Materials Science and Engineering Commons^™

Formation Of Organized Nanostructures From Unstable Bilayers Of Thin Metallic Liquids, Mikhail Khenner, Sagar Yadavali, Ramki Kalyanaraman

Mathematics Faculty Publications

Dewetting of pulsed-laser irradiated, thin (< 20 nm), optically reflective metallic bilayers on an optically transparent substrate with a reflective support layer is studied within the lubrication equations model. A steady-state bilayer film thickness (h) dependent temperature profile is derived based on the mean substrate temperature estimated from the elaborate thermal model of transient heating and melting/freezing. Large thermocapillary forces are observed along the plane of the liquid-liquid and liquid-gas interfaces due to this h-dependent temperature, which, in turn, is strongly influenced by the h-dependent laser light reflection and absorption. Consequently the dewetting is a result of the competition between thermocapillary and intermolecular forces. A linear analysis of the dewetting length scales established that the non-isothermal calculations better predict the experimental results as compared to the isothermal case within the bounding Hamaker coefficients. Subsequently, a computational non-linear dynamics study of the dewetting pathway was performed for Ag/Co and Co/Ag bilayer systems to predict the morphology evolution. We found that the systems evolve towards formation of different morphologies, including core-shell, embedded, or stacked nanostructure morphologies.

A Framework For Studying The Physical Degradation Characteristics Of Dvds And Their Relationship To Digital Errors, Brian K. Saville

Theses and Dissertations

The methods used to store data on DVD-R discs have been proven to work over the last 15 years. However, there has been a growing concern that these discs will be outlasted by the paper records they were meant to replace. The data on a DVD-R is stored as optical contrasts which have the potential to be misread and even damaged. This damage may occur either on the surface or internally to the disc, especially on the recording layer itself. The literature is saturated with studies attempting to determine the time period in which discs may fail and what the …

Effect Of Extracellular Matrix (Ecm) Protein Micropatterns On The Behavior Of Human Neuroblastoma Cells, Ishwari Poudel

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

Recent advances in patterning techniques and emerging surface microtechnologies have allowed cell micropatterning to control spatial location of the cells on a surface as well as cell shape, attachment area, and number of contacting neighbor cells. These parameters play important roles in cell cellular behaviors. Cell micropatterning has thus become one of the most important strategies for biomedical applications, such as, tissue engineering, diagnostic immunoassays, lab-on-chip devices, bio-sensing, etc., and cell biology studies as well. For neuronal cells, there have been attempts to distribute neuronal cells on specific patterns to control cell-to-cell interaction. However, there have been very limited understanding …

A Conceptual Framework And Simulation Modeling Of Engineering Change Management In A Collaborative Environment, Krishna Rao Reddi

Mechanical and Aerospace Engineering - Dissertations

Engineering Change Management (ECM) in a collaborative environment is a complex process and is crucial to the Original Equipment Manufacturer (OEM) to ensure low product development time and cost. In this thesis, the ECM in a collaborative environment has been studied and a conceptual framework to support the process is presented. New Product Development (NPD) and ECM processes have been modeled and simulated to study the associated process dynamics.

An extensive review of the literature indicated that the research on ECM in a collaborative environment is very limited. The review also highlighted that, (i) the ECM frameworks from past research …

Effect Of Vanadium On Subcritical Heat Treatment Behavior Of Hypoeutectic 16 Wt% Cr Cast Iron Containing 2 Wt% Mo, R Junsamoot, S Inthidech, K Sriprateep, P Sricharoenchai, Y Matsubara

Journal of Metals, Materials and Minerals

Subcritical heat treatment of austenite in alloyed cast iron by tempering at the temperature below pearlite transformation (A1), has been used to improve matrix hardness without hardening. Hypoeutectic high chromium cast irons containing 16 wt% Cr - 2 wt% Mo without and with V were prepared in order to clarify the effect of holding temperature and holding time on behavior of hardness and decomposition fraction of austenite in matrix (f) in subcritical heat treatment. As-cast specimens were held at temperature from 723 K to 923 K for 14.4 - 43.2 ks, and then cooled by fan air. In the as-cast …

Recovery Of Zinc From The Spent Zinc-Carbon Dry Cell Batteries Through Pyrometallurgical Route, M Haque Khan, Asw Kurny

Journal of Metals, Materials and Minerals

Spent zinc-carbon batteries of all the five types (AAA, AA, C, D and 9V) were processed to recover zinc metal. All the components of the battery were separated, chemically analyzed and the anodic zinc parts were subjected to pyrometallurgical processing. Extraction of zinc was negligible when no fluxing agent was used. However, extent of recovery increased significantly when chloride salts: sodium chloride, calcium chloride and ammonium chloride were used as a fluxing agent. Among these, ammonium chloride gave the best result as flux. Using 10 %wt. of each flux, extraction of zinc was 90% for ammonium chloride, and around 75% …

Highly Porous Silica Network Prepared From Sodium Metasilicate, R E. Essien, O A. Olaniyi, L A. Adams, R O. Shaibu

Journal of Metals, Materials and Minerals

Porous silica network was prepared from sodium metasilicate (Na2SiO3) at room temperature (27C) using hydrochloric acid (HCl) as catalyst through the sol-gel method. The gel was dried at 120C for 1 day and calcined at 800C for 3 hours and the material obtained characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The results showed the formation of amorphous silica particles of average sizes 598 nm with ordered porous network of pore sizes ranging from 0.18-0.91 ?m. This synthetic route uses sodium metasilicate as commercial precursor without pore forming templates which could be useful …

Ni Electroless Plating Of Abs Polymer By Palladium And Tin-Free Process, P Dechasit, W Trakarnpruk

Journal of Metals, Materials and Minerals

A palladium and tin-free process for the Ni electroless plating of acrylonitrile-butadiene-styrene (ABS) polymer has been developed. The ABS was first etched then activated with Ni (or Co) ions. Ni or Co adsorbed was quantified by atomic absorption spectroscopy. Sodium borohydride solution was found to be effective in reduction of Ni (or Co) ions. By immersing in a Ni plating bath the Co (or Ni) can then auto-catalytically deposit a Ni film on the ABS. The amount and thickness of Ni film determined by SEM-EDX were the highest when using 3 g/L of nickel acetate solution, 0.5 M sodium borohydride …

Preparation Of Copper Lead Frame By Powder Metallurgy Technique, P Y. Chew, A H. You, T R. Vijayaram, B K. See, P S. Lim, M C. Ng

Journal of Metals, Materials and Minerals

Pure Cu is prepared with the dimension of 17.7 mm in diameter and 10 - 15 mm in height using powder metallurgical method to characterize its electrical and mechanical properties. These samples are compacted at a constant pressure of 280 MPa. Pure Cu pellets are sintered at 600C and 950C for 3, 4 and 7 hours. Before sintering, pure Cu pellet is subjected to SEM in order to check the compactness of the pellet, and also the grain structure of the Cu. All the pellets with different temperatures are re-weighed and sintered density are calculated after sintering. Besides that, porosity …

Surface Wetting And Friction Studies Of Nano-Engineered Surfaces On Copper Substrate, Julius Sheldon Morehead

Graduate Theses and Dissertations

Nano-engineered-textures on a material surface can dramatically improve the wetting and non-wetting properties of a surface, and they also show promise to address friction issues that affect surfaces in contact. In this work, aluminum-induced crystallization (AIC) of amorphous silicon (a-Si) was used to produce nano-textures on copper (Cu) substrates. A study was performed to examine the effects of changing the annealing conditions and a-Si thickness on nano-texture formation. The creation of various nano-topographies and chemically modifying them using octafluorocyclobutane (C4F8) was performed to control hydrophilicity, hydrophobicity, and oil affinity of nano-textured surfaces. A video-based contact angle measurement system was used …

Fundamental Understanding Of Soot Induced Wear Mechanism Of Diesel Engines, Mihir Patel

Material Science and Engineering Dissertations - Archive

Emission of Oxides of nitrogen and particulates matters from diesel engines have been reduced by implementing exhaust gas recirculation (EGR) protocols but at the expense of increased wear of engine components. This problem is aggravated by Environment Protection Agency (EPA) regulation such as API CJ 4 and SAPS where chemical limits have been places on the amount of phosphorous, sulfur and sulfated ash in lubrication oil. Several studies have examined the role played by diesel soot on enhanced wear but none have provided comprehensive mechanism. This would allow the possibility to comprehend fundamental understanding of soot induced wear mechanism of …

Templated Synthesis And Characterizations Of High Moment Magnetic Nanoparticles For Bioapplications, Punnapob Punnakitikashem

Material Science and Engineering Dissertations - Archive

Magnetic nanoparticles have been widely used for biomedical applications such as drug and gene delivery, hyperthermia treatment of cancer, MRI contrast enhancement, cell labeling and magnetic separation. We present two new types of magnetic nanoparticles for bioapplications; granular superparamagnetic gold nanoparticles and multilayered nanodisks. Granular superparamagnetic gold nanoparticles consist of superparamagnetic islands embedded in a gold matrix. Multilayered nanodisks consist of two magnetic layers separated by a non-magnetic layer with two capping layers. Capping layers such as gold provide functionalization sites for biomolecule attachment. These nanoparticles possess two key magnetic requirements for bioapplications, a high saturation magnetic moment and a …

An Innovative Epitaxial Growth Method For Minimizing Dislocations In Thin-Film Quantum-Dot Optoelectronic And Photovoltaic Device Applications, Jateen Gandhi

Material Science and Engineering Dissertations - Archive

A new buffer layer method for epitaxial growth of lattice-mismatched semiconductor quantum-dots based p-i-n structures is presented. To our knowledge this is the first instance of a dislocation-reduction approach that has shown reduced dark current behavior in a quantumdot device compared to its counterpart homojunction p-n device consisted of the barrier material. The present work compared a lattice misfit strain build-up behavior between an In0.15Ga0.85As (p) / InAs (i) / In0.15Ga0.85As (n) (QD) device to an In0.15Ga0.85As (p) / In0.15Ga0.85As (n) (HOM) device, as both were grown on an un-doped gallium arsenide (GaAs) (100) substrate. The intrinsic region of QD …

Electrochemical N-Type Doping In Metal Oxides And Its Application In Photovoltaics, Xiaofei Han

Material Science and Engineering Dissertations - Archive

Electrodeposition has the advantages of low-cost, high-throughput and large-area processing which is particularly suitable for solar cells fabrication. Two common metal oxides prepared by electrodeposition are discussed here, ZnO and Cu2O. ZnO is largely used in the solar cells as the window and transparent contact material. Cu2O is potential absorption material for next generation solar cell. n-type doping of these metal oxides was revealed during electrochemical deposition. For naturally n-type ZnO, n-type doping is achieved by substituting the cation (Zn) with a group III element (Al, Ga and Y) and for naturally p-type Cu2O, n-type doping is realized by substituting …

Empirical Study: Failure Of Glass-To-Metal Seals During Shock Loading, William Horton

All Theses

The goal of this thesis was to determine the empirical failure mechanisms and sequence of cartridge actuated devices (CADs) experiencing failure of the glass-to-metal (G/M) seal. Impact loading was conducted with a drop weight machine at room temperature and 300¡F, and then empirically analyzed with high speed video. Resulting peak overload force, shear stress, and impulse were all calculated. The room temperature samples were found to absorb twice the impulse upon failure as the elevated temperature G/M seals. Closed-form and three-dimensional finite element analysis was used to determine the stress state and deformation upon loading. Furthermore, high speed data was …

Role Of Surface Coatings In Lithium-Ion Batteries, Archana Kayyar

All Theses

Rechargeable batteries that can charge and discharge at high rates have applications in hybrid and plug-in hybrid vehicles and they provide energy storages for wind energy. Various methods like reducing particle size, aliovalent doping and carbon coating have been researched in order to attain higher charge and discharge rates in rechargeable Li-ion batteries. In this work, the electrode materials were coated with amorphous films in an attempt to improve the rate capability of the batteries.
A study by Kang and Ceder suggested that a Li₄P₂O₇-like 'fast-ion conducting surface phase' could form on the surface …

Grain Boundary Behavior In An Ultrafine-Grained Aluminum Alloy, P. S. De, R. S. Mishra

Materials Science and Engineering Faculty Research & Creative Works

The low-angle grain boundary (LAGB) stability in an ultrafine-grained (UFG) Al alloy during monotonic loading was investigated by orientation imaging microscopy (OIM). the experiments show that boundaries with misorientation below ∼2.5 deg are stable, while boundaries with misorientation between 2.5 and 15 deg are unstable. Similar results were observed during cyclic loading of UFG Al alloy. This behavior was rationalized using the nonequilibrium thermodynamics concept. on the other hand, it is postulated that the grain boundary behavior in microcrystalline alloy is different because of the larger dislocation mean free path. © 2011 the Minerals, Metals & Materials Society and ASM …

Fluid Flow-Related Transport Phenomena In Steel Slab Continuous Casting Strands Under Electromagnetic Brake, Yufeng Wang, Lifeng Zhang

Materials Science and Engineering Faculty Research & Creative Works

In the current study, a three-dimensional (3D) numerical model is built to investigate the effect of a local-type electromagnetic brake (EMBr) on the fluid flow, heat transfer, and inclusion motion in slab continuous casting strands. the results indicate that the magnetic force affects the jet characteristics, including jet angle, turbulent kinetic energy, and its dissipation rate. to reduce the top surface velocity and stabilize the top surface, the magnetic flux intensity should be larger than a critical value. with a 0.39 T magnetic flux intensity, the top surface velocity and its fluctuation can be well controlled, and less slag is …

Influence Of Grain Size And Texture On Hall-Petch Relationship For A Magnesium Alloy, W. Yuan, S. K. Panigrahi, J. Q. Su, R. S. Mishra

Materials Science and Engineering Faculty Research & Creative Works

Friction stir processing was applied to a magnesium alloy to generate various grain sizes with the same intense basal texture. Subsequent tensile deformation along two orthogonal directions by easy activation or inhibition of basal slip follows the Hall-Petch relationship between yield stress and grain size in both directions. the Hall-Petch parameters are texture dependent. Easy activation of basal slip introduces lower values, while inhibition of basal slip leads to higher values. the Hall-Petch parameters are interpreted by texture and microstructural factors. © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Optical And Magnetic Properties Of Feni Slanted Columnar Thin Films Infiltrated With Pmma And Fe3O4 Nanoparticles, Dan Liang

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

In this thesis, dielectric polymer and magnetic nanoparticles were utilized to hybridize FeNi Slanted columnar thin films (SCTFs). Firstly Fe₃O₄ in PMMA matrix was prepared by physical blending process. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were used to investigate the dispersion of the nanoparticles in PMMA matrix and the preparation conditions were varied to optimize the dispersion. The hybridized materials were prepared by the infiltration of PMMA and 5 wt% Fe₃O₄ nanoparticles/PMMA to the voids of FeNi SCTFs. Spin-coating and annealing process were employed to reach an excellent infiltration.

The structural …

Strength Of Polycrystalline Ceramics Under Shock Compression, Jianbin Zhu

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

Determinations of Some polycrystalline ceramics’ strength properties and inelastic deformation mechanisms in the shocked state are critically important to the design and optimization of armor structures involving these materials. In this work, multiscale modeling and simulations have been carried out to study strength of the effects of polycrystalline microstructure, crystal anisotropy, porosity, and their interactions with microscopic deformation/damage mechanisms on the responses of several polycrystalline ceramics under shock compression and to extract their shock strengths from the wave profiles measured in the related plate impact shock wave experiments.

With a mesoscopic computational model, the roles of intragranular microplasticity and deformation …

The Development Of A Far Red To Near Infrared Fluorescent Probe For Use In Optical Imaging, Margaret Fiedler

All Theses

New techniques for biological optical imaging are of great interest for the detection and visualization of processes and disease in both clinical and research areas. One major advancement has been the use of far red and near infrared (NIR) light, as it has the ability to penetrate tissues deeper than other parts of the spectrum which are readily scatter and absorbed by the surroundings. In order to improve the signal to noise ratio and resolution of optical images, contrast agents are used. Fluorescent markers can be modified to attach to specific molecular targets, creating small molecular probes. These targets can …

4-(N,N-Diethylamino)Benzaldehyde Thiosemicarbazone As Corrosion Inhibitor For 6061 Al - 15 Vol. Pct. Sic(P) Composite And Its Base Alloy, G M. Pinto, J Nayak, A N. Shetty

Journal of Metals, Materials and Minerals

The inhibitive action of 4-(N,N-diethylamino)benzaldehyde thiosemicarbazone (DEABT) on the corrosion behavior of 6061 Al -15 vol. pct. SiC(p) composite and its base alloy was studied at different temperatures in sulfuric acid medium containing varying concentrations of it, using Tafel extrapolation and AC impedance spectroscopy (EIS) techniques. Results showed that DEABT was an effective inhibitor, showing inhibition efficiency of 80 % in 0.5 M sulfuric acid. The adsorption of DEABT on both the composite and the base alloy was found to be through physisorption obeying Langmuirs adsorption isotherm.The thermodynamic parameters such as free energy of adsorption and activation parameters were calculated.

Synthesis Of Aligned Carbon Nanotubes By Floating Catalyst Method Using Ferrocene, R Ravindra, B R. Bhat

Journal of Metals, Materials and Minerals

The aligned carbon nanotubes (CNTs) have been synthesised by floating catalyst method using ferrocene as catalyst precursor and acetylene as carbon precursor. The reaction was carried out at 850C in double stage chemical vapor deposition (CVD) apparatus. The grown aligned CNTs were purified by air oxidation and acid treatment method. The aligned CNTs were characterised by using scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. The purity of CNTs was determined by Thermal analysis and X-ray diffraction method. The average diameter of aligned CNTs were around 20nm. This process not only produces aligned CNTs but also avoids the preparation …

Multi-Properties Of Chitosan/Montmorillonite Composite Films Incorporated With Virgin And Modified Montmorillonite, S Kittinaovarat, W Nitayaphat, N Jiratumnukul, S Charuchinda

Journal of Metals, Materials and Minerals

Chitosan (CTS) composite films were prepared by blending CTS with virgin or modified montmorillonite (vMMT or mMMT, respectively) and then spin coating. XRD analysis showed a good intercalation of CTS and the mMMT in the depolymerized 15 kDa CTS/mMMT composite. The tensile strength and rigidity of the CTS/vMMT and CTS/mMMT composite films increased, whilst the elongation at break decreased, with increasing levels of vMMT or, especially, mMMT from 0.1 to 2% (w/w). Both types of CTS/MMT composite films displayed a decreased oil and water absorption with increasing levels of incorporated vMMT or mMMT. Some aggregation of vMMT but not mMMT …

Mechanical Properties Of Stir-Mixed Sicp-Reinforced Aluminium Composites, R Buntan, D Phuenchomphu, P Sukmoung, K Doomao, O Anunapiwat, T Patcharawit

Journal of Metals, Materials and Minerals

Aluminium composites have found their strength in engineering applications such as automotive, electrical and light-weight applications. To achieve uniform microstructure and good mechanical properties, the fabrication techniques are prime factors in controlling wettability and porosity problems. This research therefore aimed for studying microstructure-mechanical property relation of SiCp-reinforced 356 aluminium composites fabricated by a cost-effective stir casting process, to which three elemental additions, Al-5Ti-B, Sr, and Mg,were investigated. Furthermore, effects of SiCp additions (0-15 wt.%) and T6 heat treatment (530C/12h + 155C/4 h) on mechanical properties of the composites were also studied. The 356 aluminium ingot was melted at 700C then …

Process Parameter-Microstructure-Mechanical Property Relations Of Sicp-Reinforced Aluminum Composites Produced By Powder-Injection Casting, M Bunma, P Subarporn, R Bobuangern, T Patthannkitdamrong, T Thuanwong, T Patcharawit

Journal of Metals, Materials and Minerals

Aluminum composites are of interest for engineering applications such as electrical and especially automotive applications and their final physical and mechanical properties are usually determined by fabrication techniques. This research aimed to study effects of process parameters, which are i) argon gas flow rates at 5 and 10 l/min, and ii) casting temperatures at 620 and 680C, on integrity of the SiCp-reinforced 356 aluminum composites fabricated by powder-injection casting using a modified flux injection degassing machine. The SiCp additions are 0, 10 and 15 wt.%. Microstructure - mechanical property relations were constructed based on the predetermined process parameters. Aluminum 356 …

Synthesis Of Zinc Oxide Nanorods And Use In Biosensor Applications, Anishkumar Manoharan

Graduate Theses and Dissertations

The main aim of this research was to develop a nanorod based biosensor for biomedical applications. In this project I use zinc oxide nanorods as the bio-material for biosensor. I fabricated these nanorods using a solution-based technique. Initially I coated a zinc oxide seed layer as the base. This seed layer was then annealed at 350 degrees for almost 1 hour. As a next step, interdigitated electrodes were fabricated on the top of the seed layer using a lift off process. The zinc oxide nanorods were then grown at 90 degrees for almost 4 hours along the electrodes. In this …

Effects Of Grain Boundary Character On Dynamic Recrystallization Using A Modified Monte Carlo Method, Michael B. Morse

Boise State University Theses and Dissertations

Dynamic recrystallization (DRX) is the recrystallization that occurs during high temperature deformation of metals and alloys. While DRX has been observed experimentally, the parameters that affect the microstructure are still being explored. For example, the effects of temperature, strain rate, and initial grain size have already been studied, yet the effect of initial special boundary fraction is still unknown. Special boundaries are high-angle, low-energy grain boundaries. It is believed that higher initial fractions of special boundaries will lead to a delay in the onset of recrystallization and a higher peak stress.

Experimentation has shown that triple junctions are preferred nucleation …

Spark Plasma Sintering Of Tungsten And Tungsten-Ceria: Microstructures And Kinetics, Jeffrey Bryce Perkins

Boise State University Theses and Dissertations

Tungsten casting is impractical, and tungsten compacts are most often produced by press-and-sinter or by hot pressing. The temperatures typically required to sinter tungsten above 90% dense are above 1800 ºC, and sintering times are typically hours. Alternatively, spark plasma sintering (SPS) can be used to consolidate materials to high densities at lower temperatures and shorter times than traditional sintering techniques. In this study, pure tungsten and tungsten with 1, 4, 10, 15, and 20 weight percent ceria were spark plasma sintered at varying pressures, temperatures, and times to investigate the microstructures and the kinetics of sintering.

Densification of tungsten …