Tech Beat - September 28, 2010
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In This Issue...
Editor: Michael Baum |
NIST Strengthens Laboratory Mission Focus with New StructureAfter 20 years with its research components organized largely by scientific disciplines, the National Institute of Standards and Technology (NIST) is realigning its laboratories according to a mission-based structure. Effective on Oct. 1, 2010, the new structure will allow more day-to-day operational decisions to be made by the major laboratory units and will improve interdisciplinary research by making it easier to form research groups with the needed expertise. The change also will provide greater accountability by ensuring that individual laboratories are responsible for all major products and services that meet NIST’s specific mission authorities, from the research to develop them to the delivery of products and services to customers. “The goal of this realignment is to ensure that our laboratory managers have a clear and empowered responsibility to meet NIST’s mission of strengthening U.S. innovation and industrial competitiveness,” says NIST Director Patrick Gallagher. “It’s about optimizing our organizations to deliver both forefront research results and the related services needed by manufacturers and other customers critical to the U.S. economy.” The realignment consists of two main components:
NIST’s realignment plans are supported by the Administration and Congress. An organizational chart and additional details about the realignment are available here. Media Contact: Gail Porter, porter@nist.gov, 301-975-3392
NIST 'Vision Science Facility' Aims for Lighting RevolutionFor more information about the Vision Science Facility, click on this video. cookie disclaimer/privacy policy | download .mp4 | descriptive text for the visually impaired Light-emitting diodes, or LEDs, have become popular with backpackers and cyclists who mount them on headbands for a reliable, hands-free source of illumination. Now, a new lab at the National Institute of Standards and Technology (NIST) is helping to bring these tiny but brilliant devices into your home, to help save both energy costs and the environment. “LEDs can be very energy efficient, and they are a lot smaller and last a lot longer than light bulbs,” says NIST vision scientist Wendy Davis. “They’re what we’ll likely use in the future to light our houses and public places.” It’s a vision of illumination’s future. And to realize it, Davis, along with Yoshi Ohno and a team of physicists, created the NIST Spectrally Tunable Lighting Facility (STLF). Their main goal is to improve the quality of the light that LEDs produce, so that when you turn them on, home feels homey. “Everyone wants light that appears natural and is pleasing to the eye, but with LEDs we’re not consistently there yet,” Davis says. “LEDs offer a lot of advantages over incandescent and fluorescent lighting, but they don’t always emit light that looks ‘right.’” About 12 percent of electricity consumed in the United States powers lights. Using LEDs wherever practical would halve that, but a few problems must be overcome. When a newfangled device goes up against a product as historically omnipresent as the light bulb, the newcomer has to prove it can work better than the incumbent, and that’s where Davis and her colleagues are focusing their effort. The new STLF distinguishes itself from most optical technology labs in that it concentrates on the relationship between physical measurements of light and human perception of light and color. Here, scientists experiment with combining LEDs of different hues to produce an overall light color that pleases the eye. The lab space makes sense even to a nonscientist. One section is decorated with couches, tables, and food-filled plates, just like a living room—but above, hundreds of LEDs cover the ceiling like stars in the sky. Davis can activate varied groups of them like color-coordinated constellations. Adjusting the level of different colors demonstrates the effect lighting has on the appearance of the food and furniture below. Learning from efforts like this is helping the team develop a way to quantify how LEDs affect the colors of objects in ways meaningful to the lighting industry. They are currently developing a measurement tool called the Color Quality Scale to help manufacturers develop LEDs for general lighting. “Because the light emitted by LEDs is different from the light we get from other lighting technologies, the way that we measure color quality doesn’t always work for them. At this point, LED manufacturers don’t have a reliable way to determine the color performance of their products,” Davis says. “If we don’t handle this issue now, it could create big problems for future LED lighting products, because bad color means unhappy consumers. We want to use measurement, which is a NIST specialty, to nip this problem in the bud.” Media Contact: Chad Boutin, boutin@nist.gov, 301-975-4261
New NIST 'Standard Cigarette' Available for Fire-Resistance TestingCigarettes are the most frequent cause of fatalities from residential fires in the United States. So, it might seem surprising to learn that a cigarette that burns stronger than others has been used for decades by manufacturers of home furnishings to test the fire resistance of their products. Making certain that they can continue this life- and property-saving effort is the job of a new standard reference material (SRM) from the National Institute of Standards and Technology (NIST). NIST SRM 1196, “Standard Cigarette for Ignition Resistance Testing,” consists of 10 packs of uniform cigarettes designed to replicate the ignition performance of the “hottest burning” brand produced in the 1970s when NIST studied the fire-starting propensity of commercially sold tobacco products. The standard cigarettes are designed to be placed on a mattress, a piece of upholstered furniture or furniture components to verify if these items have been manufactured to meet mandatory and voluntary federal, state and/or industry guidelines for resistance to ignition by burning cigarettes. The cigarettes were developed by NIST in conjunction with the U.S. Consumer Product Safety Commission (CPSC) to replace the commercial cigarettes that had been used for 30 years of home furnishings testing but are no longer in production. SRM 1196 is distinctly different from another cigarette standard first issued by NIST in 2006. SRM 1082, “Cigarette Ignition Strength Standard,” also consists of 10 packs of specially designed cigarettes, but in this case, the cigarettes have a reduced propensity for igniting household furnishings. Nearly all of the United States and Canada are covered by regulations that require all cigarettes sold to have this safety performance trait (commonly, but incorrectly, referred to as being “fire-safe”). SRM 1082 helps cigarette manufacturers, testing laboratories and regulatory agencies make accurate measurements to determine if commercially sold brands meet the regulations. SRM 1196, on the other hand, will be used to test the fire safety of household furnishings. Standard reference materials are among the most widely distributed and used products from NIST. The agency prepares, analyzes and distributes more than a thousand different materials that are used throughout the world to check the accuracy of instruments and test procedures used in manufacturing, clinical chemistry, environmental monitoring, electronics, criminal forensics and dozens of other fields. For more information on SRM 1196, including purchase data, see www.nist.gov/ts/msd/srm. Media Contact: Michael E. Newman, michael.newman@nist.gov, 301-975-3025
Growing Nanowires Horizontally Yields New Benefit: 'Nano-LEDs'While refining their novel method for making nanoscale wires, chemists at the National Institute of Standards and Technology (NIST) discovered an unexpected bonus—a new way to create nanowires that produce light similar to that from light-emitting diodes (LEDs). These “nano-LEDs” may one day have their light-emission abilities put to work serving miniature devices such as nanogenerators or lab-on-a-chip systems.
Nanowires typically are “grown” by the controlled deposition of molecules—zinc oxide, for example—from a gas onto a base material, a process called chemical vapor deposition (CVD). Most CVD techniques form nanowires that rise vertically from the surface like brush bristles. Because the wire only contacts the substrate at one end, it tends not to share characteristics with the substrate material—a less-than-preferred trait because the exact composition of the nanowire will then be hard to define. Vertical growth also produces a dense forest of nanowires, making it difficult to find and re-position individual wires of superior quality. To remedy these shortcomings, NIST chemists Babak Nikoobakht and Andrew Herzing developed a “surface-directed” method for growing nanowires horizontally across the substrate (see “NIST Demos Industrial-Grade Nanowire Device Fabrication” NIST Tech Beat, Oct. 25, 2007, at http://www.nist.gov/public_affairs/techbeat/tb2007_1025.htm#nanowire). Like many vertical growth CVD methods, the NIST fabrication technique uses gold as a catalyst for crystal formation. The difference is that the gold deposited in the NIST method is heated to 900 degrees Celsius (1,652 degrees Fahrenheit), converting it to a nanoparticle that serves as growth site and medium for the crystallization of zinc oxide molecules. As the zinc oxide nanocrystal grows, it pushes the gold nanoparticle along the surface of the substrate (in this experiment, gallium nitride) to form a nanowire that grows horizontally across the substrate and so exhibits properties strongly influenced by its base material. In recent work published in ACS Nano,* Nikoobakht and Herzing increased the thickness of the gold catalyst nanoparticle from less than 8 nanometers to approximately 20 nanometers. The change resulted in nanowires that grew a secondary structure, a shark-like “dorsal fin” (referred to as a “nanowall”) where the zinc oxide portion is electron-rich and the gallium nitride portion is electron-poor. The interface between these two materials—known as a p-n heterojunction—allows electrons to flow across it when the nanowire-nanowall combination was charged with electricity. In turn, the movement of electrons produced light and led the researchers to dub it a “nano LED.”
Unlike previous techniques for producing heterojunctions, the NIST “surface-directed” fabrication method makes it easy to locate individual heterojunctions on the surface. This feature is especially useful when a large number of heterojunctions must be grouped in an array so that they can be electrically charged as a light-emitting unit. Transmission electron microscope (TEM) examination of the zinc oxide-gallium nitride nanowires and nanowalls revealed few structural defects in the nanowires and very distinct p-n heterojunctions in the nanowalls, both affirmations of the effectiveness of the NIST “surface directed” fabrication method. Nikoobakht and Herzing hope to improve the nano LEDs in future experiments using better geometry and material designs, and then apply them in the development of light sources and detectors useful in photonic devices or lab-on-a-chip platforms. * B. Nikkoobakht and A. Herzing. Formation of planar arrays of one-dimensional p-n heterojunctions using surface-directed growth of nanowires and nanowalls. ACS Nano. Published online Sept. 15, 2010. Media Contact: Michael E. Newman, michael.newman@nist.gov, 301-975-3025
NIST Clock Experiment Demonstrates That Your Head is Older Than Your FeetScientists have long known that time passes faster at higher elevations—a curious aspect of Einstein’s theories of relativity that previously has been measured by comparing clocks on the Earth’s surface and a high-flying rocket. Now, physicists at the National Institute of Standards and Technology (NIST) have measured this effect at a more down-to-earth scale of 33 centimeters, or about 1 foot, demonstrating, for instance, that you age faster when you stand a couple of steps higher on a staircase.
Described in the Sept. 24 issue of Science,* the difference is much too small for humans to perceive directly—adding up to approximately 90 billionths of a second over a 79-year lifetime—but may provide practical applications in geophysics and other fields. The NIST researchers also observed another aspect of relativity—that time passes more slowly when you move faster—at speeds comparable to a car travelling about 20 miles per hour, a more comprehensible scale than previous measurements made using jet aircraft. NIST scientists performed the new “time dilation” experiments by comparing operations of a pair of the world’s best experimental atomic clocks. The nearly identical clocks are each based on the “ticking” of a single aluminum ion as it vibrates between two energy levels over a million billion times per second. One clock keeps time to within 1 second in about 3.7 billion years (see NIST announcement from Feb. 4, 2010, “NIST’s Second ‘Quantum Logic Clock’ Based on Aluminum Ion is Now World’s Most Precise Clock” at http://www.nist.gov/physlab/div847/logicclock_020410.cfm) and the other is close behind in performance. The clocks are precise and stable enough to reveal slight differences that could not be seen until now. The NIST experiments test two predictions of Einstein’s theories of relativity. First, when two clocks are subjected to unequal gravitational forces due to their different elevations above the surface of the Earth, the higher clock—experiencing a smaller gravitational force—runs faster. Second, when an observer is moving, a stationary clock’s tick appears to last longer, so the clock appears to run slow. Scientists refer to this as the “twin paradox,” in which a twin sibling who travels on a fast-moving rocket ship would return home younger than the other twin. In one set of experiments, scientists raised one of the clocks by jacking up the laser table to a height one-third of a meter (about a foot) above the second clock. Sure enough, the higher clock ran at a slightly faster rate than the lower clock, exactly as predicted. The second set of experiments examined the effects of altering the physical motion of the ion in one clock. The ions are almost completely motionless during normal clock operations. NIST scientists tweaked the one ion so that it gyrated back and forth at speeds equivalent to several meters per second. That clock ticked at a slightly slower rate than the second clock, as predicted by relativity. Such comparisons of super-precise clocks eventually may be useful in geodesy, the science of measuring the Earth and its gravitational field, with applications in geophysics and hydrology, and possibly in space-based tests of fundamental physics theories, suggests physicist Till Rosenband, leader of NIST’s aluminum ion clock team. The research was supported in part by the Office of Naval Research. For more details, see the NIST Sept. 23, 2010, announcement, “NIST Pair of Aluminum Atomic Clocks Reveal Einstein’s Relativity at a Personal Scale” at http://www.nist.gov/public_affairs/releases/aluminum-atomic-clock_092310.cfm. * C.W. Chou, D.B. Hume, T. Rosenband and D.J. Wineland. Optical clocks and relativity. Science. Sept. 24, 2010. Media Contact: Laura Ost, laura.ost@nist.gov, 303-497-4880
NIST Residential Fire Study Education Kit Now AvailableResearchers from the National Institute of Standards and Technology (NIST) and the International Association of Fire Fighters have prepared an educational resource for fire chiefs, firefighters, and public officials to summarize and explain the key results of a landmark study on the effect of the size of firefighting crews on the ability of the fire service to protect lives and property in residential fires.
The study, Report on Residential Fireground Field Experiments, was published by NIST last April. The study is the first to quantify the effects of crew sizes and arrival times on the fire service’s lifesaving and firefighting operations for residential fires. Little scientific data on the topic had been previously available. The research demonstrated that four-person firefighting crews were able to complete 22 essential firefighting and rescue tasks in a typical residential structure 30 percent faster than two-person crews and 25 percent faster than three-person crews. (More information on the study is available at http://www.nist.gov/bfrl/fire_research/residential-fire-report_042810.cfm.) “The results from this rigorous scientific study on the most common and deadly fire scenarios in the country—those in single-family residences—provide quantitative data to fire chiefs and public officials responsible for determining safe staffing levels, station locations and appropriate funding for community and firefighter safety,” says NIST’s Jason Averill, one of the study’s principal investigators. The educational toolkit was developed to provide policymakers with a quantitative and qualitative understanding of the research. The toolkit was funded by the Federal Emergency Management Agency’s Assistance to Firefighters (FIRE Act) grant program. The toolkit contains a bound copy of the report, a brochure of the executive summary for use in public meetings, a DVD with side-by-side video comparing the timing of various tasks for different crew sizes, fact sheets on key findings, time-to-task results, and results on the effect of crew size on the time to apply water on a fire, the fire growth rate, and occupant exposure to toxins. A press release describing the study, stakeholder quotes, and public statements by principal investigators are also included in the toolkit. The toolkit may be requested by sending email to shildebrant@iaff.org or jason.averill@nist.gov. The partner organizations contributing to this study— the International Association of Fire Chiefs, the Commission on Fire Accreditation International, and Worcester Polytechnic Institute—also will make the toolkits available. The Report on Residential Fireground Field Experiments, NIST Technical Note 1661, can be downloaded at: (http://www.nist.gov/manuscript-publication-search.cfm?pub_id=904607). Media Contact: Evelyn Brown, evelyn.brown@nist.gov, 301-975-5661
NIST to Award Up to $15 Million to UMD to Support Nanotechnology ResearchThe National Institute of Standards and Technology (NIST) Center for Nanoscale Science and Technology (CNST) will award a five-year cooperative agreement totaling $15 million to the University of Maryland (UMD), College Park, Md., to develop and implement a Postdoctoral Researcher and Visiting Fellow Measurement Science and Engineering Program. This program will advance the CNST’s mission to support the development of nanotechnology by providing as many as 100 researchers with one- to two-year appointments at the CNST. Visiting researchers supported by the cooperative agreement will aid in the development of measurement and fabrication methods, standards and technology in a wide range of areas including future electronics; nanofabrication and nanomanufacturing; energy transport, storage, and conversion; and bionanotechnology. In addition to providing new research opportunities for U.S. industrial, university, and government scientists, the funding will provide training for the next generation of nanotechnologists by providing recent Ph.D. recipients postdoctoral research opportunities to work under the mentorship of CNST project leaders and have access to a state-of-the-art nanofabrication facility, the CNST NanoFab. Under the terms of the cooperative agreement, UMD will identify candidates for the available research projects based on cooperatively developed criteria. The positions are open to all qualified applicants. For more information and to apply, visit the Maryland Nanocenter Web site, http://www.nanocenter.umd.edu/cnst.php. Media Contact: Mark Esser, mark.esser@nist.gov, 301-975-8735
Metric Week Begins 10/10/10!Every day is a metric day at the National Institute of Standards and Technology (NIST). But that won’t stop the agency from celebrating Metric Week, held annually the week of Oct. 10—the tenth day of the tenth month.
This year marks the 34th annual celebration of Metric Week. Begun by the National Council of Teachers of Mathematics on May 10, 1976, approximately one year after the Metric Conversion Act of 1975, Metric Week serves as an opportunity for teachers, students and the public to learn about the metric system, also known as the international system of units, or SI for short, and promote its use. The U.S. government has adopted SI, long the standard measurement system of science and engineering, as the preferred system of weights and measures for commerce and industry. Based on units of ten, SI is very easy to learn, and many Americans know it better than they think. Many products, from bottled drinks to medicines, are already sold and conversed about in terms of their metric measures. "SI knowledge, skills and abilities are essential for students as they pursue Science, Technology, Engineering and Mathematics (STEM) careers," says Elizabeth Gentry, a metric coordinator at NIST. "Developing proficiency in metric measurements will prepare U.S. students to work with cutting edge technology and develop innovative consumer products of the future." This year, representatives from the NIST Metric Program will be celebrating Metric Week with more than 4,000 students and teachers at the Science and Technology Education Partnership (STEP) conference in Riverside, Calif. Teachers and students who are interested in learning more about SI may download a variety of educational materials from NIST:
More information about Metric Week can be found at these sites:
Media Contact: Mark Esser, mark.esser@nist.gov, 301-975-8735
NIST Names 15 to New Smart Grid Advisory CommitteeThe National Institute of Standards and Technology (NIST) has named 15 leaders from a cross section of U.S. industry, academia and trade and professional organizations to serve on its newly formed Smart Grid Advisory Committee, which convenes its first meeting on Sept. 29, 2010. The new committee will advise NIST Director Pat Gallagher on the direction of NIST’s Smart Grid-related programs and activities. Under the Energy Independence and Security Act of 2007, NIST leads a nationwide effort to expedite development of consensus interoperability standards that enable two-way flows of energy and information on the Smart Grid. It also conducts research on Smart Grid topics including cyber security and advanced performance-monitoring devices known as synchrophasors and energy management systems for buildings. (For more information, go to: http://www.nist.gov/smartgrid/index.cfm.) Dan Sheflin, chief technology officer at Honeywell Automation and Control Systems, will chair the committee. David Owens, executive vice president of business operations at the Edison Electric Institute, will serve as vice chair. Other new advisory committee members are: Jon Arnold, Managing Director, Worldwide Power & Utilities Industry, Microsoft Corporation; William O. Ball, Executive Vice President and Chief Transmission Officer, Southern Company; Lynne Ellyn, Senior Vice President and Chief Information Officer, DTE Energy; Evan R. Gaddis, President and Chief Executive Officer, National Electrical Manufacturers Association (NEMA); Lawrence E. Jones, Director, Strategy and Special Projects Worldwide, ALSTOM Grid; Suedeen G. Kelly, Partner, Patton Boggs, LLP; Susan M. Miller, President and Chief Executive Officer, Alliance for Telecommunications Industry Solutions (ATIS); Terry Mohn, Founder and Chief Strategy Officer, General MicroGrids, Inc.; Kevin F. Nolan, Vice President of Technology, GE Appliances; Simon Pontin, Vice President for Development, Itron Oconee Manufacturing Facility; William H. Sanders, Director, Information Trust Institute and Donald Biggar Willett Professor of Engineering, University of Illinois at Urbana-Champaign; Thomas J. Tobin, Vice President - R&D, S&C Electric Company; and David Vieau, Chief Executive Officer and President, A123 Systems. Media Contact: Chad Boutin, boutin@nist.gov, 301-975-4261
DuPont Scientist Joins NIST Advisory GroupPatrick Gallagher, director of the National Institute of Standards and Technology (NIST), has named Uma Chowdhry of DuPont to serve on the Visiting Committee on Advanced Technology (VCAT), the agency’s primary private-sector policy advisory group. Chowdhry—who will serve a three-year term starting on October 1, 2010—brings the body’s number to 14. Chowdhry is Chief Science and Technology Officer Emeritus at DuPont, a position she assumed in September 2010 after announcing her plans to retire at the end of this year. She was senior vice president and chief science and technology officer (CSTO) at DuPont from 2006-2010. Chowdhry joined DuPont in 1977 as a research scientist, subsequently took on various research and management roles, and in December, 2004, she assumed responsibility for the company’s core research programs. In June 2006, she was appointed to the CSTO position, in which she has been responsible for the company’s market-driven science and technology-based innovations. In 1996, Chowdhry was elected as a member of National Academy of Engineering. She received a B.S. in physics from the Indian Institute of Science, Mumbai University, an M.S. in engineering science from the California Institute of Technology, and a Ph.D. in materials science from the Massachusetts Institute of Technology. The VCAT was established by Congress in 1988 to review and make recommendations on NIST’s policies, organization, budget and programs. The VCAT chair is Vinton Cerf, vice president and chief Internet evangelist for Google. VCAT’s vice chair is Alan Taub, vice president for global research and development at General Motors. Media Contact: Ben Stein, ben.stein@nist.gov, 301-975-3097 |
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