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Tech Beat - September 14, 2010

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Editor: Michael Baum
Date created: September 27, 2010
Date Modified: September 27, 2010 
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New Wave: Spin Soliton Could Be a Hit in Cell Phone Communication

Researchers at the National Institute of Standards and Technology (NIST) have found theoretical evidence* of a new way to generate the high-frequency waves used in modern communication devices such as cell phones. Their analysis, if supported by experimental evidence, could contribute to a new generation of wireless technology that would be more secure and resistant to interference than conventional devices.

soliton

This animation shows the development of the soliton over the course of about 2.7 nanoseconds. Current begins passing through the channel (center), causing the magnetization to oscillate. These oscillations initially move throughout the layer, but after 1.8 ns the magnetization under the channel inverts to form the soliton (center changes to red) and the oscillations are then localized.

Credit: NIST
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The team’s findings point toward an oscillator that would harness the spin of electrons to generate microwaves—electromagnetic waves in the frequencies used by mobile devices. Electron spin is a fundamental property, in addition to basic electrical charge, that can be used in electronic circuits. The discovery adds another potential effect to the list of spin’s capabilities.

The team’s work—a novel variation on several types of previously proposed experimental oscillators—predicts that a special type of stationary wave called a “soliton” can be created in a layer of a multilayered magnetic sandwich. Solitons are shape-preserving waves that have been seen in a variety of media. (They first were observed in a boat canal in 1834 and now are used in optical fiber communications.) Creating the soliton requires that one of the sandwich layers be magnetized perpendicular to the plane of the sandwiched layers; then an electric current is forced through a small channel in the sandwich. Once the soliton is established, the magnetic orientation oscillates at more than a billion times a second.

“That’s the frequency of microwaves,” says NIST physicist Thomas Silva. “You might use this effect to create an oscillator in cell phones that would use less energy than those in use today. And the military could use them in secure communications as well. In theory, you could change the frequency of these devices quite rapidly, making the signals very hard for enemies to intercept or jam.”

Silva adds that the oscillator is predicted to be very stable—its frequency remaining constant even with variations in current—a distinct practical advantage, as it would reduce unwanted noise in the system. It also appears to create an output signal that would be both steady and strong.

The team’s prediction also has value for fundamental research.

“All we’ve done at this point is the mathematics, but the equations predict these effects will occur in devices that we think we can realize,” Silva says, pointing out that the research was inspired by materials that already exist. “We’d like to start looking for experimental evidence that these localized excitations occur, not least because solitons in other materials are hard to generate. If they occur in these devices as our predictions indicate, we might have found a relatively easy way to explore their properties.”

* M.A. Hoefer, T.J. Silva and M.W. Keller. Theory for a dissipative droplet soliton excited by a spin torque nanocontact. Physical Review B, 82, 054432 (2010), Aug. 30. 2010. DOI: 10.1103/PhysRevB.82.054432

Media Contact: Chad Boutin, boutin@nist.gov, 301-975-4261

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Research Shows Radiometric Dating Still Reliable (Again)

Recent puzzling observations of tiny variations in nuclear decay rates have led some to question the science of using decay rates to determine the relative ages of rocks and organic materials. Scientists from the National Institute of Standards and Technology (NIST), working with researchers from Purdue University, the University of Tennessee, Oak Ridge National Laboratory and Wabash College, tested the hypothesis that solar radiation might affect the rate at which radioactive elements decay and found no detectable effect.

photo of fossil

Radioactive elements transmute into more stable materials by shooting off particles at a steady rate. For instance, half the mass of carbon-14, an unstable isotope of carbon, will decay into nitrogen-14 over a period of 5,730 years. Archaeologists routinely use radiometric dating to determine the age of materials such as ancient campfires and mammoth teeth.

©Zoltan Pataki/courtesy Shutterstock

Atoms of radioactive isotopes are unstable and decay over time by shooting off particles at a fixed rate, transmuting the material into a more stable substance. For instance, half the mass of carbon-14, an unstable isotope of carbon, will decay into nitrogen-14 over a period of 5,730 years. The unswerving regularity of this decay allows scientists to determine the age of extremely old organic materials—such as remains of Paleolithic campfires—with a fair degree of precision. The decay of uranium-238, which has a half-life of nearly 4.5 billion years, enabled geologists to determine the age of the Earth.

Many scientists, including Marie and Pierre Curie, Ernest Rutherford and George de Hevesy, have attempted to influence the rate of radioactive decay by radically changing the pressure, temperature, magnetic field, acceleration, or radiation environment of the source. No experiment to date has detected any change in rates of decay.

Recently, however, researchers at Purdue University observed a small (a fraction of a percent), transitory deviation in radioactive decay at the time of a huge solar flare. Data from laboratories in New York and Germany also have shown similarly tiny deviations over the course of a year. This has led some to suggest that Earth’s distance from the sun, which varies during the year and affects the planet’s exposure to solar neutrinos, might be related to these anomalies.

Researchers from NIST and Purdue tested this by comparing radioactive gold-198 in two shapes, spheres and thin foils, with the same mass and activity. Gold-198 releases neutrinos as it decays. The team reasoned that if neutrinos are affecting the decay rate, the atoms in the spheres should decay more slowly than the atoms in the foil because the neutrinos emitted by the atoms in the spheres would have a greater chance of interacting with their neighboring atoms. The maximum neutrino flux in the sample in their experiments was several times greater than the flux of neutrinos from the sun. The researchers followed the gamma-ray emission rate of each source for several weeks and found no difference between the decay rate of the spheres and the corresponding foils.

According to NIST scientist emeritus Richard Lindstrom, the variations observed in other experiments may have been due to environmental conditions interfering with the instruments themselves.

“There are always more unknowns in your measurements than you can think of,” Lindstrom says.

* R.M. Lindstrom, E. Fischbach, J.B. Buncher, G.L. Greene, J.H. Jenkins, D.E. Krause, J.J. Mattes and A. Yue. Study of the dependence of 198Au half-life on source geometry. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. doi:10.1016/j.nima.2010.06.270

Media Contact: Mark Esser, mark.esser@nist.gov, 301-975-8735

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New GSI Web site Experience Puts Product Standards on the Map

Those looking for the latest product standards-related news, regulatory developments, events and workshops around the world now can turn to the new Global Standards Information (GSI) Web site (http://gsi.nist.gov). Launched on Sept. 1, 2010, the new site includes a variety of interactive tools and will serve as an essential “first stop” for users seeking up-to-date information on international product standards.

“Given the rapid adoption and complexity of new product standards both locally and globally, we realized we needed to create a new way for our customers to find and share information,” says Gordon Gillerman, chief of the National Institute of Standards and Technology (NIST) Standards Services Division. “We created this site with the goal of providing the most up-to-date information in an engaging and easy-to-use format.”

Visitors to the site are greeted by a large, colorful and interactive world map, which enables them to drill down to a specific region or country to find key fast facts and contacts, the latest global standards news and events, in-depth resources, and highlights of proposed regulations that may affect product market access.

A key feature of the GSI Web site is the ability for visitors to register to receive customized email updates for specific regions or on topics of interest to them. In the coming months, the site will offer additional multimedia features and specialized regional and local content.

For more information about the new Web site’s features, contact Pat Harris, (301) 975-8409.

Media Contact: Mark Esser, mark.esser@nist.gov, 301-975-8735

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Puzzling New Physics from Graphene Quartet’s Quantum Harmonies

Using a one-of-a-kind instrument designed and built at the National Institute of Standards and Technology (NIST), an international team of researchers have unveiled a quartet of graphene’s electron states and discovered that electrons in graphene can split up into an unexpected and tantalizing set of energy levels when exposed to extremely low temperatures and extremely high magnetic fields. Published in the Sept. 9th, 2010, issue of Nature,* this new research raises several intriguing questions about the fundamental physics of this exciting material and reveals new effects that may make graphene even more powerful than previously expected for practical applications.

artist's rendition illustrates the electron energy levels in graphene

This artist's rendition illustrates the electron energy levels in graphene as revealed by a unique NIST instrument. Because of graphene's properties, an electron in any given energy level (the wide, purple band) comprises four quantum states (the four rings), called a "quartet." This quartet of levels split into different energies when immersed in a magnetic field. The two smaller bands on the outermost ring represent the further splitting of a graphene electronic state.

Credit: T. Schindler and K. Talbott/NIST
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Graphene is one of the simplest materials—a single-atom-thick sheet of carbon atoms arranged in a honeycomb-like lattice—yet it has many remarkable and surprisingly complex properties. Measuring and understanding how electrons carry current through the sheet is important to realizing its technological promise in wide-ranging applications, including high-speed electronics and sensors. For example, the electrons in graphene act as if they have no mass and are almost 100 times more mobile than in silicon. Moreover, the speed with which electrons move through graphene is not related to their energy, unlike materials such as silicon where more voltage must be applied to increase their speed, which creates heat that is detrimental to most applications.

NIST recently constructed the world’s most powerful and stable scanning-probe microscope, with an unprecedented combination of low temperature (as low as 10 millikelvin, or 10 thousandths of a degree above absolute zero), ultra-high vacuum and high magnetic field. In the first measurements made with this instrument, the team has used its power to resolve the finest differences in the electron energies in graphene, atom-by-atom.

Because of the geometry and electromagnetic properties of graphene’s structure, an electron in any given energy level populates four possible sublevels, called a “quartet.” Theorists have predicted that this quartet of levels would split into different energies when immersed in a magnetic field, but until recently there had not been an instrument sensitive enough to resolve these differences. The experiment, according to the research team, revealed unexpected complex quantum behavior of the electrons in a high magnetic field at extremely low temperatures. The electrons apparently interact strongly with one another in ways that affect their energy levels.

One possible explanation for this behavior, the team says, is that the electrons have formed a “condensate” in which they cease moving independently of one another and act as a single coordinated unit. If so, the work could point the way to the creation of smaller, very-low-heat-producing, highly energy efficient electronic devices based upon graphene.

The research team includes collaborators from NIST, the University of Maryland, Seoul National University, the Georgia Institute of Technology and the University of Texas at Austin. For more details, see NIST's Sept. 8th, 2010, news announcement, “NIST Researchers Hear Puzzling New Physics from Graphene Quartet’s Quantum Harmonies” online at www.nist.gov/cnst/graphene_quartet.cfm.

* Y.J. Song, A.F. Otte, Y. Kuk, Y.Hu, D.B. Torrance, P.N. First, W.A. de Heer, H. Min, S. Adam, M.D. Stiles, A.H. MacDonald and J.A. Stroscio. High resolution tunneling spectroscopy of a graphene quartet. Nature. Sept. 9, 2010.

Media Contact: Mark Esser, mark.esser@nist.gov, 301-975-8735

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NIST Data: Enabling the Technical-Basis for Evacuation Planning of High-Rise Buildings

Researchers at the National Institute of Standards and Technology (NIST) are stepping up the pace for designing safer building evacuations by releasing large, numerical data sets that track the movement of people on stairs during high-rise building evacuation drills. The data sets will ensure that architects, engineers, emergency planners and others involved in building design have a strong technical basis for safer, more cost-effective building evacuations.

“While stairs have been used in buildings for ages, there is little scientific understanding of how people use them,” explained NIST researcher Erica Kuligowski. “For example, we know little of how the width of the stair affects the flow rate, whether people grow fatigued as they descend from tall buildings, or how people merge into a crowded stairwell.”

illustration of a person going downstairs

©andrzej80/courtesy Shutterstock

Working with the Public Buildings Service at the U.S. General Services Administration (GSA), NIST researchers made video recordings of evacuation drills in stairwells at nine buildings ranging in height from six to 62 stories tall. The first data sets being released (available at www.nist.gov/bfrl/fire_research/building-occupant-evacuation.cfm) come from four of the buildings and include movement information on more than 3,000 people. Other evacuation data will be posted on the NIST Web site as it becomes available.

NIST researchers have already reported analysis of some of the underlying data at human behavior and fire conferences and will report more in the future. These reports, like most egress studies, provide their findings, but without the raw data.

“The raw data NIST is providing will help to ensure that GSA and others have the scientific basis necessary to provide safe and cost-effective building evacuation,” said Kuligowski.

GSA provided research funding support for the project. NIST researchers hope that making the data available will help to develop new evacuation models, provide assessment of the accuracy of existing egress models, and ensure that building owners and managers have a sound basis for evacuation planning.

Before each drill, researchers positioned video cameras to record an overhead view of the evacuation that would not interfere with occupants evacuating the building. Images were pixilated to protect the identity of the building occupants. In most experiments, cameras captured a view of that floor’s main landing, the door opening into the stairwell and two to three steps on both sides of the main landing.

Using the videos, researchers developed spreadsheets of data on people's movements. For each occupant, researchers noted the time the individual first entered the video and captured data about their movements until they left the building. Additionally, researchers noted other factors that might influence speed, including the number of people in close proximity, whether they were helping another person, and whether they were carrying something. They also noted if the occupant handrail was used and how much space the person occupied in the stairwell.

“These data will allow researchers to calculate movement speeds of people traveling down stairs as a function of stair width, occupant density, total distance traveled, and merging characteristics at stair landings that could influence updating building safety requirements,” Kuligowski said.

This knowledge also will assist in building design and perhaps influence standards on how occupants evacuate during emergencies, she added.

Media Contact: Evelyn Brown, evelyn.brown@nist.gov, 301-975-5661

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16 Organizations Chosen to Receive Site Visits for 2010 Baldrige Award

The Panel of Judges for the Malcolm Baldrige National Quality Award, the nation’s highest recognition for organizational performance excellence, has selected 16 organizations for the final review stage for the 2010 award. Starting next month, teams of business, education, health care and nonprofit experts will make site visits to two organizations in the manufacturing category, four in small business, one in service, one in education, seven in health care and one in nonprofit. This is the first year since the addition of the newest category, nonprofit (in 2007), in which organizations from all six categories will receive site visits.

The Baldrige Program received 83 applications in 2010 (three manufacturers, two service companies, seven small businesses, 10 educational organizations, 54 health care organizations and seven nonprofit/governmental organizations). The applicants were evaluated rigorously by an independent board of examiners in seven areas: leadership; strategic planning; customer focus; measurement, analysis and knowledge management; workforce focus; process management; and results. Examiners will provide 300 to 1,000 hours of review to each applicant receiving a site visit, and all applicants will receive a detailed report on the organization’s strengths and opportunities for improvement.

The 2010 Baldrige Award recipients are expected to be announced in late November, 2010.

Named after Malcolm Baldrige, the 26th Secretary of Commerce, the Baldrige Award was established by Congress in 1987. The award—managed by the National Institute of Standards and Technology (NIST) in collaboration with the private sector—promotes excellence in organizational performance, recognizes the achievements and results of U.S. organizations, and publicizes successful performance strategies. The award is not given for specific products or services. Since 1988, 80 organizations have received Baldrige Awards.

Thousands of organizations use the Baldrige Criteria for Performance Excellence to guide their enterprises, improve performance and get sustainable results. This proven improvement and innovation framework offers organizations an integrated approach to key management areas.

For more information on the Baldrige National Quality Program, see www.nist.gov/baldrige.

Media Contact: Michael E. Newman, michael.newman@nist.gov, 301-975-3025

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NIST to Host Third Annual Maryland Stem Cell Research Symposium

On Wednesday, Sept. 22, 2010, the National Institute of Standards and Technology (NIST) will host the Third Annual Maryland Stem Cell Research Symposium at NIST’s main campus in Gaithersburg, Md. Sponsored by the Maryland Stem Cell Research Commission in partnership with the National Institutes of Health and NIST, the symposium, “Facilitating State and National Collaboration to Advance Groundbreaking Life Science Research,” will feature research supported by the Maryland Stem Cell Research Fund (MSCRF) and federal agencies in the state of Maryland.

Registration for the full-day event is open for one more day at www.nist.gov/cstl/maryland_stem_cell_research_symposium.cfm. The cost to attend is $100 per person. Advanced media credentialing is required for reporters wishing to cover the event. For more information or to request a media pass, please contact Kathleen Shaffer at (410) 902-5053, kshaffer@mghus.com.

The agenda includes presentations and poster sessions by researchers who have been awarded MSCRF grants over the past four years and federally funded researchers. Four sessions will cover the topics of hematopoietic and mesenchymal stem cells, induced pluripotent stem cells, stem cells and neurodegenerative diseases, and clinical trials with stem cells.

For a full list of presentations, speakers and a detailed agenda, visit www.mscrf.org.

Media Contact: Mark Esser, mark.esser@nist.gov, 301-975-8734

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NIST Finalizes Initial Set of Smart Grid Cyber Security Guidelines

The National Institute of Standards and Technology (NIST) has issued its first Guidelines for Smart Grid Cyber Security, which includes high-level security requirements, a framework for assessing risks, an evaluation of privacy issues at personal residences, and additional information for businesses and organizations to use as they craft strategies to protect the modernizing power grid from attacks, malicious code, cascading errors and other threats.

The product of two formal public reviews and the focus of numerous workshops and teleconferences over the past 17 months, the three-volume set of guidelines is intended to facilitate organization-specific Smart Grid cyber security strategies focused on prevention, detection, response and recovery.

The new report was prepared by the Cyber Security Working Group (CSWG) of the Smart Grid Interoperability Panel, a public-private partnership launched by NIST with American Recovery and Reinvestment Act funding from the Department of Energy. The guidelines are the second major output of NIST-coordinated efforts to identify and develop standards needed to convert the nation’s aging electric grid into an advanced, digital infrastructure with two-way capabilities for communicating information, controlling equipment and distributing energy.

“These advisory guidelines are a starting point for the sustained national effort that will be required to build a safe, secure and reliable Smart Grid,” said George Arnold, NIST’s national coordinator for Smart Grid interoperability. “They provide a technical foundation for utilities, hardware and software manufacturers, energy management service providers, and others to build upon. Each organization’s implementation of cyber security requirements should evolve as technology advances and new threats to grid security arise.”

The report advocates a layered—or “defense in depth”—approach to security. Because cyber security threats are diverse and evolving, the report recommends implementing multiple levels of security.

The guidelines identify 137 interfaces—points of data exchange or other types of interactions within or between different Smart Grid systems and subsystems. These are assigned to one or more of 22 categories on the basis of shared or similar functional and security characteristics. In all, the report details 189 high-level security requirements applicable either to the entire Smart Grid or to particular parts of the grid and associated interface categories.

All three volumes of Guidelines for Smart Grid Cyber Security (NISTIR 7628) can be downloaded at: http://csrc.nist.gov/publications/PubsNISTIRs.html#NIST-IR-7628.

Under the Energy Independence and Security Act of 2007, Congress assigned NIST to coordinate development of a framework that would enable a Smart Grid that is safe, secure and interoperable from end to end. In its January 2010 report, NIST described a high-level conceptual reference model for the Smart Grid, identified existing or emerging standards relevant to the ongoing development of an interoperable Smart Grid, and spelled out several high-priority standards-related gaps and issues that NIST and its partners are now addressing.

For more details, see NIST's Sept. 2nd, 2010, news report, “NIST Finalizes Initial Set of Smart Grid Cyber Security Guidelines” on line at www.nist.gov/public_affairs/releases/nist-finalizes-initial-set-of-smart-grid-cyber-security-guidelines.cfm.

Media Contact: Mark Bello, mark.bello@nist.gov, 301-975-3776

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