NIST Tech Beat - November 22, 2006

The blow-torch-like flames erupting from the windows of an abandoned, 16-story Chicago apartment building on Nov. 10 were certainly dramatic to watch from the street below. However, for a team of investigators from the Chicago Fire Department (CFD), the Chicago Housing Authority (CHA) and the National Institute of Standards and Technology (NIST), the real excitement was what was happening to the environment inside the building's corridors and stairwells.

The controlled fires on the third, 10th and 15th floors of the Windy City high-rise were part of a real-world laboratory experiment to study the effectiveness in multistory buildings of positive pressure ventilation (PPV). PPV is the use of powerful fans during fires to force smoke and heat from corridors and stairwells so that they stay passable and safe for both escaping occupants and entering emergency responders. In past events—such as the October 2003 blaze in a government building in Chicago where six people died—fire flow into corridors and stairwells often has resulted in tragedy.

Eleven NIST researchers worked with more than 70 CFD and CHA staff for the two weeks prior to the experiment to prepare the building. All 16 floors were equipped with temperature and pressure monitors while the three burn floors also included cameras, heat flux gauges and typical apartment furnishings. The entire setup was connected to the data acquisition center by seven miles of cable.

Once the fires were under way, a variety of ventilation tests were conducted. For example, in one test, a large fan was placed at the front door to force cool air up through the building. In another test, two smaller fans—one on the first floor and one two floors below the fire floor, both forcing air into the stairwell—were used to achieve the same PPV effect. Preliminary results from both scenarios show that PPV significantly reduced the temperature and amount of smoke in the corridors and stairwells outside the burn rooms. In one case, the temperature quickly dropped from 316 degrees Celsius to 16 degrees (600 degrees Fahrenheit to 60).

Three major fan manufacturers and fire departments from New York City; Delaware County, Pa.; Toledo, Ohio; and Ottawa, Canada, also participated in the exercise. Underwriters Laboratories personnel used the setting to assess smoke detector activation in high-rise fires. The experiment was sponsored in part by the U.S. Department of Homeland Security.

Researchers at the National Institute of Standards and Technology (NIST) and the University of Colorado at Boulder (CU) have designed a carbon nanotube knife that, in theory, would work like a tight-wire cheese slicer. In a paper presented this month at the 2006 International Mechanical Engineering Congress and Exposition*, the research team announced a prototype nanoknife that could, in the future, become a tabletop tool of biology, allowing scientists to cut and study cells more precisely than they can today.

For years, biologists have wrestled with conventional diamond or glass knives, which cut frozen cell samples at a large angle, forcing the samples to bend and sometimes later crack. Because carbon nanotubes are extremely strong and slender in diameter, they make ideal materials for thinly cutting precise slivers of cells. In particular, scientists might use the nanoknife to make 3D images of cells and tissues for electron tomography, which requires samples less than 300 nanometers thick.

By manipulating carbon nanotubes inside scanning electron microscopes, 21st-century nanosmiths have begun crafting a suite of research tools, including nanotweezers, nanobearings and nano-oscillators. To design the nanoknife, the NIST and CU scientists welded a carbon nanotube between two electrochemically sharpened tungsten needles. In the resulting prototype, the nanotube stretches between two ends of a tungsten wire loop. The knife resembles a steel wire that cuts a block of cheese.

To begin demonstrating the feasibility of their knife design, the researchers assessed its mechanical strength in force tests, applying increasing pressure to the device. The team found that the welds were the weakest point of the nanoknife, and they are now experimenting with alternative welding techniques. The researchers plan to test the nanoknife on a block of wax later this year (cells typically are immobilized in wax for dissection and microscopy.)

*G. Singh, P. Rice, R.J. McIntosh and R.L. Mahajan. Fabrication and mechanical characterization of carbon nanotube based nanoknives. Proceedings of IMECE2006, 2006 ASME International Mechanical Engineering Congress and Exposition. November 2006.

Three organizations have been named as winners of the 2006 Malcolm Baldrige National Quality Award, the nation's highest Presidential honor for organizational performance excellence. The awards were announced Tuesday by President Bush and Commerce Secretary Carlos Gutierrez.

The 2006 Baldrige Award recipients are MESA Products, Inc., Tulsa, Okla. (small business); Premier, Inc., San Diego, Calif. (service); and North Mississippi Medical Center, Tupelo, Miss. (health care). The three were selected from among 76 applicants. The 2006 Baldrige Award recipients are expected to be presented with their award in a ceremony in Washington, D.C., early next year.

The Baldrige Award was established by Congress in 1987 to enhance the competitiveness and performance of U.S. businesses, and was expanded in 1998 to include education and health care. The award may be presented to five types of organizations: manufacturers, service companies, small businesses, education organizations and health care organizations. In 2007, non-profit organizations, including charities, trade and professional associations, and government agencies, will be eligible to receive a Baldrige Award. Applicants are evaluated by an independent board of examiners in seven areas: leadership; strategic planning; customer and market focus; measurement, analysis and knowledge management; human resource focus; process management; and results.

We're in the end game. It soon may be possible to write international standards documents with decimal points in them. The issue is more than academic—it can affect sales of U.S. exports. The breakthrough comes as a result of dogged determination on the part of the National Institute of Standards and Technology (NIST) and ANSI, the official U.S. representative body in major international standards organizations.

Until recently, the rule at the International Organization for Standardization (ISO—the world's largest developer of standards) and the International Electrotechnical Commission (IEC—the leading global electrical and electronic standards organization) was that all numbers with a decimal part must be written in formal documents with a comma decimal separator, the prevailing fashion in Europe. The constant pi, for example, starts 3,141 592 653.

This had been something of an irritant for the English-speaking world (plus such notable countries as China, India and Japan) where the decimal point is used. Moreover, it could be expensive. Countries that adopted labeling or import documentation regulations based on ISO or IEC standards could block imports from the U.S. on the strength of decimal points in their specifications.

That sort of change doesn't happen overnight. The first step was to secure a resolution by the General Conference on Weights and Measures (CGPM—the reigning international treaty organization dealing with measurement) endorsing the use of the point on the line as a decimal sign. That was in 2003. Then NIST, working through ANSI, went to work to get revisions to the formal ISO and IEC documentation standards and procedures eliminating language that forbade the use of the decimal point. In June, ISO agree to make such revisions subject to IEC agreement and an effective implementation plan. In September, IEC agreed with ISO.

The last remaining hurdle is to develop the implementation plan that makes sure that ISO and IEC staff change their publication style policies to reflect the now-legitimate use of decimal points in English-language documents. We'll make a point of it.

The National Institute of Standards and Technology (NIST) recently announced that an enhanced version of its CONTAM indoor air quality modeling software is now available. CONTAM 2.4b is the latest edition of the popular NIST tool that predicts airflows and contaminant concentrations in multizone building systems. CONTAM is based on a graphic interface that allows the user to draw floor plans on a “sketchpad” and employ “icons” to represent airflow paths, ventilation system components and contaminant sources. CONTAM has been used at NIST to study the indoor air quality impacts of heating, ventilation and air conditioning systems in single-family residential buildings, ventilation in large mechanically ventilated office buildings, and radon entry and transport in large residential, office and school buildings. CONTAM 2.4b may be downloaded free of charge at www.bfrl.nist.gov/IAQanalysis/software/index.htm.

Telemedicine, the electronic exchange of medical information, can have a tremendous impact on the accessibility, quality and cost of healthcare. But the continued advancement and application of telemedicine depends on developing and implementing technical, clinical and administrative standards and guidelines. The National Institute of Standards and Technology, the American Telemedicine Association and the National Library of Medicine are sponsoring a workshop on Dec. 13, 2006, to discuss gaps and future needs for standards and guidelines and technical barriers and to develop an action plan. The workshop will be held at the Natcher Center on the campus of the National Institutes of Health in Bethesda, Md. For more information and to register, see www.nist.gov/public_affairs/confpage/061213.htm.

The American Physical Society (APS) has named National Institute of Standards and Technology (NIST) physicist Kent Irwin as the recipient of the society's 2007 Joseph F. Keithley Award For Advances in Measurement Science. The award recognizes “physicists who have been instrumental in the development of measurement techniques or equipment that have an impact on the physics community by providing better measurements.”

Irwin, project leader for NIST's Quantum Sensors Project, was recognized “for the development of SQUID multiplexers used in large-format arrays of superconducting transition-edge sensors that have impacted such fields as particle physics, astronomy, materials analysis, cosmology, and nuclear physics.” Irwin developed the use of the SQUID (for “superconducting quantum interference device”) in a mode where it functions as a supersensitive detector for electromagnetic signals. More recently his group has developed methods to assemble large arrays of the devices to detect extraordinarily faint electromagnetic signals, with applications ranging from astronomy, and materials research to the detection of nuclear materials for homeland defense applications. The award will be presented at the 2007 meeting of the APS in Denver, Colo.

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Editor: Michael Baum

Date created: November 22, 2006
Date updated: November 22, 2006
Contact: inquiries@nist.gov