In This Issue: Remembering the Beginning as NIST Starts its 100th Year NIST Helps Building Join Ohio College Faculty Study Shows Quality Pays for Software-Driven Devices ATP Partner Moves DNA in the Right Direction Helping Concrete Go with the Flow Atoms, Check Your Engines! Tech Trivia
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Remembering the Beginning as NIST Starts its 100th Year
It seems that the U.S. government likes to hold birthdays on March 3.
On that date in 1845, Florida became the 45th state of the Union. Four years later, the US Department of the Interior was founded. And on March 3, 1931, "The Star-Spangled Banner" celebrated its first day as the national anthem of the United States.
So, it was appropriate that on March 3, 1901, Congress enacted the law that gave birth to the National Bureau of Standards, the predecessor to the National Institute of Standards and Technology. While the bill defining NBS only took up two pages, the words carried much importance as the United States desperately needed a standards and measurement agency. Or to quote a committee report to the House of Representatives 10 months earlier: "It is therefore the unanimous opinion of your committee that no more essential aid could be given to manufacturing, commerce, the makers of scientific apparatus, the scientific work of the Government, of schools, colleges, and universities than by the establishment of the institution proposed in this bill."
Today, these words adorn the entrance to the NIST headquarters in Gaithersburg, Md., and serve to inspire the staff. During NIST's 100th year of operation, NIST Tech Beat will honor our Centennial year by sharing one story each month from its rich history, recalling a significant event or accomplishment that occurred during that month.
We hope you enjoy the look back!
Michael E. Newman, (301) 975-3025
NIST Helps Building Join Ohio College Faculty
Buildings can talk and even teach. You just have to know how to listen. That's the thesis of Oberlin College's David Orr. According to the professor of environmental studies at the Ohio institution, "curriculum embedded in any building instructs as fully and as effectively as any course taught in it."
The Building and Fire Research Laboratory at the National Institute of Standards and Technology agrees. Working closely with Oberlin's Office of Facilities Planning and Construction as well as with its environmental studies program, BFRL has begun monitoring ventilation and indoor air quality in Oberlin's new Adam Joseph Lewis Center for Environmental Studies. The testing, which may be conducted until this fall, is part of a program for developing building design methods that achieve good indoor air quality. NIST is taking automated measurements of building ventilation rates and indoor pollutant levels in order to verify the accuracy of the measurement systems and facilitate their use in other buildings. Data collected also will determine how well the Lewis Center's special design features achieve desired air quality levels.
Orr expects the results to contribute to an interactive learning environment at the center, which houses classes in environmental design, environment and society, and environmental education. The 1,421 square-meter (13,500 square-foot) campus building is considered one of the most advanced examples of ecological architecture in the United States and is a recipient of two architectural awards.
John Blair , (301) 975-4261
Study Shows Quality Pays for Software-Driven Devices
Companies that sell software-based products could save a great deal of money simply by following well-known software quality practices, according to a recent study conducted by the National Institute of Standards and Technology.
NIST obtained data related to failures in medical devices, ranging from heart monitors to ventilators. Approximately 6 percent-342-of these problems were due to software. The study analyzed these software-related failures to identify their causes. While none resulted in death or injury, all triggered costly recalls.
NIST computer scientists concluded that, in many cases, the manufacturers could have prevented system failures through improved testing and other quality assurance techniques. In some cases, failure might have been avoided if the software programmers had been familiar with the medical devices themselves, and not just with the associated software.
While the NIST study focused on medical devices, its authors believe failures with similar origins occur in other industries as well.
NIST chose the medical device industry simply because a great deal of public information was available. Computer scientists at the agency's Information Technology Laboratory hope to conduct similar studies that can help a broad range of industries improve software quality.
Philip Bulman , (301) 975-5661
ATP Partner Moves DNA in the Right Direction
Researchers at CuraGen Corp. (New Haven, Conn.) have built what are believed to be the world's smallest working pumps. With individual components only a micrometer or less wide, the tiny pumps are engineered like integrated circuits on silicon wafers in order to move fragments of DNA from one place to another.
Called a "Brownian ratchet device," the CuraGen pump has no moving parts. Instead, it has pairs of interlaced microelectrodes that resemble an electronic fish ladder (the device that helps salmon swim upstream over dams). When electricity is applied, the fields create a string of potential "wells" that trap DNA fragments. When the fields are off, the DNA fragments begin to diffuse due to Brownian motion, the normal jostling of molecules. Pulsing the electric fields on and off results in the molecules gradually being "pumped" from one end of the device to the other. Experimental devices built by CuraGen have transported DNA fragments across the face of a microfabricated chip.
Developed with support from the Advanced Technology Program of the National Institute of Standards and Technology, the tiny pumps are potential components in DNA analysis chips-miniaturized devices that combine the functions of an entire DNA laboratory on a chip similar to a computer microchip. Along with moving DNA across chips, the CuraGen researchers believe that the micropumps also may be useful in the important analytic task of separating DNA fragments by size, since the smaller pieces tend to go through the pump faster.
Michael Baum , (301) 975-2763
Helping Concrete Go with the Flow
As the most commonly used building material comprising a $50 billion industry, concrete is big business. But for something so ubiquitous, building researchers still have a lot to learn about how to optimize the performance of concrete for specific types of jobs. For example, fresh concrete should flow smoothly for easy placement, without sacrificing strength and durability when hardened. With funding and cooperation from the private sector, National Institute of Standards and Technology researchers are studying factors affecting the flow of concrete.
The basic method for gauging concrete flow has remained essentially unchanged for a century. A standard cone-shaped mold is filled with concrete and then the mold is removed. As the concrete spreads under its own weight, its "slump" is measured.
To help develop better instruments for such tests, NIST researchers have begun simulating how concrete flows using computer models that take into account the ratio of water to cement, the amount and sizes of rocks and sand grains, and the presence of chemicals like "superplasticizers" that improve flow. This information then is used to help explain the flow behavior of different concrete mixtures in the laboratory. NIST researchers hope their results will provide a predictive tool for optimizing concrete mixtures for specific applications.
John Blair, (301) 975-4261
Atoms, Check Your Engines!
For most of us, driving an Indy racer around a track at 330 kilometers (200 miles) per hour would be thrilling, but for physicists at the National Institute of Standards and Technology and the University of Colorado at Boulder, it can't compare to their excitement over driving on an atomic-scale speedway.
The scientists have created a 10-centimeter (3.9-inch) long curved track that steers rubidium atoms in an effort to achieve the difficult task of precisely manipulating large numbers of neutral atoms (those carrying no electrical charge). The track consists of two parallel copper "wires" 0.1-millimeter (0.004-inch) thick and spaced a tenth of a millimeter apart, laid down on a rigid glass plate. The track's left-right-left curves keep the atoms from deviating more than 2 millimeters (0.08 of an inch) from a straight line over the abbreviated course.
When equal electric currents are passed through the wires, a magnetic field is generated around each one that cancels to zero in between the wires. Rubidium atoms, which are previously chilled to about 42 millionths of a Kelvin above absolute zero (minus 273.15 degrees Celsius), are injected into the track at a rate of 2 million per second and a speed of 10 meters (34 feet) per second. Attracted toward the lowest magnetic field, they are guided along the track without hitting the sides.
Potential uses for such guided atoms include exquisitely sensitive atomic measurements that may one day be used to develop ultraprecise navigational devices.
Collier Smith (Boulder), (303) 497-3198
Following the September 1925 crash of the 207-meter (680-foot) long Navy dirigible ZR-1 (the Shenandoah), structural specimens from the wreckage were sent to NIST for analysis. An alloy, duralumin, was found to have become corroded and brittle with time. NIST also determined that a layer of aluminum would correct the problem; however, the remaining two US airships did not survive long enough to prove the coating's success.
NIST's organics plastics section was only six years old when the United States entered World War II in 1941, but it already was considered the ultimate authority on testing of plastic products. Among the military items sent to NIST for evaluation were helmet liners, resinous coatings for steel hardware, bayonet handles, binocular housings, bugles, canteens, compass dials, raincoats, goggles, insect screening, shaving brushes and aircraft housings.
Because the impartiality of the December 1969 draft lottery-the first since World War II-was suspect, the Selective Service System asked NIST to devise a unquestionably random method for drawing dates and rankings for its July 1, 1970, draft. Twenty-five calendars and 25 priority permutations were developed. The first selection using the unbiased mixing system was number 259 (September 16) and ranking 139.