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May/June 2002

  In This Issue:
bullet Detectors Soon Will Be No Match for NIST-Tuned Radar Guns
bullet NIST Chocolate Standard Raises the ‘Bar’ on Accuracy
bullet NIST Chemists Define and Refine Properties of Plastic Microsystems
bullet New NIST Booklet Tells How to Short Circuit Surges
bullet Need the Time or Need to Know About Time ... Go to NIST!
bullet Tech Trivia

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Law Enforcement

Detectors Soon Will Be No Match for NIST-Tuned Radar Guns

There’s no worse feeling than being waved off the road by a police officer with a radar gun in his hand. Unless you’re that officer trying to enforce the speed limit with traditional equipment.

“Across-the-road” Doppler photo radars—aimed across a thoroughfare instead of parallel to or alongside it—are increasingly being used for measuring vehicle speeds on the nation’s highways. These devices provide distinct advantages over older radar guns: easier concealment, better differentiation between vehicles, automated identification of offenders using complementary photographic equipment, and best of all for officers—nothing that will triggger a radar detector. Unfortunately, the radars currently also require frequent calibration to ensure their accuracy.

At the request of the National Highway Traffic Safety Administration, the National Institute of Standards and Technology (NIST) has developed calibrator/simulator units that will certify the performance and accuracy of across-the-road traffic radars. The units soon will undergo field tests.

The calibrator/simulator units are self-contained with software that simulates vehicles from motorcycles to trucks over speeds from 24 to 193 kilometers per hour (15 to 120 miles per hour) with an expected accuracy of plus or minus 2 kilometers per hour (1 mile per hour). The calibrator units are reliable, simple in design and should be inexpensive when manufactured in quantity.

Media Contact:
Fred McGehan Boulder,  (303) 497-7000Up



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Food Measurement

NIST Chocolate Standard Raises the ‘Bar’ on Accuracy

Chocoholics, rejoice. Now there’s a way to know more precisely than ever how much fat (and other constituents) are in chocolate and similar foods.

The National Institute of Standards and Technology (NIST) has issued Standard Reference Material (SRM) 2384, Baking Chocolate, which has been characterized with state-of-the-art measurement methods to show how much fat, protein, carbohydrates, individual fatty acids, elements, vitamins and other components it contains. It is part of a series of food-matrix SRMs that can be used by food processors to validate analytical methods and for quality assurance when assigning values to products with similar compositions.

The baking chocolate SRM is the first standard to contain a high proportion of fat—more than 50 percent. A high-fat food standard has been identified as a priority by manufacturers. Because of this high fat content, the new SRM can be analyzed by manufacturers of chocolate and by quality assurance labs of companies that produce other types of fatty products, such as black olives and potato chips. This SRM also is the first to have values assigned for catechins (which, as antioxidants, may help protect the body against damage associated with age-related diseases) and caffeine.

NIST’s food-matrix SRMs will help manufacturers comply with the Food and Drug Administration labeling requirements.

Media Contact:
Michael E. Newman,  (301) 975-3025Up


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FluidicsLaurie Locascio places a water sample on a tiny sensing chip that detects toxic chemicals.

NIST Chemists Define and Refine Properties of Plastic Microsystems

There may well be a plastic biochip in your future, thanks in part to the National Institute of Standards and Technology (NIST).

Microfluidics devices, also known as “lab-on-a-chip” systems, are miniaturized chemical and biochemical analyzers that one day may be used for quick, inexpensive tests in physicians’ offices. Most microfluidics devices today are made of glass materials. Cheaper, disposable devices could be made of plastics, but their properties are not yet well understood.

NIST is contributing to the development of these plastic microfluidics. One study looked at how fluids flowed in plastic microchannels by tracking fluorescent dye in the fluids. NIST researchers also developed an easy technique for accurately measuring fluid temperatures—an important parameter for chemical reactions.

A third project spawned a method for concentrating and separating an ionic (charged) substance in solution within microchannels. The technique concentrates the substance as much as 10,000-fold or more, making it easier to detect in ultrasmall quantities (nanoliters—a billionth of a liter—or less).

Finally, NIST staff designed a novel system to overcome the difficult problem of slow mixing in microfluidics devices. The mixer consists of a T-shaped microchannel imprinted in plastic that is modified with a laser to create a series of slanted wells. The wells speed the mixing of two streams entering the passage.

Media Contact:
Michael E. Newman,  (301) 975-3025Up


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NIST Keeps Users from Getting Burned by Bad Pepper Sprays

Pepper spray, which irritates the eyes, skin and airways, can temporarily disable an attacker without the need for physical force or weaponry. For this reason, police officers increasingly use pepper sprays in the line of duty. However, the last thing they need to find out in a dangerous situation is that their spray doesn’t work.

Under the direction of the Office of Law Enforcement Standards (OLES) at the National Institute of Standards and Technology (NIST), researchers at the University of Utah Center for Human Toxicology are evaluating the amount of oleoresin capsicum (OC, the active ingredient oil extracted from the cayenne pepper plant) in pepper sprays and then assessing just how well they live up to claims of effectiveness.

An analysis of 10 commercial sprays revealed wide variations in OC content. The spray with the strongest OC concentration had about 40 times the amount in the weakest spray.

OLES also is looking at dose response relationships (what levels of response are evoked by different levels of OC) and evaluating the specific effects of pepper sprays on the skin.

In the future, NIST plans to use the data from this project to make recommendations about standardizing the labeling of pepper sprays so that consumers—especially those in law enforcement—will know exactly what they are purchasing.

NIST’s work in this area has been funded by the National Institute of Justice, the research arm of the U.S. Department of Justice.

Media Contact:
Philip Bulman,  (301) 975-5661



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Consumer Information

New NIST Booklet Tells How to Short Circuit Surges

You might think that lightning strikes “in the blink of an eye,” but a typical voltage surge in your house as a result of lightning happens much faster. Although the surge happens quickly, its effects—such as computers and other appliances going haywire—can leave sensitive electrical devices with permanent damage.

The National Institute of Standards and Technology (NIST) has produced a new booklet titled Surges Happen! to inform the public about how to protect their home appliances from this threat.

The booklet—created by NIST’s Electronics and Electrical Engineering Laboratory—explains how and why electrical surges take place, and the impact they can have on various appliances. Additionally, it describes the different classes of surge protectors on the market and how they work. While the booklet gives consumers useful information about how to decide which kinds of surge protectors they need (if any), it is an objective guide that does not endorse any particular product or manufacturer.

Consumers may obtain free copies of the booklet by faxing a request to (301) 926-1630 or sending an e-mail message to Internet users may download a copy in Adobe Acrobat format from

Media Contact:
Michael E. Newman,  (301) 975-3025Up


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Time & Frequency

Need the Time or Need to Know About Time ... Go to NIST!

If only the World Wide Web had been around in 1970, the musical group Chicago would have never asked the question “Does anyone really know what time it is?” All the band would have needed is to go to the National Institute of Standards and Technology (NIST) Web site at

From the home page of NIST’s Time and Frequency Division, one can access the NIST Internet time service ( and download software for synchronizing computer clocks to Coordinated Universal Time via the Internet. The NIST Internet Time Service now receives 450 million hits per day, a figure that is expected to grow by 8 percent per month.

Many of these requests come from commercial and industrial users who need accurate time signals to synchronize point-of-sale terminals, validate the processing of transactions or control automated metering and billing equipment. In fact, the National Association of Securities Dealers requires that member transactions be time-stamped with a clock whose accuracy is traceable to NIST.

Along with getting accurate time, visitors to the Time and Frequency Web site also may take “A Walk Through Time” at This illustrated description of the evolution of timekeeping recently has been revised and updated. It describes how humanity has developed a multitude of ways to measure and keep track of the passage of time.

The “walk” culminates in today’s atomic clocks, including the NIST-F1, accurate to within one second in nearly 20 million years. Written for a general audience, “A Walk Through Time” includes a bibliography for further exploration of the topic.

Media Contact:
Michael E. Newman,  (301) 975-3025Up


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Tech Trivia

In 1972, NIST evaluated the noise levels of 13 tractor-trailer trucks and a delivery van. The trucks were operated in range of two series of microphones—one set inside the vehicles to register what a driver would hear and the other outside to determine what other drivers and residents along the road would experience. The trucks produced between 75 and 95 decibels, prompting the Occupational Safety and Health Administration to establish guidelines to prevent hearing loss.

An anechoic (sound absorbing) chamber was built at NIST’s Gaithersburg, Md., facility in the 1970s. The room was lined with large fiberglass wedges arranged in a pattern that absorbed more than 99 percent of the sound originating in it. Among the items tested in the chamber were hearing aids, microphones, loudspeakers and hearing protectors used on firing ranges. In 1976, the Julliard String Quartet played inside the chamber to test the acoustical properties of their 17th and 18th century instruments.

In direct contrast to the anechoic chamber, a reverberation chamber in operation at NIST’s Maryland campus during the 1970s reflected about 95 percent of the sound striking its concrete walls. The acoustic absorption of architectural materials and the intensity of sound emitted by machinery were two of the evaluations conducted in the reverberation room.

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Editor: Michael E. Newman

Date created: 6/20/02