A capsule newsletter of science and technology news briefs from NIST written for general audiences; published monthly

March 1998

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In This Issue:

blueball.gif - 0.93 K'Book 'em, Nano !'
blueball.gif - 0.93 KNIST Makes Sure Windows in Space Are Reliable
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Oh Baby! New Food Standards Improves Nutrition Labeling
blueball.gif - 0.93 KWhere There's Fire, There's Smoke
blueball.gif - 0.93 KBabe and Friends Miss Cookies, Company Profits
blueball.gif - 0.93 KExtremely Cold Refrigerator Goes on Next Space Shuttle
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Tech Trivia

[Credits] [NIST Tech Beat Archives] [Media Contacts] [Subscription Information]

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Law Enforcement

'Book 'em, Nano !'

Nanometer-scale scratches on a bullet recovered at a crime scene can be as incriminating as fingerprints. Unfortunately, methods for analyzing these tell-tale forensic "signatures" still entail manual comparisons, making firearms-ballistics databases impractical.

With an assist from the National Institute of Standards and Technology, Intelligent Automation, Inc., of Rockville, Md., aims to provide police with powerful tools for quickly tracking crime weapons. IAI and its partner, Mnemonic Systems, sell RotoScan, a system for analyzing two-dimensional images of microscopic scratches etched into bullets as they travel through a gun barrel. RotoScan speeds manual comparisons, but when used automatically, it has a false match rate of 10 percent--too high to make large ballistics databases practical. NIST is evaluating probes for measuring the depths of barrel-inflicted scratches, which are tiny fractions of the thickness of a human hair. IAI believes that, with high-precision measurements in three dimensions, false-match rates can be reduced to less than 1 percent. Even more ambitious, says IAI President Leonard Haynes, is a plan to "fingerprint" all guns as they are manufactured, which would require an additional tenfold reduction in the false match rate. The work is supported by the National Institute of Justice.

Media Contact:
Mark Bello (301) 975-3776

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NIST Makes Sure Windows in Space Are Reliable

The international space station will involve many experiments, but NASA is taking no chances with the windows. With the space station's first U.S. section--called Node 1--set to launch in mid-1998 aboard shuttle flight STS-88, NASA has asked the National Institute of Standards and Technology to make sure that Node 1's round windows will withstand the rigors of space.

Because the relevant properties of the window material are unknown, NIST is performing a series of experiments to determine the fracture characteristics of this glass. "We take a lot more caution because, if our glass breaks, people's lives are in serious jeopardy," says Lynda Estes of the Structures and Dynamics Branch at NASA's Johnson Space Center.

NIST also is testing fused silica used in the space shuttle's 11 multipaned windows. Fused silica is a commercial glass, but the glass manufacturer is switching to a different processing method, so NASA wants to make sure the new material performs like the old. The reliability of brittle materials like glass depends on the distribution of surface defects as well as exposure to moisture, which causes small defects to grow over time. The tests performed by NIST's Materials Science and Engineering Laboratory will measure static fatigue, strength, toughness and crack growth. A statistical analysis will project the lifetime of the material at a specified confidence level.

Media Contact:
Anne Enright Shepherd (301) 975-4858

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Oh Baby! New Food Standard Improves Nutrition Labeling

Since when is baby food an advanced scientific ruler? Since scientists at the National Institute of Standards and Technology recently issued Standard Reference Material 2383, Baby Food Composite. This sophisticated measurement tool will help food processors and manufacturers more accurately assess the exact amount of vitamins, minerals, fat, protein, carbohydrates and calories in their products. NIST produced SRM 2383 in order to help the food industry meet requirements of the Nutrition Labeling and Education Act of 1990.

The Baby Food Composite standard is a blend of the ingredients found in commercially available baby foods, including orange juice, infant formula, corn, creamed spinach, carrots, beef, macaroni and other foods. This blend is designed to represent measurement challenges in food analysis, rather than a typical infant diet. Chemists at NIST and collaborating laboratories carefully determined the concentration of fat, protein, carbohydrates, calories, carotenoids (such as beta-carotene) and many vitamins and minerals in the new standard. Food manufacturers can use the baby food standard to check the accuracy of their analytical methods and results and to evaluate the accuracy of their own in-house quality control standards. The Baby Food Composite SRM is one of a series of standards being developed to help meet food industry needs. Consumers also benefit by having more accurate nutritional information. SRM 2383 is now for sale in NIST's Standard Reference Materials Program.

Media Contact:
Linda Joy (301) 975-4403

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Where There's Fire, There's Smoke

Where there's smoke there's fire" is the adage. But for the National Institute of Standards and Technology that's just part of the story. Smoke, itself, can obscure visibility and damage human lungs. NIST fire researchers have created a computer-based model to predict the downwind distribution of smoke particulate and combustion products from large outdoor fires.

The program called ALOFT-FT also enables users to estimate the chemical concentrations in segments from ground level to the top of the plume. ALOFT-FT, which can be run on a Windows-based personal computer, requires as input data wind speed and variability, atmospheric temperature, number of fires and heat release rate. Results can be displayed as downwind, cross wind and vertical smoke concentration contours. NIST developed ALOFT-FT to aid in the planning process for intentional burning of crude oil spills on water. The program also can be used in predicting the smoke plume trajectory from other large outdoor fires such as that caused by a burning building. ALOFT-FT is available at http://fire.nist.gov/aloft/aloft-ftdownload.htm. The PC model is for smoke plumes forming over flat terrain. Future releases will incorporate complex terrrain features.

Media Contact:
John Blair (301) 975-4261

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Babe and Friends Miss Cookies, Company Profits

Babe and his barnyard friends are going to be awfully disappointed with Interbake Foods' scrap reduction program. Interbake is one of only two manufacturers licensed to make the perennially popular Girl Scout cookies. One particular cookie--the Caramel deLite--makes up about half of the plant's Girl Scout cookie volume. It's also the hardest to make. And anything not up to specs gets tossed into a bin for eventual shipment to some lucky farm critters.

In 1995, Interbake's management decided to take a hard look at the waste produced by its baking lines. Engineers quickly found that two-thirds of the plant's waste was solid--cookies that failed to meet specifications. In the meantime, the Virginia-based commercial baker learned about the pollution prevention grant program offered by Virginia's A.L. Philpott Manufacturing Extension Partnership--an affiliate of the National Institute of Standards and Technology's Manufacturing Extension Partnership.

A matching grant helped Interbake buy computers to monitor bins of rejected cookies. Production workers also have started pulling samples every 15 minutes, which are weighed to determine whether adjustments are needed in the amount of caramel, coconut or chocolate the cookies are receiving. The latest data can be accessed with just a few strokes on the computer keyboard. Interbake's scrap reduction effort yielded savings of about $290,000 during its first year, and the matching grant has been extended for a second year.

Media Contact:
Jan Kosko (301) 975-2767

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Extremely Cold Refrigerator Goes on Next Space Shuttle

The next space shuttle mission, scheduled for launch in April 1998, will contain the world's smallest version of a new type of refrigerator, known as a pulse tube refrigerator. These refrigerators, or cryocoolers, can be used to cool infrared sensors or other devices to temperatures of 80 Kelvin (about -315 F). Very cold sensor temperatures are needed to study temperature variations in the atmosphere and the oceans to aid in understanding the ozone hole, global warming and long-range weather forecasting. The current cryocooler was designed, built and tested under an agreement between the National Institute of Standards and Technology and Lockheed Martin Astronautics of Denver with significant contributions from NASA Ames Research Center.

One advantage of this cryocooler is that there are no moving parts at the cold tip, which leads to lower vibration, higher reliability and simpler control electronics. The battery-operated cryocooler in this experiment is only about 12.5 centimeters (five inches) long and weighs less than one kilogram (two pounds). The batteries, control electronics and an onboard computer to record all of the data weigh less than 100 kilograms (about 200 pounds). This experiment will test the pulse tube cooling technology in zero gravity and provide experience in space with the smallest such cryocooler yet built.

Media Contact:
Fred McGehan (Boulder) (303) 497-3246
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Tech Trivia

Edward Condon, a former director of the National Bureau of Standards (now NIST), led a two-year investigation, "Scientific Study of Unidentified Flying Objects," for the Air Force Office of Scientific Research. Completed in 1968, the study concluded that the study of UFOs has not added to scientific knowledge.

In 1942, at the request of the Office of Civilian Defense, the National Bureau of Standards (now NIST) tested textiles and paper as blackout materials to eliminate upward light from car headlights and improved Army blackout headlamps.

During WWII, the National Bureau of Standards (now NIST) determined acoustic properties of suitable air-raid alarms, including sirens, steam and compressed-air whistles and loudspeakers. NBS sent alarm system guidelines to city, town and federal offices around the country.

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U.S. Department of Commerce
Technology Administration
National Institute of Standards and Technology

Editor: Linda Joy
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