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Search Publications by: David R Black (Fed)

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Displaying 26 - 50 of 56

X-Ray Topography to Characterize Surface Damage on CdZnTe Crystals

January 7, 2008
Author(s)
David R. Black, Joseph C. Woicik, Martine Duff, Douglas Hunter, Arnold Burger, Michael Groza
Synthetic CdZnTe or CZT crystals can be used for room temperature detection of ?-radiation. Structural/morphological heterogeneities within CZT, such as twinning, secondary phases (often referred to as inclusions or precipitates), and polycrystallinity can

Characterization of Spatial Heterogenieties in Detector Grade CdZnTe

December 4, 2007
Author(s)
Martine Duff, Douglas Hunter, Arnold Burger, Michael Groza, V Buliga, J Bradley, G Graham, Z Dai, N Teslich, David R. Black, H E. Burdette, A Lanzirotti
Synthetic Cd1-xZnxTe or CZT crystals are highly suitable for the room temperature-based spectroscopy of gamma radiation. Structural/morphological heterogeneities within CZT, such as secondary phases that are thought to consist of Te metal, can have

X-Ray Topography for Fractography of Single-Crystal Components

June 15, 2006
Author(s)
David R. Black, George D. Quinn
X-ray diffraction topography, which is sensitive to local strain and/or crystallographic orientation, provides a unique view of single-crystal samples both before and after fracture. It can find strength and performance limiting surface and subsurface

Using X-Ray Topography to Inspect Surfaces of Single-Crystal Components

July 1, 2005
Author(s)
David R. Black
X-ray diffraction topography, which is sensitive to local strain and/or crystallographic orientation, provides a unique view of the surface of single-crystal samples and can be used to nondestructively inspect for surface and subsurface damage. The

Array Ordering in Dendritic Crystals and the Influence on Crystal Perfection

December 1, 2004
Author(s)
R E. Napolitano, David R. Black
In the work reported here, several important issues regarding the role of the evolving dendritic structure in the generation of crystal defects are investigated. Industrially produced single-crystal castings are examined, and the dendritic arrays are

X-Ray Topography

February 4, 2004
Author(s)
David R. Black, Gabrielle G. Long
The study of the interrelationships between processing, structure and properties of materials is fundamental to the field of materials science and engineering. The need to understand the microstructure of materials has driven the development of a wide

X-Ray Topography of Microgravity-Grown Ribonuclease S Crystals

August 1, 2003
Author(s)
David T. Gallagher, C Stover, D Charlton, L Arnowitz, David R. Black
Crystals of the enzyme RNase S were grown at micro and unit gravity using a dialysis-based dynamically controlled device. Crystals were grown at 24 C on space shuttle flights STS 93 and STS 95. Control crystals were grown simultaneously in ground

Neutron Irradiation of Sapphire for Compressive Strengthening; II. Physical Properties

January 1, 2002
Author(s)
T M. Regan, D C. Harris, D W. Blodgett, K C. Baldwin, J A. Miragliotta, M E. Thomas, M J. Linevsky, J W. Giles, T A. Kennedy, M Fatemi, David R. Black, P D. Lagerl f
Irradiation of sapphire with fast neutrons (0.8-10 MeV) at a fluence of 1022/m2 increases thec-axis compressive strength and the c-plane biaxial flexure strength at 600 C by a factor of 2.5. Both effects are attributed to inhibition of r-plane twin

Using X-Ray Topography to Study Fracture of Single-Crystal Ceramics

October 1, 2001
Author(s)
David R. Black, Robert S. Polvani, George D. Quinn
X-ray topography provides a unique view of the surfaces of single-crystal samples, both before and after fracture. The diffraction topograph, which is sensitive to local strain and/or crystallographic orientation, can be used to inspect samples prior to

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

Sapphire Statistical Characterization and Risk Reduction Program

September 1, 2001
Author(s)
D R. McClure, R W. Cayse, David R. Black, S M. Goodrich, K Peter, D Lagerloef, D C. Harris, D McCullum, D H. Platus, C E. Patty, Robert S. Polvani
The Sapphire Statistical Characterization and Risk Reduction Program tested 1400 4-point flexure bars with different crystal orientations at different temperatures to establish a mechanical strength database for engineering design. Sapphire coupons were

Compressive Strengthening of Sapphire by Neutron Irradiation

May 9, 2001
Author(s)
T M. Regan, D C. Harris, R M. Stroud, J R. White, D W. Blodgett, K C. Baldwin, J A. Miragliotta, M E. Thomas, M J. Linevsky, J W. Giles, T A. Kennedy, M Fatemi, David R. Black
Neutron irradiation of sapphire with 1 1022(=1 MeV)/m2 increases the c-axis compressive strength by a factor of 3 at 600 C. The mechanism of strength enhancement is the retardation of r-plane twin propagation by radiation-induced defects. 10B and Cd

Applying X-Ray Topography and Diffractometry to Improve Protein Crystal Growth

February 21, 2001
Author(s)
David R. Black, L Arnowitz, David T. Gallagher
In order to obtain adequate diffraction data to determine the structure of the protein of interest, crystal quality is important. Although in this context there may be no single concise definition of quality, it must involve adequate size, singleness

Sapphire Statistical Characterization and Risk Reduction Program

January 1, 2001
Author(s)
Donald McClure, Robert Cayse, David R. Black, Steven Goodrich, K Lagerloef, D Peter, Daniel C. Harris, Dale McCullum, Daniel H. Platus, Charles E. Patty, Robert S. Polvani
The Sapphire Statistical Characterization and Risk Reduction Program tested 1400 4-point flexure bars with different crystal orientations at different temperatures to establish a mechanical strength database for engineering design. Sapphire coupons were