U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Search Publications

NIST Authors in Bold

Displaying 49376 - 49400 of 73832

Scalar Dissipation in Axisymmetric Jets

November 21, 1999
Author(s)
William M. Pitts
Scalar dissipation, defined as twice the product of the molecular diffusion coefficient and the local gradient of the mixture fraction taken as a dot product with itself, characterizes molecular mixing rates in turbulent flows and has a central role in

Two-Dimensional Index Profiling of Fibers and Waveguides

November 20, 1999
Author(s)
N. H. Fontaine, M. Young
We have constructued a two-dimensional refracted-ray scanner that can resolve index-of-refraction increments of approximately 4 x 10 -5. this resolution is an order of magnitude finer than the uncertainty of the measurement. The scanner can be adapted to

Microhotplate Gas Sensor Arrays

November 18, 1999
Author(s)
Richard E. Cavicchi, Stephen Semancik, R M. Walton, B Panchapakesan, Don L. DeVoe, M I. Aquino-Class, J D. Allen, John S. Suehle
In this work, micromachining and planar processing has been used to achieve solid state sensing devices with lower power consumption at lower cost. The small size brings new advantages for chemical selectivity as well: multi-element whose time-varying

Comparative Calibration of Heat Flux Sensors in Two Blackbody Facilities

November 17, 1999
Author(s)
A V. Murthy, Benjamin K. Tsai, Robert D. Saunders
This paper presents the results of heat flux sensor calibrations in two blackbody facilities: the 25 mm variable temperature blackbody (VTBB) primary facility and a recently developed 51 mm aperture spherical blackbody (SPBB) facility. Three Schmidt

Determination of Texture From Individual Grain Orientation Measurements

November 17, 1999
Author(s)
J Blendell, Mark D. Vaudin, Lin-Sien H. Lum
We present a technique for determining the texture of a polycrystalline material based on the measurement of the orientation of a number of individual grains. We assume that the sample has fiber texture and that the texture can be characterized by a

Lessons from 342 Medical Device Failures

November 17, 1999
Author(s)
D Wallace, David R. Kuhn
Today's highly complex systems often contain software. Lessons can be learned about softwaredevelopment and assurance concerning quality practices, from system failures activated bysoftware faults. This paper presents an analysis of failures of medical

On the Diffraction Limit for Lensless Imaging

November 17, 1999
Author(s)
Klaus Mielenz
The diffraction limit for lensless imaging, defined as the smallest obtainable point image, is analyzed and compared to the corresponding limit for imaging with lenses by means of theoretical considerations and numerical computations using the Fresnel

Status Report on the First Round of the Development of the Advanced Encryption Standard

November 17, 1999
Author(s)
James R. Nechvatal, Elaine B. Barker, Donna F. Dodson, Morris J. Dworkin, James Foti, E Roback
In 1997, the National Institute of Standards and Technology (NIST) initiated a process to select a symmetric-key encryption algorithm to be used to protect sensitive (unclassified) Federal Information, in furtherance of NIST's statutory responsibilities

Acquiring and Deploying Intrusion Detection Systems

November 16, 1999
Author(s)
Peter M. Mell
This ITL Bulletin provides basic information about intrusion detection systems (IDSs) to help organizations avoid common pitfalls in acquiring, deploying, and maintaining IDSs.

Using Chaos to Generate White Noise

November 15, 1999
Author(s)
Richard L. Kautz
Numerical simulations reveal that a phase-locked loop can be operated in a chaotic regime to generate a high level of noise which is approximately white over a broad frequency range. Heuristic arguments indicate that the low-frequency power spectrum may be

A Knowledge-Based Inspection Workstation

November 3, 1999
Author(s)
Elena R. Messina, John A. Horst, Thomas R. Kramer, Hui-Min Huang, Tsung-Ming Tsai, E Amatucci
We are building an inspection workstation development environment to use as a testbed for understanding what types of knowledge, e.g., data, algorithms, and processes, can increase the productivity of inspection operations. Inspection can be more efficient

The Engineering of Mind

November 2, 1999
Author(s)
James S. Albus
While the mind remains a mysterious and inaccessible phenomenon, many of the components of mind, such as perception, behavior generation, knowledge representation, value judgment, reason, intention, emotion, memory, imagination, recognition, learning

A General Quantitative Method to Validate Instrument Calibration Techniques

November 1, 1999
Author(s)
Steven D. Phillips
In this paper a method to validate proposed calibration procedures for coordinate measuring machines (CMMs) is presented. Conceptually, the validation procedure is based on a computer generated population of CMMs assumed to include any real CMM that a

Acoustic Evidence Against BCS Behavior in Monocrystal YBa 2 Cu 3 0 7

November 1, 1999
Author(s)
M Lei, Albert Migliori, H M. Ledbetter
Using a detwinned YBa 2Cu 30 7 monocrystal and acoustic-resonance spectroscopy, we measured internal friction Q- = A If through the 91-K superconducting-transition temperature. We show measurements for the first ten macroscopic resonance frequencies f r

An Information System to Support Calibration

November 1, 1999
Author(s)
Kevin G. Brady
The National Institute of Standards and Technology (NIST) performs calibrations that achieve the highest level of measurement quality for the makers and users of precision devices world-wide. The information system that administers these calibrations

Antenna-Coupled Niobium Bolometers for MM-Wave Imaging Arrays

November 1, 1999
Author(s)
Shalva Nolen, Jonathan A. Koch, Nicholas Paulter, Carl D. Reintsema, Erich N. Grossman
Antenna-coupled thin-film niobium microbolometers designed for mm-wave imaging arrays have been fabricated and their electrical properties measured. The niobium bolometers are operated at room temperature and are located at the feeds of half-wave dipole
Displaying 49376 - 49400 of 73832
Was this page helpful?