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Search Publications

NIST Authors in Bold

Displaying 1951 - 1975 of 2146

Crack Tip Opening Angle: Measurement and Modeling of Fracture Resistance in Low and High Strength Pipeline Steels

September 1, 2006
Author(s)
Philippe P. Darcis, Joseph D. McColskey, Christopher N. McCowan, Thomas A. Siewert, Gabriel Kohn, Arry Bussiba, Richard J. Fields
Crack tip opening angle (CTOA) is becoming one of the more widely accepted properties for characterizing fully plastic fracture. In fact, it has been recognized as a measure of the resistance of a material to fracture, in cases where there is a large

Fatigue Crack Growth Rates in Five Pipeline Steels

September 1, 2006
Author(s)
Arry Bussiba, Philippe P. Darcis, J D. McCloskey, Christopher N. McCowan, Thomas A. Siewert, Gabriel Kohn, R P. Smith, J. Merritt
This study presents fatigue data for six different pipeline steels, with strengths ranging from Grade B to X100. A fatigue crack growth test for full-thickness pipeline samples was developed using a Middle Tension (MT) type specimen. The six steels showed

Second Symposium on Pendulum Impact Machines: Procedures and Specimens

August 1, 2006
Author(s)
Thomas A. Siewert, Christopher N. McCowan, M. P. Manahan
This publication consists primarily of the papers presented at the Second Symposium on Pendulum Impact Machines: Procedures and Specimens, sponsored by ASTM Committee E28 on Mechanical Testing and its Subcommittee E28.07 on Impact Testing. The Symposium

Phase Formation, Crystal Chemistry, and Properties in the Magnetic Dielectric System Bi 2 O 3- Fe 2 O 3- Nb 2 O 5

June 22, 2006
Author(s)
M W. Lufaso, Terrell A. Vanderah, I M. Pazos, Igor Levin, Juan C. Nino, Virgil Provenzano, Peter K. Schenck, Robert S. Roth
Subsolidus phase relations have been determined for the Bi2O3-Fe2O3-Nb2O5 system in air (900-1075 C). Three new ternary phases were observed Bi3Fe0.5Nb1.5O9 with an Aurivillius-type structure, and two phases with approximate stoichiometries Bi17Fe2Nb31O106

An Octagonal Architecture for High Strength PIT Nb 3 Sn Conductors

June 6, 2006
Author(s)
L. R. Motowidlo, E Barzi, D. Turrioni, Najib Cheggour, Loren F. Goodrich
Powder-in-Tube (PIT) Nb 3Sn conductors have been fabricated utilizing a low-cost intermetallic Cu 5Sn 4 powder as the tin source. A novel octagonal PIT design that incorporates dispersion strengthened copper as well as a hexagonal PIT design were

Kinetics Governing Phase Separation of Nanostructured Sn(x)Ge(1a 'x) Alloys.

June 5, 2006
Author(s)
Regina Regan, Harry A. Atwater, Jonathan E. Guyer, Erik Meserole, Mark S. Gorrsky
We have studied the dynamic phenomenon of SnxGe1a 'x/Ge phase separation during deposition by molecular beam epitaxy on Ge(001) substrates.Phase-separation leads to the formation of direct bandgap semiconductor nanowire arrays embedded in Ge oriented along

Fatigue Resistant Miniature Piezoceramic Actuators

May 17, 2006
Author(s)
Stephanie A. Hooker, Jens Mueller, Clayton Kostelecky, K. Womer
Piezoelectric ceramics are desirable actuator materials for many biomedical applications due to their ability to generate precise, controlled motion with applied voltage. Herein, we report the fabrication of miniature piezoceramic actuators and their

Effect of Self-Assembled Monolayer Film Order on Nanofriction

May 11, 2006
Author(s)
S Sambasivan, S Hsieh, Daniel A. Fischer, Stephen M. Hsu
Self-assembled monolayers (SAMs) have increasingly being explored as potential protective films in devices friction and adhesion. However, accurate determination of the nanomechanical properties of monolayer films is difficult and fraught with

Anisotropic elastic properties of nanocrystalline nickel thin films

May 1, 2006
Author(s)
Donna C. Hurley, Roy H. Geiss, N Jennett, Malgorzata Kopycinska-Mueller, A Maxwell, Jens Mueller, David T. Read, J Wright
As length scales continue to shrink, new tools are needed to measure mechanical properties. We are developing two such tools using different nondestructive acoustical techniques. Surface acoustic wave spectroscopy (SAWS) uses laser-ultrasonic methods to

International Comparison of Impact Reference Materials (2004)

April 3, 2006
Author(s)
Christopher N. McCowan, G. Roebben, Y. Yamaguchi, S. Lefrancois, Jolene D. Splett, S. Takagi, A. Lamberty
A three-year horizontal comparison has been completed between national laboratories that certify specimens for the indirect verification of Charpy impact test machines. The participants in this study were the Institute for Reference Materials and

Characterizing reliability of multilayer PZT actuators

February 26, 2006
Author(s)
Stephanie A. Hooker
Many new applications are emerging for piezoelectric ceramics including adaptive structures, active-flow-control devices, and vibration and noise suppression systems. Additionally, there are opportunities to use these devices in the biomedical field for

Comparison of the Fouling Release Properties of Hydrophobic Fluorinated and Hydrophilic PEGylated Block Copolymer Surfaces

January 19, 2006
Author(s)
S Krishman, N Wang, Christopher K. Ober, J Finlay, M E. Callow, J A. Callow, A Hexemer, K E. Sohn, E J. Kramer, Daniel A. Fischer
To understand the role of surface-wettability on adhesion of cells, the attachment of two different marine algae was studied on hydrophobic and hydrophilic polymer surfaces. Adhesion of cells of the diatom Navicula and sporelings (young plants) of the

Kramers-Kronig analysis of attenuation and dispersion in trabecular bonea

December 1, 2005
Author(s)
Kendall Waters, B K. Hoffmeister
A restricted-bandwidth form of the Kramers-Kronig dispersion relations is applied to in vitro measurements of ultrasonic attenuation and dispersion properties of trabecular bone specimens from bovine tibia. The Kramers-Kronig analysis utilizes only

Zeroing in on a Lead-Free Solder Database

October 1, 2005
Author(s)
Thomas A. Siewert, David R. Smith
The rising interest in lead-free solders creates a need for complete property data on the various lead-free solder compositions. Circuit designers need these data to assess the impact of the transition on product life, and production engineers need these

Multilayer and functional coatings on carbon nanotubes using atomic layer deposition

September 14, 2005
Author(s)
Cari F. Herrmann, F Fabreguette, Dudley Finch, Roy H. Geiss, S M. George
Atomic layer deposition can be used to deposit ultra thin and conformal films on substrates with very high aspect ratios such as nanotubes and nanowires. In this paper, we demonstrate that functionalized and multilayered ALD coatings can be deposited

Relative Permittivity and Loss Tangent Measurement Using the NIST 60 mm Cylindrical Cavity

August 31, 2005
Author(s)
Michael D. Janezic, Jolene D. Splett, Kevin J. Coakley, Raian K. Kaiser, John H. Grosvenor Jr
In order to develop a dielectric Standard Reference Material (SRM), a measurement system for measuring the relative permittivity and loss tangent of dielectric materials is presented. To achieve the necessary level of measurement accuracy, we selected the
Displaying 1951 - 1975 of 2146