In This Issue:
Kammer to be
Nominated as NIST Director
'Virtual' Fires
Could Save Real Buildings, People
Special
Thermometers Increase Radiometer's Sensitivity
Wanted:
Input on Rapid Prototyping Issues
Improved
Substrate Measurements Use NDT
Paper Shows
How to Model Thermodynamic Properties
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Administration
Kammer to be Nominated as NIST Director
The White House announced on Sept. 4 that President Clinton intends to nominate Ray Kammer to become the 11th NIST director. Kammer, 50, the deputy director of NIST (from 1980 to 1991 and from 1993 to the present), most recently has been serving on an acting basis as chief financial officer, assistant secretary for administration and chief information officer for the Department of Commerce. From 1991 to 1993, Kammer was deputy under secretary of commerce for oceans and atmosphere, the chief operating officer of the National Oceanic and Atmospheric Administration. He began his career with Commerce in 1969 as a program analyst. Prior to his appointment as NIST deputy director, Kammer held a number of management positions at NIST and Commerce.
Once the nomination has gone forward, Kammer must be confirmed by the U.S. Senate.
Media Contact:
Michael Newman (301)
975-3025
Fire Research
'Virtual' Fires Could Save Real Buildings, People
Virtual reality technology soon could enable fire safety engineers and architects to evaluate building designs and fire codes from the perspective of people in a burning building--without leaving their computer screen. This advance is the goal of NIST-sponsored work that integrates NIST's Consolidated Model of Fire and Smoke Transport software program (known as CFAST) with the University of California, Berkeley's Architectural Walkthrough Program (known as Walkthru).
CFAST provides accurate simulation of the impact of fire and its byproducts on a building environment. Walkthru, using AutoCAD floor plans, provides interactive, three-dimensional, simulated (10 frames per second) movement through buildings. Together, they provide real-time scientific visualization of building conditions in a fire hazard situation. Users can observe the room-to-room spread of flame and smoke from a fire. Visualization techniques depict concentrations of toxic compounds or the temperatures of the atmosphere, walls and floor. Simulating fires in virtual building environments could enable users to preview architectural designs, evaluate their performance with various real-world circumstances and experiment with hypothetical situations cheaply and with no risk to life or property.
BFRL fire safety scientists and engineers are looking for industrial partners to help develop a personal computer version of the software that can be adapted readily to multiple building plans.
For more information, contact Walter Jones, A249 Polymer Bldg., NIST, Gaithersburg, Md. 20899-0001, (301) 975-6887.
Media Contact:
John Blair (301) 975-4261
Radiation
Special Thermometers Increase Radiometer's Sensitivity
NIST scientists have designed and measured the performance of the first-ever electrical substitution radiometer based on superconducting thermometers. It will permit highly precise measurements of far-infrared blackbody radiation.
Electrical substitution radiometry is the standard technique for performing radiometric power measurements with high accuracy. ESR consists of incorporating a radiation absorber, a thermometer and an electrical heater onto a single thermal node. The accuracy and precision of the measurement of electrical power can be transferred to the measure of optical power using this technique.
NIST has built an ESR in which the thermometers consist of superconducting thin films instead of conventional thermometers such as germanium thermistors (known as GRTs). Because of the sharpness of the superconducting transition, the thermometers offer an enhancement that is as much as three orders of magnitude in sensitivity greater than GRTs. This increased sensitivity enables high precision measurements of power at exceptionally low power levels.
A new NIST paper (no. 26-97) describes the ESR radiometer, discussing its physical configuration, thermal design, electronics, experimental results, and accuracy and precision. For a copy, contact Sarabeth Harris, MC 104, NIST, Boulder, Colo. 80303-3328, (303) 497-3237.
Media Contact:
Fred McGehan (Boulder)
(303) 497-3246
Manufacturing
Wanted: Input on Rapid Prototyping Issues
From curiosity to a staple of many manufacturing operations, rapid prototyping has taken off. However, a dearth of standards and industry-accepted measurement methods ultimately may limit the usefulness and performance of the technology.
For example, file exchanges between design systems and RP machines often result in errors. And as RP outputs diversify well beyond visual aids for designers and engineers, dimensional accuracy becomes a critical issue.
NIST and two partners have decided to survey the field and solicit U.S. industry's ideas on what standards and measurement-related issues warrant the agency's attention. As a first step, NIST, the National Center for Manufacturing Sciences and the Rapid Prototyping Association of the Society of Manufacturing Engineers will host an industry workshop Oct. 16-17, 1997, at NIST's headquarters in Gaithersburg, Md. Categories to be covered include processes, equipment, materials, software and data interfaces.
Users and developers of RP systems are encouraged to submit their suggestions on priority technical needs and problems that NIST should address. The agency's Manufacturing Engineering Laboratory will use the workshop proceedings and submitted comments to guide its planning of activities in the fast-growing rapid prototyping area (where equipment sales are estimated to be increasing about 50 percent annually).
For more information or to submit comments, contact either Kevin Jurrens, (301) 975-5486, or Dick Rhorer, (301) 975-6506.
Media Contact:
Mark Bello (301) 975-3776
Electromagnetics
Improved Substrate Measurements Use NDT
The electromagnetic properties of the substrates used in microwave printed circuits and phased-array antennas must be determined very accurately in order to produce efficient and cost-effective designs. Most currently used measurement methods are destructive and not suitable for production-line settings, or produce errors of up to 10 percent.
NIST has developed a new mathematical model (a full-field solution) and software for use with a common test procedure, the open-end coaxial probe. It accounts for errors due to the air gap lift-off (the tiny but unavoidable gap between probe face and material surface), finite layer thickness, and (optionally) termination by a conductive backing. By deliberately introducing a small, known amount of lift-off, NIST has demonstrated routine accuracies of 3 percent or better.
The NIST software is now available to industry and other government agencies. It runs on common personal computers and supports additional measurement options such as remote network analyzer control.
For more information, contact Andy Repjar, MC 813.08, NIST, Boulder, Colo. 80303-3328, (303) 497-5703.
Media Contact:
Collier Smith (Boulder)
(303) 497-3198
Alternative Refrigerants
Paper Shows How to Model Thermodynamic Properties
Refrigeration engineers, environmental researchers and others interested in alternatives to ozone-damaging chlorofluorocarbon refrigerants will want a new technical paper from NIST. Written by NIST researchers Mark O. McLinden and Eric W. Lemmon, along with Richard T Jacobsen of the University of Idaho, the paper gives an overview of the models used to calculate the thermodynamic properties of refrigerants and refrigerant mixtures.
Thermodynamic properties are so important in the design of refrigeration equipment that a considerable number of pages are devoted to their tabulation in engineering handbooks. The calculations are always done with some sort of model because it is impossible to measure every property of interest at every combination of temperature, pressure and, in the case of mixtures, composition.
The NIST paper is not an exhaustive review but highlights the approaches most commonly used for the refrigerants. It also points to sources for high-accuracy formulations used to define properties of pure refrigerants and provides a summary of the data available for some alternative refrigerant mixtures of current interest (such as those containing R32, R125, R143a and R152a).
For a copy of paper 32-97, contact Sarabeth Harris, MC 104, NIST, Boulder, Colo. 80303-3328, (303) 497-3237.
Media Contact:
Fred McGehan (Boulder)
(303) 497-3246
