Engineering Commons^™

Spatially Resolved Elastic Modulus Of Magnesium Silicate Hydrate: A Cementitious Material, Arif Syed

Material Science and Engineering Theses

Magnesium-based cements such as magnesium silicate hydrate (MSH) have drawn interest as an environmentally friendly substitute for ordinary Portland cement because of their potential for reduced carbon footprint. The precise determination of these materials' elastic moduli is important to better assess their mechanical performance. Atomic force microscopy (AFM) is an effective tool for precise and spatially resolved quantification of nanomechanical characteristics of materials, including thin films. In this study, elastic modulus maps of MSH grown on single crystal mica surfaces were obtained using amplitude modulation-frequency modulation AFM. The effects of the Mg:Si ratio and morphology on the elastic modulus of …

Fabrication Of Alumina Membranes From Uv Resin– Alumina Particle Slurries, Dominique Henry Porcincula

Master's Theses

Ceramics membranes are made in a wide variety of different techniques using a wide variety of different materials. However, many of the common techniques utilize a slurry of ceramic particles, additives, and either organic solvent or water that is shaped into a membrane, left to dry, and then sintered together. Drying is a time consuming process, often requiring several hours for the liquid medium to evaporate. Defect formation caused by development of partial pressures across the drying membrane, including cracks and warpage, also typically occurs during the drying process. To address this, slurries of ceramic particles made with a low …

Peg-Water Electrolyte For High-Performance Zinc Iodine Dual-Ion Batteries, Xiao-Feng Qu, Yu-Ting Tang, Xin-Cheng He, Jia-Sheng Zhou, Zi-Heng Tang, Wen-Hua Feng, Jun Liu

Journal of Electrochemistry

Thanks to abundant resource and rapid redox reaction kinetics, iodine is regarded as promising positive materials inthe batteries. However, the shuttling effect due to the high solubility of iodine in the electrolyte makes the performance of battery poor. In this paper, polyethylene glycol (PEG400) and potassium iodide were added into zinc-ion aqueous electrolyte. PEG400 could complex with iodine to reduce the dissolution of iodine, therefore alleviating the formation of soluble triiodide (I₃^–) from iodine and iodide ions. Furthermore, this electrolyte was used in the battery with double carbon cloths as the current collectors, double separators and zinc …

Lif-Sn Composite Modification Layer To Modify Garnet/Lithium Metal Interface, Wu Yang, Xue-Fan Zheng, Yu-Qi Wu, Zheng-Liang Gong

Journal of Electrochemistry

The growing demands for electric vehicles and consumer electronics; as well as the expanding renewable energy storage market; have promoted extensive research on energy storage technologies with low costhigh energy density and safety. Lithium (Li) metal and solid-state electrolytes are considered as important components for next-generation batteries because of their great potential for improvements in energy density and safety performance. Inorganic garnet-type solid electrolytes with high Li-ion conductivity (about 10^-3 S·cm^-1) and high shear modulus (55 GPa) are considered to be ideal solid-state electrolytes; however; the issue of Li dendrite growth still obstructs their practical application. Herein; …

Constructing Carbon-Encapsulated Nifev-Based Electrocatalysts By Alkoxide-Based Self-Template Method For Oxygen Evolution Reaction, En-Hui Ma, Xu-Po Liu, Tao Shen, De-Li Wang

Journal of Electrochemistry

The development of green and sustainable water-splitting hydrogen production technology is beneficial to reducing the over-reliance on fossil fuels and realizing the strategic goal of "carbon neutral". As one of the half reactions for water splitting, oxygen evolution reaction has suffered the problems of sluggish four-electron transfer process and relatively slow reaction kinetics. Therefore, exploring efficient and stable catalysts for oxygen evolution reaction is of critical importance for water-splitting technology. Metal alkoxides are a series of compounds formed by the coordination function of metal ions with alcohol molecules. Metal alkoxides possess the double advantages of organic materials and inorganic materials, …

Preparation And Lithium Storage Properties Of Carbon Confined Li3Vo4 Nano Materials, Jia-Qi Fan, Huan-Qiao Song, Jia-Ying An, Amantai A-Yi-Da-Na, Mo Chen

Journal of Electrochemistry

Li₃VO₄, as a promising anode material for lithium ion batteries, has been widely studied because of its low and safe voltage, and large capacity. However, its poor electronic conductivity impedes the practical application of Li₃VO₄ particularly at high rates. In this paper, carbon confined Li₃VO₄ nano materials (Li₃VO₄/C) were synthesized by hydrothermal and solid-phase method, and for comparison, the Li₃VO₄ (N) nano materials without carbon confinement and Li3VO4 (B) materials were also synthesized by pure solid-phase method. The composition, structure, morphology and specific …

The Effects Of Engineering Summer Camps On Middle And High School Students’ Engineering Interest And Identity Formation: A Multi-Methods Study, Timothy Robinson, Adam Kirn, Jenny Amos, Indira Chatterjee

Journal of Pre-College Engineering Education Research (J-PEER)

This multi-methods study explores changes in engineering interest and identity of middle and high school students (n = 79) attending introductory-level engineering summer camps at a large western land grant university. Middle school is a critical time when student interest, identity, and subsequently career choice begin to emerge and hence it is important that at this age students are given accurate information about engineering majors in college and future career opportunities in engineering. Data were collected over a period of two years in six summer camps. Three separate populations of middle and high school students participated in the summer …

Pursuing Excitonic Energy Transfer With Programmable Dna-Based Optical Breadboards, Divita Mathur, Sebastián A. Díaz, Niko Hildebrandt, Ryan D. Pensack, Bernard Yurke, Austin Biaggne, Lan Li, Joseph S. Melinger, Mario G. Ancona, William B. Knowlton, Igor L. Medintz

Materials Science and Engineering Faculty Publications and Presentations

DNA nanotechnology has now enabled the self-assembly of almost any prescribed 3-dimensional nanoscale structure in large numbers and with high fidelity. These structures are also amenable to site-specific modification with a variety of small molecules ranging from drugs to reporter dyes. Beyond obvious application in biotechnology, such DNA structures are being pursued as programmable nanoscale optical breadboards where multiple different/identical fluorophores can be positioned with sub-nanometer resolution in a manner designed to allow them to engage in multistep excitonic energy-transfer (ET) via Förster resonance energy transfer (FRET) or other related processes. Not only is the ability to create such complex …

Carrier Dynamics In Green Iii-Nitride Leds Using Small-Signal Electroluminescence, Xuefeng Li

Optical Science and Engineering ETDs

Solid-state lighting has achieved significant success over the past two decades, but the low quantum efficiency of green LEDs (i.e., the “green gap”) remains a barrier to full red-green-blue (RGB) displays in numerous applications. Combating efficiency reduction in longer-wavelength LEDs requires understanding the relative roles of intrinsic effects (e.g., wave-function overlap, carrier-current density relationship, phase-space filling (PSF)) vs. extrinsic effects (e.g., material degradation due to increased defect density, compositional inhomogeneities, etc.). A systematic study of the carrier dynamics in InGaN/GaN LEDs is very important for understanding the origin of the green gap and for providing solutions to improve the efficiency …

Head Impact Effects In Small Remotely Piloted Aircraft System (Srpas) Collisions: Gender Specific Risks And Vulnerable Population Protection, Md Farhan Hoque Sagar

Electronic Thesis and Dissertation Repository

This study focuses on supporting the development of safety regulations for vulnerable populations during drone to head impacts. First, the small female head and neck model was compared to cadaveric data. Then, combined with lab’s previous work, gender-based disparities in head impact responses were highlighted, with small females experiencing higher injury risk metrics, despite lower skull von Mises stress. Beyond small females, children of various ages and their head responses during impacts were also analyzed. In addition to the previously developed quadcopter drone model, a new Mavic Pro drone model was developed, and this model was integrated with human head …

Modeling Hydration Kinetics Of Sustainable Cementitious Binders Using An Advanced Nucleation And Growth Approach, Taihao Han, Jie Huang, Gaurav Sant, Narayanan Neithalath, Ashutosh Goel, Aditya Kumar

Electrical and Computer Engineering Faculty Research & Creative Works

Supplementary cementitious materials (SCMs) are utilized to partially substitute Portland cement (PC) in binders, reducing carbon-footprint and maintaining excellent performance. Nonetheless, predicting the hydration kinetics of [PC + SCM] binders is challenging for current analytical models due to the extensive diversity of chemical compositions and molecular structures present in both SCMs and PC. This study develops an advanced phase boundary nucleation and growth (pBNG) model to yield a priori predictions of hydration kinetics—i.e., time-resolved exothermic heat release profiles—of [PC + SCM] binders. The advanced pBNG model integrates artificial intelligence as an add-on, enabling it to accurately simulate hydration kinetics for …

A Computational Approach For Mapping Electrochemical Activity Of Multi-Principal Element Alloys, Jodie A. Yuwono, Xinyu Li, Tyler D. Dolezal, Adib J. Samin, Javen Qinfeng Shi, Zhipeng Li, Nick Birbilis

Faculty Publications

Multi principal element alloys (MPEAs) comprise an atypical class of metal alloys. MPEAs have been demonstrated to possess several exceptional properties, including, as most relevant to the present study a high corrosion resistance. In the context of MPEA design, the vast number of potential alloying elements and the staggering number of elemental combinations favours a computational alloy design approach. In order to computationally assess the prospective corrosion performance of MPEA, an approach was developed in this study. A density functional theory (DFT) – based Monte Carlo method was used for the development of MPEA ‘structure’; with the AlCrTiV alloy used …

Syntheses, Photophysics, & Application Of Porphyrinic Metal-Organic Frameworks, Zachary L. Magnuson

USF Tampa Graduate Theses and Dissertations

Porphyrins are a group of heterocyclic macrocycles that play crucial roles in various biological processes such as electron transfer, catalysis, and sensing. Hemoglobin, which carries oxygen in the blood of mammals, and chlorophyll, which drives photosynthesis in plants and algae, are both porphyrins. The ability of porphyrins to bind metal ions and their unique electronic and photophysical properties make them an excellent platform for designing functional materials for various applications, often drawing inspiration from their function in nature. Metal-organic frameworks (MOFs) are a class of porous materials that have been extensively studied in recent years due to their high surface …

Characterization Analysis And Design Of Mid-Wave Infrared Iii- V-Based Type-Ii Superlattice Nbn Photodetectors For Space Applications, Alexander Timothy Newell

Electrical and Computer Engineering ETDs

The performance of the mid-wave infrared InGaAs/InAsSb nBn photodetector is investigated and its viability for space applications is assessed. Three structures are grown with unique absorber layer doping profiles via molecular beam epitaxy. Material and device characterizations are performed and analyzed to determine the effects of doping on fundamental material parameters and detector performance. Noise-equivalent irradiance is calculated to be a factor of 4x that of an ideal detector exhibiting Rule 07 dark current and 100% quantum efficiency, demonstrating high sensitivity. The structures are then irradiated with 63 MeV protons to evaluate the extent of performance degradation over the course …

Corrosion Of Oil Pipeline: A Case Study On The Niger Delta Region Of Nigeria., Victor U. Okoro

Corrosion Research

Corrosion of oil pipelines in Nigeria, particularly in the Niger Delta region, has extensive and detrimental environmental and societal impacts. This issue results in substantial financial losses and reputational damage for oil companies operating in the area. Local communities suffer economically, affecting agriculture and food security. Furthermore, corrosion-related oil spills lead to air quality degradation by releasing volatile organic compounds and greenhouse gases, contributing to respiratory issues and worsening climate change.

These oil spill cleanups are costly and time-consuming, with estimated expenses reaching billions of dollars. Using the Nembe Creek Trunk Line (NCTL) case study, it is evident that addressing …

Exciton Delocalization In A Fully Synthetic Dna-Templated Bacteriochlorin Dimer, Olga A. Mass, Devan R. Watt, Lance K. Patten, Ryan D. Pensack, Jeunghoon Lee, Daniel B. Turner, Bernard Yurke, William B. Knowlton

Materials Science and Engineering Faculty Publications and Presentations

A bacteriochlorophyll a (Bchla) dimer is a basic functional unit in the LH1 and LH2 photosynthetic pigment–protein antenna complexes of purple bacteria, where an ordered, close arrangement of Bchla pigments—secured by noncovalent bonding to a protein template—enables exciton delocalization at room temperature. Stable and tunable synthetic analogs of this key photosynthetic subunit could lead to facile engineering of exciton-based systems such as in artificial photosynthesis, organic optoelectronics, and molecular quantum computing. Here, using a combination of synthesis and theory, we demonstrate that exciton delocalization can be achieved in a dimer of a synthetic bacteriochlorin (BC …

Effect Of Hf Alloying On Magnetic, Structural, And Magnetostrictive Properties In Feco Films For Magnetoelectric Heterostructure Devices, Thomas Mion, Margo Staruch, Konrad Bussmann, Goran Karapetrov, Olaf Van 'T Erve, Sara Mills, Heonjune Ryou, Ramasis Goswami, Patrick G. Callahan, David J. Rowenhorst, Syed B. Qadri, Samuel Lofland, Peter Finkel

Faculty Scholarship for the College of Science & Mathematics

Materials with high magnetoelectric coupling are attractive for use in engineered multiferroic heterostructures with applications such as ultra-low power magnetic sensors, parametric inductors, and non-volatile random-access memory devices. Iron-cobalt alloys exhibit both high magnetostriction and high saturation magnetization that are required for achieving significantly higher magnetoelectric coupling. We report on sputter-deposited (Fe0.5Co0.5)1-xHfx (x = 0 - 0.14) alloy thin films and the beneficial influence of Hafnium alloying on the magnetic and magnetostrictive properties. We found that co-sputtering Hf results in the realization of the peening mechanism that drives film stress from highly tensile to slightly compressive. Scanning electron microscopy and …

Thermo-Mechanical Instabilities In Next-Generation Friction Materials In High-Speed Sliding Systems, Kingsford Koranteng

Electronic Theses and Dissertations

For centuries, the manufacturing industry has incorporated metals like copper into friction materials to enhance thermal properties and minimize thermo-mechanical instabilities (TMI) in high-speed sliding systems. Unfortunately, these metals have adverse environmental effects due to the emission of hazardous particulate matter. As a result, there is a growing movement towards adopting next-generation friction materials as an alternative solution.

The study begins by conducting experimental and numerical investigations to examine the instabilities found in metal-based friction materials. The primary objective is to utilize the insights gained from the investigations to computationally explore effective strategies for mitigating various instabilities that may arise …

Molecular Dynamics Study Of Characterization In Metal-Free Friction Materials, Yizhan Zhang

Electronic Theses and Dissertations

Metallic friction materials currently used in industry may adversely impact the environment. Substitutions for metals in friction materials, on the other hand, can introduce operational safety issues and other unforeseeable issues such as thermal-mechanical instabilities and insufficient strength. In view of it, this dissertation focuses on developing different kinds of materials from simple structure to complex structure and evaluating the material properties with the assistance of molecular dynamics (MD) tools at the nano scale.

First, the concept of the contacted surfaces in friction at the atomic scale was introduced in order to get accurate understanding of the friction process compared …

Quantitative, Photocurrent Multidimensional Coherent Spectroscopy, Adam Halaoui

Electronic Theses and Dissertations

Multidimensional coherent spectroscopy (MDCS) is a quickly growing field that has a lot of advantages over more conventional forms of spectroscopy. These advantages all come from the fact that MDCS allows us to get time resolved correlated emission and absorption spectra using very precisely chosen interactions between the density matrix and the excitation laser. MDCS spectra gives the researcher a lot of information that can be extracted purely through qualitative analysis. This is possible because state couplings are entirely separated on the spectra, and once we know how to read the data, we can see how carriers transport in the …

Effect Of Blending Of Medium-Temperature Phase Change Material On The Bitumen Storage Heat, Loubna Najemi, Imane Belyamani, Mohsine Bouya

All Works

This study aims to investigate the feasibility of using D-Mannitol as a phase-change material (PCM) to increase the energy storage capacity and improve the thermomechanical characteristics of the modified bitumen. D-mannitol (Dm) was incorporated into Bitumen (Bm) using a high-speed shearing method. The results showed that the integration of PCM enhanced the physical characteristics of the basic bitumen, with the modified bitumen having a melting point close to that of D-mannitol (Tm = 164 °C). The D-mannitol was found to crystallize during cooling, indicating that it can store or release heat in the latent form. The specific heat capacity of …

Analysis Of Bombyx Mori Silk And Polyimide Nanofibers, Sabrina Leseul

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

This thesis presents a study on the properties of Bombyx Mori silk nanofibers and polyimide (PI) nanofibers. Firstly, a Bombyx Mori silk solution has been created with degummed silkworm cocoons in order to separate the fibroin and the sericin, the two main proteins of the silk. The fibroin was then centrifuged to remove insoluble particles and stored and 4°C before mixing with hexafluoroisopropanol (HFIP). On the second part, a polyimide solution, made with shavings of polyimide and N,N-dimethylformamide (DMF). Both solutions are then electrospun. Electrospinning parameters are studied. In this way, a part of my thesis has been dedicated to …

Hydroxyapatite-Based Coatings On Silicon Wafers And Printed Zirconia, Antoine Chauvin

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

Dental surgery needs a naturally attract implant design that can ensure both osseointegration and soft tissue integration. Hydroxyapatite (HAp), the main mineral constituent of dentine and tooth enamel, is commonly used as a coating component, notably for overlaying titanium– or ceramics–based implants. This thesis aims to investigate the behavior of a HAp-based coating, specifically designed to be compatible with a porous substrate. Coating layers are made by sol–gel dip coating by immersion of porous substrates made by additive manufacturing into solutions of HAp, having been mixed with polyethyleneimine (PEI), to improve the adhesion of HAp on the substrate. First, the …

Applications Of Femtosecond Laser-Processed And Nanoneedle-Synthesized Surfaces To Enhance Pool Boiling Heat Transfer, Peter Efosa Ohenhen

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

In the present work, the integration of femtosecond laser surface processing (FLSP) with copper hydroxide on hybrid surfaces was examined. The goal was to determine the impact on pool boiling enhancement. The samples for the investigation were fabricated by first functionalizing with FLSP, and the process was then followed by citric acid cleaning (CAC) to eliminate the oxides generated on the copper surface during the FLSP process. After the citric acid cleaning, the samples were immersed in ethanol and subjected to an ultrasonic bath for 25 minutes. This step was performed to eliminate any residual citric acid and loose particles. …

An Investigation Into The Challenges Of Contemporary Additive Manufacturing: Insights Into The Metallurgical Response Of Materials And Relevant Solution, Huan Ding

LSU Doctoral Dissertations

Additive Manufacturing (AM) has gained attention in recent years due to its unique capabilities in the fabrication of complex parts. As with any new research, there is still a lack of sufficient understanding in the field of additive manufacturing, and further investigation is needed to solve existing problems. Ultimately, the aim is to enable the widespread use of AM components across various industries.

Chapter One provides a brief introduction to the background and current bottlenecks of additive manufacturing technology. Chapter two focuses on the development of high-strength 7075 aluminum alloy (Al7075) for Fused Deposition Modeling and Sintering (FDMS) technology. Al7075 …

Boosting Snr Of Cascaded Fbgs In A Sapphire Fiber Through A Rapid Heat Treatment, Farhan Mumtaz, Hanok Tekle, Bohong Zhang, Jeffrey D. Smith, Ronald J. O'Malley, Rex E. Gerald, Jie Huang

Electrical and Computer Engineering Faculty Research & Creative Works

This Letter reports the performance of femtosecond (fs) laser-written distributed fiber Bragg gratings (FBGs) under high-temperature conditions up to 1600°C and explores the impact of rapid heat treatment on signal-to-noise ratio (SNR) enhancement. FBGs are essential for reliable optical sensing in extreme temperature environments. Comprehensive tests demonstrate the remarkable performance and resilience of FBGs at temperatures up to 1600°C, confirming their suitability for deployment in such conditions. The study also reveals significant fringe visibility improvements of up to ∼10 dB on a 1-m-long sapphire optical fiber through rapid heat treatment, representing a first-time achievement to the best of our knowledge. …

Impact Of Silicon Ion Irradiation On Aluminum Nitride-Transduced Microelectromechanical Resonators, David D. Lynes, Joshua Young, Eric Lang, Hengky Chandrahalim

Faculty Publications

Microelectromechanical systems (MEMS) resonators use is widespread, from electronic filters and oscillators to physical sensors such as accelerometers and gyroscopes. These devices' ubiquity, small size, and low power consumption make them ideal for use in systems such as CubeSats, micro aerial vehicles, autonomous underwater vehicles, and micro-robots operating in radiation environments. Radiation's interaction with materials manifests as atomic displacement and ionization, resulting in mechanical and electronic property changes, photocurrents, and charge buildup. This study examines silicon (Si) ion irradiation's interaction with piezoelectrically transduced MEMS resonators. Furthermore, the effect of adding a dielectric silicon oxide (SiO₂) thin film is …

Vacancy Ordering In Zirconium Carbide With Different Carbon Contents, Yue Zhou, Jeremy Lee Watts, Cheng Li, William Fahrenholtz, Gregory E. Hilmas

Materials Science and Engineering Faculty Research & Creative Works

Zirconium carbide (ZrCx) ceramics with different carbon contents were prepared by reactive hot-pressing. The rock-salt structure of ZrCx was the only phase detected by x-ray diffraction of the hot pressed ceramics. The relative densities of ZrCx decreased as carbon content increased, in general. The actual carbon contents were measured by completely oxidizing the ZrCx ceramics to ZrO₂. For most compositions, the actual carbon contents were higher than nominal batched compositions, presumably due to carbon uptake from the graphite furnace and hot press dies. Selected area electron diffraction and neutron powder diffraction revealed the presence of carbon vacancy ordering …

Research Progress And Performance Improvement Strategies Of Hard Carbon Anode Materials For Sodium-Ion Batteries, Xiu-Ping Yin, Yu-Feng Zhao, Jiu-Jun Zhang

Journal of Electrochemistry

This paper systematically summarizes the research progress of hard carbon anode materials in sodium ion batteries(SIBs) and the development of the corresponding sodium storage mechanism in recent years, and reviews the performance improvement strategies of hard carbon materials from the aspects of structural design and electrolyte regulation. The effects of the selection of precursors, carbonization temperature, pretreatment, pore formers, heteroatom doping, material compounding, electrolyte regulation and pre-sodiumization on the sodium storage performance of hard carbon anode materials are briefly described. This paper provides new insights into the design, synthesis and electrolyte
matching of high-performance and low-cost hard carbon materials, and …

Surface Modifications Of Lini0.96Co0.02Mn0.02O2 With Tungsten Oxide And Phosphotungstic Acid, Gang Zhao, Zheng-Liang Gong, Yi-Xiao Li, Yong Yang

Journal of Electrochemistry

With the rapid development of electric vehicles, enormous demands are made for higher energy density, better cycling performance and lower cost of lithium-ion batteries (LIBs). As an important high capacity cathode material for LIBs, the high nickel layered oxide material LiNi_0.8Co_0.1Mn_0.1O₂(NCM811) can reach an energy density of 760 Wh·kg^-1. The ultra-high nickel ternary positive electrode material (LiNi_1-x-yCo_xMn_yO₂, x ≥ 0.90) has a specific capacity of more than 210 mAh·g^-1, and can realize higher energy density. Besides, an ultra-high nickel material …