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Search Publications

NIST Authors in Bold

Displaying 1376 - 1400 of 1729

Fractographic Analysis of Machining Cracks in Silicon Nitride Rods and Bars

October 1, 2001
Author(s)
George D. Quinn, L K. Ives, S Jahanmir, P Koshy
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

Role of Flaw Statistics in Contact Fracture of Brittle Coatings

October 1, 2001
Author(s)
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

Standards for Reliability Testing of Heavy Vehicle

October 1, 2001
Author(s)
S Jahanmir, James F. Kelly, William E. Luecke
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

Time-Resolved Isothermal Crystallization of Absorbable PGA-co-PLA Copolymer by Synchrotron Small-Angle X-Ray Scattering and Wide-Angle X-Ray Diffraction

October 1, 2001
Author(s)
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

Sapphire Statistical Strength Characterization

September 7, 2001
Author(s)
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

Microstructural Characterization Studies to Relate the Properties of Thermal Spray Coatings to Feedstock and Spray Conditions

September 1, 2001
Author(s)
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

MSEL FY 2001 Programs and Accomplishments: Polymers Division

September 1, 2001
Author(s)
B M. Fanconi, Eric J. Amis
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

Phase Equilibria of the SrO-Yb 2 O 3 -CuO x System in Air

September 1, 2001
Author(s)
J Dillingham, Winnie Wong-Ng, Igor Levin
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

Workshop on Standards for Biomedical Materials and Devices

September 1, 2001
Author(s)
John A. Tesk, D Hall
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

X-Ray Standing-Wave Investigation of Valence-Electronic Structure

September 1, 2001
Author(s)
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

X-Ray Standing-Wave Investigations of Valence Electronic Structure

September 1, 2001
Author(s)
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

Electrochemical Properties of Nanocrystalline Cadmium Stannate Films

August 1, 2001
Author(s)
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

Low Angle Grain Boundary Dewetting in Sapphire

August 1, 2001
Author(s)
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

MatML-Materials Markup Language Workshop Report

August 1, 2001
Author(s)
C P. Sturrock, E F. Begley, J G. Kaufman
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

Silicon Nitride for Gas Turbines

August 1, 2001
Author(s)
Sheldon M. Wiederhorn, M Ferber
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

Small Angle Neutron Scattering Study on Polymer-Clay Solutions

August 1, 2001
Author(s)
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
Displaying 1376 - 1400 of 1729
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