Materials Science and Engineering Commons^™

Electrical Impedance Imaging Of Corrosion On A Partially Accessible 2-Dimensional Region, Court Hoang, Katherine Osenbach

Mathematical Sciences Technical Reports (MSTR)

In this paper we examine the inverse problem of determining the amount of corrosion on an inaccessible surface of a two-dimensional region. Using numerical methods, we develop an algorithm for approximating corrosion profile using measurements of electrical potential along the accessible portion of the region. We also evaluate the effect of error on the problem, address the issue of ill-posedness, and develop a method of regularization to correct for this error. An examination of solution uniqueness is also presented.

Preparation And Hydrogen Absorption/Desorption Of Nanoporous Palladium Thin Films, Wen-Chung Li, Thomas John Balk

Chemical and Materials Engineering Faculty Publications

Nanoporous Pd (np-Pd) was prepared by co-sputtering Pd-Ni alloy films onto Si substrates, followed by chemical dealloying with sulfuric acid. X-ray diffractometry and chemical analysis were used to track the extent of dealloying. The np-Pd structure was changed from particle-like to sponge-like by diluting the sulfuric acid etchant. Using suitable precursor alloy composition and dealloying conditions, np-Pd films were prepared with uniform and open sponge-like structures, with interconnected ligaments and no cracks, yielding a large amount of surface area for reactions with hydrogen. Np-Pd films exhibited shorter response time for hydrogen absorption/desorption than dense Pd films, showing promise for hydrogen …

Self-Organized Nanolayers Of Organosilane Molecules, Ocelio V. Lima

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

There is a high degree of interest in organic thin films for lightweight, low power, rugged and flexible electronics. Conjugated organic molecules with polycyclic rings are being considered a major enabler of such applications. Due to a surface tension mismatch between the organic molecule with the inorganic support (mainly silicon oxides), molecular packing inside these thin films is often disordered, which suppresses the device performance. There are major efforts focused on modifying the bulk properties, for instance, maximizing orbital overlaps in the solid state, little attention was paid to receive long-range ordered thin films. A novel approach to afford conjugated …

Production Of Iron Using Environmentally-Benign Renewable Or Recycled Reducing Agents, Timothy C. Eisele, Surendra Komar Kawatra

Michigan Tech Patents

To produce metallic iron from iron ore, a composition comprising a mass of material formed from a mixture of iron ore particles and particles of a reductant that is either a biomass material in particulate form or a plastic resinous material in particulate form is used. The reductant can also be a mixture of biomass material and resin in any proportions. The mass of material comprises at least one body having a shape adapted for smelting such as pellets, briquettes, pieces or lumps. The pellets have sufficient cohesion to maintain the shape into which they have been formed. The invention …

Optical Properties Of Semiconducting Boron Carbide For Neutron Detection Applications, Ravi B. Billa

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Solid state neutron detection devices based on semiconducting boron carbide have the potential for nearly ideal neutron detection effciency for thermal neutrons. The present work is focused on characterizing optical properties of this semiconducting boron carbide material as a step in further development of the material for neutron detection and other applications.

Semiconducting boron carbide films were grown on silicon substrates using plasma enhanced chemical vapor deposition and their optical properties were characterized using variable angle spectroscopic ellipsometry over a wide spectral range, from mid-infrared to vacuum-ultraviolet wavelengths. The effects of deposition substrate temperature and of post-deposition heat treatments on …

Modeling Of Metal-Ferroelectric-Insulator-Semiconductor Structures Based On Langmuir–Blodgett Copolymer Films, Timothy J. Reece, Stephen Ducharme

Stephen Ducharme Publications

Among the ferroelectric thin films used in field-effect transistor devices; the ferroelectric copolymer of polyvinylidene fluoride PVDF –CH2–CF2–, with trifluoroethylene TrFE –CHF–CF2–, has distinct advantages, including low dielectric constant, low processing temperature, low cost, and compatibility with organic semiconductors. The operation of a metal-ferroelectric insulatorsemiconductor structure with PVDF-TrFE as the ferroelectric layer was analyzed and optimized by numerical solution of the Miller and McWhorter model. A model device consisting of 20 nm PVDF/TrFE on a 10-nm-thick high-k dielectric buffer exhibits a memory window of 5 V with an operating voltage of 15 V. The operating voltage can be reduced to …

Synthesis Of Zeolite A Membrane From Rice Husk Ash, C Bhavornthanayod, P Rungrojchaipon

Journal of Metals, Materials and Minerals

Rice husk is a major by-product of the rice-processing industries. The burning of rice husk in air results in the formation of rice husk ash (RHA) with a content in SiO2 that varies from 85 to 98% depending on the burning conditions, the furnace type and the rice variety. Numerous studies aimed at using RHA as a cheap alternative source of amorphous silica for the production of silicon based materials with industrial and technological interests. The zeolite gel was prepared with the following batch composition: 3.1Na2O : Al2O3: 1.9SiO2: 128H2O synthesized by hydrothermal treatment with various times from 15 min …

Thermocapillary Effects In Driven Dewetting And Self-Assembly Of Pulsed Laser-Irradiated Metallic Films, Mikhail Khenner

Mathematics Faculty Publications

A mathematical model for the evolution of pulsed laser-irradiated, molten metallic films has been developed using the lubrication theory. The heat transfer problem that incorporates the absorbed heat from a single laser beam or the interfering laser beams is solved analytically. Using this temperature field, we derive the 3D long-wave evolution PDE for the film height. To get insights into dynamics of dewetting, we study the 2D version of the evolution equation by means of a linear stability analysis and by numerical simulations. The stabilizing and destabilizing effects of various system parameters, such as the reflectivity, the peak laser beam …

Influence Of Grain Boundary Character On Creep Void Formation In Alloy 617, Thomas Lillo, James Cole, Megan Frary, Scott Schlegel

Materials Science and Engineering Faculty Publications and Presentations

Alloy 617, a high temperature creep-resistant, nickel-based alloy, is being considered for the primary heat exchanger for the Next Generation Nuclear Plant (NGNP) which will operate at temperatures exceeding 760^oC. Orientation imaging microscopy (OIM) is used to characterize the grain boundaries in the vicinity of creep voids that develop during high temperature creep tests (800-1000^oC at creep stresses ranging from 20-85 MPa) terminated at creep strains ranging from 5-40%. Observations using optical microscopy indicate creep rate does not significantly influence the creep void fraction at a given creep strain. Preliminary analysis of the OIM data indicates …

Thermocapillary Effects In Driven Dewetting And Self-Assembly Of Pulsed Laser-Irradiated Metallic Films, Mikhail Khenner

Mathematics Faculty Publications

A mathematical model for the evolution of pulsed laser-irradiated, molten metallic films has been developed using the lubrication theory. The heat transfer problem that incorporates the absorbed heat from a single laser beam or the interfering laser beams is solved analytically. Using this temperature field, we derive the 3D long-wave evolution PDE for the film height. To get insights into dynamics of dewetting, we study the 2D version of the evolution equation by means of a linear stability analysis and by numerical simulations. The stabilizing and destabilizing effects of various system parameters, such as the reflectivity, the peak laser beam …

Thermocapillary Effects In Driven Dewetting And Self-Assembly Of Pulsed Laser-Irradiated Metallic Films, Mikhail Khenner

Mathematics Faculty Publications

A mathematical model for the evolution of pulsed laser-irradiated, molten metallic films has been developed using the lubrication theory. The heat transfer problem that incorporates the absorbed heat from a single laser beam or the interfering laser beams is solved analytically. Using this temperature field, we derive the 3D long-wave evolution PDE for the film height. To get insights into dynamics of dewetting, we study the 2D version of the evolution equation by means of a linear stability analysis and by numerical simulations. The stabilizing and destabilizing effects of various system parameters, such as the reflectivity, the peak laser beam …

Precipitate Redistribution During Creep Of Alloy 617, Scott Schlegel, Sharla Hopkins, E. Young, James Cole, Thomas Lillo, Megan Frary

Materials Science and Engineering Faculty Publications and Presentations

Nickel-based superalloys are being considered for applications within advanced nuclear power generation systems due to their high temperature strength and corrosion resistance. Alloy 617, a candidate for use in heat exchangers, derives its strength from both solid solution strengthening and the precipitation of carbide particles. However, during creep, carbides that are supposed to retard grain boundary motion are found to dissolve and re-precipitate on boundaries in tension. To quantify the redistribution, we have used electron backscatter diffraction and energy dispersive spectroscopy to analyze the microstructure of 617 after creep testing at 900 and 1000°C. The data were analyzed with respect …

Synthesis And Evaluation Of Bioceramics For Orthopedics And Tissue Culture Applications, Hande Demirkiran

Material Science and Engineering Dissertations - Archive

Hydroxyapatite is the most well known phosphate in the biologically active phosphate ceramic family by virtue of its similarity to natural bone mineral. Among all bioglass compositions Bioglass®45S5 is one of the most bioactive glasses. This study initially started by adding different amounts (1, 2.5, 5, 10, and 25 wt. %) of Bioglass®45S5 to synthetic hydroxyapatite in order to improve the bioactivity of these bioceramics.The chemistries formed by sintering and their effect on different material properties including bioactivity were identified by using various techniques, such as powder and thin film x-ray diffraction, scanning electron microscopy coupled with energy dispersive X-ray …

Tribological Performance Of Ashless Antiwear Additives Under Extreme Pressure Conditions, Bohoon Kim

Material Science and Engineering Dissertations - Archive

Zinc diakyl dithiophosphate (ZDDP) has been used in engine oil for several decades as an antiwear additive. However, ZDDP is the primary source of P, S and Zn in the exhaust, which results in frequent maintenance or replacement of exhaust gas treatment systems. The use of ashless additives is more desirable because of recent environmental regulations. The main goal of this research was to develop a fundamental understanding of how ashless compounds protect the tribological surface in comparison to ZDDP. X-ray absorption near edge structure spectroscopy (XANES) has been performed on tribo and thermal films in order to investigate the …

Self Powered Sensing By Combining Novel Sensor Architectures With Energy Harvesting, Vishwas Bedekar

Material Science and Engineering Dissertations - Archive

Recent advancements in the field of wireless sensor networks have resulted in increasing demand for self-powering techniques that reduces the dependence on batteries. In order to address this problem, there has been significant effort on generating small electrical power locally by harvesting energy from freely available environmental sources such as mechanical vibrations, wind, and stray magnetic field. Further, there is need for inventing new sensing techniques to reduce the overall power consumption. The road for reaching the destination of self-powered sensor networks requires cooperative progress in reduction in sensor power consumption by developing new sensing mechanisms and local generation of …

A Simple Method For Production Of Humidity Indicating Silica Gel From Rice Husk Ash, J Nayak, J Bera

Journal of Metals, Materials and Minerals

The objective of the present work is to develop a procedure for obtaining and characterizing active blue silica from rice husk ash. About 25 wt.% silica powder (from total mass of rice husk) of 95% pure silica could be produced after heat-treating at 700°C for 6 hours. A simple method based on alkaline extraction followed by acid precipitation was developed to produce pure silica hydrogel from RHA. A well-defined very minimum amount CoCl2-containing blue silica gel was prepared by impregnation of the aqueous solution of the salt to silica hydrogel, ageing and drying method. The sharp colour changing from blue …

Crystal Habit Of Caco3 Under Different Carbonation Methods, J Ariyaprayoon, U Leela-Adisorn, A Supsakulchai

Journal of Metals, Materials and Minerals

The saturated solutions of Ca(OH)2 were carbonated by CO2 in air under static and turbulent conditions. The saturation state of starting solution and carbonation methods had effect on the crystal habit. The phase of CaCO3 precipitated from saturated solution is calcite. No metastable phase of CaCO3 was found.

Influence Of Impurity Ions On Rice Husk Combustion, L Xiong, K Saito, E H. Sekiya, P Sujaridworakun, S Wada

Journal of Metals, Materials and Minerals

Rice husk (RH) contains various impurity ions such as K+ , Al3+, Fe3+, Mnn+ (n = 2 - 4), and P-containing acid ions. In the present work, some of their oxides, formed in RH combustion, were found to exert a strong influence on the middle- and late stages of RH combustion, and consequently, strongly affected the structure and properties of the final ash. Very recently, we proved for the first time that the existence of the transition metallic ions in rice husk can lead to a decrease of about 70°C in the terminal combustion temperature (Ttc) of RH. This catalytic …

Effect Of Black Rice Husk Ash Substituted Opc On Strength And Leaching Of Solidified Plating Sludge, R Piyaphanuwat, S Asavapisit

Journal of Metals, Materials and Minerals

Strength and leachability of the solidified plating sludge using OPC and BHA as solidification binders were investigated. BHA was used to replace OPC at 0, 20 and 30 wt.%, and was used to solidify 30 and 50 wt.% of the plating sludge. Results showed that no strength was observed during the first 7 days of curing when OPC was used to solidify the plating sludge. But when 20 and 30 wt.% of BHA were used to substitute OPC, the solidified wastes containing 50 wt.% of the plating sludge gave strength of 4.5 kg/cm2 at the age of 3 and 4.1 …

Burning Temperature Dependence Of Rice Husk Ashes In Structure And Property, L Xiong, E H. Sekiya, P Sujaridworakun, S Wada, K Saito

Journal of Metals, Materials and Minerals

Much attention has been paid to the characterization of the structure and properties of rice husk ash (RHA), but little to the burning temperature dependence of its structure and properties. This dependence is important for the structure and property optimization of RHA in a controllable manner. In this paper, we present a research on the burning temperature dependence of RHA. Rice husk (RH) was burned at various temperatures either as received or after pretreatment by HCl washing. The obtained ashes of both groups exhibit a strong burning temperature dependence of the specific surface area and pore volume, based on the …

Design And Performance Of Load Bearing Shear Walls Made From Composite Rice Straw Blocks, Kevin Robert Camann

Master's Theses

Although rice straw and other grains have been used in building since pre-history, in the past two decades, there has been a move to utilize this rapidly renewable, locally available, agricultural byproduct as part of the sustainable construction movement. Up to this point, this has been done by simply stacking up the full straw bales. Stak Block, invented by Oryzatech, Inc., is a modular, interlocking block made of a composite of rice straw and binding agent that serves as an evolution in straw construction. This study investigates the feasibility of using these Stak Blocks as a structural system. The report …

A Global Defect Chemistry Model For P-Type Mixed Ionic And Electronic Conductors, Xiao Dong Zhou, Harlan U. Anderson

Materials Science and Engineering Faculty Research & Creative Works

A global defect chemistry model is presented to relate the properties of a variety of p-type perovskite conductors, including chromites, manganites, and ferrites, which can be tailored as mixed ionic and electronic conductors (MIECs). It is found that oxygen nonstoichiometry in these p-type MIECs can be correlated using reaction constant for oxygen vacancy generation. the values of reaction constant for oxygen vacancy formation can be obtained by simulating the electronic conductivity as a function of oxygen activity and temperature with the existing global model that is based on the concept of localized electron holes. the global defect chemistry model allows …

Synthesis, Characterization And Potential Applications Of Fept Nanoparticles, Vikas Nandwana

Material Science and Engineering Dissertations - Archive

Monodisperse FePt nanoparticles with controlled size and geometry have drawn great attention in the last decade for fundamental scientific studies and for their potential applications in advanced materials and devices such as ultra-high-density magnetic recording media, exchange-coupled nanocomposite magnets, biomedicines and nanodevices. This dissertation focuses on the synthesis and characterization of FePt nanoparticles and their use in potential applications. The FePt nanoparticles of different size (2 to 16 nm) and shape (spherical, cubic, rod) were synthesized by a chemical solution method. The size and shape of these particles were controlled by adjusting reaction parameters. The as-synthesized FePt nanoparticles have chemically …

Exergetic And Thermoeconomic Analyses Of The Rice-Husk Power Plant In Thailand, P Peerapong, B Limmeechokchai

Journal of Metals, Materials and Minerals

The purpose of this study is to analyze a rice husk power plant, and consider the efficiency of the power plant through both the first law and the second law of thermodynamics. The energetic and exergetic performance criteria such as thermal efficiency, exergy efficiency, and exergy loss have been found to be useful methods in design, evaluation, optimization and improvement of thermal power plants. The exergetic efficiency of a power plant shows that the boiler is the major component contributing to total loss, with its exergetic efficiency of 30%, while the steam turbine has the exergetic efficiency of 76%. The …

Ziegler-Natta Catalyst With High Activity And Good Hydrogen Response, L Sinthusai, W Trakarnpruk, R Strauss

Journal of Metals, Materials and Minerals

Ziegler-Natta catalysts were prepared from chemical reaction route comprising of steps of 1) magnesium complex formation between butyloctyl magnesium and 2-ethyl-1-hexanol, 2) MgCl2 support preparation from the reaction between the magnesium complex and TiCl4 as chlorinating agent and 3) titanation with TiCl4. The catalysts were used for ethylene polymerization using triethylaluminum as a cocatalyst. Effects influencing properties of catalysts and polymerization performance were investigated: triethylaluminum/Mg molar ratio, Ti/Mg molar ratio, addition of electron donor and aging step. Results show that addition of ethylbenzoate as an electron donor resulted in decreased catalytic activity. However it was found that catalytic stability under …

Synthesis And Characterization Of Sio2 Nanowires Prepared From Rice Husk Ash, S Pukird, P Chamninok, S Samran, P Kasian, K Noipa, L Chow

Journal of Metals, Materials and Minerals

SiO2 nanowires were synthesized by thermal evaporation of rice husk ash and coconut shell charcoal with the ratio of 1:2 by weight heated at a temperature of 1,350ο C in atmosphere of nitrogen for 1 hour. The scanning electron microscope and X-rays diffraction instrument are used to characterize the SiO2 nanowires. The SiO2 nanowires synthesized have diameters varying from 40 nm to 200 nm while the lengths were a few micrometers.

Utilization Of Rice Husk To Synthesize High-Performance Phosphors, L Xiong, K Saito, S Wada, E H. Sekiya

Journal of Metals, Materials and Minerals

Rice husk (RH) has high C and Si contents, so it can be used not only as a fuel candidate, but also as a low-cost Si source for synthesizing high-performance products. In the present work, we proposed a low-cost route to synthesize high-performance silicate phosphors with RH. RH was burned either as received or as pretreated by HCl washing. The resulting ashes were, respectively, utilized to react with other raw materials at high temperatures to form silicate phosphors. The high-temperature solid-state reaction process was optimized by varying either the temperature or the holding time. The crystallographic and fluorescent properties of …

Preparation Of Silica Gel From Rice Husk Ash Using Microwave Heating, S Rungrodnimitchai, W Phokhanusai, N Sungkhaho

Journal of Metals, Materials and Minerals

The purpose of this research is to separate silica gel from rice husk ash by microwave heating. The experiments were performed by heating rice husk ash in sodium hydroxide solution with various concentrations in microwave oven for 5 or 10 minutes. The obtained sodium silicate was neutralized to give silica gel. The best condition for silica gel production was the reaction with 2.0 M sodium hydroxide at microwave power of 800 W for 10 minutes. The ability of silica gel as desiccant was investigated by adsorption test. The results showed that silica gel prepared by low concentration of sodium hydroxide …

Utilization Of Silica In Rice Hulls As Raw Materials For Silicon Semiconductors, T Okutani

Journal of Metals, Materials and Minerals

Highly pure silicon and silicon compounds are required in high technology products such as semiconductors and solar cells. Rice hulls consist of 71 to 87wt% organic components such as cellulose and 13 to 29wt% inorganic components. In rice hulls, 87 to 97wt% of the inorganic components are silica (SiO2). Rice plants absorb water-soluble siliceous ions via the roots. These ions are transported to stems, leaves and rice hulls by sap flow. In rice hulls, siliceous ions accumulate at the cuticle outside of the epidermis. The production of pure silicon compound (SiCl4) and of silicon metal as the starting material for …

Pozzolanic Activity Of Rice Husk Ash: Comparison Of Various Electrical Methods, S Wansom, S Janjaturaphan, S Sinthupinyo

Journal of Metals, Materials and Minerals

The great abundance of rice husk ash (RHA) as low-cost agricultural waste in Thailand makes it the most suitable material for cement-based applications. However, the use of RHA as a supplementary cementitious material (SCM) is not yet widespread in Thailand due to the poor pozzolanic activity of most agricultural RHA. Most RHA is incinerated at too high temperatures (usually in excess of 1000ºC) or under uncontrolled conditions as biomass fuel. This reduces the amount of amorphous SiO2 and hence worsens the pozzolanic activity of the resulting RHA. To enhance the use of RHA as an SCM in Thailand, a proper …