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Materials Science and Engineering Faculty Research & Creative Works

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Full-Text Articles in Ceramic Materials

Kinetics Of Corrosion Of Bn-Zro2-Sic Ceramics In Contact With Si-Killed Steel, Abhishek Kumar, Vivek Thapliyal, David G.C. Robertson, Jeffrey D. Smith May 2015

Kinetics Of Corrosion Of Bn-Zro2-Sic Ceramics In Contact With Si-Killed Steel, Abhishek Kumar, Vivek Thapliyal, David G.C. Robertson, Jeffrey D. Smith

Materials Science and Engineering Faculty Research & Creative Works

The mechanism and kinetics of corrosion of BN-ZrO2-SiC (MYCROSINT®SO43) by molten Si-killed steel was studied. Isothermal corrosion tests were performed for duration between 2 and 8 h. Refractory and steel composition and morphology changes were investigated. A kinetic model using process simulation software METSIM and thermochemical software FactSage was developed to understand refractory-steel interactions. The corrosion process showed a deviation from parabolic kinetics and was fitted by a combination of linear and parabolic terms. It was determined that corrosion of the BN-ZrO2-SiC refractory was governed by dissolution of SiC and BN and removal of ZrO2 …


Method And System For Purifying Charged Radioisotopes, Cathy Sue Cutler, Gary John Ehrhardt, Hendrik Petrus Engelbrecht, D. E. Day Jan 2015

Method And System For Purifying Charged Radioisotopes, Cathy Sue Cutler, Gary John Ehrhardt, Hendrik Petrus Engelbrecht, D. E. Day

Materials Science and Engineering Faculty Research & Creative Works

The present invention provides a simple and inexpensive method for removing metal and other impurities in a radioisotope solution. The invention further includes the development of a new parent/daughter generator system for collecting the daughter isotope in a concentrated solution.


Congenital Epidermoid Cyst Results In Muscle Fusion Defect In The Upper Lip, Fatih Dogan, Ibrahim Hakan Bucak Dec 2014

Congenital Epidermoid Cyst Results In Muscle Fusion Defect In The Upper Lip, Fatih Dogan, Ibrahim Hakan Bucak

Materials Science and Engineering Faculty Research & Creative Works

Epidermoid cysts are rarely detected malformations in the oral cavity. Their development sites are the sublingual, submaxillary, and submandibular spaces. In this paper, we report a three-month-old infant who was admitted to our hospital due upper lip swelling. Magnetic resonance imaging showed that she had a two-centimeter cystic lesion and fusion defects of orbicularis oris muscle. The cyst was surgically removed, and histopathological diagnosis was “epidermoid cyst.” In recent literature, we could not find reports related to orbicularis oris muscle fusion defects because of epidermoid cyst.


Interaction Of Bn-Zro2-Sic Ceramics With Inclusions In Si-Killed Steel, Abhishek Kumar, Vivek Thapliyal, Jeffrey D. Smith Nov 2014

Interaction Of Bn-Zro2-Sic Ceramics With Inclusions In Si-Killed Steel, Abhishek Kumar, Vivek Thapliyal, Jeffrey D. Smith

Materials Science and Engineering Faculty Research & Creative Works

Boron nitride (BN)-based ceramics are often used as containment refractory in thin-strip steel production. The interaction of this material (BN-ZrO2-SiC: -MYCROSINT® SO43) was studied using a steel-inclusion system in a laboratory setup. Isothermal interaction tests were performed to evaluate the interaction of inclusions with this refractory. It was determined that corrosion of the BN refractory occurs through a dissolution mechanism and it was more severe in contact with steel compared to slag. A thermodynamic model was developed using FactSage to study the change in liquid steel/slag composition with refractory interaction. Thermodynamic predictions were in agreement with the experimental …


Modulating Notochordal Differentiation Of Human Induced Pluripotent Stem Cells Using Natural Nucleus Pulposus Tissue Matrix, Yongxing Liu, M. N. Rahaman, B. Sonny Bal Jul 2014

Modulating Notochordal Differentiation Of Human Induced Pluripotent Stem Cells Using Natural Nucleus Pulposus Tissue Matrix, Yongxing Liu, M. N. Rahaman, B. Sonny Bal

Materials Science and Engineering Faculty Research & Creative Works

Human induced pluripotent stem cells (hiPSCs) can differentiate into notochordal cell (NC)-like cells when cultured in the presence of natural porcine nucleus pulposus (NP) tissue matrix. The method promises massive production of high-quality, functional cells to treat degenerative intervertebral discs (IVDs). Based on our previous work, we further examined the effect of cell-NP matrix contact and culture medium on the differentiation, and further assessed the functional differentiation ability of the generated NC-like. The study showed that direct contact between hiPSCs and NP matrix can promote the differentiation yield, whilst both the contact and non-contact cultures can generate functional NC-like cells. …


Ceramic Welds, And A Method For Producing The Same, Greg Hilmas, William Fahrenholtz, Jeremy Lee Watts, Harlan James Brown-Shaklee May 2014

Ceramic Welds, And A Method For Producing The Same, Greg Hilmas, William Fahrenholtz, Jeremy Lee Watts, Harlan James Brown-Shaklee

Materials Science and Engineering Faculty Research & Creative Works

A method of producing a ceramic weld, including identifying a ceramic first surface and a ceramic second surface to be bonded together, maintaining a non-oxidizing atmosphere over the first and second surfaces, and engaging the first and second surfaces to define a joint. An arc is generated between an electrode and the joint to create a liquid phase, and the liquid phase is cooled to yield a solid fusion layer, wherein the first and second surfaces are joined in the fusion layer.


Nanostructured Dielectric Materials For High Energy Density Multilayer Ceramic Capacitors, Fatih Dogan, Alan Devoe, Ian Burn Feb 2014

Nanostructured Dielectric Materials For High Energy Density Multilayer Ceramic Capacitors, Fatih Dogan, Alan Devoe, Ian Burn

Materials Science and Engineering Faculty Research & Creative Works

A multilayer ceramic capacitor, having a plurality of electrode layers and a plurality of substantially titanium dioxide dielectric layers, wherein each respective titanium dioxide dielectric layer is substantially free of porosity, wherein each respective substantially titanium dioxide dielectric layer is positioned between two respective electrode layers, wherein each respective substantially titanium dioxide dielectric layer has an average grain size of between about 200 and about 400 nanometers, wherein each respective substantially titanium dioxide dielectric layer has maximum particle size of less than about 500 nanometers. Typically, each respective substantially titanium dioxide dielectric layer further includes at least one dopant selected …


Nanostructured Dielectric Materials For High Energy Density Multilayer Ceramic Capacitors, Fatih Dogan, Alan Devoe, Ian Burns Feb 2014

Nanostructured Dielectric Materials For High Energy Density Multilayer Ceramic Capacitors, Fatih Dogan, Alan Devoe, Ian Burns

Materials Science and Engineering Faculty Research & Creative Works

A multilayer ceramic capacitor, having a plurality of electrode layers and a plurality of substantially titanium dioxide dielectric layers, wherein each respective titanium dioxide dielectric layer is substantially free of porosity, wherein each respective substantially titanium dioxide dielectric layer is positioned between two respective electrode layers, wherein each respective substantially titanium dioxide dielectric layer has an average grain size of between about 200 and about 400 nanometers, wherein each respective substantially titanium dioxide dielectric layer has maximum particle size of less than about 500 nanometers. Typically, each respective substantially titanium dioxide dielectric layer further includes at least one dopant selected …


A Novel Injectable Borate Bioactive Glass Cement As An Antibiotic Delivery Vehicle For Treating Osteomyelitis, Hao Ding, Cunju Zhao, Xu Cui, Yifei Gu, Weitao Jia, M. N. Rahaman, Yang Wang, Wenhai Huang, Changqing Zhang Jan 2014

A Novel Injectable Borate Bioactive Glass Cement As An Antibiotic Delivery Vehicle For Treating Osteomyelitis, Hao Ding, Cunju Zhao, Xu Cui, Yifei Gu, Weitao Jia, M. N. Rahaman, Yang Wang, Wenhai Huang, Changqing Zhang

Materials Science and Engineering Faculty Research & Creative Works

Background: A novel injectable cement composed of chitosan-bonded borate bioactive glass (BG) particles was evaluated as a carrier for local delivery of vancomycin in the treatment of osteomyelitis in a rabbit tibial model. Materials and Methods: The setting time, injectability, and compressive strength of the borate BG cement, and the release profile of vancomycin from the cement were measured in vitro. The capacity of the vancomycin-loaded BG cement to eradicate methicillin-resistant Staphylococcus aureus (MRSA)-induced osteomyelitis in rabbit tibiae in vivo was evaluated and compared with that for a vancomycin-loaded calcium sulfate (CS) cement and for intravenous injection of vancomycin. Results: …


Development And Application Of Improved Shotctrete Refractory For Aluminum Rotary Furnace Applications, James G. Hemrick, Angela Rodrigues-Schroer, Dominick Colavito, Jeffrey D. Smith, Kelley O'Hara Jan 2014

Development And Application Of Improved Shotctrete Refractory For Aluminum Rotary Furnace Applications, James G. Hemrick, Angela Rodrigues-Schroer, Dominick Colavito, Jeffrey D. Smith, Kelley O'Hara

Materials Science and Engineering Faculty Research & Creative Works

Oak Ridge National Laboratory, in collaboration with refractory manufacturer Minteq International, Inc., academic partner Missouri University of Science and Technology and refractory end users have developed novel refractory systems and techniques to reduce energy consumption of refractory lined vessels. The objective of this U.S. DOE funded project was to address the need for innovative refractory compositions by developing novel gunnable refractory compositions for use in high temperature and high alkali environments. Developed materials utilized new aggregate materials, bond systems, protective coatings, and phase formation techniques. Under this project, materials were developed specifically for aluminum rotary dross furnace applications and a …


Spinel-Based Refractories For Improved Performance In Coal Gasification Environments, James G. Hemrick, Beth Armstrong, Angela Rodrigues-Schroer, Dominick Colavito, Jeffrey D. Smith Jan 2014

Spinel-Based Refractories For Improved Performance In Coal Gasification Environments, James G. Hemrick, Beth Armstrong, Angela Rodrigues-Schroer, Dominick Colavito, Jeffrey D. Smith

Materials Science and Engineering Faculty Research & Creative Works

Oak Ridge National Laboratory, in collaboration with Minteq International, Inc., Missouri University of Science and Technology and refractory end users, has developed novel refractory systems and techniques to reduce energy consumption of refractory lined vessels. The objective of this U.S. DOE funded project was to address the need for innovative refractory compositions by developing MgO-Al2O3 spinel gunnable refractory compositions utilizing new aggregate materials, bond systems, protective coatings, and phase formation techniques. Materials have been developed specifically for coal gasification environments and work has been performed to develop and apply low cost coatings using a colloidal approach for …


Wound Care, Steven B. Jung, D. E. Day Sep 2013

Wound Care, Steven B. Jung, D. E. Day

Materials Science and Engineering Faculty Research & Creative Works

A method for treating a wound, and a dressing for wound care management comprising a three-dimensional body of glass-based fibers comprising one or more glass-formers selected from the group consisting of P2O5, SiO2, and B2O3; at least about 25 wt % of the fibers have a diameter between about 200 nm and about 4000 nm, and a length:width aspect ratio of at least about 10. In another form, the glasses are in the form of particles in an ointment or cream applied to a wound. In yet other forms the glasses are …


Mechanical Properties Of Polypropylene (Pp) + High-Density Polyethylene (Hdpe) Binary Blends: Non-Isothermal Degradation Kinetics Of Pp + Hdpe (80/20) Blends, Kamil Sirin, Fatih Dogan, Murat Canli, Mesut Yavuz Aug 2013

Mechanical Properties Of Polypropylene (Pp) + High-Density Polyethylene (Hdpe) Binary Blends: Non-Isothermal Degradation Kinetics Of Pp + Hdpe (80/20) Blends, Kamil Sirin, Fatih Dogan, Murat Canli, Mesut Yavuz

Materials Science and Engineering Faculty Research & Creative Works

In this study, the mechanical properties and non-isothermal degradation kinetics of polypropylene (PP), high-density polyethylene (HDPE) with dilauroyl peroxide and their blends in different mixture ratios were investigated. The effects of adding dilauroyl peroxide (0–0.20 wt.%) on the mechanical and thermal properties of PP + HDPE blends have been studied. On the other hand, the kinetics of the thermal degradation and thermal oxidative degradation of PP + HDPE (80/20 wt.%) blends were studied in different atmospheres, to analyze their thermal stability. The kinetic and thermodynamic parameters such as the activation energy, Ea., the pre-exponential factor, A, the reaction order, n, …


Impedance Analysis Of Dielectric Nanoparticles Enabled Via A Self-Assembled Monolayer, Sasidhar Siddabattuni, Thomas P. Schuman, Vladimir Petrovsky, Fatih Dogan May 2013

Impedance Analysis Of Dielectric Nanoparticles Enabled Via A Self-Assembled Monolayer, Sasidhar Siddabattuni, Thomas P. Schuman, Vladimir Petrovsky, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

Impedance spectroscopy has been shown to be a powerful tool to investigate the dielectric characteristics of powders suspended in suitable liquids. The electrical and dielectrical contributions of different components of the slurry can be extracted from the impedance spectra through measurement of frequency-dependent relaxations. However, for ferroelectric powders that possess innate surface conductivity, such as BaTiO3, nanoparticles have sufficient conductivity to exclude low frequency fields that preclude impedance characterization of the particle core. In this work, the slurry technique is shown to be effective for dielectric characterization of not only micrometer-sized particles through equivalent circuit modeling but also …


Dielectric Properties Of Polymer–Particle Nanocomposites Influenced By Electronic Nature Of Filler Surfaces, Sasidhar Siddabattuni, Thomas P. Schuman, Fatih Dogan Mar 2013

Dielectric Properties Of Polymer–Particle Nanocomposites Influenced By Electronic Nature Of Filler Surfaces, Sasidhar Siddabattuni, Thomas P. Schuman, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

The interface between the polymer and the particle has a critical role in altering the properties of a composite dielectric. Polymer-ceramic nanocomposites are promising dielectric materials for many electronic and power devices, combining the high dielectric constant of ceramic particles with the high dielectric breakdown strength of a polymer. Self-assembled monolayers of electron rich or electron poor organophosphate coupling groups were applied to affect the filler–polymer interface and investigate the role of this interface on composite behavior. The interface has potential to influence dielectric properties, in particular the leakage and breakdown resistance. The composite films synthesized from the modified filler …


Scaffold For Bone And Tissue Repair In Mammals, D. E. Day, Steven B. Jung Jan 2013

Scaffold For Bone And Tissue Repair In Mammals, D. E. Day, Steven B. Jung

Materials Science and Engineering Faculty Research & Creative Works

A mammalian tissue scaffold and method for making a tissue scaffold including a rigid scaffold body of biocompatible glass fibers bonded together and in special alignment to define open channels within the scaffold to allow fluid flow into and within the scaffold.


Nanostructured Dielectric Materials For High Energy Density Multi Layer Ceramic Capacitors, Fatih Dogan Sep 2012

Nanostructured Dielectric Materials For High Energy Density Multi Layer Ceramic Capacitors, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

A high energy density multilayer ceramic capacitor, having at least two electrode layers and at least one substantially dense polycrystalline dielectric layer positioned therebetween. The at polycrystalline dielectric layer has an average grain size of less than about 300 nanometers, a particle size distribution of between about 150 nanometers and about 3 micrometers, and a maximum porosity of about 1 percent. The dielectric layer is selected from the group including TiO2, BaTiO3, Al2O3, ZrO2, lead zirconium titanate, and combinations thereof and has a breakdown strength of at least about 1100 …


Method For Producing Pressurelessly Sintered Zirconium Diboride/Silicon Carbide Composite Bodies, Shi C. Zhang, Greg Hilmas, William Fahrenholtz Jul 2012

Method For Producing Pressurelessly Sintered Zirconium Diboride/Silicon Carbide Composite Bodies, Shi C. Zhang, Greg Hilmas, William Fahrenholtz

Materials Science and Engineering Faculty Research & Creative Works

A method of sintering a ZrB2-SiC composite body at ambient pressures, including blending a first predetermined amount of ZrB2 powder with a second predetermined amount of SiC powder, wherein both powders are characterized by the presence of surface oxide impurities. Next the blended powders are mixed to yield a substantially homogeneous powder mixture and a portion of the substantially homogeneous powder mixture is formed into a green body. The body is fired to a first temperature, wherein substantially all surface oxide impurities are reduced and/or volatilized to substantially eliminate oxides from the green body, and the body …


Glasses For Radiotherapy, Delbert E. Day May 2012

Glasses For Radiotherapy, Delbert E. Day

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.


Effective Dielectric Constant Of Two Phase Dielectric Systems, Vladimir Petrovsky, Piotr Jasinski, Fatih Dogan May 2012

Effective Dielectric Constant Of Two Phase Dielectric Systems, Vladimir Petrovsky, Piotr Jasinski, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

Various theoretical approaches are implemented for electrical characterization of two-phase material systems. Most of these approaches do not include possibility of percolation of the dispersed material. In this article brick wall model is extended on the systems exhibiting percolation. Transition from brick wall geometry to corresponding equivalent circuits provides final equations for effective dielectric constant. Comparison of theoretical results with experimental data shows that developed equations provide good fitting of effective dielectric constant to experimental values. Dielectric constants of both phases and percolation threshold calculated from the fitting match the corresponding experimental values of the phases.


High-Density Pressurelessly Sintered Zirconium Diboride/Silicon Carbide Composite Bodies And A Method For Producing The Same, Shi C. Zhang, Greg Hilmas, William Fahrenholtz Jan 2012

High-Density Pressurelessly Sintered Zirconium Diboride/Silicon Carbide Composite Bodies And A Method For Producing The Same, Shi C. Zhang, Greg Hilmas, William Fahrenholtz

Materials Science and Engineering Faculty Research & Creative Works

A method of sintering a ZrB2-SiC composite body at ambient pressures, including blending a first predetermined amount of ZrB2 powder with a second predetermined amount of SiC powder, wherein both powders are characterized by the presence of surface oxide impurities. Next the blended powders are mixed to yield a substantially homogeneous powder mixture and a portion of the substantially homogeneous powder mixture is formed into a green body. The body is fired to a first temperature, wherein substantially all surface oxide impurities are reduced and/or volatilized to substantially eliminate oxides from the green body, and the body …


Processing And Dielectric Properties Of Tio2 Thick Films For High-Energy Density Capacitor Applications, Sheng Chao, Fatih Dogan Nov 2011

Processing And Dielectric Properties Of Tio2 Thick Films For High-Energy Density Capacitor Applications, Sheng Chao, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

Nanosized titanium dioxide (TiO2) powders (∼40 nm) were used for preparation of tape-casting slurries. Effect of various solvents and dispersants on the dispersibility of TiO2 slurries was studied by sedimentation tests and rheology measurements. TiO2 green tapes were prepared by tape-casting method and densified at 1000°C with a sintered density >95%. Dielectric properties of TiO2 tapes were studied by measuring of dielectric constant, loss factor and dielectric breakdown strength (BDS) with respect to their microstructural development. BDS values as high as ∼1400 kV/cm were obtained for sintered tapes so that energy densities up to 14 …


Batio3–Srtio3 Layered Dielectrics For Energy Storage, Sheng Chao, Fatih Dogan Mar 2011

Batio3–Srtio3 Layered Dielectrics For Energy Storage, Sheng Chao, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

BaTiO3–SrTiO3 (BST) thick films (~ 250–390 μm) with layered structures were fabricated by tape-casting and lamination process. Layered composites with various Ba/Sr ratios were obtained by lamination of BaTiO3 (BT) and SrTiO3 (ST) tapes in different spatial configurations (2–2). As-prepared BST ceramics showed much improved sinterability over the laminates of pure BT or pure ST tapes. Dielectric properties of materials were measured in the temperature range of 25 °C to 200 °C. The method of utilizing of layered structures offered flexibility to maximize the energy storage capability at specific operating conditions: (temperature and electric field) …


Hollow Hydroxyapatite Microspheres For Controlled Delivery Of Proteins, H. Fu, M. N. Rahaman, D. E. Day Jan 2011

Hollow Hydroxyapatite Microspheres For Controlled Delivery Of Proteins, H. Fu, M. N. Rahaman, D. E. Day

Materials Science and Engineering Faculty Research & Creative Works

Hollow hydroxyapatite (HA) microspheres were prepared by reacting solid microspheres of a lithium-calcium-borate glass (106-150 microns) for 2 days in K2HPO4 solution (0.02 M; 37°C) and evaluated as a controlled delivery device for a model protein, bovine serum albumin (BSA). the as-prepared HA microspheres had a hollow core with a diameter equal to 0.6 the external diameter, a surface area of V100 m2/g, and a mesoporous shell wall (pore size of ≈13 nm). after loading the hollow HA microspheres with a solution of BSA, release of the BSA into a medium of phosphate-buffered saline (PBS) …


Method For Determining The Dielectric Constant Of Particles, Vladimir Petrovsky, Fatih Dogan Oct 2010

Method For Determining The Dielectric Constant Of Particles, Vladimir Petrovsky, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

A method of measuring the dielectric constant of a powder, including selecting a powder having an unknown first dielectric constant, selecting a liquid having a known second dielectric constant, and introducing a predetermined amount of powder into a predetermined volume of liquid to define a slurry characterized by a known volume fraction of powder. Next, the impedance spectra of the slurry are plotted over a predetermined frequency range, the measured dielectric constant data is read and the appropriate equivalent circuit for the slurry is determined. Appropriate equivalent circuit equations are applied to the measured dielectric constant data, and the first …


Complex Impedance Study Of Fine And Coarse Grain Tio2 Ceramics, Sheng Chao, Vladimir Petrovsky, Fatih Dogan Oct 2010

Complex Impedance Study Of Fine And Coarse Grain Tio2 Ceramics, Sheng Chao, Vladimir Petrovsky, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

Titanium dioxide (TiO2) ceramics with various grain sizes were investigated by impedance spectroscopy techniques. Dielectric loss peak identified in coarse grain TiO2 was attributed to space charge polarization occurring at the grain boundaries. Electric modulus representation of the impedance data showed two types of relaxation processes in coarse grain TiO2, whereas only one type was observed in fine grain TiO2. Long-range migration of oxygen vacancies was found to be the dominant conduction mechanism for fine grain TiO2, while electron hopping between localized states was attributed to dielectric relaxation in coarse grain …


Freeze Extrusion Fabrication Of 13-93 Bioactive Glass Scaffolds For Bone Repair, Tieshu Huang, Nikhil D. Doiphode, M. N. Rahaman, Ming-Chuan Leu, B. Sonny Bal, D. E. Day Aug 2010

Freeze Extrusion Fabrication Of 13-93 Bioactive Glass Scaffolds For Bone Repair, Tieshu Huang, Nikhil D. Doiphode, M. N. Rahaman, Ming-Chuan Leu, B. Sonny Bal, D. E. Day

Materials Science and Engineering Faculty Research & Creative Works

There is an increasing demand for synthetic scaffolds with the requisite biocompatibility, internal architecture, and mechanical properties for the bone repair and regeneration. In this work, scaffolds of a silicate bioactive glass (13-93) were prepared by a freeze extrusion fabrication (FEF) method and evaluated in vitro for potential applications in bone repair and regeneration. The process parameters for FEF production of scaffolds with the requisite microstructural characteristics, as well as the mechanical and cell culture response of the scaffolds were evaluated. After binder burnout and sintering (60 min at 700°C), the scaffolds consisted of a dense glass network with interpenetrating …


Hydrogen Fuel Cell Analysis: Lessons Learned From Stationary Power Generation Final Report, Scott E. Grasman, John W. Sheffield, Fatih Dogan, Sunggyu Lee, Umit O. Koylu, Angie Rolufs Apr 2010

Hydrogen Fuel Cell Analysis: Lessons Learned From Stationary Power Generation Final Report, Scott E. Grasman, John W. Sheffield, Fatih Dogan, Sunggyu Lee, Umit O. Koylu, Angie Rolufs

Materials Science and Engineering Faculty Research & Creative Works

This study considered opportunities for hydrogen in stationary applications in order to make recommendations related to RD&D strategies that incorporate lessons learned and best practices from relevant national and international stationary power efforts, as well as cost and environmental modeling of pathways. The study analyzed the different strategies utilized in power generation systems and identified the different challenges and opportunities for producing and using hydrogen as an energy carrier. Specific objectives included both a synopsis/critical analysis of lessons learned from previous stationary power programs and recommendations for a strategy for hydrogen infrastructure deployment. This strategy incorporates all hydrogen pathways and …


Reaction Sintered Zirconium Carbide/Tungsten Composite Bodies And A Method For Producing The Same, Shi C. Zhang, Greg Hilmas, William Fahrenholtz Jan 2010

Reaction Sintered Zirconium Carbide/Tungsten Composite Bodies And A Method For Producing The Same, Shi C. Zhang, Greg Hilmas, William Fahrenholtz

Materials Science and Engineering Faculty Research & Creative Works

A method of sintering a composite body characterized by a transition metal carbide phase (such as a ZrC phase) substantially evenly distributed in a second, typically refractory, transition metal (such as W) matrix at ambient pressures, including blending a first predetermined amount of first transition metal oxide powder (such as ZrO2) with a second predetermined amount of second transition metal carbide powder (such as WC powder). Next the blended powders are mixed to yield a substantially homogeneous powder mixture and a portion of the substantially homogeneous powder mixture is formed into a green body. The body is fired …


Freeze-Spray Deposition Of Layered Alumina/Zirconia Composites, Qiang Fu, Oratai Jongprateep, Ashlee Abbott, Fatih Dogan Apr 2009

Freeze-Spray Deposition Of Layered Alumina/Zirconia Composites, Qiang Fu, Oratai Jongprateep, Ashlee Abbott, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

Freeze-spray deposition (FSD) method is described for rapid fabrication of layered composites with controlled layer thickness and uniform microstructure. The graded alumina/zirconia composites are fabricated by FSD of ceramic slurries followed by freeze drying. Aqueous slurries with glycerol addition are sprayed on a cooled substrate using an automated 3D gantry system. Processing parameters such as viscosity of the ceramic slurries, composition and thickness of deposited layers as well as sintering conditions are investigated to optimize the fabrication process. Microstructural analysis of the fabricated composites revealed uniform and crack-free transitional layers indicating a strong interfacial bonding between the layers.