| International Conference on Thermal and Environmental Barrier Coatings held at Kloster Irsee, Germany, on 17-22 Aug 2003 |
04 OCT 2004 |
14 pages |
| Authors:
David R. Clarke; CALIFORNIA UNIV SANTA BARBARA DEPT OF MATERIALS
|
 | An international conference on "Thermal and Environmental Barrier Coatings" was held at the Swabian Conference Center, Irsee, Germany, under the auspices of Engineering Conferences International and with partial financial support from both the Air Force Office of Scientific Research and the Office of Naval Research. The conference was the first international conference on the subject open to the materials community at large. The conference attracted scientists and engineers from 12 ... |
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| Organic Glasses and Crystals for Miniature Electro-Optic Devices: Synthesis, Characterization, and Applications |
OCT 2004 |
104 pages |
| Authors:
Felix E. Fernandez; Tanja Timofeeva; Sergey S. Sarkisov; PUERTO RICO UNIV MAYAGUEZ
|
| A high-level computational analysis of two-photon absorbing derivatives of piperidone and cyclohexanone was carried out. Obtained data were compared with the experimental results. The molecular cross-section of the two- photon absorption of these compounds, as high as 3000x10(exp -50) cu cm s/photon at nanosecond pumping, makes then promising nonlinear materials for optical limiting in near-infrared region. They also exhibit an intense two-photon exciting fluorescence, of the same order as that ... |
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| Reactive and Nonreactive Binders in Glass/Vinyl Ester Composites |
SEP 2004 |
44 pages |
| Authors:
John C. Brody; John W. Gillespie Jr; DELAWARE UNIV NEWARK CENTER FOR COMPOSITE MATERIALS
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| This study characterizes and evaluates two types of preform binders reactive thermosets and nonreactive thermoplastics. The interply adhesion between woven glass plies was measured as a function of binder type, concentration, and preforming conditions. It was found that reactive binders offer the potential to provide much larger interply adhesions between glass plies in a preform than thermoplastics and are thus superior choices for the fabrication of complex-shaped preforms requiring little ... |
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| Spall Strength of Silicon Carbide Under Normal and Simultaneous Compression-Shear Shock Wave Loading |
SEP 2004 |
17 pages |
| Authors:
Dattatraya P. Dandekar; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
|
| Spall strength data of sintered and hot-pressed silicon carbide show an initial increase with an increase in the shock-induced stress to around 4 GPa. At impact stress around 6 GPa and above, spall strength data of these materials show a continuous decrease in the magnitude of spall strength. This unusual trend in the spall strength of silicon carbides may be due to the competing roles of (1) localized plasticity, (2) ... |
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| Fuel Cell Support Testing. Delivery Order 0029: Fuel Cells for Aerospace Power |
SEP 2004 |
48 pages |
| Authors:
Binod Kumar; DAYTON UNIV OH RESEARCH INST
|
| The purpose of this effort was the basic advancement of high temperature solid oxide fuel cell electrolyte technology. This paper reports the effects of heterogeneously doped Al2O3 on the ionic conductivity of yttria stabilized zirconia (YSZ). At lower dopant concentration, grain growth occurred and the grain boundaries were re-formed. Subsequent increases in the dopant concentration decreased the transport of oxygen ions. the presence of Al2O3 also leads to a blocking ... |
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| Strength Enhancement and Application Development of Carbon Foam for Thermal Protection Systems |
SEP 2004 |
6 pages |
| Authors:
Christopher Duston; Steve Seghi; Roland Watts; CERAMIC COMPOSITES INC MILLERSVILLE MD
|
| Carbon foam is recognized as having great potential as a component within hybrid (rainbow) Thermal Protection Systems for low angle re-entry vehicles. In this concept, the carbon foam supports a ceramic matrix composite surface by providing selectable insulating or thermally conductive dual-use properties. An initial barrier to implementation was the inherent weakness and friability of the carbon foams. Under a MDA funded SBIR program, Ceramic Composites Inc. has demonstrated the ... |
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| Multifunctional Structural Ceramics with Ferroelastic and Martensitic Transformations |
31 AUG 2004 |
29 pages |
| Authors:
A. Sayir; CASE WESTERN RESERVE UNIV CLEVELAND OH
|
| This program had 2 objectives that were pursued simultaneously. These objectives were: (i) development of process models designed to produce a new family of tough and novel ceramic materials with specific microstructures and (ii) coordinate the findings of the proposed research with the parallel efforts on the material characterization addressed from the atomistic and continuum length scales, where correlations are made between atomic structure and bonding. It was concluded that ... |
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| Implementation of 3D Angular Selective Achromatic Diffraction Optical Grating Device |
10 AUG 2004 |
17 pages |
| Authors:
L. Glebov; V. Smirnov; N. Tabirian; B. Zeldovich; UNIVERSITY OF CENTRAL FLORIDA ORLANDO SCHOOL OF OPTICS/CREOL
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| Angular Selective Achromatic Diffraction Optical Grating (ASADOG) device has been implemented. Surface reflective grating had 1200 lines per mm. Two identical volume holograms were implemented using Photo-Thermo- Refractive (PTR) glass technology, with spatial frequency 1697 lines per mm. Sequential diffraction of incident light by surface grating by first volume grating and then by second one oriented at 90 degrees resulted in angular selection of incident beam, completely achromatic within the ... |
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| Wave Propagation in a Volume Hologram with Multiple Diffraction Gratings |
10 AUG 2004 |
24 pages |
| Authors:
Steven J. Frederick; FRANCIS MARION UNIV FLORENCE SC
|
| In the last 10 years, Bragg diffraction gratings have been developed at CREOL using photo-thermo-refractive (PTR) glass, which is not sensitive to radiation or temperatures to 400 degrees C, and can withstand high-intensity laser beams without damage or change in the Bragg angle. In this work, a new type of Bragg grating, not yet fabricated, is being studied to predict its properties. It is composed of two gratings in the ... |
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| Efficient Local Packing in Metallic Glasses |
AUG 2004 |
11 pages |
| Authors:
D. B. Miracle; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
|
| A simple topological model in an earlier manuscript has shown that efficient atomic packing is a fundamental principle in the formation of metallic glasses. An approach for defining and quantifying the local packing efficiency, P. was developed for solute-centered clusters that contained only solvent atoms in the first coordination shell. In the present research. this methodology is extended to allow quantification of P when more than one atomic species is ... |
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| Fundamentals of Friction and Vapor Phase Lubrication |
30 JUL 2004 |
14 pages |
| Authors:
Andrew J. Gellman; CARNEGIE-MELLON UNIV PITTSBURGH PA DEPT OF CHEMICAL ENGINEERING
|
| This is the final report for the three year research program on "Fundamentals of Friction and Vapor Phase Lubrication" conducted at Carnegie Mellon with support from AFOSR grant number F49630-01-1-0069. The report summarizes the program objectives and summarizes the accomplishments and progress of the research towards the development of new methods for high temperature, vapor phase lubrication (VPL), understanding the tribological properties of quasicrystalline films and the development of a ... |
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| Numerical Modeling of Penetration Into a Compressible Viscoplastic Media |
22 JUL 2004 |
20 pages |
| Authors:
Ioan R. Ionescu; UNIVERSITE DE SAVOIE LE BOURGET-DU-LAC (FRANCE)
|
| This report results from a contract tasking Universite de Savole as follows: The contractor will develop new computational techniques and use them to gain fundamental understanding of the physical phenomena associated with penetration into a semi-infinite geological target of a hard (rigid) penetrator at intermediate impact velocities (typically below 1000 m/s). The contractor we will implement viscoplastic models accounting for the combined effects of high strain rate and high confinement ... |
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| High Temperature Studies of La-Monazite |
JUL 2004 |
103 pages |
| Authors:
David Marshall; Janet B. Davis; ROCKWELL SCIENTIFIC CO THOUSAND OAKS CA
|
| This report summarizes results from a 3-year research effort aimed at gaining a basic understanding of high-temperature properties of LaP04, with a view to its application in high-temperature structural composites. Previous studies at Rockwell and the Air Force established that LaP04 has a unique set of properties that make it suitable as a weakly bonded interphase material that enables damage tolerance by decoupling damage in the matrix and the reinforcing ... |
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| Hybrid Fiber Sizings for Enhanced Energy Absorption in Glass-Reinforced Composites |
JUL 2004 |
45 pages |
| Authors:
Robert E. Jensen; Steven H. McKnight; Dave P. Flanagan; Alan R. Teets; Donovan Harris; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| Achieving high-impact energy absorption without loss of structural performance in a glass fiber-reinforced composite can be obtained through a materials by design approach of the fiber matrix interphase through modification of current commercially formulated silane-based fiber-sizing packages. In this report, we document the structural and impact performance of composites produced using a fiber-sizing package designed to provide strong fiber-matrix bonding at low-impact rates and weak fiber-matrix bonding at high-impact rates. ... |
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| Solid Bonded Films or Monolithic Ceramics in Tracked Chains of Construction Equipments for Wear Management |
01 JUN 2004 |
21 pages |
| Authors:
M. Ketting; F. Tintrup; H. Halama; J. Tomaszewski; M. Woydt; IBAF GMBH BOCHUM (GERMANY)
|
| Unlubricated tracked chains were realized using soft solid bonded films for the inner wear of the tribosystem of bushing/pin and monolithic ceramic bushings for the outer wear of the tribosystem bushing/sprocket. Both novel approaches were tested on D6 22-to. dozers. Selected solid bonded films and specific monolithic ceramics, offer a potential for simplifying the design, reducing weight and designing a dry-running longlife chain. These results can be further transferred to ... |
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| Replacement Alternatives to the Chromate Wash Primer DOD-P-15328D |
JUN 2004 |
26 pages |
| Authors:
Pauline Smith; Kestutis Chesonis; Christopher Miller; John Escarsega; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| The major advantage of the Department of Defense (DOD)-P-15328DD1 wash primer is to enhance corrosion resistance through the passivation of the metal surface. In the U.S. Army's Chemical Agent Resistant Coating (CARC) system, the wash primer DOD-P-15328D is overcoated with an epoxy primer and followed by a camouflage urethane topcoat. Several coating procedures specify the use of the wash primer, DOD-P-15328D, as a surface treatment prior to the application of ... |
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| The Effect of Hot Isostastic Pressing on the Optical Properties Of Spinel |
20 MAY 2004 |
18 pages |
| Authors:
Gary Gilde; Parimal Patel; Philip Patterson; David Blodgett; Donald Duncan; Daniel Hahn; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| The effect of different hot isostatic pressing (HIP) temperatures and pressures on the optical transmission of hot pressed spinel was studied. The transmittance and extinction coefficient were measured. The transmittance data was used to determine the relative size of the scattering sites. HIP temperatures as low as 1500 degree C were seen to be effective in increasing the transmittance. The transmittance increased with increasing HIP temperature and pressure. The size ... |
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| A Century of Sapphire Crystal Growth |
17 MAY 2004 |
74 pages |
| Authors:
Daniel C. Harris; NAVAL AIR SYSTEMS COMMAND CHINA LAKE CA
|
| In Paris around 1890, A. V. L. Verneuil developed a flame fusion process to produce ruby and sapphire. By 1900 there was brisk demand for ruby manufactured by Verneuil's method, which was used with little alteration for 50 years. From 1932-1953, S. K. Popov in the Soviet Union established a capability for manufacturing high quality sapphire by the Verneuil process. In the U.S., under government contract during World War II, ... |
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| PTR Glass Melting Facility for Fabrication of Diffractive Optical Elements |
15 MAY 2004 |
18 pages |
| Authors:
Leonid Glebov; UNIVERSITY OF CENTRAL FLORIDA ORLANDO SCHOOL OF OPTICS/CREOL
|
| The proposed research instrumentation, a Photo-Thermo-Refractive (PTR) Glass Melting Facility, is used to support MDA-funded and new research initiatives in the study of photosensitive glass for rugged volume diffractive optical elements. This instrumentation significantly impacts existing efforts in hologram recording in PTR glasses. Diffractive optical elements made from this glass are used in the BMDO/MDA-funded program "Holographic Narrow-Band Filter and Data Storage for Optical Target Characterization" and a number of ... |
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| Design and Analysis of a 15-kV Package for Wide Bandgap Semiconductor |
MAY 2004 |
18 pages |
| Authors:
Dimeji Ibitayo; C. W. Tipton; ARMY RESEARCH LAB ADELPHI MD
|
| The development of wide bandgap semiconductor materials such as silicon carbide (SiC) has made possible devices that exceed the voltage ratings of conventional component packaging schemes. As such a new class of high voltage packages must be developed to realize the full potential of these technologies. We report on the electrostatic analysis and design of a t5-kV ceramic package using the ANSYS Multiphysics software. To baseline our work. a standard ... |
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| Laser Heated Gradient NMR Studies of Ceramic Liquids |
MAY 2004 |
8 pages |
| Authors:
R. F. Marzke; G. H. Wolf; ARIZONA STATE UNIV TEMPE DEPT OF PHYSICS
|
| We report progress in two areas of research on NMR of ceramic liquids: the synthesis and characterization of new materials along La-monazite - alumina/CaO joins, and the 27Al NMR measurement of incoherent Al motions in aluminum-containing ceramic melts. The addition of La-monazite to molten alumina or to molten C12A7 produces an increase in tetrahedral bonding in the liquid, as evidenced by the change of 27Al chemical shift to higher 4-fold ... |
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| Tb and Ce Doped Y123 Films Processed by Pulsed Laser Deposition |
MAY 2004 |
6 pages |
| Authors:
Joseph W. Kell; Timothy J. Haugan; Mary Frances Locke; Paul N. Barnes; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIRECTORATE
|
| To evaluate possible flux pinning enhancement in YBa2Cu3O7(7-x)(Y123) films due to partial rare-earth ion substitutions, Ce and Tb doping are studied. Bulk ceramic targets of varying compositions (Y(1-x)RE(x)Ba2Cu3O7(7-x) were made with several doping levels (x = 0.001 to 0.1, RE = Ce or Tb) by using regular solid-state reaction and sintering procedures. These targets were used to deposit Ce and Tb doped YBCO films onto SrTiO3 single crystal substrates by ... |
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| Flux Pinning and Properties of Solid-Solution (Y,Nd)1+XBa2-x Cu3O7-delta Superconductors Processed in Air and Partial Oxygen Atmospheres (Preprint) |
APR 2004 |
8 pages |
| Authors:
T. J. Haugan; J. M. Evans; J. C. Tolliver; I. Maartense; P. N. Barnes; W. Wong-Ng; L. P. Cook; R. D. Shull; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIRECTORATE
|
| The effect of chemical composition substitutions on the flux pinning and physical properties of (Y,Nd) 1 + (XB(alpha2)-xCu3O7(-gamma)) superconductors was studied in powders processed by solid-state reaction and equilibrated in air at 910 deg C. The powders were subsequently processed in 1% O2 atmosphere at |
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| Effect of Sc and Heat Treatment on Microstructure and Properties of a 7XXX DC Cast Alloy |
01 MAR 2004 |
|
| Authors:
O. N. Senkov; R. B. Bhat; S. V. Senkova; J. Tatalovich; AEROJET SACRAMENTO CA
|
 | Four developmental 7XXX series alloys modified with Sc, Zr and other dispersoid-forming elements were produced by continuous direct chill (DC) casting. Microstructure and mechanical properties were evaluated in both the longitudinal and transverse directions at room and cryogenic temperatures. The homogenization, solution treatment and aging schedules were optimized to obtain superior mechanical properties. In particular, the Sccontaining cast alloys showed tensile properties similar or even superior to the properties of ... |
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| Directionally Solidified Eutectic Ceramics; In-Situ Composites for High Temperature Structural Applications |
25 FEB 2004 |
111 pages |
| Authors:
Ali Sayir; CASE WESTERN RESERVE UNIV CLEVELAND OHDEPT OF MATERIALS SCIENCE AND ENGINEERING
|
| Eutectics are multiphase structures formed by the cooperative growth of two or more phases. Although the internal structure can vary widely, the development of continuous rods or plates in a matrix can be achieved and, within limits, can be controlled or "tailored" through directional solidification. The eutectic architecture of a continuous reinforcing phase within a higher volume phase or matrix, can be described as a naturally occurring in-situ composite. In-situ ... |
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| Photo-Stereo Lithography System for Polymer Derived Ceramic Microsystems |
20 FEB 2004 |
16 pages |
| Authors:
Rishi Raj; COLORADO UNIV AT BOULDER DEPT OF MECHANICAL ENGINEERING
|
| A photo-stereolithography system, Viper s12, sold by the company 3D Systems, as described in the original proposal, was acquired in the summer of 2003. The system was delivered and installed by the vendor in June 2003. A graduate student, Tsali Cross, and a post-doctoral associate, Neil Cramer, from the College of Engineering at the University of Colorado received intensive training at the company site in California during Fall 2003. Since ... |
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| Prediction of the Formulation Dependence of the Glass Transition Temperature for Amine-Epoxy Copolymers Using a Quantitative Structure-Property Relationship Based on the AM1 Method |
FEB 2004 |
30 pages |
| Authors:
Jason A. Morrill; Robert E. Jensen; Phillip H. Madison; Cary F. Chabalowski; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| A designer Quantitative Structure-Property Relationsbip (QSPR) based upon molecular properties calculated using the AM1 semi-empirical quantum mechanical metbod was developed to predict the glass transition temperature (Tg) of an%ine-cured epoxy resins based on tbe diglycidyl etber of bisphenol A. The QSPR (R2 - 0.9977) was generated using the regression analysis progran% Con%prebensive Descriptors for Structural and Statistical Analysis (CODESSA). By applying an ad hoc treatn%ent based on elen%entary probability fl%eory ... |
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| Lightweight, Robust and Low Cost Carbide/Tungsten Composites in Near Net Shapes for Advanced Solid-Fueled Rocket Nozzles for the IHPRPT Program |
FEB 2004 |
64 pages |
| Authors:
Ken H. Sandhage; GEORGIA INST OF TECH ATLANTA SCHOOL OFMATERIALS SCIENCE AND ENGINEERING
|
| The DCP process has been used to synthesize very-high-melting, lightweight tungsten/carbide or tungsten/boride composites via conversion reactions of the following type: (M) + WX(s) = MX(s) + W(s) (1) where (M) is a reactive element dissolved within a Cu-bearing melt, and WX and MX are ceramic reactant and product phases, respectively. Reactions leading to ZrC/W, TiC/W, HfC/W, and ZrB2/W composites at <1300 deg C have been demonstrated. Conversion reactions leading ... |
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| Genetically-Engineered Microdevices |
FEB 2004 |
16 pages |
| Authors:
Ken H. Sandhage; GEORGIA INST OF TECH ATLANTA SCHOOL OFMATERIALS SCIENCE AND ENGINEERING
|
| Gas/solid displacement reactions have been examined as a means of altering the chemistry of bioclastic silica structures (e.g., the self-assembled microshells of diatoms, a type of aquatic algae) into other ceramic compositions. Complex-shaped silica microshells with nanoscale features were exposed to Mg(g) at <9OO deg C. The silica microshells underwent the following net displacement reaction: 2Mg(g) + SiO2(s) yields 2MgO(s) + ?Si) (1) where ?Si! refers to silicon dissolved within ... |
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| Selection of a Material Model for Simulating Concrete Masonry Walls Subjected to Blast |
FEB 2004 |
147 pages |
| Authors:
James S. Davidson; Lee Moradi; Robert J. Dinan; ALABAMA UNIV IN BIRMINGHAM
|
| One of the most common methods of construction is the use of concrete masonry units (CMU) in the walls of buildings. However, they are vulnerable to blast, and result in collapse, fragmentation, and severe injury to occupants. An understanding of the behavior of CMU walls during blast is key to developing mitigation techniques. Research has been conducted using the finite element method to simulate structural failure due to blast. A ... |
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| Injectable Ceramic Microcast Silicon Carbonitride (SiCN) microelectromechanical System (MEMS) for Extreme Temperature Environments with Extension: Micro Packages for Nano-Devices |
JAN 2004 |
134 pages |
| Authors:
Victor M. Bright; Rishi Raj; Martin L. Dunn; John W. Daily; COLORADO UNIV AT BOULDER OFFICE OF CONTRACTS AND GRANTS
|
| MEMS that can survive ultrahigh-temperatures and corrosive environments are important in a variety of unique applications. This work develops an innovative microfabrication technology for high temperature MEMS: microcasting of injectable polymer-derived SiCN ceramic materials. The techniques allow realization of MEMS with complex, three-dimensional and multilayer geometry useable to 1500 C. Our approach is easy and low cost. Several MEMS were realized and evaluated. The objectives of the extension research project ... |
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| Multifunctional Hybrid Carbon Foams: Processing, Characterization and Modeling |
2004 |
7 pages |
| Authors:
Ozden O. Ochoa; M. D. Sarzynski; K. Lafdi; TEXAS A AND M UNIV COLLEGE STATION DEPT OF MECHANICAL ENGINEERING
|
| Carbon and ceramic foams are at the center of intensive development for thermal management, thermal protection, filtration, packing, sensor and structural applications 1,2. The objective of this research is to develop and characterize multi-functional foams with optimal thermal, electrical, magnetic and oxidation resistant properties. |
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| Near Net-Shape, Ultra-High Melting, Recession-Resistant ZrC/W-Based Rocket Nozzle Liners via the Displacive Compensation of Porosity (DCP) Method (POSTPRINT) |
2004 |
12 pages |
| Authors:
M. B. Dickerson; P .J. Wurm; J. R. Schorr; W. P. Hoffman; P. G. Wapner; K. H. Sandhage; GEORGIA INST OF TECH ATLANTA SCHOOL OF MATERIALS SCIENCE AND ENGINEERING
|
| Dense, near net-shaped ZrC/W-based composites have been fabricated at modest temperatures and at ambient pressure by a reactive infiltration process known as the Displacive Compensation of Porosity (DCP) method. Porous WC preforms with hourglass shapes (for rocket nozzle liners) were produced by gel casting, whereas simple bar-shaped preforms were produced by uniaxial pressing. The porous preforms were exposed to molten Zr2Cu at 1200-1300 deg C and ambient pressure. The Zr2Cu ... |
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| Structure-Forming Principles for Amorphous Metals |
2004 |
|
| Authors:
D. B. Miracle; O. N. Senkov; W. S. Sanders; K. L. Kendig; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
|
| The purpose of this research is to establish structure forming principles that govern the atomic structures of metallic glasses. A structural model based on efficient atomic packing will be discussed and applied to the topological systems that represent most metallic glass alloys. The concept of efficient atomic packing has direct and specific implications regarding the local structure and composition of metallic glasses. Specific solute-to-solvent atomic radius ratios and specific solute ... |
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| Oxygen Effects on Glass Formation of Plasma Arc Sprayed Cu47Ti33Zr11Ni8Si1 Surface Coatings |
2004 |
5 pages |
| Authors:
D. J. Sordelet; M. F. Besser; AMES LAB IA
|
| A series of thermal spray experiments were performed to produce Cu47Ti33Zr11Ni8Si1 coatings from gas atomized powders synthesized with oxygen contents ranging from 0.125 to 0.79 wt.%. The amount of oxygen increased with decreasing particle size, which suggests the oxide is present as a surface film. Surface coatings were deposited using plasma arc spraying (PAS) in air and in an argon environment within an environmental chamber. The amount of amorphous phase ... |
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| High Temperature Strengths and Deformation of Ceramics |
15 DEC 2003 |
12 pages |
| Authors:
Sidney Yip; MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF NUCLEAR ENGINEERING
|
| This project developed a computational modeling capability to study the theoretical strengths and deformation mechanisms of structural ceramics for high temperature applications. The approach adopted was molecular dynamics simulation based on appropriate interatomic potential models. The studies focused on ZrC that has excellent high-temperature properties, and to a lesser extent on SiC and SiO2. Strain-to-failure simulations were performed to observe the details of the structural instability and subsequent microstructural evolution. ... |
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| On an Exact Mapping and a Higher Order Born Rule for Use in Analyzing Graphene Carbon Nanotubes |
DEC 2003 |
24 pages |
| Authors:
Michael J. Leamy; Peter W. Chung; Raju Namburu; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| As part of an effort to model single-walled graphene carbon nanotubes, a transformation is first described which maps atom locations originally on a planar sheet to atom locations on a cylindrical nanotube. The mapping is parametrized by the two components describing the chiral vector, and thus is valid for generating the atomic locations of arbitrary chirality nanotubes. Attention is then turned towards quantifying the dimensions of the unit cell, again ... |
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| Direct Fabrication of Patterned Functional Ceramic Films by Soft Solution Processing without Post-Firing |
19 NOV 2003 |
9 pages |
| Authors:
Masahiro Yoshimura; Tomoaki Watanabe; Takeshi Fujiware; Ryo Teranishi; TOKYO INST OF TECH YOKOHAMA (JAPAN) CENTER FOR MATERIALS DESIGNS MATERIALS AND STRUCTURES LAB
|
| We are proposing an innovative concept and technology, Soft Solution Processing (SSP) for ceramics, which aims to achieve direct fabrication of shaped, sized, located, oriented ceramic materials from solutions without firing and/or sintering. We have successfully fabricated thin and thick films of BaTiO3, SrTiO3, BaWO4, SrMoO4, LiCoO2, and LiNiO2 by SSP in aqueous solutions from room temperature to 200 deg. C. In these experiments, interfacial reactions between a solid reactant ... |
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| Development of PZT Suspensions for Ceramic Ink-Jet Printing |
19 NOV 2003 |
7 pages |
| Authors:
B. Derby; D. H. Lee; T. Wang; D. Hall; MANCHESTER UNIV (UNITED KINGDOM) MATERIALS SCIENCE CENTER
|
| The direct ink-jet printing of ceramic powders requires the development of highly fluid suspensions of ceramic particles with viscosity |
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| Predicting the Effect of Defect Distributions in the Bulk and on Surfaces of Ceramic Materials |
31 OCT 2003 |
25 pages |
| Authors:
Mark R. Levy; Robin W. Grimes; IMPERIAL COLL LONDON (UNITED KINGDOM)
|
| This report results from a contract tasking Imperial College, London as follows: The contractor will investigate and ultimately develop ways to select optimum compositions for materials using atomic scale computer simulation. The particular material systems to be studied are: pyrochiores and fluorites (important in fuel cell and oxygen generator applications and as thermal barrier coatings on turbine blades in jet engines), and the perovskites, important electronic ceramics that also act ... |
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| The Challenge for Materials Design. Integrating Modeling and Computation |
08 SEP 2003 |
56 pages |
| Authors:
Craig S. Hartley; AIR FORCE OFFICE OF SCIENTIFIC RESEARCHARLINGTON VA
|
| Briefing charts from presentation on "The Challenge for Material Design: Integrating Modeling and Computation." |
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| High-Temperature, High-Bandwidth Fiber Optic Pressure and Temperature Sensors for Gas Turbine Applications |
08 SEP 2003 |
8 pages |
| Authors:
Robert S. Fielder; Matthew E. Palmer; LUNA INNOVATIONS INC BLACKSBURG VA
|
| The accurate measurement of gas flow conditions in the compressor, combustors, and turbines of gas turbine engines is important to assess performance, predict failure, and facilitate data-driven maintenance. Surface and point measurements of pressure and temperature in the high temperature regions of the turbine help engineers optimize performance, improve fuel mixing and burning in the combustor, and redesign compressor and turbine stages based on actual measurements. There currently exists no ... |
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| Effect of Radiation on Silicon and Borosilicate Glass |
SEP 2003 |
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| Authors:
Clark L. Allred; MASSACHUSETTS INST OF TECH CAMBRIDGE
|
| A study was made that is logically divided into two parts, both involving radiation damage effects. The first is a study of the effects of neutron and gamma radiation on the dimensions of two borosilicate glasses, pyrex and Hoya SD-2. These two glasses are commonly used as substrates for silicon microelectromechanical (MEMS) devices, and radiation-induced compaction in a substrate can have deleterious effects on device performance. Results are presented for ... |
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| Concurrent Research on High Gravity (g) Combustion and Enabling Materials |
SEP 2003 |
6 pages |
| Authors:
Joseph Zelina; R. J. Kerans; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH TURBINE ENGINE DIV
|
| A gas turbine engine has been proposed that uses a near constant temperature (NCT) cycle and Inter-Turbine Burner (ITB) to provide large amounts of power extraction from the low-pressure turbine. This level of energy is achieved with a modest temperature rise across the ITB. The additional energy can be used to power a large fan for an ultra-high bypass ratio transport aircraft, or to drive an alternator for large amounts ... |
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| A Characterization System for Ceramic Powders |
31 AUG 2003 |
8 pages |
| Authors:
I-Wei Chen; PENNSYLVANIA UNIV PHILADELPHIA DEPT OFMATERIALS SCIENCE AND ENGINEERING
|
| The grant was initiated on April 1, 2001. We have purchased a laser particle size analyzer, a powder surface area analyzer, a mercury powder pore size analyzer, and an ultracentrifuge for powder separation. These instruments have all been installed and in operation. We have proceeded with powder and green body characterization of the bulk silicon nitride and SiAlONs. This includes the study of the effect of seeding with micrometer-sized crystals ... |
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| Fundamental Studies of Novel Contact-Damage Resistant Ceramics |
25 AUG 2003 |
20 pages |
| Authors:
Nitin P. Fadture; Subra Suresh; CONNECTICUT UNIV STORRS DEPT OF METALLURGY
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| The concept of elastic-modulus-graded ceramics for improved resistance to quasi-static contact damage (Hertzian-indentation), sliding- contact damage, and wear was investigated. In these graded materials, the in- plane elastic modulus (E) is low at the contact surface and high in the interior (substrate) with a continuous, or step-wise continuous, E-gradation in-between. Processing strategies for fabricating such E-graded ceramic composites in the A12O3(-)glass, the Si3N4(-)glass, and the Si3N4(-)SiC systems are described. The ... |
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| The Mechanisms of Creep Resistance of Advanced Ceramic Eutectics: Experiments and Modeling |
15 AUG 2003 |
46 pages |
| Authors:
Ali S. Argon; MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF MECHANICAL ENGINEERING
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| The creep resistance of the directionally solidified ceramic eutectics of alumina/cubic- zirconia was studied experimentally in the 1200-1520 degrees C, and 100-275 Mpa stress range, with associated TEM and SEM microscopy, as a generic example of ceramic eutectics. Additional (computer simulations were done both at the atomic level and by FEM methods to study: a) the core structure of pyramidal edge dislocations in alumina-that can only climb but not glide; ... |
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| Acquisition of a Nanoindenter for Research on Small-Scale Materials and Structures |
AUG 2003 |
6 pages |
| Authors:
Frank W. Zok; D. R. Clarke; N. C. MacDonald; Kimberly L. Turner; CALIFORNIA UNIV SANTA BARBARA DEPT OF MECHANICAL AND ENVIRONMENTAL ENGINEERING
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| The first project is "Matrix Enabled Damage Tolerance in Oxide Continuous Fiber Reinforced Ceramic Composites", PIs: Frank Zok, Carlos Levi and Robert McMeeking, funded by AFOSR. Here, the nanoindenter is being used for measuring the mechanical properties of fiber-matrix interfaces, through the so- called "fiber push-in" test. In essence, the test involves pushing an individual fiber past the surrounding matrix while simultaneously measuring the sliding displacement at the fiber/matrix interface. ... |
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| X-ray Diffractometer for Texture and Residual Stress Studies of Advanced Materials |
01 JUL 2003 |
7 pages |
| Authors:
Elizabeth C. Dickey; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF MATERIALS SCIENCE AND ENGINEERING
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| Through AFOSR DURIP grant # F49620-00-1-0245, a four circle goniometer x-ray diffractometer outfitted with a high temperature stage was purchased from Philips Analytical. The instrumentation facilitates residual stress measurements in highly textured materials up to 900 deg C. The instrument has significantly enhanced the AFOSR funded research efforts of the Pl on directionally solidified ceramic eutectics. Initial studies have measured the residual stresses in highly textured AlO3-ZrO2(Y2O3) eutectics as a ... |
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| Blast-Resistant Window Concepts |
JUL 2003 |
11 pages |
| Authors:
William S. Strickland; Mark Anderson; Dov Dover; AIR FORCE RESEARCH LAB TYNDALL AFB FL
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| Terrorist bombs threaten American civilians and military personnel both at home and abroad. Analysis of data from previous terror attacks indicates the largest number of injuries result from projected glass shards from shattered windows and facades. Three key issues have led to increased interest in new window materials as well as changes in building design codes: (1) actual terror attacks, (2) the threat of future terror attacks, and (3) monetary ... |
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Ceramics, Refractories and Glass
