Engineering Science and Materials Commons^™

Preparation And Performance Of Sn-Co-M-C（M = Zn, Fe）Composites As An Anode Material, Guo-Qing Fang, Wei-Wei Liu, Shi-Ci He, Qian Zhang, Jun-Wei Zheng, De-Cheng Li

Journal of Electrochemistry

The anode materials of Sn-Co-M-C (M = Zn, Fe) composites were prepared by carbothermal reduction method from metal oxides and sucrose in N₂ atmosphere. Their structural and electrochemical properties were studied by XRD, SEM and charge-discharge test. Among them, the Sn-Co-Zn-C composite showed higher specific capacity and good cycle performance. The initial specific discharge capacity of 571 mAh·g^-1 could be obtained, while 369 mAh·g^-1 was still kept after 45 cycles.

Carbon Nanotubes With Ni2P Nanoparticles As A Counter Electrode In Dye-Sensitized Solar Cells, Yan-Ye Dou, Nan-Fu Yan, Guo-Ran Li, Xue-Ping Gao

Journal of Electrochemistry

Carbon nanotubes (CNTs) supported by Ni₂P nanoparticles are prepared and used as a counter electrode in dye-sensitized solar cells (DSSCs) for the first time. The CNTs-Ni₂P composite was prepared by the heat treatment of a mixed precursor including nickel chloride, sodium hypophosphite and CNTs in argon atmosphere. The X-Ray diffraction (XRD) results indicate that the as-prepared sample consists of hexagonal Ni2P and carbon nanotubes. No peaks of other nickel phosphides are observed in the XRD pattern. Microstructure of the Ni₂P-CNTs composite was investigated using transmission electron microscopy (TEM). It is shown that the Ni …

A Facile Approach To Prepare Lifepo4/C Composite With High-Rate Performance, Peng Zhang, Ling-Bin Kong, Yong-Chun Luo, Long Kang

Journal of Electrochemistry

The LiFePO₄/C composite electrode material was synthesized by a moderate in situ carbothermal reduction method at 600 °C using FeCl_3·6H₂O, LiOH·H₂O, and NH₄H₂PO₄ as starting materials, soluble starch sol as a carbon source and a reducing agent. This method is readily reproducible and possibly feasible to carry out large-scale synthesis. The structure and morphology of the LiFePO₄/C samples were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The synthesized LiFePO₄/C composite was in pure phase of olivine-type, …

Electrochemical Performances Of Layered Polypyrrole/Chemically Reduced Graphene Oxide Nanocomposites As Supercapacitor Electrodes, Si-Zhe Xu, Xue-Jiao Zhou, Kun Wu, Yong-Qiang Yang, Hai-Xia Wu

Journal of Electrochemistry

Nanocomposites of polypyrrole (Ppy) and chemically reduced graphene oxide (CRGO), Ppy/CRGO, have been fabricated through in-situ polymerization of pyrrole on graphene oxide (GO) sheets. The as-synthesized Ppy/CRGO composites were characterized complementarily using scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Fourier transformed infrared spectroscopy (FT-IR). By controlling the initial ratio of the GO to pyrrole, the layered composites could be obtained and their thickness could be tuned properly. The Ppy/CRGO electrodes were prepared using a mechanical compressing technique and their electrical conductivity and electrochemical properties were characterized systematically. We demonstrated that as electrodes for supercapacitor, the Ppy/CRGO composites with Ppy …

Electrochemical Corrosion And Protection Of Copper Foil Treated By Surface Siloxane Filming, Wei-Jun Miao, Yu-Bao Zhang, Ning-Yu Gu, Feng Liu

Journal of Electrochemistry

Copper foil specimens were immersed in hydro-alcoholic solution of 3-amino-propyl-trimethoxy-silane (γ-APS) to prepare a protective self-assembled siloxane membrane on the surface. Potentiodynamic polarization and electrochemical impedance spectroscopic tests were performed in 0.1 mol.L^-1 NaCl to evaluate the effects of the self-assembled siloxane membranes prepared at different pH of γ-APS on corrosion of copper foil. The surface morphology of siloxane membrane was studied by SEM. Experimental results revealed that the γ-APS self-assembled siloxane membranes effectively inhibited the corrosion of copper foil and the optimum anti-corrosion effect was found when the pH value of the silane solution was 7.

Electrochemical Immunosensor Based On Polycalconcarboxylic Acid Modified Electrode For The Determination Of Alpha-Fetoprotein, Xiao Lin, Shao-Huang Weng, Jian-Zhang Zhou, Ai-Lin Liu, Xin-Hua Lin, Yong-Ji You

Journal of Electrochemistry

A highly sensitive electrochemical immunosensor based on novel electropolymerized polycalconcarboxylic acid modified electrode (poly-CCA/GC) has been fabricated for the detection of alpha-fetoprotein (AFP). The differences of the poly-CCA/GC electrodes before and after the immobilization of AFP antibody were characterized via scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). The immobilization of antibody/antigen/antibody-HRP sandwich was formed on the poly-CCA modified electrode for the determination of special AFP concentrations. The electrochemical signals generated from the HRP which catalyzed the TMB substrate were measured. Experiment results indicated that the developed immunosensor showed a good sensitivity and precision.

Electrocatalytic Activities Of Mb/Aunps/Mwnts/Gc Electrode For Hydrogen Peroxide Reduction, Zheng-Juan Huang, Hua-Ping Peng, Dai-Jun Cha, Ai-Lin Liu, Wei Chen, Xin-Hua Lin, Yong-Ji You

Journal of Electrochemistry

A novel matrix, multiwalled carbon nanotubes supported Au nanoparticles composite nanomaterial (AuNPs/MWNTs), for immobilization of protein and biosensing was designed using a simple and effective one-step in situ synthesis route. Using myoglobin (Mb) as a model, the direct electrochemistry of the immobilized proteins on the AuNPs/MWNTs composite was studied. The results showed that the AuNPs/MWNTs composite can maintain the bioactivity and facilitate the direct electrochemistry of Mb in the Mb/AuNPs/MWNTs/GC electrode. Based on the direct electron transfer of the immobilized Mb, the protein electrode exhibited excellent electrocatalytic activity to the reduction of H₂O₂ with a linear range …

Naf-M (M = Fe, Cu) Nanocomposites As Conversion Cathode Materials For Sodium Ion Batteries, Ting Li, Zhong-Xue Chen, Yu-Liang Cao, Han-Xi Yang

Journal of Electrochemistry

The NaF-M (M = Fe, Cu) nanocomposites were prepared by high-energy ball milling using TiN grinding nanoparticles and investigated as cathode materials for sodium ion batteries. The experimental results demonstrated that NaF-Fe and NaF-Cu nanocomposites can go through electrochemical conversion reaction with Na⁺ uptake or removal, delivering a reversible capacity of ~ 150 mAh·g^-1, even through a reversed conversion from initial discharged state to a charged state. These results reveal the possibility to realize a conversion reaction as long as NaF and elemental metal particles are intimately contacted to form active nanocomposites at nanodomain, which suggests a …

Synthesis And Electrochemical Properties Of High-Capacity Cathode Material 0.08lico0.75Al0.25O2-0.92linio2, Ru-Ying Wang, Tian Qiu, Chong Mao, Wen-Sheng Yang

Journal of Electrochemistry

CoAl-LDH or Co(OH)₂ coated spherical Ni(OH)₂ precursors were obtained via a co-precipitation method at a constant pH. The mixtures of the precursors and LiOH·H₂O were annealed at high temperature in O₂ atmosphere, and then the cathode materials of 0.08LiCo_0.75Al_0.25O₂-0.92LiNiO₂, 0.08LiCoO₂-0.92LiNiO₂ and LiNiO₂ were synthesized. Effects of the coating layer were also studied. The results showed that the 0.08LiCo_0.75Al_0.25O₂-0.92LiNiO₂ material possessed the best rate and cycle life performance. The discharging capacities at 0.1C, 0.5C and 3C were …

Poly(Aniline/O-Nitroaniline): A High Capacity Cathode Material For Lithium Ion Batteries, Rui-Rui Zhao, Li-Min Zhu, Jiang-Feng Qian, Han-Xi Yang

Journal of Electrochemistry

Polyaniline can be used as a high capacity cathode material due to the advantages of material abundance and synthetic simplicity. However, its practical application in battery has been hindered by poor electrochemical utilization and cycling instability. To solve these problems, we synthesized the poly(aniline/o-Nitroaniline) (P(AN-oNA)) by introducing the electron-drawing group-nitroaniline onto the polyaniline chains, so as to enhance electrochemical utilization and stability of the polyaniline derivative. The as-prepared Li/P(AN-oNA) copolymer shows a greatly enhanced discharge capacities of 186 mAh·g^-1 at initial cycles, about 37% higher than its parent PAN, and remains 168 mAh·g^-1 after 60th cycle. Also, the …

Synthesis And Electrochemical Characterization Of Li3V2(Po4)3/C Cathode Material By Ball-Milling Assisted Microwave Method, Zhi-Yuan Tang, Wen-Feng Mao, Ji Yan, Wei Yuan, Xin-He Zhang

Journal of Electrochemistry

The cathode materials of Li₃V₂(PO₄)₃/C were successfully synthesized by ball-milling assisted microwave method and the microwave irradiation time was also optimized. It is found that the Li₃V₂(PO₄)₃/C material obtained at a microwave power of 640 W for 18 min showed the best electrochemical performance with the initial reversible capacity of 101.3 mAh·g^-1 and the remained 100.8 mAh·g^-1 at 5C rate after 300 cycles. This excellent electrochemical capability may be resulted from good crystallinity, smaller and uniform particle size of the material, showing …

Electrochemical Performance Of Yf3-Coated Li(Li0.22Ni0.17Mn0.61)O2 Cathode Material For Li-Ion Batteries, Xin Feng, Guo-Ran Li, Shi-Hai Ye, Xue-Ping Gao

Journal of Electrochemistry

The Li(Li_0.22Ni_0.17Mn_0.61)O₂ was prepared with oxalic co-precipitation and coated with an YF₃ layer by a chemical deposition method. The as-prepared and YF₃-coated Li-rich materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The results demonstrate that the as-prepared and YF₃-coated Li(Li_0.22Ni_0.17Mn_0.61)O₂ materials have a typical layered structure and are composed of sphere-like particles with a diameter of 100~200 nm. Galvanostatic charge-discharge tests show that the discharge capacity of the YF₃-coated Li(Li_{0.22 …}

Preparation And Modification Of Li4Ti5O12 As Anode Materials For Lithium-Ion Batteries, Jin-Long Liu, Zhou-Guang Lu, Yang Ren, Ya-Jie Zhu, Shan-Shan Hu, Zhong Peng, Dong Qian, You-Gen Tang

Journal of Electrochemistry

Anode Material Li₄Ti₅O₁₂ for lithium-ion batteries was successfully prepared using half-solid-state method. Furthermore, carbon coating modification of Li₄Ti₅O₁₂ was also carried out. The phase structure and morphology were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM). The electrochemical properties were investigated by constant current discharge-charge tests, cyclic voltammetry and electrochemical impedance techniques. The results indicated that the electrochemical performance of Li₄Ti₅O₁₂ without modification declined seriously due to the aggregation of Li₄Ti …

Electrochemical Sensing Of Guanine And Adenine Based On The Boron-Doped Carbon Nanotubes Modified Electrode, Ya-Lin Xia, Chun-Yan Deng, Juan Xiang

Journal of Electrochemistry

In this work, the boron-doped carbon nanotubes (BCNTs) modified glassy carbon (GC) electrode was simply fabricated, and the electrochemical oxidation behaviors of guanine and adenine at the BCNTs/GC electrode were investigated. Compared with the bare GC and CNTs/GC electrodes, the BCNTs-modified electrode exhibited extraordinary electrocatalytic activity towards the oxidations of guanine and adenine as indicated by the obvious increase in current responses. Moreover, the peak separation between guanine and adenine was large enough for their potential recognition in mixture without any separation or pretreatment. Therefore, the simultaneous determination of guanine and adenine was successfully achieved. The BCNTs/GC electrode showed high …

Friction Stir Spot Welding Of Ultra-High Strength Steel, Trent J. Hartman

Theses and Dissertations

Friction stir spot welding (FSSW) is quickly becoming a method of interest for welding of high strength steel (HSS) and ultra high strength steel (UHSS). FSSW has been shown to produce high quality welds in these materials, without the drawbacks associated with fusion welding. Tool grade for polycrystalline cubic boron nitride (PCBN) tools has a significant impact on wear resistance, weld quality, and tool failure in FSSW of DP 980 steel sheet. More specifically, for a nominal composition of 90% CBN, the grain size has a significant impact on the wear resistance of the tool. A-type tools performed the best, …

Selective Laser Sintering; A Design Of Experiments, Philip David Hopkins, Victor Castillo Phd

STAR Program Research Presentations

Additive Manufacturing (AM), also commonly known as 3D Printing or Rapid Prototyping, is a method of manufacturing that provides for the ability to make intricate internal features and easily customizable parts. The concept is to break a Computer Aided Design (CAD) file into a series of thin layers that are sent to the machine and laid down one layer at a time. Just like any other form of processing, material properties can alter by undergoing this process. Manipulating various parameters of the AM process can allow for different properties to be achieved. For this reason, an in depth study will …

A Resistance Based Structural Health Monitoring System For Composite Structure Applications, Dennis N. Boettcher

Master's Theses

This research effort explored the possibility of using interwoven conductive and nonconductive fibers in a composite laminate for structural health monitoring (SHM). Traditional SHM systems utilize fiber optics, piezoelectrics, or detect defects by nondestructive test methods by use of sonar graphs or x-rays. However, these approaches are often expensive, time consuming and complicated.

The primary objective of this research was to apply a resistance based method of structural health monitoring to a composite structure to determine structural integrity and presence of defects.

The conductive properties of fiber such as carbon, copper, or constantan - a copper-nickel alloy - can be …

Shear-Horizontal Vibration Modes Of An Oblate Elliptical Cylinder And Energy Trapping In Contoured Acoustic Wave Resonators, Huijing He, Jiashi Yang, John A. Kosinski

Department of Mechanical and Materials Engineering: Faculty Publications

We study shear-horizontal free vibrations of an elastic cylinder with an oblate elliptical cross section and a traction-free surface. Exact vibration modes and frequencies are obtained. The results show the existence of thickness-shear and thickness-twist modes. The energy-trapping behavior of these modes is examined. Trapped modes are found wherein the vibration energy is largely confined to the central portion of the cross section and little vibration energy is found at the edges. It is also shown that face-shear modes are not allowed in such a cylinder. The results are useful for the understanding of the energy trapping phenomenon in contoured …

Determining The Proper Point Size For Display Type On Packaging, Joanna Fischer

All Theses

Through the use of a preference test, the proper point size of display text on a package was evaluated in relation to a package's proportions. The test involved the examination of packaging images displaying the product or brand name in various point sizes by 150 participants who were then asked to choose the option they most preferred. The participants were then provided with a post-survey intended to gather additional information regarding potential preference motives.
The primary purpose of this study was to determine the most preferred display type size of a package based on its relationship with the package's proportions. …

Dynamical Properties Of Ferroelectric Perovskites (Ba,Sr)Tio3 And Pb(Zr,Ti)O3 Systems From First Principles, Jeevaka Weerasinghe

Graduate Theses and Dissertations

A first-principles-based effective Hamiltonian scheme which incorporates coupling between ferroelectric (FE) and antiferrodistortive (AFD) motions is applied to Pb(Zr,Ti)O₃ alloys. It validates the existence of two modes of E symmetry (rather than the single E(1TO) soft mode) in the 50-75 cm^-1 range for temperatures smaller than 200 K and for compositions falling within the Rhombohedral R3c phase. Coupling between long-range-ordered FE and AFD motions is shown to be the cause of the additional mode and more insight into its nature is provided. This scheme is further used to reveal a field-induced anticrossing involving FE and AFD degrees of …

Development And Characterization Of Shellac-Hydroxypropyl Methyl Cellulose Composite Films With Acid Catalyst, Sana Asrar

All Theses

The objective of this research was to develop a shellac-hydroproyl methyl cellulose (Sh-HPMC) composite film with enhanced water vapor barrier. Citric acid (CA) was used as an acid catalyst, to promote miscibility between HPMC and shellac. In a preliminary test, three different concentrations of CA (1000:1, 200:1, 100:1) were tested to identify the best Sh:CA ratio. Based on the Water vapor permeability properties and mechanical properties, Sh-CA (1000:1 ratio) had the most enhanced water vapor barrier and the lowest reduction in tensile strength compared to the pure HPMC film (control). In the later part of the research, the effect of …

The Effect Of Food Ingredients On The Oxygen Barrier Properties Of Retort Materials, Amanda Ward

All Theses

An unexplored area in research is addressing how retorted food ingredients interact with retort packaging's oxygen barrier. Ten common food ingredients (whey protein isolate, soy protein isolate, bovine gelatin, fish gelatin, high molecular weight fish gelatin, water, air, oil, potato starch, and hydroxypropyl methylcellulose) were assessed to find their effect on the barrier properties of CPP, PET, and high barrier commercial retort pouches. OxySense Gen III 300 and Mocon OxTran 2/21 were used to evaluate the samples. CPP pouches were first assessed with the OxTran 2/21 and indicated that treatments affected the OTR's of the film materials. However, results from …

Relating Burst Pressure To Seal Peel Strength In Pouches, William Bernal

All Theses

This work was aimed at studying the relationship between burst pressure and seal peel strength. Past researchers developed a force balance equation based on the analysis of a force diagram to relate burst pressure to seal strength. The theoretical formula S=P(D/2) (S=Seal Strength, P=Burst Pressure, D=Restraining Plate Gap) has been studied by past researchers with contrasting results.
The theoretical formula was tested by varying dwell time to produce seals of varying strength. Pouches were burst tested at each of these dwell times to obtain burst pressures, burst peeling times, and burst locations. Corresponding peel tests were performed with crosshead speeds …

Efficient Airframe Management Using In-Situ Structural Health Monitoring, Mark M. Derriso, M. S. Leonard, Martin P. Desimio, Steven E. Olson

Student Publications

The United States Air Force utilizes the Aircraft Structural Integrity Program (ASIP) to service and maintain its airframes. This schedule-based maintenance approach works well for ensuring system integrity; however, it is very costly, labor-intensive, and it reduces system availability. As a result, the Air Force intends to transition to a process that services aircraft based on their actual condition instead of the presumptive schedule-based approach. Structural health monitoring (SHM) technologies are being investigated to enable such real-time state awareness and decision-making. This paper provides a brief review of ASIP and the required inspections to investigate structural fatigue. The current ASIP …

Propagation Of Ultrasound Through Freshly Excised Human Calvarium, Armando Garcia Noguera

Department of Engineering Mechanics: Dissertations, Theses, and Student Research

The propagation of ultrasound through complex biological media, such as the human calvarium, poses a great challenge for modern medicine. Several ultrasonic techniques commonly used for treatment and diagnosis in most of the human body are still difficult to apply to the human brain, in part, because of the properties of the skull. Moreover, an understanding of the biomechanics of transcranial ultrasound may provide needed insight into the problem of blast wave induced traumatic brain injury (TBI). In the present study, the spatial variability of ultrasonic properties was evaluated for relevant frequencies of 0.5, 1, and 2.25 MHz. A total …

Nonlinear Mechanical Behavior Of The Human Common, External And Internal Carotid Arteries In Vivo, Alexey Kamenskiy, Yuris A. Dzenis, Jason N. Mactaggart, Thomas G. Lynch, Syed A. Jaffar Kazmi, Iraklis I. Pipinos

Department of Mechanical and Materials Engineering: Faculty Publications

Introduction—The mechanical environment and properties of the carotid artery play an important role in the formation and progression of atherosclerosis in the carotid bifurcation. The purpose of this work was to measure and compare the range and variation of circumferential stress and tangent elastic moduli in the human common (CCA), external (ECA) and internal (ICA) carotid arteries over the cardiac cycle in vivo.

Methods—Measurements were performed in the surgically exposed proximal cervical CCA, distal ECA and distal ICA of normotensive patients (n = 16) undergoing carotid endarterectomy. All measurements were completed in vivo over the cardiac cycle …

Preparation And Electrochemical Performance Of Tio2/Gns Nanocomposite As Anode Materials For Lithium-Ion Batteries, Lin-Lin Qin, Huan Zhang, Xiao-Jing Liu, Jian-Hui Xu, Yi-Ning Shi, Ming-Sen Zheng, Quan-Feng Dong

Journal of Electrochemistry

The honeycomb-like porous TiO₂/graphenes (TiO₂/GNs) nanocomposite was prepared by a reflux method. SEM and TEM results showed that nanosized anatase TiO₂ (about 5~10 nm) were dispersed uniformly on the surface of the GNs. The TiO₂/GNs composite showed excellent rate and cycling performance: A stable charge capacity of 169.5 mAh·g^-1 was obtained at 30C, and can restore to 241.7 mAh·g^-1 while current went back to 1C. The stable charge capacity of TiO₂/GNs nanocomposite electrode up to 201.9 mAh·g^-1 was achieved at 10C in the first cycle, and could be …

Novel Molten-Salt Electrolysis Processes Towards Low-Carbon Metallurgy, Wei Xiao, Hua Zhu, Hua-Yi Yin, De-Hua Wang

Journal of Electrochemistry

This review focuses on recent developments in molten-salt electrolytic metallurgical processes with respect to 1) high-efficiency metallurgical technologies via electrolytic reduction of solid oxides in molten chlorides and 2) zero-carbon-footprint electrochemical splitting metallurgical technologies. Initiating with an introduction on dynamic solid/solid/liquid three-phrase interlines electrochemistry for electrochemical reduction of solid cathode, the former aspect is discussed in terms of facilitating mass transfer throughout solid cathode, one-step production of functional alloy powders with the assistance of under-potential electroreduction of active metals and near-net-shape production of metal/alloy components. Whilst the latter is summarized by introducing some zero-carbon molten-salt electrolytic technologies including electro-splitting of …

Comments On Internal Alternating Current Resistance Test Standard And Methods Of Lithium-Ion Batteries, Ya-Li Zhang, Sen Xin, Yu-Guo Guo, Li-Jun Wan

Journal of Electrochemistry

The sustainable development of energy and environment is one of the most influential issues of this century. Batteries, especially secondary batteries are important for powering out daily life. However, in many practical applications, such as in electric vehicles and hybrid electric vehicles, batteries should be used in packs and the performance consistency of each battery in the pack should be taken into consideration. As one of the performance parameters being used to characterize the battery consistency, internal resistance is of great importance to the industrial fabrication and the use of batteries. Currently, internal resistance tests of secondary batteries, such as …

Methodological Significance Of "Property-Activity Relationship" For Catalyst Studies, Jun-Tao Lu, Li Xiao, De-Li Wang, Yu-Bao Sun, Yan-Ge Suo, Lin Zhuang

Journal of Electrochemistry

Instead of attempting the structure-activity relationship (SAR), which is commonly regarded as the core problem for catalyst studies, this paper highlights the methodological significance of “property-activity relationship (PAR)”. The “property” here refers to an index （such as the adsorption energy of an intermediate） or a group of indexes reflecting the behavior of a catalyst which interacts with reactants or intermediates, and is a bridge between structure and activity. Because property is related to activity more directly than structure to activity, PAR should be simpler, less difficult and, therefore, more feasible to be accessed than SAR. Once the key property is …