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

November 1997

Tech Beat

In This Issue:

blueball.gif - 0.93 KReally Cool Laser Experiments Net NIST Physicist Nobel Prize
blueball.gif - 0.93 KPlease Pass the DNA Chips
blueball.gif - 0.93 KChemical Needles in a Haystack? Here's a 'Solution' Solution
blueball.gif - 0.93 KNIST Marks 10 Years of Finding New Refrigerant Fluids
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Fire Alarm System Pack a Wallop
blueball.gif - 0.93 KNIST Nanotechnologists to Get a 'Grip'
blueball.gif - 0.93 KTech Trivia

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Really Cool Laser Experiments Net NIST Physicist Nobel Prize

How cold is cold? Scientists at the National Institute of Standards and Technology in Boulder, Colo., and Gaithersburg, Md., have achieved the coldest temperatures in the universe, far colder than interstellar space, using lasers and magnetic fields to trap and chill clouds of atoms. For developing methods to cool and trap atoms with laser light, NIST Gaithersburg physicist William Phillips will share the 1997 Nobel Prize in Physics with Steven Chu of Stanford University and Claude Cohen-Tannoudji of the College de France and Ecole Normale Superieure, Paris, France.

At room temperature, atoms in the air zoom around and bounce off each other at nearly the speed of sound, or hundreds of meters per second. Because it's much easier to measure certain atomic properties when atoms are still, scientists sought ways to slow them down. Since the late 1970s, Phillips and the team he leads at NIST have developed ways to chill atoms close to absolute zero, the theoretical temperature at which random atomic motion would completely cease. Methods developed by the NIST team have allowed scientists to bring atoms to a crawl of just a few millimeters per second.

Media Contact:
Linda Joy (301) 975-4403

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Please Pass the DNA Chips

Although they're not going to be too tasty when dunked in your favorite sour cream and onion dip, DNA chips have the potential to revolutionize disease diagnosis, DNA sequencing, environmental sampling and other analytical jobs. Many U.S. biotech firms are working to develop new DNA-based medical diagnostics and environmental sensors that will be fast, inexpensive and very accurate. To support this emerging technology, scientists at the National Institute of Standards and Technology are providing useful information on the fundamental molecular structure of the DNA chip components.

NIST scientists construct DNA chips from single-stranded DNA molecules, which with the help of a sticky sulfur end-group conveniently organize themselves into a uniform monolayer film on a gold surface. The surface-tethered DNA can then bind complementary small fragments of single-stranded DNA from a sample. Research at NIST has helped industry to better understand how the DNA molecules assemble on a surface and how to obtain the best coverage of DNA on the chip for improved sensitivity. They also are studying the physical characteristics of the surface-tethered DNA and devising new ways to monitor DNA binding.

These DNA chips could become the basis for very fast sensors used to diagnose a bacterial infection in a patient, E. Coli in ground beef or Pfiesteria piscicida in a suspect water sample. In theory, sensors could be developed to check for many bacteria and viruses at the same time.

Media Contact:
Linda Joy (301) 975-4403

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Chemical Processing

Chemical Needles in a Haystack? Here's a 'Solution' Solution

Maxwell's Demon, so it's said, could sort out the fast molecules from the slow. All very nice, but call us when he can separate the gold from the dross. Or don't bother, because IBC already can, and lots more besides.

Chemical separation technology is a potentially lucrative field, with applications including recovering precious metals from waste and removing trace impurities from products. However, when the target molecules are in very low concentrations or mixed with other species that are very similar chemically, it's a difficult task, particularly if you want to do it on a commercial scale.

IBC Advanced Technologies, Inc., of American Fork, Utah, has a "solution" solution, based on research sponsored by the National Institute of Standards and Technology's Advanced Technology Program. Their technique involves tailored organic chemicals called macrocycles that capture specific "guest" molecules--the platinum group metals mixed in catalytic converter scrap, for example. The host macrocycles carrying their guests are easily separated from the waste stream, and a simple chemical reaction detaches the guest, leaving the macrocycle ready for reuse. In addition to recovery of precious metals, the technology could be applied to such tasks as refining ultra-pure substances (pharmaceuticals, for example), treating nuclear waste and removing environmental contaminants.

Media Contact:
Michael Baum (301) 975-2763

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NIST Marks 10 Years of Finding New Refrigerant Fluids

For a decade, scientists at the National Institute of Standards and Technology have been helping industry phase out a common refrigerant fluid that's been found to harm the environment. Ten years ago, many nations signed the Montreal Protocol, pledging by Jan. 1, 2000, to stop using CFCs (chlorofluorocarbons), which harm the Earth's protective ozone layer. With more than 5,000 American companies relying on refrigerants to produce goods and services worth billions of dollars, industry faced an urgent problem. And it turned to NIST.

Scientists in NIST's Physical and Chemical Properties Division, in both Boulder, Colo., and Gaithersburg, Md., have determined thermophysical properties of alternative refrigerant fluids, as well as data crucial to understanding the fate these fluids will face when released to the atmosphere. NIST's Building and Fire Research Laboratory performed fire and efficiency tests on the new fluids. Such information was essential for industry engineers designing systems to run on non-CFC refrigerant fluids.

This is not the first time NIST has assisted industry with critical data for refrigerant fluids. Prior to the 1930s and the widespread use of CFCs, the young refrigeration industry used ammonia and other fluids in its equipment. Engineers then also relied on National Bureau of Standards (now NIST) data tables as they designed refrigeration systems.

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

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Fire Safety

Fire Alarm System to Pack a Wallop

The next time a wall begins to talk, best listen up! At least that's the advice of fire safety researchers at the National Institute of Standards and Technology who are working with the fire detector industry to build an in-wall system capable of discovering a fire, pinpointing its location and predicting the short- and long-term effects of its fire growth and smoke spread. The cybernetic alarm, which combines NIST fire modeling software with advanced sensors and annunciator panels, would use building plans, contents and sensor data to provide continuous estimates of a building's safety.

The ability to isolate the location, size and potential growth of a specific fire or other hazardous event, such as too much carbon monoxide in a room, would be especially useful for predictions for escape and rescue. "Smart sensing" also could mean the end of false alarms that empty entire buildings. For very large facilities, the system also would enable a measured response on the part of firefighters. Incidents could be isolated and extinguished without general interruption of business. The researchers hope to have a working model of the system ready by 2002. NIST is seeking industrial partners for the five-year project.

Media Contact:
John Blair (301) 975-4261

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NIST Nanotechnologists to Get a 'Grip'

It might sound like a new line of luggage for people with an obsessive fear of air or dust, but the "vacuum suitcase" under development at the National Institute of Standards and Technology was designed with neither anemophobes nor amathophobes in mind. Rather, the intended beneficiaries are U.S. makers of semiconductors and data-storage devices--technologies with vanishingly small components. Both types of manufacturers already take extreme steps to eliminate dust and airborne contaminants from their production facilities. In the future, even air molecules may pose a threat, forming potentially troublesome films on features with atomic-scale dimensions.

NIST's initial objective is to build a portable ultrahigh vacuum container to support collaborative efforts to develop measurement aids based on nature's own geometry--the spacings and features on crystal surfaces. Such measurement tools--assembled, perhaps, atom by atom--may have to "spend their entire life in a vacuum," explains Richard Rhorer, head of the team that is building a prototype vacuum suitcase. Complete with pump, specimen handling system and other accessories, the hefty suitcase will permit "airless" exchanges of these fragile atomic rulers between instruments and even between geographically separated facilities. Industry does not yet require this capability, but further miniaturization could present the need within the next decade or so, says Rhorer.

Media Contact:
Mark Bello (301) 975-3776
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Tech Trivia

One of NASA's longest running experiments--on the moon since 1969--contains a reflector designed at JILA, which is operated cooperatively by NIST and the University of Colorado. The reflector has been used to measure the distance from the Earth to the moon within 2.5 centimeters (1 inch).

The National Bureau of Standards (now NIST) measured driver reaction times in early automobiles by attaching two pistols to a vehicle's running board. The driver would brake when he heard the first pistol, thus triggering the second. Reaction times were calculated by car speed and distance between bullet marks on the pavement.

National Bureau of Standards (now NIST) researchers invented the first atomic clock in 1949. Such clocks keep time by using natural characteristic frequencies of atoms. The current generation atomic clock, NIST-7, is so accurate that it neither gains nor loses a second in 6.3 million years.

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National Institute of Standards and Technology

Editor: Linda Joy
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