing equations and a distinct shearing boundary condition. Microbeam equations is derived from …

Encapsulated 2d Materials And The Potential For 1d Electrical Contacts, Sarah Wittenburg

Physics Undergraduate Honors Theses

The utilization of two-dimensional materials and heterostructures, particularly graphene and hexagonal boron nitride, have garnered significant attention in the realm of nanoelectronics due to their unique properties and versatile functionalities. This study focuses on the synthesis and fabrication processes of monolayer graphene encapsulated between layers of hBN, aiming to explore the potential of these heterostructures for various electronic applications. The encapsulation of graphene within hBN layers not only enhances device performance but also shields graphene from environmental contaminants, ensuring long-term stability. Experimental techniques, including mechanical exfoliation and stamp-assisted transfer, are employed to construct three-layer stacks comprising hBN-graphene-hBN. The fabrication process …

Investigation Of Domain Formation During Phase Separation In A Mixture Of Flexible And Rigid Biopolymers, Steven Huntley

All Theses

Complex fluids and heterogenous mixtures composed of multiple types of polymers are found throughout industrial and biological fluid systems. For example, extrusion based additive manufacturing systems pass dense mixtures of polymers through the extrusion heads to deposit composite polymeric materials. In cells, active and complex mixtures of biopolymers self-organize into assemblies that perform critical physiological functions.

Polymers in dense solutions undergo phase separation as a result of differences in physiochemical properties. A few examples of these properties include charge, structure, rigidity, and hydrophobicity. We observe the formation of polymer domains composed of rigid and a flexible biopolymer species that phase …

The Analysis Of Mechanical Exfoliation Of Graphene For Various Fabrication And Automation Techniques, Lance Yarbrough

Mechanical Engineering Undergraduate Honors Theses

Mechanical Exfoliation of Graphene is an often-overlooked portion of the fabrication of quantum devices, and to create more devices quickly, optimizing this process to generate better flakes is critical. In addition, it would be valuable to simulate test pulls quickly, to gain insight on flake quality of various materials and exfoliation conditions. Physical pulls of graphene at various temperatures, pull forces, and pull repetitions were analyzed and compared to the results of ANSYS simulations, solved for similar results. Using ANSYS’ ability to predict trends in exfoliations, flake thickness and coverage using stress and deflection analyses were investigated. Generally, both strongly …

Numerical Simulation Of Laser Induced Elastic Waves In Response To Short And Ultrashort Laser Pulses., Alireza Zarei

All Dissertations

In an era of intensified market competition, the demand for cost-effective, high-quality, high-performance, and reliable products continues to rise. Meeting this demand necessitates the mass production of premium products through the integration of cutting-edge technologies and advanced materials while ensuring their integrity and safety. In this context, Nondestructive Testing (NDT) techniques emerge as indispensable tools for guaranteeing the integrity, reliability, and safety of products across diverse industries.

Various NDT techniques, including ultrasonic testing, computed tomography, thermography, and acoustic emissions, have long served as cornerstones for inspecting materials and structures. Among these, ultrasonic testing stands out as the most prevalent method, …

Drag Reduction In Channel Flow Configurations For Laminar And Turbulent Flow Past Superhydrophobic Surfaces, Henry Louis Ems

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

In this work, we present friction drag reduction in minichannel laminar flow past superhydrophobic metallic surfaces. Femtosecond laser surface processing (FLSP), a one-step scalable method, was used to create permanent microscale and nanoscale structures on 316 stainless steel plates. The resulting superhydrophilic plates were covered by tall (215 μm) or short (27 μm) structures. The FLSP plates were then transitioned to superhydrophobic by evaporative deposition of a fluorinated silane, a low surface energy coating. Using purified water, the friction factor was obtained by measuring pressure drop along a minichannel with a rectangular cross section for flow rates corresponding …

Crystalline Colloidal Arrays: Exploring Light-Matter Interactions, Haley W. Jones

All Dissertations

Understanding and manipulating quantum light-matter interactions, especially in the context of nanostructured environments, is highly critical for technological progress and inventive solutions in the fields of telecommunications, energy-efficient lighting, and cutting-edge quantum computing technologies. The fundamental interactions of photons with a surrounding environment directly impact the performance and efficiency of devices such as lasers, light-emitting diodes (LEDs), and quantum computing elements, which leverage the unique properties of confined structured environments. Since the late 1980s, the connection between a structured environment and the decay kinetics of an embedded fluorophore has been a highly debated and unresolved topic in the literature. More …

Engineering Multifunctional Silicon Nanostructures From Biorenewable Cellulose Nanocrystals, Nancy Chen

All Dissertations

The imperative search for alternative materials to address the pressing demand for advance energy storage is underscored by the escalating environmental predicaments. Lithium-ion batteries (LIBs) with graphite anodes have become the benchmark in energy storage; however, they are approaching a saturation point in terms of energy density. Silicon emerges as a promising contender to supplant graphite, owing to its profuse availability, cost-effectiveness, and impressive specific capacity of 4200 mAh g^-1. By integrating silicon anodes, LIBs stand to undergo a radical transformation, markedly diminishing in weight and size, thus heralding a novel wave of compact, lightweight energy storage systems. …

A Manufacturing-To-Response Pathway For Manufacturing Optimization Of Carbon Fiber Reinforced Polymer Composite Structures, Madhura Limaye

All Dissertations

Over the past decade, there has been an increased adoption of thermoplastic and thermoset based continuous carbon fiber reinforced polymer (CFRP) composites for structural applications in several industries. Among the different manufacturing methods, thermoforming process for thermoplastic based continuous CFRP’s offer a major advantage in reducing cycle times for large scale productions. Similarly, out-of-autoclave curing process for thermoset based continuous CFRP’s using heated tooling enables production of large composite structures. However, these manufacturing processes can have a significant impact on the structural performance of parts by inducing undesirable effects. These effects include inhomogeneous fiber orientations, thickness variations, and residual stresses …

Boron-Doped Diamond As A Resilient Electrode Material In Molten Salts, Hannah Katherine Patenaude

UNLV Theses, Dissertations, Professional Papers, and Capstones

Molten salt chemistry has a range of applications within nuclear technology, including for the Molten Salt Reactors (MSRs) and pyroprocessing to recover valuable actinides for energy and national security needs. However, the high-temperature, corrosive nature of molten salts makes them particularly challenging to deploy on an industrial scale and study in benchtop measurements. Material accountability and corrosion monitoring of MSR fuels are essential components to the successful deployment of MSRs, and electroanalytical techniques like cyclic voltammetry (CV) and spectroelectrochemistry (SEC) can provide a wealth of information to describe salt systems in situ. To perform such measurements, it is imperative to …

Sliding Markov Decision Processes For Dynamic Task Planning On Uncrewed Aerial Vehicles, Trent Wiens

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Mission and flight planning problems for uncrewed aircraft systems (UASs) are typically large and complex in space and computational requirements. With enough time and computing resources, some of these problems may be solvable offline and then executed during flight. In dynamic or uncertain environments, however, the mission may require online adaptation and replanning. In this work, we will discuss methods of creating MDPs for online applications, and a method of using a sliding resolution and receding horizon approach to build and solve Markov Decision Processes (MDPs) in practical planing applications for UASs. In this strategy, called a Sliding Markov Decision …

Revealing The Three-Dimensional Arrangement Of Polar Topology In Nanoparticles, Chaewa Jeong, Juhyeok Lee, Hyesung Jo, Jaewhan Oh, Hionsuck Baik, Kyoung-June Go, Junwoo Son, Si-Young Choi, Sergey Prosandeev, Laurent Bellaiche, Yongsoo Yang

Physics Faculty Publications and Presentations

In the early 2000s, low dimensional ferroelectric systems were predicted to have topologically nontrivial polar structures, such as vortices or skyrmions, depending on mechanical or electrical boundary conditions. A few variants of these structures have been experimentally observed in thin film model systems, where they are engineered by balancing electrostatic charge and elastic distortion energies. However, the measurement and classification of topological textures for general ferroelectric nanostructures have remained elusive, as it requires mapping the local polarization at the atomic scale in three dimensions. Here we unveil topological polar structures in ferroelectric BaTiO₃ nanoparticles via atomic electron tomography, which …

Surface Treatments' Effects On The Capacitor's Dielectric Performance Under Electro-Thermal Stresses, Haider. M. Umran, Feipeng Wang

Karbala International Journal of Modern Science

Biaxial-oriented polypropylene (BOPP) films are characterized by unfavorable aging behavior because of their poor susceptibility to high temperatures, humidity, and high electric fields. This makes them unqualified to withstand harsh operating conditions, such as in capacitor applications. This study investigates the impact of annealing BOPP samples at 100 °C for five hours after fluorination at different times (15, 30, and 60 minutes) on their electrical and mechanical performance under electro-thermal stresses. Scanning electron microscope (SEM) images confirm that there is an increase in surface roughness and the formation of a dense layer of fluorine-containing groups monotonically with fluorination time. So, …

Towards A Practical Method For Monitoring Kinetic Processes In Polymers With Low-Frequency Raman Spectroscopy, Robert Vito Chimenti

Theses and Dissertations

Unlike liquids and crystalline solids, glassy materials exist in a constant state of structural nonequilibrium. Therefore, a comprehensive understanding of material kinetics is critical for understanding the structure-property-processing relationships of polymeric materials. Amorphous materials universally display low-frequency Raman features related to the phonon density of states resulting in a broad disorder band for Raman shifts below 100 cm-1, which is related to the conformational entropy and the modulus. This disorder band is dominated by the Boson peak, a feature due to phonon scattering because of disorder and can be related to the transverse sound velocity of the material, and a …

Deep Selenium Donors In Zngep2 Crystals: An Electron Paramagnetic Resonance Study Of A Nonlinear Optical Material, Timothy D. Gustafson, Larry E. Halliburton, Nancy C. Giles, Peter G. Schunemann, Kevin T. Zawilski, J. Jesenovec, Kent L. Averett, Jonathan E. Slagle [*]

Faculty Publications

Zinc germanium diphosphide (ZnGeP₂) is a ternary semiconductor best known for its nonlinear optical properties. A primary application is optical parametric oscillators operating in the mid-infrared region. Controlled donor doping provides a method to minimize the acceptor-related absorption bands that limit the output power of these devices. In the present study, a ZnGeP₂ crystal is doped with selenium during growth. Selenium substitutes for phosphorus and serves as a deep donor. Significant concentrations of native defects (zinc vacancies, germanium-on-zinc antisites, and phosphorous vacancies) are also present in the crystal. Electron paramagnetic resonance (EPR) is used to establish the …

Seeding Effects Of Submicron Caal-No3 Ldh Particles On The Hydration And Properties Of Portland Cement And Sulfoaluminate Cement Pastes, Sukanta K. Mondal, Monday Uchenna Okoronkwo

Chemical and Biochemical Engineering Faculty Research & Creative Works

Layered double hydroxide (LDH) is reported to improve the durability of concretes, primarily due to its ability to exchange anionic species, including chloride, which is implicated in corrosion-driven durability issues. However, there is no comprehensive study investigating the effect of LDH on the properties of different cement systems at both early and mature ages. in this study, the early age and mature age properties of Portland cement (OPC) and calcium sulfoaluminate (CSA) cement pastes seeded with submicron-sized calcium aluminum-NO3 LDH (CaAl-NO3 LDH) were investigated. the effects of the 1–5%mass dosage of LDH on the hydration of both cement systems were …

Thermal Frontal Polymerization – Applications In Coatings And Composites, Maria Martinez

LSU Doctoral Dissertations

Thermal frontal polymerization has long been used as a method to cure composites and coatings. However, this is the first time these applications have been used without the use of a catalyst, for the case of composites and coatings.

Chapter 2 discusses how to optimize cure-on-demand, thin layer coatings, using frontal polymerization. Previously, for the use of curing thin layer coating using thermal FP, it was known to just make the formulation viscous enough, as this would prevent premature quenching caused by heat loss. It was discovered that for a given layer thickness, a minimum viscosity and initiator concentration were …

Uncertainty Analysis In Machine Learning Models, Ayorinde E. Olatunde, Weiqi Yue, Pawan K. Tripathi, Roger H. French, Anirban Mondal

Faculty Scholarship

No abstract provided.

Shorting At Long Duration: Impact Of Extended Discharge Capacity On Battery Solid Electrolytes, Ryan C. Hill, Amanda S. Peretti, Leo J. Small, Erik D. Spoerke, Yang-Tse Cheng

Chemical and Materials Engineering Faculty Publications

Long-duration energy storage (LDES) is critical to a stable, resilient, and decarbonized electric grid. While batteries are emerging as important LDES devices, extended, high-power discharges necessary for cost-competitive LDES present new materials challenges. Focusing on a new generation of low-temperature molten sodium batteries, we explore here unique phenomena related to long-duration discharge through a well-known solid electrolyte, NaSICON. Specifically, molten sodium symmetric cells at 110 ° C were cycled at 0.1 A cm−2 for 1–23 h discharges. Longer discharges led to unstable overpotentials, reduced resistances, and decreased electrolyte strength, caused by massive sodium penetration not observed in shorter duration discharges. …

Longitudinal Solid Polarized Target For Clas12 And Study Of Spin Structure Of Nucleons, Pushpa Pandey

Physics Theses & Dissertations

A suite of experiments measuring target-spin observables in electron-nucleon scattering (dubbed Run Group C) was conducted at Jefferson Lab’s Hall B in Newport News, VA with a new polarized nuclear target known as ‘APOLLO’ (Ammonia Polarized Longitudinally). This innovative target is engineered to seamlessly integrate with the advanced 12 GeV CEBAF (Continuous Electron Beam Accelerator Facility) accelerator and the Hall B CLAS12 (12 GeV CEBAF Large Acceptance Spectrometer) detector array. The ‘APOLLO’ target harnesses the power of Dynamic Nuclear Polarization (DNP) to achieve longitudinal polarization of solid ammonia, thereby creating a net polarization in both protons (NH₃) and …

Advancements In Characterization Of Ancient Potteries From Southeast Asia: A Review Of Analytical Techniques, Chitnarong Sirisathitkul

Makara Journal of Science

Ancient potteries offer valuable information regarding technological advancements, life dynamics, cultural diversity, and trade routes in the past. Earthenware, stoneware, and porcelain from Southeast Asia have been characterized using several analytical techniques, as reviewed in this article. Fluorescent and diffracted X-rays give rise to elemental and phase compositions, respectively. Examination of molecular bonds requires vibrational spectroscopy, which is useful for the identification of organic materials in ancient potteries. With the advent of portable X-ray fluorescence and Raman spectrometry, on-site analysis of archeological ceramics is now possible. For in-depth analysis, synchrotron light sources can provide new insights into artifacts through X-ray …

Recent Advances In Solar Photo(Electro)Catalytic Nitrogen Fixation, Jun-Bo Ma, Sheng Lin, Zhiqun Lin, Lan Sun, Chang-Jian Lin

Journal of Electrochemistry

Ammonia (NH₃) is an essential chemical in modern society. It is currently produced in industry by the Haber-Bosch process using H₂ and N₂ as reactants in the presence of iron-based catalysts at high-temperature (400–600 ^oC) and extremely highpressure (20–40 MPa) conditions. However, its efficiency is limited to 10% to 15%. At the same time, a large amount of energy is consumed, and CO₂ emission is inevitably. The development of a sustainable, clean, and environmentally friendly energy system represents a key strategy to address energy crisis and environmental pollution, ultimately aiming to achieve carbon neutrality. …

Micropatterning And Functionalization Of Single Layer Graphene: Tuning Its Electron Transport Properties, Miao-Miao Cui, Lian-Huan Han, Lan-Ping Zeng, Jia-Yao Guo, Wei-Ying Song, Chuan Liu, Yuan-Fei Wu, Shi-Yi Luo, Yun-Hua Liu, Dong-Ping Zhan

Journal of Electrochemistry

As a promising 2D material, graphene exhibits excellent physical properties including single-atom-scale thickness and remarkably high charge carrier mobility. However, its semi-metallic nature with a zero bandgap poses challenges for its application in high-performance field-effect transistors (FETs). In order to overcome these limitations, various approaches have been explored to modulate graphene's bandgap, including nanoscale confinement, external field induction, doping, and chemical micropatterning. Nevertheless, the stability and controllability still need to be improved. In this study, we propose a feasible method that combines electrochemical bromination and photolithography to precisely tune the electron transport properties of single layer graphene (SLG). Through this …