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Full-Text Articles in Materials Science and Engineering

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 …


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 …


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 …


Design, Fabrication, And Properties Of 2-2 Connectivity Cement/Polymer Based Piezoelectric Composites With Varied Piezoelectric Phase Distribution, Xu Dongyu, Cheng Xin, Sourav Banerjee, Huang Shifeng Jan 2014

Design, Fabrication, And Properties Of 2-2 Connectivity Cement/Polymer Based Piezoelectric Composites With Varied Piezoelectric Phase Distribution, Xu Dongyu, Cheng Xin, Sourav Banerjee, Huang Shifeng

Faculty Publications

The laminated 2-2 connectivity cement/polymer based piezoelectric composites with variedpiezoelectric phase distribution were fabricated by employing Lead Zirconium Titanate ceramicas active phase, and mixture of cement powder, epoxy resin, and hardener as matrix phase with a mass proportion of 4:4:1. The dielectric, piezoelectric, and electromechanical coupling properties of the composites were studied. The composites with large total volume fraction ofpiezoelectric phase have large piezoelectric strain constant and relative permittivity, and thepiezoelectric and dielectric properties of the composites are independent of the dimensional variations of the piezoelectric ceramic layer. The composites with small total volume fraction of piezoelectric phase have large …


Freeze Thaw Durability Of Internally Cured Concrete Made Using Superabsorbent Polymers, Wesley A. Jones, W. Jason Weiss Jan 2014

Freeze Thaw Durability Of Internally Cured Concrete Made Using Superabsorbent Polymers, Wesley A. Jones, W. Jason Weiss

International Conference on Durability of Concrete Structures

The use of superabsorbent polymers (SAPs) to produce internally cured concrete has been shown to be effective in reducing the potential for restrained shrinkage cracking of high performance concrete mixtures. However, not much is known regarding the freeze–thaw durability of concrete mixtures that incorporate SAPs for internal curing (IC). When SAP particles desorb (or partially desorb) the “water” (pore fluid) they contain for the purposes of IC, some believe that the void space created by these particles can provide enough empty voids to accommodate the additional volume caused by water expansion upon freezing. This paper investigates the freeze–thaw durability of …


Influence Of Ferrite Phase In Alite-Calcium Sulfoaluminate Cements, Tristana Y. Duvallet Jan 2014

Influence Of Ferrite Phase In Alite-Calcium Sulfoaluminate Cements, Tristana Y. Duvallet

Theses and Dissertations--Chemical and Materials Engineering

Since the energy crisis in 1970’s, research on low energy cements with low CO2-emissions has been increasing. Numerous solutions have been investigated, and the goal of this original research is to create a viable hybrid cement with the components of both Ordinary Portland cement (OPC) and calcium sulfoaluminate cement (CSAC), by forming a material that contains both alite and calcium sulfoaluminate clinker phases. Furthermore, this research focuses on keeping the cost of this material reasonable by reducing aluminum requirements through its substitution with iron. The aim of this work would produce a cement that can use large amounts …


The Development And Biocompatibility Of Low Temperature Co-Fired Ceramic (Ltcc) For Microfluidic And Biosensor Applications, Jin Luo Jan 2014

The Development And Biocompatibility Of Low Temperature Co-Fired Ceramic (Ltcc) For Microfluidic And Biosensor Applications, Jin Luo

Theses and Dissertations--Chemical and Materials Engineering

Low temperature co-fired ceramic (LTCC) electronic packaging materials are applied for their electrical and mechanical properties, high reliability, chemical stability and ease of fabrication. Three dimensional features can also be prepared allowing integration of microfluidic channels and cavities inside LTCC modules. Mechanical, optical, electrical, microfluidic functions have been realized in single LTCC modules. For these reasons LTCC is attractive for biomedical microfluidics and Lab-on-a-Chip systems. However, commercial LTCC systems, optimized for microelectrics applications, have unknown cytocompatibility, and are not compatible with common surface functionalization chemistries.

The first goal of this work is to develop biocompatible LTCC materials for biomedical applications. …


Effect Of Solid Solutions And Second Phases On The Thermal Conductivity Of Zirconium Diboride Ceramics, Gregory John Kenneth Harrington Jan 2014

Effect Of Solid Solutions And Second Phases On The Thermal Conductivity Of Zirconium Diboride Ceramics, Gregory John Kenneth Harrington

Doctoral Dissertations

"The research presented in this dissertation is focused on the thermal conductivity (k) of ZrB2 ceramics. The goal was to develop a better understanding of how various solid solutions and second phases affect the thermal and electrical transport in ZrB2, with a focus on the effect of C, W, and ZrC. The first study showed C additions improved densification and it was proposed that the reduction of boria was the impetus for this result. Boron carbide was formed by the reaction of excess C with reduced B and its formation was mitigated by the addition of ZrH …


Elevated Temperature Mechanical Properties Of Zirconium Diboride Based Ceramics, Eric W. Neuman Jan 2014

Elevated Temperature Mechanical Properties Of Zirconium Diboride Based Ceramics, Eric W. Neuman

Doctoral Dissertations

"Research presented in this dissertation focused on the mechanical behavior of ZrB₂ based ceramic at elevated temperatures. Flexure strength, fracture toughness, and elastic modulus were measured at temperatures up to 2300ºC for three compositions: monolithic ZrB₂ (Z); ZrB₂ - 30 vol% SiC - 2 vol% B₄ C (ZS); and ZrB₂ - 10 vol% ZrC (ZC). In argon, Z, ZS, and ZC had strengths of 210 (at 2300ºC), 260 (at 2200ºC), and 295 MPa (at 2300ºC), the highest temperatures tested for each composition. Fractography was used extensively to characterize the strength limiting flaws as a function of temperature. Strength of ZS …


Impact Of Alkaline Doping And Reducing Conditions On Lafeo3, Geoffrey L. Beausoleil Dec 2013

Impact Of Alkaline Doping And Reducing Conditions On Lafeo3, Geoffrey L. Beausoleil

Boise State University Theses and Dissertations

Efficient and reliable materials for gas separation, syngas production, and hybrid nuclear power plants must be capable of reliably operating at a high-temperature range of 700-1000°C and under exposure to highly oxidizing and reducing conditions. Candidate materials for these applications include alkaline metal doped lanthanum ferrite.

In the first study, the impact of A site substitution by different alkaline metals on lanthanum ferrite (LMF, M=Ca, Sr, and Ba) was investigated. The study focused on thermal expansion near the Néel transition temperature and a magneto-elastic contribution to thermal expansion was identified for each sample. Iron oxidation, Fe3+ to Fe4+ …


Characterization Of Lead-Free Piezo-Ceramics, Hanhan Zhou, John Blendell Oct 2013

Characterization Of Lead-Free Piezo-Ceramics, Hanhan Zhou, John Blendell

The Summer Undergraduate Research Fellowship (SURF) Symposium

Lead zirconate titanate (PZT) has been the most commonly used piezoelectric material due to its high piezoelectric performance under varied operating conditions. However, it has been noticed that the lead component is toxic, causing some environmental issues and a lead free substitute material was introduced. The substituted environmental friendly piezoelectric material, Ba(Zr0.2Ti0.8)O3–x(Ba0.7Ca0.3)TiO3 (BZT-xBCT) system that can fulfill the need of high piezoelectricity has been developed. The research was conducted to characterize the BZT-xBCT system with five different compositions (x=0.06, 0.08, 0.1, 0.12 and 0.14).. XRD was applied to examine the crystal structure of the samples before and after poling and …


Computation Of Piezo-Electric Materials, Seung Yun Song, R. Edwin García Oct 2013

Computation Of Piezo-Electric Materials, Seung Yun Song, R. Edwin García

The Summer Undergraduate Research Fellowship (SURF) Symposium

Piezo -electric materials are materials that will change its shape and size when an electric field is applied to the material. Vice versa, these materials will generate a certain voltage when they are bent, vibrated, or deformed. These materials show promising future , because they link mechanical and electrical properties of a material. In 21st century when electronic devices such as smart phones or touch-screen TV’s depend highly on mechanical input such as human’s touch, developing and researching materials that can link the mechanical and electrical properties can greatly improve the quality of i-phones. The main challenge regarding piezo-electric …


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 …


Quantum Computing Circuits, Cheng-Hsiao Wu, Casey Andrew Cain Sep 2013

Quantum Computing Circuits, Cheng-Hsiao Wu, Casey Andrew Cain

Electrical and Computer Engineering Faculty Research & Creative Works

A system for performing digital operations, including a first device configured to transform a digital input into one or more signals, at least one AB ring, the at least one AB ring irreducibly-coupled and configured to include at least three terminals, a second device configured to read a portion of a signal expressed upon two or more of the at least three terminals, and a third device configured to transform the portion of the signal expressed upon two or more of the at least three terminals into a digital output, the third device operationally connected to the second device.


Effect Of Architecture And Porosity On Mechanical Properties Of Borate Glass Scaffolds Made By Selective Laser Sintering, Krishna C. R. Kolan, Ming-Chuan Leu, Greg Hilmas, Taylor Comte Aug 2013

Effect Of Architecture And Porosity On Mechanical Properties Of Borate Glass Scaffolds Made By Selective Laser Sintering, Krishna C. R. Kolan, Ming-Chuan Leu, Greg Hilmas, Taylor Comte

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The porosity and architecture of bone scaffolds, intended for use in bone repair or replacement, are two of the most important parameters in the field of bone tissue engineering. The two parameters not only affect the mechanical properties of the scaffolds but also aid in determining the amount of bone regeneration after implantation. Scaffolds with five different architectures and four porosity levels were fabricated using borate bioactive glass (13-93B3) using the selective laser sintering (SLS) process. The pore size of the scaffolds varied from 400 to 1300 μm. The compressive strength of the scaffolds varied from 1.7 to 15.5 MPa …


Wetting And Reactive Air Brazing Of Bscf For Oxygen Separation Devices, Richard Ladouceur, Alan Meier, Ph.D. Aug 2013

Wetting And Reactive Air Brazing Of Bscf For Oxygen Separation Devices, Richard Ladouceur, Alan Meier, Ph.D.

2013 Undergraduate Research

The goals of this project are to develop a Reactive Air Brazing (RAB) alloy and process for joining Barium strontium cobalt ferrite (BSCF), and to develop a fundamental understanding of the wettability and microstructral development due to reaction kinetics in BSCF/Ag-MexOy systems.


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 …


Hydraulic And Thermal Performances Of A High Temperature Ceramic Plate-Fin Heat Exchanger (Pfhe), Vijaisri Nagarajan, Yitung Chen, Qiuwang Wang, Ting Ma Apr 2013

Hydraulic And Thermal Performances Of A High Temperature Ceramic Plate-Fin Heat Exchanger (Pfhe), Vijaisri Nagarajan, Yitung Chen, Qiuwang Wang, Ting Ma

College of Engineering: Graduate Celebration Programs

  • Numerical analysis was carried for novel configuration of high temperature PFHE
  • Fluid flow and heat transfer properties were studied for various fin configurations
  • Ripsaw fin design with thickness of 0.05 mm gives maximum heat transfer with less pressure drop and friction factor
  • Validation and parametric study were carried out for all fin configurations


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 …


Migration Grid #26, Stanton Hunter Mar 2013

Migration Grid #26, Stanton Hunter

The Transdisciplinary STEAM+ Journal

This work is inspired by invisible sky grids formed by Ultra Violet (UV) light researchers discovered that guide Monarch butterflies on their migration from the mid-western United States to the Sierra Madre Mountains in Mexico. I use terrestrial material, clay, to make something celestial. Earth, associated with mass and permanence, is translated into these shifting, ephemeral, and ethereal sky-forms. The work encompasses void more than object and the complex shadows they cast are immaterial. Together, the objects and shadows point to what can’t be seen, at least by the human eye.


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.


Diagnosis Of Systemic Inflammation Using Transendothelial Electrical Resistance And Low-Temperature Co-Fired Ceramic Materials, William L. Mercke Jan 2013

Diagnosis Of Systemic Inflammation Using Transendothelial Electrical Resistance And Low-Temperature Co-Fired Ceramic Materials, William L. Mercke

Theses and Dissertations--Chemical and Materials Engineering

Systemic inflammation involves a complex array of cytokines that can result in organ dysfunction. Mortality remains high despite the vast amount of research conducted to find an effective biomarker. The cause of systemic inflammation can be broad and non-specific; therefore, this research investigates using transendothelial electrical resistance (TEER) measurements to better define systemic inflammatory response syndrome (SIRS)/sepsis within a patient. Results show a difference in TEER measurements between healthy individuals and SIRS-rated patients. This research also displays correlations between TEER measurements and biomarkers currently studied with systemic inflammation (tumor necrosis factor-α, C- reactive protein, procalcitonin). Furthermore, this research also presents …


Liquid Phase Sintering Of 20bi(Zn₀.₅Ti₀.₅)O₃-80batio₃ Dielectrics With Bismuth-Zinc-Borate And Bismuth Borosilicate Glasses, David I. Shahin Jan 2013

Liquid Phase Sintering Of 20bi(Zn₀.₅Ti₀.₅)O₃-80batio₃ Dielectrics With Bismuth-Zinc-Borate And Bismuth Borosilicate Glasses, David I. Shahin

Masters Theses

"Dielectrics in the Bi(Zn₀.₅Ti₀.₅O₃-BaTiO₃ system (specifically 20BZT-80BT, in mol%) are promising candidates for high energy density capacitor applications due to broad temperature-dependent dielectric constant maxima and a relatively field-independent permittivity. Bulk samples require sintering temperatures of greater than 1180ºC to reach useful densities. Due to incompatibility of Bi with low-pO₂ processing, BZT-BT-based multilayer capacitors must utilize noble metal electrodes that resist oxidation during sintering. Sintering temperatures must be reduced to allow use of less expensive electrode materials (Cu, etc.). This work studies the reduced temperature sintering behavior and dielectric properties of BZT-BT sintered with 30 Bi₂O₃-30ZnO-40B₂O₃ and 50Bi₂O₃-25B₂O₃-25SiO₂ (mol%) liquid …


Processing And Properties Of Zrb₂-Zrsi₂ Matrix Composites Reinforced With Continuous Sic Fiber, Benjamin John Bowin Lai Jan 2013

Processing And Properties Of Zrb₂-Zrsi₂ Matrix Composites Reinforced With Continuous Sic Fiber, Benjamin John Bowin Lai

Masters Theses

"The research presented in this thesis focuses on the processing, microstructure, and mechanical properties of ZrB₂-based composites. The main goal was to develop a process that incorporates high strength continuous SiC fiber in a ZrB₂-based matrix. In order to achieve this, the densification, microstructure, and mechanical properties of ZrB₂-ZrSi₂ monolithic ceramics were characterized along with various SiC fiber reinforced ceramic matrix composites (CMCs) utilizing the same matrix.

There were two main areas of study in this thesis. The initial study demonstrated that additions of ZrSi₂ into a ZrB₂ ceramic increases densification at significantly reduced processing temperatures ≤1600ºC). This study revealed …


Bioactive Glass Scaffolds For The Regeneration Of Load-Bearing Bone, Xin Liu Jan 2013

Bioactive Glass Scaffolds For The Regeneration Of Load-Bearing Bone, Xin Liu

Doctoral Dissertations

"Biocompatible scaffolds that replicate the structure and function of bone would be ideal bone substitutes for structural bone loss, provided they have the requisite mechanical properties for reliable long-term loading. In this dissertation, strong porous scaffolds of silicate 13-93 bioactive glass, created with two different microstructures, were evaluated to determine their mechanical properties and their capacity to regenerate bone in a rat calvarial defect model. Scaffolds with an oriented microstructure of columnar pores were prepared by unidirectional freezing of camphene-based suspensions, followed by thermal annealing and sintering. By optimizing the freezing conditions, annealing time, and sintering temperature, constructs (porosity = …


Recrystallization Kinetics Of 3c Silicon Carbide Implanted With 400 Kev Cesium Ions, Daniel Denell Osterberg Dec 2012

Recrystallization Kinetics Of 3c Silicon Carbide Implanted With 400 Kev Cesium Ions, Daniel Denell Osterberg

Boise State University Theses and Dissertations

Polycrystalline 3C silicon carbide was implanted at room temperature with 400 keV cesium ions to a dose of 1016 ions·cm-2. The samples were then annealed at 600 – 1000°C for 0-48 hours in ultra-high purity argon. The implanted zone of each sample was characterized by transmission electron microscopy and secondary ion mass spectroscopy. It is shown that the implantation resulted in a 217 ± 2 nm amorphous region with microstructural damage extending to approximately 250 nm below the surface. Recrystallization of the amorphous region was observed at 725°C, although minimal densification was observed until ≥ 800°C. Densification …


Comparison And Simulation Of Salt-Ceramic Composites For Use In High Temperature Concentrated Solar Power, Lauren Michelle Fossile Dec 2012

Comparison And Simulation Of Salt-Ceramic Composites For Use In High Temperature Concentrated Solar Power, Lauren Michelle Fossile

UNLV Theses, Dissertations, Professional Papers, and Capstones

Due to the inherently intermittent nature of solar energy caused by cloud cover among other sources, thermal storage systems are needed to make solar energy more consistent. This same technology could be used to prolong the daily number of useful hours of solar energy power plants. Salt-ceramic materials are a relatively new prospect for heat storage, but have been researched mostly with magnesium oxide and several different carbonate salts. Salt ceramics are a phase change material where the salt changes phase inside the ceramic structure allowing for the system to use the sensible heat of both materials and the latent …