Engineering Science and Materials Commons^™

Simple Analysis And Possible Solutions Of The Unusual Interfacial Reactions In Li-S Batteries, Xin-Ping Ai, Yu-Liang Cao, Han-Xi Yang

Journal of Electrochemistry

Rechargeable Li-S batteries are a promising power source with realizable energy densities several times higher than current Li-ion batteries. However, the capacity utilization and cycling stability of the existing Li-S technologies are still insufficient for battery applications. The causes for the electrochemical instability of this redox system arise probably from the changes in the surface structures and electrochemical microenvironments of the Li anode and sulfur cathode during charge-discharge reactions, which includes the frustrated electron transfer in the sulfur-carbon interface, the dissoluble diffusion of the polysulfide intermediates, and the shuttle reaction inbetween the sulfur and Li electrodes. To deal with these …

Preparation And Characterization Of Prussian Blue Modified Nanoelectrode, Wei Wang, Bao-Fa Su, Dong-Ping Zhan

Journal of Electrochemistry

The Pt nanoelectrodes were fabricated by using a laser-based pipet puller and the recessed nanoelectrodes were prepared by etching of disk Pt nanoelectrodes wtih high frequency ac voltage. Prussian blue microcrystal was synthesized electrochemically on the both disk and recessed Pt nanoelectrodes. The strength of mechanical adhesion for the Prussian blue microcrystal on the nanoelectrode was enhanced. A novel method for the controllable synthesis of single particle is proposed, which has potential applications in modified electrodes and single particle electrocatalysis.

The Electrocatalytic Performance Of Pd Catalysts Supported On Pvp Modified Mwcnts For Formic Acid Oxidation, Jing Zhang, Xiao Zhao, Chang-Peng Liu, Wei Xing

Journal of Electrochemistry

In this paper the MWCNTs were modified by Poly (N-vinyl-2-pyrrolidone) (PVP) to support Pd nanoparticles, which were used as the catalyst for formic acid electrooxidation. And the performance of Pd/PVP-MWCNTs catalysts was studied by electrochemical measurements. The observations from Fourier transforms infrared spectrometer (FTIR) and transmission electron microscopy (TEM) illustrated that the Pd nanoparticles with a small size and narrow size distribution were highly dispersed on PVP-MWCNT support. Therefore, the Pd/PVP-MWCNTs catalysts showed excellent catalytic activity for formic acid electrooxidation.

Synthesis Of Spherical Ni3S4 By Solvothermal Method As Supercapacitor Electrodes, Qing-Na Huan, Li-Fang Jiao, Qing-Hong Wang, Hong-Mei Du, Jia-Qin Yang, Wen-Xiu Peng, Yi-Jing Wang, Hua-Tang Yuan

Journal of Electrochemistry

The Ni₃S₄ microspheres have been synthesized via a facile solvothermal method. The crystal structure and surface morphology are characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Microspherical Ni₃S₄ exhibits good electrochemical capacitance validated by electrochemical measurements. The specific capacities of 1120.6 F∙g^-1 at 0.5 A∙g^-1 and 433.4 F∙g^-1 at 4 A∙g^-1 with the capacitance retention of 89.37 % and 84.88 % were obtained after 1000 cycles, respectively. The electrochemical reaction is expected due to the transformation of Ni(OH)₂ and NiOOH based on the XRD, XPS and CV …

Detection Of Pml/Rarî± Fusion Gene Using Gold Nanopaticles Modified Electrode By Chronocoulometry, Li-Man Wang, Li-Qing Lin, Shao-Huang Weng, Xin-Hua Lin, Yuan-Zhong Chen

Journal of Electrochemistry

A gold nanoparticles modified electrode was prepared by electrodeposition at constant potential. The sulfydryl modified probe was immobilized onto surface of gold nanoparticles via Au-S covalent bond and hybridized with complementary target DNA sequences, then the DNA sensor was fabricated for the detection of PML/RARα fusion gene by chronocoulometry in acute promyelocytic leukemia (APL). Scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS) were used to characterize the surface morphology of gold nanoparticles and the constructing process of sensor. With hexaammineruthenium(Ⅲ) chloride (RuHex) as a novel electrochemical indicator, the chronocoulometric DNA biosensor was employed to monitor artificial APL PML/RARα fusion …

Application Of First Principles Calculations In Anode Materials For Lithium Ion Batteries, Tian-Ran Zhang, Dai-Xin Li, Si-Qi Yang, Zhan-Liang Tao, Jun Chen

Journal of Electrochemistry

First principles calculations play an important role in the study and development of new materials for lithium batteries. In this paper, we review the application of first principles calculations in the design of anode materials, including the modeling of the interaction of lithium in the anode materials, capacity, voltage, electrochemical reaction process, diffusion, rate capability, the relationship between the structure and properties, and the experimental phenomena interpreting. Based on the discussions, we emphasize on the importance of first principles calculations and demonstrate their requirement for further development.

An Overview Of Electrode Materials In Microbial Fuel Cells, Su-Qin Ci, Na Wu, Zhen-Hai Wen, Jing-Hong Li

Journal of Electrochemistry

Microbial fuel cells (MFCs) are devices that can directly convert organic chemical energy into electrical energy with microbial as catalysts. MFCs are a promising bio-electrochemical system with the potential to degrade organic sewage and produce electricity. This article supplies a critical and comprehensive review for the electrode materials concerning about anode and cathode in MFCs, including the fabrications, functional modifications and surface constructions of electrode materials, as well as their applications in MFCs. Additionally, the existing problems of electrode materials in current MFCs have been demonstrated in order to provide the guideline for exploring the next-generation electrode materials for MFCs.

Preparation And Electrochemical Performance Of Tin@Mno Fibers By Coaxial Electrospinning, Chao-Qun Shang, Hai-Yan Yang, Xin-Hong Zhou, Zhong-Lei Man, Peng-Xian Han, Jian-Hua Yao, Yu-Long Duan, Guang-Lei Cui

Journal of Electrochemistry

In this study, the titanium nitride (TiN) @manganese oxide (MnO) core-shell structured fibers were prepared by the coaxial electrospinning using tetrabutyl titanate and manganese acetylacetonate as raw materials, and polyvinylpyrrolidone (PVP) as the template. And then the fibers were annealed in ammonia to finally obtain the coaxial TiN@MnO fibers. XRD, FESEM, TEM, EDX and physical adsorption instrument were used to characterize the phase structure, morphology, composition and specific surface areas and pore sizes of the samples. It was demonstrated that the as-synthesized TiN@MnO fibers possessed coaxial structure with a surface area of 16 m²·g^-1. As indicated …

Performnces Of Lini0.5Mn0.5O2 Thin Film Electrodes Prepared By Pulsed Laser Deposition, Yun-Hai Wan, Guo-Liang Yuan, Hui Xia

Journal of Electrochemistry

The all-solid-state thin-film Li-ion batteries with high energy density, power density and temperature stability are the ideal power sources for microelectronic devices. Developing new thin-film cathodes with large specific capacity is the key to their practical applications. The LiNi_0.5Mn_0.5O₂ with a layered structure has a higher reversible capacity and better structural stability compared with traditional LiCoO₂ cathode material. In this work, the LiNi_0.5Mn_0.5O₂ thin film cathodes were prepared by pulsed laser deposition. The effects of substrate material and temperature on the microstructure, surface morphology and composition of the thin …

Transient Turbine Engine Modeling With Hardware-In-The-Loop Power Extraction, Michael W. Corbett, Peter T. Lamm, Philip R. Owen, S. Danny Phillips, Mark J. Blackwelder, J. Timothy Alt, John M. Mcnichols, Michael A. Boyd, Mitch Wolff

Mechanical and Materials Engineering Faculty Publications

Increasingly high aircraft power demands require that the interactions between an aircraft’s electrical subsystem and the engine subsystem be considered in dynamic, systemlevel tests. Traditionally, system-level dynamics have only been captured in completely assembled aircraft systems. Component-level or subsystem-level optimization is no longer appropriate because highly interdependent dynamics between subsystems only become apparent during system-level analysis. In an effort to reduce the high cost of testing integrated power and propulsion systems in an altitude-simulating wind tunnel, alternatives such as modeling and simulation are considered. Synchronizing and coupling simulations of vastly different time scales is possible, but the resulting system simulation …

Design, Fabrication And Testing Of Tunable Rf Meta-Atoms, Derrick Langley

Theses and Dissertations

Metamaterials are engineered structures designed to alter the propagation of electromagnetic waves incident upon the structure. The focus of this research was the effect of metamaterials on electromagnetic signals at radio frequencies. RF meta-atoms were investigated to further develop the theory, modeling, design and fabrication of metamaterials. Comparing the analytic modeling and experimental testing, the results provide a deeper understanding into metamaterials which could lead to applications for beam steering, invisibility cloaking, negative refraction, super lenses, and hyper lenses. RF meta-atoms integrated with microelectromechanical systems produce tunable meta-atoms in the 10 - 15 GHz and 1 - 4 GHz frequency …

Three-Dimensional Geometry Of The Human Carotid Artery, Alexey Kamenskiy, Jason N. Mactaggart, Iraklis I. Pipinos, Jai Bikhchandani, Yuris A. Dzenis

Department of Mechanical and Materials Engineering: Faculty Publications

Accurate characterization of carotid artery geometry is vital to our understanding of the pathogenesis of atherosclerosis. Three-dimensional computer reconstructions based on medical imaging are now ubiquitous; however, mean carotid artery geometry has not yet been comprehensively characterized. The goal of this work was to build and study such geometry based on data from 16 male patients with severe carotid artery disease. Results of computerized tomography angiography were used to analyze the cross-sectional images implementing a semiautomated segmentation algorithm. Extracted data were used to reconstruct the mean three-dimensional geometry and to determine average values and variability of bifurcation and planarity angles, …

Me-Em Enewsbrief, June 2012, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University

Department of Mechanical and Aerospace Engineering eNewsBrief

No abstract provided.

Development And Validation Of A Model For Granular Material Volume Measurements, Pourya Fasounaki

Department of Industrial and Management Systems Engineering: Dissertations, Theses, and Student Research

Keeping inventory record of packed grains in silos poses challenges since the bulk material’s different segments do not discharge uniformly, leading to formation of random peaks and valleys on the surface. To facilitate obtaining accurate volume measurement of the grains by taking into account this non-linear behavior on the surface, laser or plumb-bob level-sensing devices are employed at different part of the surface to probe the level of material under those regions.

The main goals of this research is to study the behavior of granular material in silo while discharging downward and by doing so, differentiate certain flow patterns formed …

Finite Element Modeling Of Ballistic Impact On A Glass Fiber Composite Armor, Dan M. Davis

Master's Theses

Finite Element Modeling of Ballistic Impact on a Glass Fiber Composite Armor

Dan Davis

Experiments measuring the ballistic performance of a commercially available fiberglass armor plate were used to guide the development of constitutive laws for a finite element model of the impact. The test samples are commercially available armor panels, made from E-glass fiber reinforced polyester rated to NIJ level III. Quasi-static tensile tests were used to establish material properties of the test panels. These properties were then used to create models in the explicit finite element code LSDYNA.

Ballistic impact testing of the panels was conducted using a …

Correlation Of Shear Strength Between Longitudial And Transverse Specimens, Erasto A. Fernandez

LSU New Orleans Theses and Dissertations

In this thesis, new methods for shear strength are proposed and backed up through extensive experimentation, ABAQUS models and data analysis of Titanium welds of three different alloys. The results are compared with those obtained by using the procedure outlined by AWS B4 for calculating Shear Strength in the transverse and longitudinal directions; this equation is widely used by the American Welding Society (AWS) and all those in search of more efficient designs involving welding.

It is a well-documented issue that the equation provided by AWS yields a large discrepancy between the values for shear strength of longitudinal and transverse …

Rehabilitation And Exercise Machine, Judith M. Burnfield, Yu Shu, Thad W. Buster, Carl Nelson

Department of Mechanical and Materials Engineering: Faculty Publications

An improved rehabilitation and exercise machine is provided which allows a person with physical limitations, disabilities or chronic conditions to use the machine in order to rehabilitate their muscles, improve joint flexibility, and enhance cardiovascular fitness.

Laboratory And Field Evaluation Of Two Warm-Mix Additives In Connecticut And Validation Of An Alternative Moisture Susceptibility Test, Alexander K. Bernier

Master's Theses

The first official state Warm-Mix Asphalt (WMA) pavement project in Connecticut was constructed between July 20th and 22nd, 2010 and it involved three experimental sections, i.e. one section with a conventional HMA (control section) and two WMA sections with different technologies, wax and foamed asphalt. All three sections are located on Route 70 in central Connecticut. The materials were collected in loose form and reheated and compacted in laboratory conditions (laboratory fabricated specimens). This paper discusses the effect of mix type on the results from several tests conducted in the laboratory, such as Semi-Circular Bending, Hamburg Wheel Tracking, Indirect Tensile, …

Molecular Dynamics Study Of Diffusion Of O2 Penetrates In Uncrosslinked Polydimethysiloxane (Pdms), Crosslinked Pdms, And Pdms-Based Nanocomposites, Varun Ullal

Graduate Theses and Dissertations

Molecular dynamics simulations are used to study diffusion of O₂ molecules in pure polydimethysiloxane (PDMS), crosslinked PDMS, and PDMS-based nanocomposites. The PDMS chains and penetrates are modeled using a hybrid interatomic potential which treats the Si-O atoms along the chain backbone explicitly while coarse-graining the methyl side groups and penetrates. By tracking the diffusion of penetrates in the system and subsequently computing their mean-squared displacement, diffusion coefficients are obtained. In pure PDMS models of varying molecular weight, diffusivity of the O₂2 penetrates is found to have an inverse relationship with chain length. Simulation models with longer chains …

Analytic And Finite Element Solutions Of The Power-Law Euler-Bernoulli Beams, Dongming Wei, Yu Liu

Mathematics Faculty Publications

In this paper, we use Hermite cubic finite elements to approximate the solutions

of a nonlinear Euler-Bernoulli beam equation. The equation is derived

from Hollomon’s generalized Hooke’s law for work hardening materials with

the assumptions of the Euler-Bernoulli beam theory. The Ritz-Galerkin finite

element procedure is used to form a finite dimensional nonlinear program

problem, and a nonlinear conjugate gradient scheme is implemented to find

the minimizer of the Lagrangian. Convergence of the finite element approximations

is analyzed and some error estimates are presented. A Matlab finite

element code is developed to provide numerical solutions to the beam equation.

Some …