Engineering Science and Materials Commons^™

Numerical Simulation Of Nonlinear Elastic Wave Propagation In Piecewise Homogeneous Media, Arkadi Berezovski, Mihhail Berezovski, Juri Engelbrecht

Publications

Systematic experimental work [S. Zhuang, G. Ravichandran, D. Grady, J. Mech. Phys. Solids 51 (2003) 245–265] on laminated composites subjected to high velocity impact loading exhibits the dispersed wave field and the oscillatory behavior of waves with respect to a mean value. Such a behavior is absent in homogeneous solids. An approximate solution to the plate impact in layered heterogeneous solids has been developed in [X. Chen, N. Chandra, A.M. Rajendran, Int. J. Solids Struct. 41 (2004) 4635–4659]. The influence of the particle velocity on many process characteristics was demonstrated. Based on earlier results [A. Berezovski, J. Engelbrecht, G.A. Maugin, …

Me-Em 2006 Annual Report, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University

Department of Mechanical and Aerospace Engineering Annual Reports

Table of Contents

• Overview, Mission, and Vision
• Comments on the Strategic Plan
• Enrollment, Degrees, and Expenditure Data
• External Advisory Board
• Faculty and Staff
• Students
• Alumni
• Resources
• Graduates
• Publications

Nanoparticle-Induced Negative Differential Resistance And Memory Effect In Polymer Bistable Light-Emitting Device, Ricky J. Tseng, Jianyong Ouyang, Chih-Wei Chu, Jinsong Huang, Yang Yang

Department of Mechanical and Materials Engineering: Faculty Publications

Recently, electrical bistability was demonstrated in polymer thin films incorporated with metal nanoparticles [J. Ouyang, C. W. Chu, C. R. Szmanda, L. P. Ma, and Y. Yang, Nat. Mater. 3, 918 (2004)]. In this letter, we show the evidence that electrons are the dominant charge carriers in these bistable devices. Direct integration of bistable polymer layer with a light-emitting polymer layer shows a unique light-emitting property modulated by the electrical bistability. A unique negative differential resistance induced by the charged gold nanoparticles is observed due to the charge trapping effect from the nanoparticles when interfaced with the light-emitting layer.

In Vivo Laparoscopic Robotics, Mark E. Rentschler, Stephen R. Platt, Jason Dumpert, Shane M. Farritor, Dmitry Oleynikov

Department of Mechanical and Materials Engineering: Faculty Publications

Robotic laparoscopic surgery is evolving to include in vivo robotic assistants. The impetus for the development of this technology is to provide surgeons with additional viewpoints and unconstrained manipulators that improve safety and reduce patient trauma. A family of these robots have been developed to provide vision and task assistance. Fixed-base and mobile robots have been designed and tested in animal models with much success. A cholecystectomy, prostatectomy, and nephrectomy have all been performed with the assistance of these robots. These early successful tests show how in vivo laparoscopic robotics may be part of the next advancement in surgical technology.

Non-Operative Management Of Posterior Tibialis Tendon Dysfunction: Design Of A Randomized Clinical Trial [Nct00279630], Kornelia Kulig, Amy B. Pomrantz, Judith M. Burnfield, Stephen F. Reischl, Susan Mais-Requejo, David B. Thordarson, Ronald W. Smith

Department of Mechanical and Materials Engineering: Faculty Publications

Background: Posterior tibialis tendon dysfunction (PTTD) is a common cause of foot pain and dysfunction in adults. Clinical observations strongly suggest that the condition is progressive. There are currently no controlled studies evaluating the effectiveness of exercise, orthoses, or orthoses and exercise on Stage I or IIA PTTD. Our study will explore the effectiveness of an eccentric versus concentric strengthening intervention to results obtained with the use of orthoses alone. Findings from this study will guide the development of more efficacious PTTD intervention programs and contribute to enhanced function and quality of life in persons with posterior tibialis tendon dysfunction. …

Study Of Low Speed Transitional Regime Gas Flows In Microchannels Using Information Preservation (Ip) Method, Umit Kursun

Electronic Theses and Dissertations

Proper design of thermal management solutions for future nano-scale electronics or photonics will require knowledge of flow and transport through micron-scale ducts. As in the macro-scale conventional counterparts, such micron-scale flow systems would require robust simulation tools for early-stage design iterations. It can be envisioned that an ideal Nanoscale thermal management (NSTM) solution will involve two-phase flow, liquid flow and gas flow. This study focuses on numerical simulation gas flow in microchannels as a fundamental thermal management technique in any future NSTM solution. A wellknown particle-based method, Direct Simulation Monte Carlo (DSMC) is selected as the simulation tool. Unlike continuum …

Low Temperature Co-Fired Ceramics For Micro-Fluidics, John Youngsman, Brian Marx, Martin Schimpf, Scott Wolter, Jeff Glass, Amy Moll

Materials Science and Engineering Faculty Publications and Presentations

The miniaturization of analytical instruments and packaging of novel sensors is an area that has attracted significant research interest and offers many opportunities for product commercialization. Low Temperature Co-fired Ceramics (LTCC) is a materials system composed of alumina and glass in an organic binder. LTCC is a good choice for sensor development because of the ease of incorporating features in the ‘green’ or unfired state such as electrical traces, fluidic pathways and passive electrical components. After a firing cycle, what remains is a robust, monolithic device with features embedded in the package. In order for LTCC to be a successful …

The Role Of Electrospinning In The Emerging Field Of Nanomedicine, S. Y. Chew, Y. Wen, Yuris A. Dzenis, K. W. Leong

Department of Mechanical and Materials Engineering: Faculty Publications

The fact that in vivo the extracellular matrix or substratum with which cells interact often includes topography at the nanoscale underscores the importance of investigating cell-substrate interactions and performing cell culture at the submicron scale. An important and exciting direction of research in nanomedicine would be to gain an understanding and exploit the cellular response to nanostructures. Electrospinning is a simple and versatile technique that can produce a macroporous scaffold comprising randomly oriented or aligned nanofibers. It can also accommodate the incorporation of drug delivery function into the fibrous scaffold. Endowed with both topographical and biochemical signals such electrospun nanofibrous …

Response To "Comment On Variational Approach To The Volume Viscosity Of Fluids" [Phys. Fluids 18, 109101 (2006)], Allen J. Zuckerwar, Robert L. Ash

Mechanical & Aerospace Engineering Faculty Publications

We respond to the Comment of Markus Scholle and therewith revise our material entropy constraint to account for the production of entropy. (c) 2006 American Institute of Physics.

Design And Performance Evaluation Of An Integrated Miniature Single Stage Centrifugal Compressor And Permanent Magnet Synchronous Motor, Dipjyoti Acharya

Electronic Theses and Dissertations

An attempt has been made in this present work to design, fabricate and performance evaluate an integrated single stage centrifugal compressor and permanent magnet synchronous motor which is a key component of the reverse brayton cycle cryocooler. An off the shelf compressor – the driven and electric motor – the driver was not available commercially to suffice the requirements of the reverse brayton cryocooler. The integrated compressor-motor system was designed and tested with air as the working fluid at mass flow rate of 7.3 grams per sec, with a compression ratio of 1.58 and driven by a 2 KW permanent …

Commissioning Of A Dynamic Mechanical Analyzerfor The Characterization Of Low Temperature Nitife Shape Memory Alloys, Maruthi Diwakar Nandiraju

Electronic Theses and Dissertations

NiTiFe shape memory alloys can undergo transformations between cubic, trigonal and monoclinic phases at low temperatures. The low hysteresis associated with the trigonal R-phase transformation make them candidates for actuator applications at low temperatures. However, the literature available on these alloys is limited and there is a need to establish processing structure-property correlations. This study was undertaken with the objective of determining and understanding such correlations in a Ni46.8Ti50Fe3.2 alloy. First, a dynamic mechanical analyzer (DMA) was successfully commissioned to facilitate mechanical testing between -150 and 600ºC. The experiments performed over selected ranges of stress and temperature probed a range …

Thermal Sprayed Surface Coatings And Optical Characterisation, Yueqiang Xue

Masters

This research work aims to establish the potential of defect detection of thermal sprayed surface coatings by using a newly developed optical non-destructive interferometric technique – Electronic Speckle Pattern Shearing Interferometry (ESPSI), rather than using mechanical destructive testing methods and other non-destructive methods. This technique has been used in many industries for non-destructive testing (NDT). However, it is innovative to use this technique for NDT of thermal sprayed metal alloy coatings, especially those that are produced by flame powder spraying process. Investigations were carried out by the SUPERJET spray process, which was the flame powder spray process utilised in this …

A Micromechanical Approach For Predicting The Complex Shear Modulus And Accumulated Shear Strain Of Asphalt Mixtures From Binder And Mastics, Cristian Druta

LSU Doctoral Dissertations

Asphalt mixtures are particulate composite materials consisting of uniformly distributed mineral aggregates, asphalt binder and air voids. Mixtures of asphalt binder and filler, also called mastics, are often assumed to behave as simple viscoelastic materials, where the binders are stiffened by the filler. Because the workability and performance of bituminous mixes are known to be affected by the filler-asphalt mixture (or mastic) properties, this study is intended for performing rheological tests on asphalt binder and mastics and use the results in order to estimate performance parameters of asphalt mixture. The present work uses the PG64-22 asphalt binder test data initially …

Design And Fabrication Of Micro Transducers Using Cured Su-8 Polymer As Main Structural Material, Wen Dai

LSU Doctoral Dissertations

Polymer based micro-transducers have many advantages over the traditional silicon based micro-transducers, such as easy integration with metal structures, design flexibility, and low fabrication costs. The characteristics of micro-transducers include converting electrical signals to/from mechanical response, the ability to sustain loading, sensitivity to external excitation, and etc. Some of the difficulties in realizing these characteristics include: characterizing material mechanical properties, techniques for producing electrically conductive polymer structures, and reliable fabrication procedures. In this dissertation, research addressing these difficulties is presented. The developed techniques are demonstrated in the design and fabrication of a SU-8 polymer based comb-drive micro-actuator. The micro-actuator used …

Towards A Generalized Team Task Complexity Model, Ashok Darisipudi

LSU Doctoral Dissertations

The objective of this research was to develop and validate a generalized team task-complexity model and framework by drawing on the literature from various team and task factors grouped into three task-dimensions, which compose task-complexity space and how these affect the task-performance. A number of task typologies have been presented in the teams' literature to better define and understand the critical role of the tasks and the associated team processes. In addition, most of the research work has defined team measures as highly abstract concepts not capable of providing the quantitative comparison of team performances from various domains. This research …

Ultra-Violet Lithography Of Thick Photoresist For The Applications In Biomems And Micro Optics, Ren Yang

LSU Doctoral Dissertations

UV lithography of thick photoresist is widely used in microelectromechanical systems (MEMS) and micro-optoelectromechanical systems (MOEMS). SU-8 is a typical negative tone thick photoresist for micro systems, and can be used for both structural material and pattern transfer. This dissertation presents an effort to comprehensively study these important subjects. The first part, and the most fundamental part of this dissertation concentrated on the numerical analysis and experimental study of the wavelength dependent absorbance of SU-8 and the diffraction effects on the sidewall profiles of the microstructures made using UV lithography of SU-8. This study has laid the foundation for all …

Shear Band Evolution In Zr/Hf-Based Bulk Metallic Glasses Under Static And Dynamic Indentations, Hongwen Zhang

Dissertations, Master's Theses and Master's Reports - Open

Bulk metallic glasses (BMGs) exhibit superior mechanical properties as compared with other conventional materials and have been proposed for numerous engineering and technological applications. Zr/Hf-based BMGs or tungsten reinforced BMG composites are considered as a potential replacement for depleted uranium armor-piercing projectiles because of their ability to form localized shear bands during impact, which has been known to be the dominant plastic deformation mechanism in BMGs. However, in conventional tensile, compressive and bending tests, limited ductility has been observed because of fracture initiation immediately following the shear band formation. To fully investigate shear band characteristics, indentation tests that can confine …

Variational Approach To The Volume Viscosity Of Fluids, Allan J. Zuckerwar, Robert L. Ash

Mechanical & Aerospace Engineering Faculty Publications

The variational principle of Hamilton is applied to develop an analytical formulation to describe the volume viscosity in fluids. The procedure described here differs from those used in the past in that a dissipative process is represented by the chemical affinity and progress variable (sometimes called "order parameter") of a reacting species. These state variables appear in the variational integral in two places: first, in the expression for the internal energy, and second, in a subsidiary condition accounting for the conservation of the reacting species. As a result of the variational procedure, two dissipative terms appear in the Navier-Stokes equation. …

Fabrication Of Oxide Superconducting Thin Films Using Colloid Of Nanoparticles As Precursor, Vamsee K. Chintamaneni

Browse all Theses and Dissertations

This thesis reports the development of a new approach for the fabrication of superconducting thin films. Among the liquid phase methods of fabricating high temperature superconductors having critical current density about 1 MA/cm², metalorganic deposition using metal trifluoroacetates (TFA-MOD) is the best known method. In this project, detailed spectroscopic and microscopic analysis was performed at every stage of the TFA-MOD process to understand the evolution of crystalline superconducting film. It was observed that the TFA-MOD has some inherent disadvantages such as long process time, evolution of HF gas and results porosity in films. A new liquid phase process …

Efficient Inverted Polymer Solar Cells, G. Li, C.-W. Chu, V. Shrotriya, Jinsong Huang, Y. Yang

Department of Mechanical and Materials Engineering: Faculty Publications

We investigate the effect of interfacial buffer layers—vanadium oxide (V₂O₅) and cesium carbonate (Cs₂CO₃)—on the performance of polymer solar cells based on regioregular poly-(3-hexylthiophene) and [6,6]-phenyl C₆₀ butyric acid methyl ester blend. The polarity of solar cells can be controlled by the relative positions of these two interfacial layers. Efficient inverted polymer solar cells were fabricated with the structure of indium tin oxide (ITO)/Cs₂CO₃/polymer blend/vanadium oxide (V₂O₅)/aluminum (Al). Short-circuit current of 8.42 mA/cm2, open-circuit voltage of 0.56 V, and power conversion efficiency of …

Improving The Power Efficiency Of White Light-Emitting Diode By Doping Electron Transport Material, Jinsong Huang, Wei-Jen Hou, Juo-Hao Li, Gang Li, Yang Yang

Department of Mechanical and Materials Engineering: Faculty Publications

Highly efficient white light emission was realized via the partial energy transfer from blue host polyfluorene (PF) to orange light emission dopant rubrene. A more balanced charge transport was achieved by adding an electron transport material, 2-(4-biphenylyl)-5-(4-tertbutylphenyl)-1,3,4-oxadiazole (PBD), into the PF-rubrene system to enhance the electron transportation. Efficiency improvement by as much as a factor of 2 has been observed through the addition of PBD. These devices can easily reach high luminance at low driving voltages, thus achieving high power efficiency at high luminance (14.8, 13.5, and 12.0 lm/W at the luminances of 1000, 2000, and 4000 cd/m², …

Piezoelectromagnetic Waves In A Ceramic Plate Between Two Ceramic Half-Spaces, S. N. Jiang, Q. Jiang, X. F. Li, S. H. Guo, H. G. Zhou, J. S. Chang

Department of Mechanical and Materials Engineering: Faculty Publications

We analyze the propagation of piezoelectromagnetic waves guided by a plate of polarized ceramics between two ceramic half-spaces. An exact dispersion relation is obtained, which reduces to a few known elastic, electromagnetic, and quasistatic piezoelectric wave solutions in the literature as special cases. Numerical solutions to the equation that determines the dispersion relation show the existence of guided waves. The results are useful for acoustic wave and microwave devices.

Loading And Recovery Behavior Of The Human Lumbar Spine Under Static Flexion, Guntulu Selen Hatipkarasulu

LSU Doctoral Dissertations

Musculoskeletal disorders account for 32 percent of work related injuries and illnesses. Extensive studies have been conducted to understand and explore the factors that affect the development of musculoskeletal disorders to provide effective control strategies. One of the most important factors that allow effective control strategies is the biomechanical factors. Among the biomechanical risk factors, exposures to repetitive static and vibratory activities are known to result in musculoskeletal disorders. A ligamento–muscular reflex activity exists in humans and animals to stabilize the knee, shoulder, elbow, ankle joints, and spine. This reflex activity decreases over time when static loading is applied, which …

Cracking Of Martensitic Alloy Ep-823 Under Controlled Potential, Ajit K. Roy, M. K. Hossain

Mechanical Engineering Faculty Research

The susceptibility of martensitic Alloy EP-823 to stress corrosion cracking was evaluated with and without an applied cathodic potential using the slow-strain-rate (SSR) testing technique. The magnitude of the applied potential was based on the corrosion potential determined by cyclic polarization. The cracking susceptibility in an acidic environment at different temperatures was expressed in terms of the true failure stress (ơ_f), time to failure (TTF), and ductility parameters, including percent elongation (%El) and percent reduction in area (%RA). The data indicate that the magnitudes of ơ_r, TTF, %El, and %RA were reduced due to cathodic charging. …

A Study Of Overcharge Characteristic Of Lithium-Ion Cells, Jing Pang, Shi-Gang Lu, Sha Liu

Journal of Electrochemistry

The overcharge characteristics and effect factors of lithium-ion cells containing LiMn₂O₄ cathodes were studied in detail. Overcharge testing of Lithium-ion cells with a systematic variation in the cell balance demonstrated that the overcharge characteristics of Lithium-ion cells was affected by the amount of cathode in the cells, which is independent of the amount of anode material. The rate of charge was found to be an important parameter, as electrolyte complete decomposition at low charge rates caused the end of overcharge testing, while high charge rates accelerated the rate of heat generation in the cells and the cell …

The Deactivation Mechanism Of Metal Oxide Anodes Under Alternative Current Electrolysis Condition, Jun-Tao Wang, Yan Han, Guang-Zhang Chen, Wen-Fa Liu

Journal of Electrochemistry

The metal oxide anodes coated on titanium used in seawater electrolysis were prepared by thermal decomposition. Their morphologies, compositions and phase structures were determined by scanning electron microscope(SEM), energy dispersive X-ray detector(EDX) and X-ray diffraction(XRD). The electrochemical properties of the anodes were characterized by accelerated life test, cyclic voltammetry and electrochemical impedance spectroscopy. SEM, EDX and XRD showed that solid solution structures of (Ru, Ir, Ti)O₂ and (Ir, Ti)O₂ were formed after pyrolysis, the solid solution structures and active components were disappeared after the deactivation of the anodes. Electrochemical results indicated that the active area decreased and the …

Solid Oxide Fuel Cells-Materials And Prospects, Molenda Janina, Marzec Jacek

Journal of Electrochemistry

The paper summarizes and discusses the basic properties of solid oxide fuel cell (SOFC) components (electrode materials and electrolyte) from the point of view of their essential functional parameters suck as chemicalstability, transport, catalytic and thermomechanical properties under operational conditions in a SOFC. An interrela-tion between the defect structure of these materials related to oxygen nonstoichiometry and their electronic propertiesand catalytic activity was shown. Single-chamber fuel cell concept was also presented.

The Optimal Sulfonation Conditions Of Self-Doped Polyaniline Obtained By Using Experimental Strategies, Wen-Yar Li, Chi-Chang Hu

Journal of Electrochemistry

The optimal sulfonation condition of self-doped sulfonated polyaniline (prepared from leucoemeraldinebase; denoted as LEB-SPANI) with a high electronic conductivity was obtained by experimental strategies, includingthe fractional factorial design (FFD) and central composite design (CCD). From the FFD experiment, the self-doped LEB-SPANI prepared at a lowtemperature (4℃), a short reaction time (1 h), and a small volume of fumingsulfuric acid (10 mL) showed a better conductivity (ca.127 mS/cm). In the CCD study coupled with a confirmationtest, the highest conductivity (ca.141 mS/cm) of the LEB-SPANI film was obtained under a sulfonation temperatureof 4℃, a sulfonation time of 75 minutes, and a volume …

A Study Of Three Corrosion Inhibitors For Reinforcing Steel In Sps Solution By Electrochemical Methods, Bing Zhao, Rong-Gui Du, Chang-Jian Lin

Journal of Electrochemistry

Some electrochemical techniques such as linear polarization,electrochemical noise and EIS have been employedto study the inhibition behavior of N-lauroyl sarcosinate, β-sodium glycerophosphate and D-sodium gluconate for the reinforcing steel immersed in simulated concrete pore solution(SPS) with NaCl addition.The results show that D-sodium gluconatehas an obvious inhibitive effect for the reinforcing steelin containing Cl^- SPS solution. It has been proposed that the corrosion inhibition of D-sodium gluconate is due to its competitive adsorption and precipitation on steel surface in the simulated concrete environment.

Copper Electrodeposition Under The Perturbation Of Hard Particles, Zeng-Wei Zhu, Di Zhu

Journal of Electrochemistry

Copper electrodepositon was carried out on the rotating cathode,with hard particles(such as ceramic beads) filling between the electrodes. The rotation of cathode led hard particles to polish and impact the surface of deposit during electrodeposition.Copper deposits with a mass of cuspidal nodules were produced in acid sulfate solutions while brittle deposits without nodules were produced in alkaline sulfate solutions. It was also found that brightening and smoothing deposit could be obtained from the alkaline solution, and the deposit was approximatively disordered orientation with granular morphology of about 100~300 nm. The results show that the polishing and impact of hard particles …