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Displaying 48226 - 48250 of 73829

User's Manual for Lidar Target Simulator

March 1, 2000
Author(s)
J A. Worthey, Kathleen M. Higgins
This is the operator's manual for a target simulator for speed-measuring lidars, and for the computer program VS, which is a key part of the simulator. This is the simulator referred to in DOT HS 808 539, Model minimum performance specifications for lidar

Vapor Pressure of Heptane from the Triple Point to the Critical Point

March 1, 2000
Author(s)
L A. Weber
We have used a metal ebulliometer to make measurements of the vapor pressure of heptane. Measurements spanned the temperature range from 335 K to 503 K, and measured pressures ranged from 30 kPa to 1597 kPa. The sample purity was determined by

Yb/Er-Codoped and Yb-Doped Waveguide Lasers in Phosphate Glass

March 1, 2000
Author(s)
D. L. Veasey, David S. Funk, P. M. Peters, Norman Sanford, Gregory E. Obarski, N. H. Fontaine, M. Young, A P. Peskin, W. Liu, S. N. Houde-Walter, Joseph S. Hayden
We present experimental and theoretical results of our recent work on the development of waveguide lasers using rare-earth-doped phosphate glasses. An improvement has been achieved over previously reported waveguide laser results using the process of ion

Neutron Irradiation to Increase the C-Axis Compressive Strength of Sapphire at Elevated Temperature

February 29, 2000
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, R M. Stroud, T A. Kennedy, M Fatemi, David R. Black
Neutron irradiation of sapphire with 1 x 10 18 neutrons (≥ 1 MeV)/cm 2 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

Automated Earthmoving Status Determination

February 28, 2000
Author(s)
William C. Stone, Geraldine S. Cheok, Robert R. Lipman
Efforts are underway at the National Institute of Standards and Technology (NIST) to develop automated non-intrusive production measurement systems and procedures for monitoring the status of general earthmoving operations at typical construction sites

Subcritical Crack Growth: Mechanisms

February 28, 2000
Author(s)
Brian R. Lawn
A brief survey is given of mechanisms of subcritical crack growth in ceramics, for a solicited article in Encyclopedia of Materials: Science and Technology.

Sensor-Driven Inverse Zone Fire Model

February 23, 2000
Author(s)
William D. Davis, Glenn P. Forney
As sensor use in buildings becomes more wide spread, it is possible to use this information as input to an inverse fire model in order to enhance the value of the information available from sensors in both fire and non-fire conditions. Typical fire models

Magnetic Switching

February 22, 2000
Author(s)
Richard G. Geyer, Pavel Kabos
Almost all present-day applications of ferromagnetic materials are based on the fact that magnetization may move from one stable state to another.

Introduction to Evaluating Biometric Systems

February 21, 2000
Author(s)
P J. Phillips, Alvin F. Martin, Charles L. Wilson, Mark A. Przybocki
Biometric technology has the potential to provide secure access using user characteristics, biometric signatures, that cannot be lost, stolen, or easily duplicated. However, the actual performance of many existing systems is unknown. Potential users of

Variance of Streaming Potential Measurements

February 18, 2000
Author(s)
M C. Wilbert, S Delagah, John Pellegrino
We evaluated sources of variance in the measurement of the surface streaming potential of flat sheet specimens of cellulose di/triacetate membranes with a commercial electrokinetic analyzer.

A Frequency Stabilized Laser Array for Use in Displacement Metrology

February 17, 2000
Author(s)
J Pedulla, R Deslattes, John R. Lawall
We have developed a frequency stabilized laser system to supply light to measure atomic-scale displacements of a stage moved in real time. Each laser in the array provides enough power (~1 mW) for four Michelson interferometers whose accuracy requires a

Modeling and Development of Polishing Processes

February 17, 2000
Author(s)
R B. Mindek
Lapping and polishing have a long history and are probably the oldest known manufacturing professions. They are considered abrasive processes and are used to produce surface finishes and profiles of extreme precision, and are still todaycritical to the

A Comparison of the SSE-CMM and NVLAP IT Security Testing

February 16, 2000
Author(s)
R J. Medlock
This paper describes the general accreditation requirements of the NIST National Voluntary Laboratory Accreditation Program (NVLAP) and the specific accreditation requirements for the Cryptographic Module Testing (CMT) and Common Criteria Testing (CCT)

A Stall Metric to Track Communication Performance

February 15, 2000
Author(s)
Alan Mink, Wayne J. Salamon, Michael D. Indovina
Probing the communication protocol stack in Linux PC-based clusters to investigate erratic TCP/IP performance has led to a new metric, data stream stall, which is analogous to instruction stream stall in CPUs. Data stream stalling correlates well with

Thermodynamics of Reactions Catalyzed by Anthranilate Synthase

February 14, 2000
Author(s)
W M. Byrnes, Robert N. Goldberg, Marcia J. Holden, M P. Mayhew, Yadu D. Tewari
Microcalorimetry and high performance liquid chromatography have been used to conduct a thermodynamic investigation of reactions catalyzed by anthranilate synthase, the enzyme located at the branch point in the chorismate biosynthetic pathway that leads to

Dielectric Ceramic Materials

February 9, 2000
Author(s)
Richard G. Geyer
Accurate rf dielectric and magnetic characterization of ferrite ceramics requires combined measurement techniques.

In situ Metrology During the Growth of Compound Semiconductors by Molecular Beam Epitaxy

February 9, 2000
Author(s)
Donald A. Gajewski, Jonathan E. Guyer, Nhan Van Nguyen, Joseph G. Pellegrino
In this poster, we present the optical response of thin film compound semiconductors measured using in situ spectroscopic ellipsometry (SE), at growth temperatures ((180 to 600) 0C), during the growth by molecular beam epitaxy (MBE). We will focus on in

X-Ray Topography Study of Surface Damage in Single-Crystal Sapphire

February 9, 2000
Author(s)
David R. Black, Robert S. Polvani, Kate Medicus, H E. Burdette
X-ray diffraction topography was used to investigate the relationship between sub-surface damage, near-surface microstructure, and fracture strength in a series of sapphire modulus of rupture (MOR) bars which had been fabricated to proof test fabrication

On the Bifurcation From Continuous to Segmented Chip Formation in Metal Cutting

February 6, 2000
Author(s)
Timothy J. Burns, Matthew A. Davies, Christopher J. Evans
We describe a new approach to modeling chip formation in orthogonal machining. Metal cutting is interpreted as a nonlinear dynamical process with thermomechanical feedback, which is similar in many ways to an open chemical reactor. As the cutting speed is

A Differentiated Optical Services Model for WDM Networks

February 1, 2000
Author(s)
Nada T. Golmie, T D. Ndousse, David H. Su
This paper addresses the issues of guaranteed and scalable end-to-end QoS in Metropolitan DWDM networks serving as transit networks for IP access networks. DWDM offering few wavelengths have in the past been deployed in the backbone network to upgrade

A Frequency Stabilized Laser Array for Use in Displacement Metrology

February 1, 2000
Author(s)
J Pedulla, R Deslattes, John R. Lawall
We have developed a frequency stabilized laser system to supply light to measure atomic-scale displacements of a stage moved in real time. Each laser in the array provides enough power ({approximately equal to} 1 mW) for four Michelson interferometers
Displaying 48226 - 48250 of 73829
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