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A new fixture for flexural strength testing was used to evaluate the effects of machining on the flexural strength of a toughened sintered reaction-bonded silicon nitride. Different grinding procedures had various effects upon the flexure strength
P Miranda, Antonia Pajares, F Guiberteau, F Cumbrera, Brian R. Lawn
A flaw statistics analysis is here developed to account for systematic differences between experimentally observed and theoretically predicted critical loads for the initiation of contact-induced radial cracks in brittle coatings on compliant substrates
The objective of this project is to develop international standard test methods for assessing the reliability of ceramic components used in diesel engines and other heavy vehicle propulsion systems. Advanced ceramics such as silicon nitrides offer unique
The tensile creep behavior of a gas-pressure-sintered silicon nitride containing silicon carbide, was carbide was characterized at temperatures between 1375 and 1450 C with applied stresses between 50 and 250 Mpa. Individual specimens were tested at fixed
Z G. Wang, X H. Wang, B S. Hsiao, S Andjelic, D Jamiolkowski, J McDivitt, J Fischer, J Zhou, Charles C. Han
The isothermal crystallization behavior of absorbable dyed and undyed PGA-co-PLA copolymers was investigated by time-resolved simultaneous synchrotron small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD) methods. The morphological
D R. McClure, R W. Cayse, S Goodrich, D McCullum, D C. Harris, K Lagerlof, C E. Patty, D H. Platus, Robert S. Polvani, David R. Black
Approximately 1400 4-point flexure specimens were tested at 300 K to 873 K to establish an engineering database for the strength of sapphire. Coupons represented material used for two missile windows and one missile dome. For one window, coupons were
The structure of the Ba 5R 8Zn 4O 21 series (R =lanthanides) was investigated using x-ray Rietveld refinements. The compounds were successfully prepared for R = Eu, Gd, Dy, Ho, Er, Tm, and Yb. For larger R, Ba 5R 8Zn 4O 21 was not stable, and tetragonal
Hisashi Abe, M Naito, R Wasche, Vincent A. Hackley, Y Hotta
The isoelectric point is a material property for the characterization of acid-base behavior of the powder surface. The IEP of two alumina powders (AKP-30 Grade A) with different particle size characteristics in aqueous suspension has been determined by
Classical mass spectrometically-based approaches to the determination of high temperature thermochemical data and functions are limited in their applicable ranges of temperature and vapor pressure. An earlier laser-based mass spectrometric approach
Andrew J. Allen, Gabrielle G. Long, H Boukari, J Ilavsky, A Kulkarni, S Sampath, H Herman, A N. Goland
This paper reports how the microstructural information, obtainable for thick plasma-sprayed ceramic deposits by small-angle scattering can be used to explore the relationships among the feedstock or spray process conditions, the anisotropic void and crack
The Polymers Division provides measurement methods, standards, and concepts to facilitate technology development, manufacture of products, commerce, and use of synthetic polymers. Projects are selected based on assessments of current needs and in
The phase diagram of the SrO-Yb 2O 3-CuO x system was investigated in air. The solid solution (Sr 14-xYb x)Cu 24O z (O 13Yb)Cu 24O z indicated that this phase is incommensurate, with the modulation wave vector q=(1/2-z)c*, znearly equal to}0.066. The Sr
The Workshop on Biomedical Materials and Devices, held June 13-14, 2001, is the latest in a series of workshops and topical meetings organized by NIST in the area of biomedical technology. The workshop complements other recent NIST efforts to make its
Joseph C. Woicik, E J. Nelson, T Kendelewicz, P Pianetta, D Heskett, J Warner, L E. Berman, B A. Karlin, I A. Vartanyants, M Z. Hasan, Z -. Shen
We introduce a new experiment method by which site-specific valence-electronic structure may be obtained. It utilizes the x-ray standing-wave interference field that results from the superposition of the incident and reflected x-ray beams within the
Joseph C. Woicik, E J. Nelson, D Heskett, J Warner, L E. Berman, B A. Karlin, I A. Vartanyants, M Z. Hasan, T Kendelewicz, Z -. Shen, P Pianetta
We have examined the valance-electron emission from Cu, Ge, GaAs, InP, and NiO single crystals under the condition of strong x-ray Bragg reflection; i.e., in the presence of the spatially modulated x-ray standing-wave interference field that is produced by
Dielectric properties of model BaTiO 3/polymer composites were measured over a broad frequency and temperature range. A series of BaTiO 3/monomer suspensions were photocured into thin wafers. The wafers were equipped with aluminum electrodes and the
Gintaras Valincius, Vytas Reipa, V L. Vilker, John T. Woodward IV, Mark D. Vaudin
Electrochemical properties of the sol-gel nanocrystalline cadmium tin oxide electrodes (CTO) were investigated in 0.2 M potassium chloride buffered at pH 7.4 with phosphate. Films were found to be n-type degenerate semiconductors with charge carrier levels
Fluorecent dyes doped into polymer resins were used to monitor the true resin temperature during procesing. Two examples of real-time process monitoring are presented: first, the effects of shear heating during extrusion are presented , and second, the
B Hockey, M K. Kang, Sheldon M. Wiederhorn, J Blendell
The structure and composition of low angle grainboundaries produced in sapphire by a liquid phase sintering process were investigated by conventional and high resolution transmission electron microscopy (CTEM and HRTEM, respectively). Considering the
The MatML - Materials Markup Language Workshop was held at NIST to consider the technical and strategic future of MatML, an extensible markup language for materials data. Following detailed description and illustrations of MatML, the views of various
A M. Gabelnick, D J. Burnett, J L. Gland, Daniel A. Fischer
Oxidation of preadsorbed propyne has been characterized on the Pt(111) surface in oxygen pressures up to 1.2 Pa. using fluorescence yield ultra-soft X-ray adsorption methods above the carbon K edge. A combination of temperature programmed reaction
Winnie K. Wong-Ng, James A. Kaduk, Igor Levin, W Greenwood, J Dillingham
X-ray Rietveld refinements were conducted on a series of 11 lanthanide phases, SR 2RGaCu 2O 7 (R=Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, and Y) that are structurally related to the High T c superconductor Ba 2YCu 3O 7. Reference patterns for these compounds
Silicon nitride is a material with a high-temperature potential and, hence, an excellent candidate for gas turbines. The incentive to use silicon nitride is substantial, as higher operating temperatures can be translated directly into higher engine
Charles C. Han, G Schmidt, A Nakatani, Paul D. Butler
The objective of this work is to investigate the influence of shear on the structure of a highly viscoelastic, aqueous polymer-clay solution. Many structural models have been proposed for such systems. However, this is the first time to observe the