Engineering Science and Materials Commons^™

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 …

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 …

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 …

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, …

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 …

Shock And Vibration Isolation System For Ambulatory And Litter Patients In Ground And Air Medical Transport, Mohamad R. Hachem

UNLV Theses, Dissertations, Professional Papers, and Capstones

This project explored the effectiveness of seat and litter air bladder technologies in reducing patient exposure to whole body shock and vibration during ground borne and airborne medical transport. Several seat and litter air bladder configurations were examined during field tests in a U.S. Army RG-33 MRAP ambulance and a U.S. Army HH-60M Black Hawk helicopter. The MRAP field tests were conducted at Ft. Detrick, Maryland. The Black Hawk field tests were conducted at Ft. Rucker, Alabama.

During the field tests, tri-axial vibration signals were recorded on a 16-channel CoCo90 Data Logger/Frequency Analyzer and then post processed in the laboratory …

Statistical Analysis Of The Stress-Energy Methodology Applied To Cushion Curve Determination, Kendalyn Paulin

All Theses

The stress-energy method is a proposed enhancement to ASTM D1596 that reduces all drop height, thickness and static load combinations into a single equation that can be used to generate any reasonable cushion curve for a particular material. There remains a question as to how accurate the stress-energy method can predict acceleration values and whether it is statistically comparable to ASTM D1596. There are three phases to this research that attempt to determine the accuracy of the stress-energy method: gathering data using the stress-energy method and analyzing the goodness of fit of the stress-energy equation, predicting a cushion curve and …

The Effect Of Full Body Versus Partial Body Graphic Labeling On Beverage Packaging, Toni Gomes

All Theses

Through the collection of quantitative and qualitative data, the shelf presence of
full body graphic labels versus partial body graphic labels on plastic beverage bottles was
examined and evaluated. Eye tracking was used to collect phenomenological data atop
the stimuli, while a shopping checklist was used to collect purchase preference. A postexperiment
survey was also conducted in order to gather qualitative data regarding
possible purchase influences.
The experiment was a 2 (label size) x 6 (beverage flavor) x 2 (age group) study,
conducted with 28 participants in a consumer retail environment using mobile eye
tracking technology. The goal of this …

Electrochemical Preparation Of Nanostructural Pt-Ni And Pd-Ni Films For Ethanol Electro-Oxidation, Chen-Zhong Yao, Hui-Xuan Ma, Bo-Hui Wei

Journal of Electrochemistry

The Pt-Ni and Pd-Ni films were successfully prepared on Ti substrates by electrodeposition method. The porous Pt-Ni nanoflakes appeared to be uniform with the thickness of the slices about 10 ~ 20 nm. The porous Pd-Ni nanoparticles with a flower shape appeared to be uniform with the diameters of 50 ~ 60 nm. The XRD patterns also indicated that the Pd-Ni and Pt-Ni nanostructures have the poor crystallinity. The onset potentials of ethanol oxidation were negatively shifted to –0.74 V on Pt-Ni electrodes and –0.71 V on Pd-Ni electrodes, respectively. Addition of Ni could enhance catalytic activities and antitoxic properties …

Synthesis Of Lini0.5Co0.2Mn0.3O2 For Lithium Ion Batteries And The Mechanism Of Capacity Fading At High Temperature, Wen Liu, Miao Wang, Ji-Tao Chen, Xin-Xiang Zhang, Heng-Hui Zhou

Journal of Electrochemistry

The Ni-rich cathode materials, LiNi_0.5Co_0.2Mn_0.3O₂, have been synthesized by Co-precipitation and high-temperature solid-phase sintering method. Constant current charge-discharge tests showed high discharge capacity of 179.2 mAh·g^-1 in the 3.0~4.4 V at 0.2C. However, at 55 °C the LiNi_0.5Co_0.2Mn_0.3O₂ experienced the dramatic capacity fading after 100 charge-discharge cycles. Electrochemical Impedance Spectroscopy, X-Ray Photoelectron Spectroscopy, Atomic Emission Spectroscopy have been employed to study the capacity fading mechanism of LiNi_0.5Co_0.2Mn_0.3O₂ cycled at high temperature in range of high-voltage charge and …

Electrochemical Performances Of Carbon-Coated Na2Ti6O13 Nanotubes, Guo-Ran Li, Shuai Sun, Xue-Ping Gao

Journal of Electrochemistry

With rutile TiO₂ and NaOH as starting materials, the Na₂Ti₆O₁₃ nanotubes were prepared by a hydrothermal reaction. The carbon-coated Na₂Ti₆O₁₃ nanotubes were obtained by treating the Na₂Ti₆O₁₃ nanotubes for 4 h in glucose aqueous solutions containing 0.1 mol·L^-1 NaOH. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microcopy (TEM). The results showed that the dimensions of carbon-coated Na₂Ti₆O₁₃ nanotubes were 14 ~ 19 nm of outer diameter, 2 ~ 5 …

Synthesis And Electrochemical Properties Of Yttrium-Doped Lini0.49Mn1.49Y0.02O4, Xian-Wen Zhang, Zheng-Xi Zhang, Li Yang, Shao-Hua Fang, Long Qu

Journal of Electrochemistry

The LiNi_0.49Mn_1.49Y_0.02O₄ cathode material was synthesized using the citric acid-assisted sol-gel method by partial substitutions of Ni and Mn with Y in the LiNi_0.5Mn_1.5O₄ material. The influences of Y doping on the structure and electrochemical properties were investigated by means of X-ray diffraction, cyclic voltammetry, galvanostatic charge/discharge tests and AC impedance spectroscopy. The results showed that the introduction of Y into the LiNi_0.5Mn_1.5O₄ greatly improved the cycle performance and rate capability. When the charge and discharge current was 1 C in the potential …