Materials Science and Engineering Commons^™

On The Feasibility Of Tailoring Copper-Nickel Functionally Graded Materials Fabricated Through Laser Metal Deposition, Sreekar Karnati, Yunlu Zhang, Frank W. Liou, Joseph William Newkirk

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this study, pulse‐width modulation of laser power was identified as a feasible means for varying the chemical gradient in copper—nickel‐graded materials. Graded material deposits of 70 wt. %. copper‐30 wt. %. nickel on 100 wt. %. nickel and vice versa were deposited and characterized. The 70/30 copper—nickel weight ratio in the feedstock powder was achieved through blending elemental copper and 96 wt. %. Ni—Delero‐22 alloy. At the dissimilar material interface over the course of four layers, the duty cycle of power was ramped down from a high value to optimized deposition conditions. This change was theorized to influence the …

To Burn-In, Or Not To Burn-In: That’S The Question, Ephraim Suhir

Mechanical and Materials Engineering Faculty Publications and Presentations

In this paper it is shown that the bathtub-curve (BTC) based time-derivative of the failure rate at the initial moment of time can be considered as a suitable criterion of whether burn-in testing (BIT) should or does not have to be conducted. It is also shown that the above criterion is, in effect, the variance of the random statistical failure rate (SFR) of the mass-produced components that the product manufacturer received from numerous vendors, whose commitments to reliability were unknown, and their random SFR might vary therefore in a very wide range, from zero to infinity. A formula for the …

Corrosion Initiation And Propagation On Carburized Martensitic Stainless Steel Surfaces Studied Via Advanced Scanning Probe Microscopy, Armen Kvryan, Corey M. Efaw, Kari A. Higginbotham, Olivia O. Maryon, Paul H. Davis, Elton Graugnard, Michael F. Hurley

Materials Science and Engineering Faculty Publications and Presentations

Historically, high carbon steels have been used in mechanical applications because their high surface hardness contributes to excellent wear performance. However, in aggressive environments, current bearing steels exhibit insufficient corrosion resistance. Martensitic stainless steels are attractive for bearing applications due to their high corrosion resistance and ability to be surface hardened via carburizing heat treatments. Here three different carburizing heat treatments were applied to UNS S42670: a high-temperature temper (HTT), a low-temperature temper (LTT), and carbo-nitriding (CN). Magnetic force microscopy showed differences in magnetic domains between the matrix and carbides, while scanning Kelvin probe force microscopy (SKPFM) revealed a 90–200 …

Computational And Experimental Development Of 2d Anisotropic Photonic Crystal Metamaterials, James A. Ethridge

Theses and Dissertations

The future of optical devices involves manipulation of nanoscale structure in order to achieve full control over the properties of the device. In fields as diverse as directed energy, remote sensing, optical communications and optical computing, these devices promise to greatly improve performance and efficiency. To advance this further, novel samples that incorporate both photonic crystal (PhC) structure and metamaterial properties, known as PhC metamaterials, are proposed. These PhC metamaterials allow for complete control over the directionality of the light-matter interaction to serve in these new applications. To develop this technology, first, metamaterials with no PhC structure are fabricated using …

Effects Of Steel Type And Sandblasting Pretreatment On The Solid-Liquid Compound Casting Characteristics Of Zinc-Coated Steel/Aluminum Bimetals, Jesik Shin, Taehyeong Kim, Kyoungmook Lim, Hoon Cho, Daeho Yang, Changyeol Jeong, Sung Yi

Mechanical and Materials Engineering Faculty Publications and Presentations

Effects of zinc-coated steel type and steel surface sandblasting pretreatment in the solid-liquid compound casting of layered type steel/aluminum bimetals were investigated. The Zn coating behavior and its effects on interfacial microstructure evolution and fracture mechanism were also discussed. The aluminum fluidity in thin plate type flow channels formed by the steel insert and the mold wall primarily depended on the insert surface roughness and secondarily on the wettability. As-galvanized (GI) steel/aluminum bimetal joints showed the bonding strength of 20 MPa and more, while galvannealed (GA) steels showed poor bonding. The interfacial bonding zone consisted of most Al13Fe4, Al8Fe2Si, Al4.5FeSi …

Cvd Preparation And Application Of 3d Graphene In Electrochemical Energy Storage, Yong-Kang Xia, Ming-Yuan Gu, Hong-Guan Yang, Xin-Zhi Yu, Bing-An Lu

Journal of Electrochemistry

Three-dimensional (3D) graphene combinations with the excellent intrinsic properties of graphene and the 3D micro/nano porous structures provide a graphene foam with high specific surface area, excellent mechanical strength and fast electron and mass transports. The 3D graphene foam and its composite nanomaterials are widely used in the fields of nano-electronics, energy storage, chemical and biological sensing. The 3D graphene foam prepared by chemical vapor deposition (CVD) method is of high purity and crystallinity.  In this review, a brief overview in the CVD preparations of 3D graphene and properties of CVD prepared 3D graphene based nanomaterials in electrochemical energy storage …

Preface On Special Issue Of Next-Generation Secondary Batteries, Zhen Zhou, Quan-Feng Dong

Journal of Electrochemistry

No abstract provided.

Synthesis Of Flower-Like Vanadium Disulfide For Lithium Storage Application, Pan Li, Jian Liu, Wei-Yi Sun, Hai-Xia Li, Zhan-Liang Tao

Journal of Electrochemistry

In order to improve the electrochemical properties of vanadium disulfide (VS₂) as an electrode material in Li-ion battery, the flower-like VS₂ was prepared by a one-step hydrothermal method with the addition of polyethylene glycol 400. The phase and morphology of the product were characterized by using X-ray diffraction and field emission scanning electron microscopy. During the growth process, it was observed that the flower-like VS₂ was interspersed with several hexagonal vanadium disulfide nanosheets, which had a high specific surface area and excellent structural stability. The flower-like VS₂ was used for the cathode material test in …

Ni/Mn3O4/Nimn2O4 Double-Shelled Hollow Spheres Embedded Into Reduced Graphene Oxide As Advanced Anodes For Sodium-Ion Batteries, Chong Yan, Hua-Ri Kou, Bo Yan, Xiao-Jing Liu, De-Jun Li, Xi-Fei Li

Journal of Electrochemistry

Delicately building the unique nanocomposite with the combination of hollow structure and reduced graphene oxide (rGO) is highly desirable and still remains a great challenge in the field of energy conversion and storage. In this work, Ni/Mn₃O₄/NiMn₂O₄ double-shelled hollow spheres coated by rGO (denoted as R-NMN) have been successfully synthetized via one-step rapid solvothermal treatment followed by subsequent annealing for the first time. Served as anodes for sodium ion batteries (SIBs), the R-NMN composite containing 25wt% rGO exhibits a high discharge capacity of 187.8 mAh·g^-1 after 100 cycles at 50 mA·g^{-1 …}

Current Status And Prospect Of Battery Configuration In Li-S System, Jia-Hang Chen, Hui-Jun Yang, Cheng Guo, Jiu-Lin Wang

Journal of Electrochemistry

Commercial lithium-ion batteries (LIBs) are incapable of satisfying the increasing demand for emerging electronic devices due to their limited energy density. Among the next-generation batteries, lithium-sulfur (Li-S) batteries are becoming a promising energy-storage system due to their high theoretical energy density and natural abundance of sulfur. However, the shuttle of soluble polysulfide intermediates between two electrodes, as well as the problem on Li metal anode,lower the utilization of active material and lead to the loss of specific capacity and rapid capacity fading. All the above challenges limit the further application of Li-S batteries. Recently, various novel battery configurations have been …

Applications Of Advanced Imaging Technologies For Critical Issues Of All-Solid-State Lithium Battery Studies, Yi-Bo Zhao, Hui-Hui Liu, Song-Liang Chen, Shou-Hang Bo

Journal of Electrochemistry

All-solid-state lithium batteries have attracted much attention for their high energy density and good safety. To increase their efficiency and prolong their service life, it is necessary to achieve high ion conductivity at the electrode/electrolyte interface and in the electrolyte, as well as to eliminate dendrites growth in the battery. Based on the critical requirements outlined above, this paper discusses the applications of advanced imaging technologies in relevant studies. Recent progresses in investigations of all-solid-state lithium batteries by imaging techniques including electron microscopy, scanning probe microscopy, X-ray tomography, magnetic resonance imaging and optical microscopy are summarized.

Recent Progress On Tio2-Based Anode Materials For Sodium-Ion Batteries, Si-Tian Lian, Jian-Shuai Lv, Qiang Yu, Guang-Wu Hu, Zhuo Chen, Liang Zhou, Li-Qiang Mai

Journal of Electrochemistry

Titanium dioxide (TiO₂) represents a stable, low-cost, and nontoxic anode material for sodium-ion batteries (SIBs). However, the low electrical conductivity limits its electrochemical activity (specific capacity) and rate capability, hindering its widespread applications. In this article, we show that different crystal forms of TiO₂ have different pore structures, resulting in the distinct sodium storage capacities. Accordingly, the article introduces how TiO₂ microstructures influence sodium storage. The nanoparticle structure can improve the rate performance of the material due to its short ion diffusion distance, and the internal cavity of the hollow structure is beneficial to cycle stability. …

Recent Progress In Vanadium-Based Electrode Materials, Meng-Lei Sun, Da-Qi Zhang, Jin-Kui Feng, Jiang-Feng Ni

Journal of Electrochemistry

It is an important solution to solve energy storage problems by developing inexpensive and safe lithium-ion and sodium-ion batteries with superior performance. Vanadium-based electrode materials are promising electrode materials because of diversified chemical valences, open structures and high theoretical capacities. In the past few years, vanadium-based electrode materials such as oxides, sulfides, and phosphates have achieved a considerable development in the battery field, It is,  therefore, necessary to summarize their recent research progress. In this review, we particularly highlight the key challenges that are facing in the application of vanadium materials, such as low ion diffusion coefficient and poor structural …

Recent Progress In Key Materials For Room-Temperature Sodium-Ion Batteries, Fan-Fan Wang, Xiao-Bin Liu, Long Chen, Cheng-Cheng Chen, Yong-Chang Liu, Li-Zhen Fan

Journal of Electrochemistry

Sodium-ion batteries (SIBs) have attracted tremendous attention in large-scale energy storage applications due to their resource advantages. However, Na+ is larger and heavier than Li+, which will limit its reversible reaction with the electrode materials and result in poor electrochemical performance. Thus, developing stable and high-efficiency electrode materials is the key to promoting the practical application of SIBs. Furthermore, the optimization of electrolyte is essential for the construction of high-safety and long-lifespan SIBs. In this review, we mainly summarize the recent advancements of electrode materials and electrolytes for room-temperature SIBs and discuss their challenges and possible resolution strategies. We hope …

Recent Developments In Surface/Interface Modulation And Structure-Performance Relationship Of Cathode Catalysts For Li-Air Batteries, Rui Gao, Jun-Kai Wang, Zhong-Bo Hu, Xiang-Feng Liu

Journal of Electrochemistry

Lithium-air battery has been considered to be one of the most promising secondary battery systems because of its high energy density. However, the sluggish kinetics of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) on the cathode, and the high overpotential, poor cycle stability and low rate capacity have severely blocked the development and application of Li-air battery. One of the effective strategies to alleviate these issues is to develop cathode catalysts for Li-air batteries. The design and development of bifunctional cathode catalysts with high activity and efficiency on both ORR and OER is highly desired for Li-air …

A Comparative Study Of Pre-Lithiated Hard Carbon And Soft Carbon As Anodes For Lithium-Ion Capacitors, Zhao Li, Xian-Zhong Sun, Wen-Jie Liu, Xiong Zhang, Kai Wang, Yan-Wei Ma

Journal of Electrochemistry

Lithium-ion capacitor (LIC) has emerged to be one of the most promising electrochemical energy storage devices. Presently, activated carbon (AC) is the mostly used cathode material for LIC. Nevertheless, various carbonaceous materials can be used as anode materials, such as hard carbon (HC) and soft carbon (SC). Therefore, HC and SC with different structural and electrochemical characteristics have been investigated as the anode materials of LICs in this work. Compared with the HC electrode, the SC electrode showed higher electronic conductivity and reversible capacity. The rate capabilities of the two carbonaceous materials as a function of coating thickness have been …

Method Of Increasing Mass Transfer Rate Of Acid Gas Scrubbing Solvents, Joseph E. Remias, Cameron A. Lippert, Kunlei Liu

Center for Applied Energy Research Faculty Patents

A method of increasing the overall mass transfer rate of acid gas scrubbing solids is disclosed. Various catalyst compounds for that purpose are also disclosed.

Computational Design Of Flexible Electride With Nontrivial Band Topology, Sheng-Cai Zhu, Lei Wang, Jing-Yu Qu, Jun-Jie Wang, Timofey Frolov, Xing-Qiu Chen, Qiang Zhu

Physics & Astronomy Faculty Research

Electrides, with their excess electrons distributed in crystal cavities playing the role of anions, exhibit a variety of unique electronic and magnetic properties. In this work, we employ the first-principles crystal structure prediction to identify a new prototype of A3B electride in which both interlayer spacings and intralayer vacancies provide channels to accommodate the excess electrons in the crystal. This A3B type of structure is calculated to be thermodynamically stable for two alkaline metals oxides (Rb3O and K3O). Remarkably, the unique feature of multiple types of cavities makes the spatial arrangement of anionic electrons highly flexible via elastic strain engineering …

Evaluation Of Novel Hemocompatible Surface Coatings For Extracorporeal Life Support: A Biocompatible Alternative To Systemic Anticoagulation, Teryn Rose Roberts

USF Tampa Graduate Theses and Dissertations

Extracorporeal life support (ECLS) is a class of technologies used to support or replace the function of failing organs. During ECLS, blood is withdrawn from systemic circulation and circulated through an artificial organ or “treatment membrane” that performs the function of the failing organ, prior to return to systemic circulation. While ECLS provides life-saving therapy to wide patient populations from pre-term infants to combat-wounded soldiers, this therapy is limited due to secondary thrombotic and bleeding complications that result from: 1) exposure of blood to the foreign surfaces in the device circuit and 2) administration of anticoagulant drugs to prevent clot …

Near-Surface Material Phases And Microstructure Of Scandate Cathodes, Xiaotao Liu, Bernard K. Vancil, Matthew J. Beck, Thomas John Balk

Chemical and Materials Engineering Faculty Publications

Scandate cathodes that were fabricated using the liquid-solid process and that exhibited excellent emission performance were characterized using complementary state-of-the-art electron microscopy techniques. Sub-micron BaAl₂O₄ particles were observed on the surfaces and edges of tungsten particles, as seen in cross-section samples extracted from the scandate cathode surface regions. Although several BaAl₂O₄ particles were observed to surround smaller Sc₂O₃ nanoparticles, no chemical mixing of the two oxides was detected, and in fact the distinct oxide phases were separately verified by chemical analysis and also by 3D elemental tomography. Nanobeam electron diffraction confirmed …

The Influence Of Asphalt Ageing On Induction Healing Effect On Porous Asphalt Concrete, Shi Xu, Xueyan Liu, Amir Tabakovic, Erik Schlangen

Articles

Induction healing is a proven technology which is able to improve the self‐healing capacity of asphalt concrete. Healing is achieved via electromagnetic current produced by passing induction machine, where steel asphalt constituents heat up which in turn soften the bitumen in the asphalt layer, allowing it to flow and close cracks, repairing the damage. This paper reports on the study which investigated the influence of ageing on the healing capacity of Porous Asphalt (PA) concrete. Porous Asphalt concrete mix was prepared first, then subjected to an accelerated (laboratory) ageing process using a ventilated oven. In order to further evaluate the …

The Influence Of Periodic Shear On Structural Relaxation And Pore Redistribution In Binary Glasses, Nikolai V. Priezjev, Maxim A. Makeev

Mechanical and Materials Engineering Faculty Publications

The evolution of porous structure, potential energy and local density in binary glasses under oscillatory shear deformation is investigated using molecular dynamics simulations. The porous glasses were initially prepared via a rapid thermal quench from the liquid state across the glass transition and allowed to phase separate and solidify at constant volume, thus producing an extended porous network in an amorphous solid. We find that under periodic shear, the potential energy decreases over consecutive cycles due to gradual rearrangement of the glassy material, and the minimum of the potential energy after thousands of shear cycles is lower at larger strain …

Hard, Soft And Off-The-Shelf Foot Orthoses And Their Effect On The Angle Of The Medial Longitudinal Arch: A Biplane Fluoroscopy Study, Megan E.R. Balsdon, Colin E. Dombroski, Kristen Bushey, Thomas Jenkyn

Mechanical and Materials Engineering Publications

Background: Foot orthoses have proven to be effective for conservative management of various pathologies. Pathologies of the lower limb can be caused by abnormal biomechanics such as abnormal foot structure and alignment, leading to inadequate support. Objectives: To compare biomechanical effects of different foot orthoses on the medial longitudinal arch (MLA) during dynamic gait using skeletal kinematics. Study Design: Prospective, cross-sectional study design. Methods: The MLA angle was measured for 12 participants among three groups: pes planus, pes cavus and normal arch. Five conditions were compared: three orthotic devices (hard custom foot orthosis (CFO), soft CFO, and off-the-shelf Barefoot Science©), …

Increasing Salt Rejection Of Polybenzimidazole Nanofiltration Membranes Via The Addition Of Immobilized And Aligned Aquaporins, Priyesh Ashokrao Wagh, Xinyi Zhang, Ryan Blood, Peter M. Kekenes-Huskey, Prasangi Rajapaksha, Yinan Wei, Isabel C. Escobar

Chemical and Materials Engineering Faculty Publications

Aquaporins are water channel proteins in cell membrane, highly specific for water molecules while restricting the passage of contaminants and small molecules, such as urea and boric acid. Cysteine functional groups were installed on aquaporin Z for covalent attachment to the polymer membrane matrix so that the proteins could be immobilized to the membranes and aligned in the direction of the flow. Depth profiling using x-ray photoelectron spectrometer (XPS) analysis showed the presence of functional groups corresponding to aquaporin Z modified with cysteine (Aqp-SH). Aqp-SH modified membranes showed a higher salt rejection as compared to unmodified membranes. For 2 M …

Micron-Sized Spinel Crystals In High Level Waste Glass Compositions: Determination Of Crystal Size And Crystal Fraction, C. (Charmayne) E. Lonergan, K. Akinloye-Brown, J. Rice, V. Gervasio, N. Canfield, M. J. Schweiger, J. D. Vienna

Materials Science and Engineering Faculty Research & Creative Works

The compositions utilized for immobilization of high-level nuclear wastes (HLW) are controlled using glass property models to avoid the deleterious effects of crystallization in the high-level waste (HLW) vitrification melters. The type and size of the crystals that precipitate during melter operations (typically at 1150 °C) and idling (∼1000 °C) are significantly impacted by glass composition and thermal history. This study was conducted to measure the impact of melt composition and heat treatment temperature on crystal size and fraction. A matrix of 31 multi-component glasses canvasing the expected Hanford HLW compositional space was developed and the glasses fabricated, and heat …

Control Upstream Austenite Grain Coarsening During Thin Slab Casting Direct Rolling (Tscdr) Process, Tihe Zhou, Ronald J. O'Malley, Hatem S. Zurob, Mani Subramanian, San-Hyun Cho, Peng Zhang

Materials Science and Engineering Faculty Research & Creative Works

Thin-slab cast direct-rolling (TSCDR) has become a major process for flat-rolled production. However, the elimination of slab reheating and limited number of thermomechanical deformation passes leave fewer opportunities for austenite grain refinement, resulting in some large grains persisting in the final microstructure. In order to achieve excellent ductile to brittle transition temperature (DBTT) and drop weight tear test (DWTT) properties in thicker gauge high-strength low-alloy products, it is necessary to control austenite grain coarsening prior to the onset of thermomechanical processing. This contribution proposes a suite of methods to refine the austenite grain from both theoretical and practical perspectives, including: …

Parallelized Particle Swarm Optimization To Estimate The Heat Transfer Coefficients Of Palm Oil, Canola Oil, Conventional, And Accelerated Petroleum Oil Quenchants, Zoltán Fried, Imre Felde, Rosa L. Simencio Otero, Jônatas M. Viscaino, George E. Totten, Lauralice Canale

Mechanical and Materials Engineering Faculty Publications and Presentations

An inverse solver for the estimation of the temporal-spatial heat transfer coefficients (HTC), without using prior information of the thermal boundary conditions, was used for immersion quenching into palm oil, canola oil, and two commercial petroleum oil quenchants. The particle swarm optimization (PSO) method was used on near-surface temperature-time cooling curve data obtained with the so-called Tensi multithermocouple, and a 12.5 by 45 mm Inconel 600 probe. The fitness function to be minimized by a PSO approach is defined by the deviation of the measured and calculated cooling curves. The PSO algorithm was parallelized and implemented on a graphics accelerator …

Fluorescence Of Cdse/Zns Quantum Dots In Toluene: Effect Of Cyclic Temperature, Ting Chen, Weiling Luan, Shaofu Zhang, Fuqian Yang

Chemical and Materials Engineering Faculty Publications

Quantum dots (QDs) are the potential material for the application in optical thermometry, and have been successfully applied to solar cells, LEDs, bio-labeling, structural health monitoring, etc. In this paper, we study the fluorescence properties of CdSe/ZnS QDs in toluene under the action of heating-cooling cycles. The experimental results show that, in a heating-cooling cycle, increasing temperature causes red-shift of the emission peak and the decrease of the PL intensity, and decreasing temperature causes blue-shift of the emission peak and the increase of the PL intensity. The surface structures of the QDs likely are dependent on the cycle numbers, which …

Optimization Of The Calcium Alginate Capsules For Self-Healing Asphalt, Shi Xu, Amir Tabakovic, Xueyan Liu, Damian Palin, Erik Schlangen

Research and Innovation - Articles

Featured Application: This self-healing technology for asphalt pavements has the potential to greatly disrupt asphalt production methods (which have been stable over the past 100 years).This paper presents a development process of ‘calcium-alginate microcapsules encapsulating an asphalt bitumen rejuvenator’. The encapsulated rejuvenator is released when required (on demand) which rejuvenates the aged binder. Once crack is initiated and starts propagating it encounters a microcapsule, energy at tip of the crack opens the microcapsule, releasing the rejuvenator (healing agent). The rejuvenator will infuse into the aged binder soften it, allowing to flow, two broken edges to get into a contact and …

An Experimental And Numerical Investigation Of Flow Accelerated Flibe Corrosion, David B. Weitzel

Nuclear Engineering ETDs

Renewed interest in molten salt reactor technology has brought to light the need for a better understanding of FLiBe corrosion. To this end a flowing FLiBe corrosion test loop was designed to test the flow effects of FLiBe corrosion. The loop consists of a pump, melt tank, and stainless-steel tubing assembly that heats the molten salt to high temperatures and circulates it over test specimens. The experiment has been constructed and has completed initial shakedown testing.

To support the flowing FLiBe experiment, a numerical corrosion model that couples FLiBe electrochemistry, solid metal diffusion, and mass transport was implemented. The model …