NIST Tech Beat - November 25, 2008

The Commerce Department’s National Institute of Standards and Technology (NIST) and President Bush today announced that three organizations are the recipients of the 2008 Malcolm Baldrige National Quality Award, the nation’s highest Presidential honor for organizational innovation and performance excellence.

The organizations honored include Cargill Corn Milling North America (Wayzata, Minn.) in the manufacturing category, Poudre Valley Health System (Fort Collins, Colo.) in the health care category, and Iredell-Statesville Schools (Statesville, N.C.) in the education category.

“I am pleased to join President Bush in announcing these three outstanding organizations that have been named to receive this year’s Baldrige Award,” said Secretary of Commerce Carlos M. Gutierrez. “Quality, innovation and competitiveness are essential to maintaining America’s global leadership and providing our citizens with world-class products, health care and education. Each of the recipients we honor today serves as a role model embodying the values of excellence, principled leadership and commitment to employees, customers, partners and community.”

The 2008 Baldrige Award recipients were selected from a field of 85 applicants. All of the applicants were evaluated rigorously by an independent board of examiners in seven areas: leadership; strategic planning; customer and market focus; measurement, analysis and knowledge management; workforce focus; process management; and results. The evaluation process for each of the recipients included about 1,000 hours of review and an on-site visit by a team of examiners to clarify questions and verify information in the applications.

The award 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 its inception in 1988, 75 organizations have received Baldrige Awards.

The National Institute of Standards and Technology (NIST) has awarded grants totaling more than $24 million to three universities to provide cost-shared support for the construction of new scientific research facilities. The winning projects were chosen from 93 applicants in a special competition announced last spring.

The special construction grants program provides cost-shared funding for the construction of new buildings or the expansion of existing buildings for the sciences as they relate to the mission of the Department of Commerce and its agencies, including NIST, the National Oceanic and Atmospheric Administration (NOAA) and the National Telecommunications and Information Administration (NTIA).

The National Institute of Standards and Technology (NIST) held a rescue robot exercise in Texas last week in which about three dozen robots were tested by developers and first responders in order to develop a standard suite of performance tests to help evaluate candidate mechanical rescuers. This exercise was sponsored by the Department of Homeland Security’s Science and Technology Directorate to develop performance standards for robots for use in urban search and rescue missions.

Urban search and rescue robots assist first responders by performing such tasks as entering partially collapsed structures to search for living victims or to sniff out poisonous chemicals. NIST is developing robot standards for testing in cooperation with industry and government partners.

“It is challenging to develop the test standards as the robots are still evolving,” explained Elena Messina, acting chief of the Intelligent Systems Division, “because standards are usually set for products already in use. But it is critical for developers to be able to compare results, which is not possible without reproducible test environments. So, we have reproducible rough terrain that everyone can build in their labs, whereas you can’t reproduce a rubble pile. This way, developers in Japan can run tests, and people in Chicago can understand what the robot achieved.”

The event took place at Disaster City, Texas, a test facility run by the Texas Engineering Extension Service (TEEX). The facility offers an airstrip, lakes, train wrecks and rubble piles that can be arranged for many types of challenging tests.

Exercises included testing battery capacity by having robots perform figure eights on an undulating terrain and mobility tests in which robots ran through increasingly challenging exercises beginning with climbing steps and escalating to climbing ramps and then making it up steps with unequal gaps. A new mapping challenge introduced at this event tests how accurate a robot-generated map can be—the robot must traverse a simulated “wooded area” that has uneven terrain and PVC pipes for trees, and create a map using its sensors. Researchers came from across the globe to collect data to feed into their mapping algorithms. NIST researchers developing ultra-high-resolution three-dimensional sensors also participated.

Communications and manipulator tests were performed and discussed at the November exercise will be submitted to ASTM International as a potential rescue robot test standard.

To see the robots in action, three videos can be viewed at the Disaster City TEEX Web site: www.teexblog.blogspot.com/.

Researchers at the National Institute of Standards and Technology (NIST) have demonstrated their ability to measure relatively low levels of stress or strain in regions of a semiconductor device as small as 10 nanometers across. Their recent results* not only will impact the design of future generations of integrated circuits but also lay to rest a long-standing disagreement in results between two different methods for measuring stress in semiconductors.

Mechanical stress and strain in semiconductors and other devices is caused by atoms in the crystal lattice being compressed or stretched out of their preferred positions, a complex—and not always harmful—phenomenon. Stress in the underlying structure of light-emitting diodes and lasers can shift output colors and lower the device’s lifetime. Stress in microelectromechanical systems can lead to fracture and buckling that also truncates their lifespan. On the other hand, stress is deliberately built into state-of-the-art microcircuits because properly applied it can increase the speed of transistors without making any other changes to the design. “Stress engineering has allowed the semiconductor industry to increase the performance of devices well beyond what was expected with the current materials set,” said NIST research physicist Robert Cook, “thus avoiding the significant engineering problems and expense associated with changing materials.”

Both the good and the bad stresses need to be measured, however, if they’re to be controlled by device designers. As the component size of microcircuits has become smaller and smaller, this has become more difficult—particularly since two different and widely used methods of stress measurement have been returning disparate results. One, electron back scattered diffraction (EBSD), deduces underlying stress by observing the patterns of electrons scattered back from the crystal planes. The other, confocal Raman microscopy (CRM), measures minute shifts in the frequency of photons that interact with the atomic bonds in the crystal—shifts that change depending on the amount of stress on the bond. The NIST team used customized, highly sensitive versions of both instruments in a series of comparison measurements to resolve the discrepancies.

The key issue, they found, was depth of penetration of the two techniques. Electron beams sample only the top 20 or 30 nanometers of the material, Cook explained, while the laser-generated photons used in CRM might penetrate as deep as a micrometer or more. The NIST researchers found that by varying the wavelength of the Raman photons and positioning the focus of the microscope they could select the depth of the features measured by the Raman technique—and when the CRM was tuned for the topmost layers of the crystal, the results were in close agreement with EBSD measurements.

The NIST instruments also demonstrate the potential for using the two techniques in combination to make reliable, nanoscale measurements of stress in silicon, which enables device developers to optimize materials and processes. EBSD, although confined to near-surface stress, can make measurements with resolutions as small as 10 nanometers. CRM resolution is about 10 times coarser, but it can return depth profiles of stress.

* M.D. Vaudin, Y.B. Gerbig, S.J. Stranick and R.F. Cook. Comparison of nanoscale measurements of strain and stress using electron back scattered diffraction and confocal Raman microscopy. Applied Physics Letters 93, 193116. (2008)

Facial recognition systems perform some very challenging tasks such as checking an individual’s photo against a database of known or suspected criminals. The task can become nearly impossible when the systems acquire poor facial images—a situation that occurs all too often in real-world environments. Now, researchers at the National Institute of Standards and Technology (NIST) have found that several simple steps can significantly improve the quality of facial images that are acquired at border entry points such as airports and seaports.*

Better yet, the NIST recommendations for improving facial images can be implemented relatively easily with existing facial recognition technology.

Travelers entering the United States have their pictures taken and their fingerprints collected digitally as part of the US-VISIT program implemented by the Department of Homeland Security (DHS). US-VISIT and NIST work together on an ongoing basis to improve processes and technology. A 2007 NIST study of facial images collected at border entry points, however, found that the captured facial images were not as clear and useful for automated recognition as they could be.

In usability and human factors research performed for US-VISIT as part of a large joint effort to improve facial recognition technology, NIST’s Mary Theofanos and her colleagues sought simple ways of obtaining better facial images in often hectic real-world conditions without having to deploy new technology. The NIST researchers first visited and observed a DHS border entry point at Dulles Airport in the Washington, D.C. area to see the facial-image capturing process.

As a result of these observations, the researchers identified and shared with US-VISIT a number of steps to take for acquiring better facial images. For example, the report recommends that operators should adjust camera settings to ensure the subject comes into sharp focus. The report also recommends using a traditional-looking camera in facial-recognition systems so that individuals could clearly recognize the camera and look into it.

Following the Dulles site visit, a study adopted these steps in taking facial images of 300 participants while mimicking the real-world conditions of a border entry point. In these tests, 100 percent of the images fully captured the participant's face; all of the participants faced the camera; and the researchers found additional improvements by using a graphical overlay to the camera display in order to better position the camera.

The researchers believe these steps will improve the performance of facial recognition systems in real-world settings using existing technology. A follow-up study is underway in which the researchers are incorporating the graphical overlay into the workflow of camera operators.

This work was sponsored by the Science and Technology Directorate at the Department of Homeland Security.

The lack of common measurement methods among light-emitting diode (LED) and lighting manufacturers has affected the commercialization of solid-state lighting products. In a recent paper,* researchers at the National Institute of Standards and Technology (NIST) proposed a new, economical method to allow LED and lighting manufacturers to obtain accurate, reproducible, and comparable measurements of LED brightness and color.

The quality of the light that high-power LEDs produce depends on their operating temperature. To speed production, LED manufacturers typically use a high-speed pulsed test to measure the color and brightness of their products. However, because pulsed measurements do not give the LED chip time to warm to its normal operating temperature, the measured light output quality is not the same as would be realized in actual lighting products.

The lighting industry uses a steady-state DC measurement approach similar to that used for traditional incandescents and fluorescents. This method involves turning the light on, letting it warm up, and measuring the characteristics of the light produced. Although time-consuming, DC measurement provides a more realistic test of how the lighting product will perform in a consumer’s living room. The problem was that researchers did not understand how the DC measurement results correlated with the pulse measurement results that LED manufacturers use.

NIST scientists Yuqin Zong and Yoshi Ohno have created a standard high-power LED measurement method that satisfies the needs of both LED and lighting manufacturers. The NIST method leverages the fact that the optical and electrical characteristics of an LED are interrelated and a function of the LED’s junction temperature (the temperature of the semiconductor chip inside the LED, which is normally very difficult to measure).

The researchers’ new method entails mounting the LED on a temperature-controlled heat sink set to the desired LED junction temperature between 10 and 100 °C. After applying a pulse of electricity through the LED and measuring the voltage flowing across the junction, scientists turn on the DC power to the LED and adjust the temperature of the heat sink to ensure the voltage remains constant. When measuring the light output of an LED, this approach allows researchers to achieve a junction temperature similar to that found in a commercial lighting fixture. The measurement results can be reproducible regardless of pulse or DC operation, or type of heat sink.

The new method also allows the measurement of heat flow in and out of the LED, enabling LED and lighting manufacturers to improve the design of the LED and the thermal management system of the associated lighting product. Effective thermal management is important in lighting products because LEDs perform more efficiently and last much longer at lower temperatures.

* Y. Zong and Y. Ohno. New practical method for measurement of high-power LEDs. Proc. CIE Expert Symposium on Advances in Photometry and Colorimetry. CIE x033:2008, 102-106 (2008).

Researchers working at the National Institute of Standards and Technology (NIST) have demonstrated for the first time the existence of a key magnetic—as opposed to electronic—property of specially built semiconductor devices. This discovery raises hopes for even smaller and faster gadgets that could result from magnetic data storage in a semiconductor material, which could then quickly process the data through built-in logic circuits controlled by electric fields.

Magnetic data storage is currently utilized with great success in consumer products such as computer hard drives and MP3 players. But these storage devices are based on metallic materials. These conventional hard drives can only hold data; they have to send the data to a semiconductor-based device to process the data, slowing down performance.

In a new paper,* researchers from NIST, Korea University and the University of Notre Dame have confirmed theorists’ hopes that thin magnetic layers of semiconductor material could exhibit a prized property known as antiferromagnetic coupling—in which one layer spontaneously aligns its magnetic pole in the opposite direction as the next magnetic layer. The discovery of antiferromagnetic coupling in metals was the basis of the 2007 Nobel Prize in Physics, but it is only recently that it has become conceivable for semiconductor materials. Semiconductors with magnetic properties would not only be able to process data, but also store it.

The most widely studied magnetic semiconductor is gallium arsenide (GaAs) with magnetic atoms (manganese) taking the place of some of the gallium atoms. Theorists had predicted that by creating thin films of this material separated by a nonmagnetic material of just the right thickness and electrical properties, one could engineer antiferromagnetic (AF) coupling. With magnetic fields, one could then switch the magnetization of one of the layers back and forth to create “spintronic” logic circuits, ones that operate not only under the usual control of electric fields but also the influence of magnetic fields (manipulating a property known as spin, which could be imagined as tiny internal bar magnets in particles such as electrons).

The team, working at the NIST Center for Neutron Research, studied these multilayer stacks using a technique known as polarized neutron reflectometry. In this technique, a beam of neutrons is bounced off the stacks. Since neutrons are magnetic, and are able to easily penetrate through the entire stack, the reflected neutrons provide information about the magnetic properties of the individual layers. At low temperatures and small magnetic fields, the polarized neutron data unambiguously confirm the existence of an antiparallel magnetic alignment of neighboring layers. When the magnetic field was increased, the neutron data indicated a parallel alignment of all layers. These results demonstrate that AF coupling is achievable in GaMnAs-based multilayers, a seminal property that now opens up a multitude of device possibilities for this novel material. While the phenomenon only occurs at very cold temperatures in the material (about 30 K), the researchers believe these results will help inform theorists who could then better understand how to create room-temperature devices with the same magnetic properties.

* J.-H. Chung, S.J. Chung, S. Lee, B.J. Kirby, J.A. Borchers, Y.J. Cho, X.Liu and J.K. Furdyna, Carrier-mediated antiferromagnetic interlayer exchange coupling in diluted magnetic semiconductor multilayers Ga1-xMnxAs/GaAs:Be. Physical Review Letters, to be published.

The National Institute of Standards and Technology (NIST) last week released its final report on the Sept. 11, 2001, collapse of the 47-story World Trade Center building 7 (WTC 7) in New York City. The final report is strengthened by clarifications and supplemental text suggested by organizations and individuals worldwide in response to the draft WTC 7 report, released for public comment on Aug. 21, but the revisions did not alter the investigation team’s major findings and recommendations, which include identification of fire as the primary cause for the building’s failure.

The extensive three-year scientific and technical building and fire safety investigation found that the fires on multiple floors in WTC 7, which were uncontrolled but otherwise similar to fires experienced in other tall buildings, caused an extraordinary event. Heating of floor beams and girders caused a critical support column to fail, initiating a fire-induced progressive collapse that brought the building down.

In response to comments from the building community, NIST conducted an additional computer analysis. The goal was to see if the loss of WTC 7’s Column 79—the structural component identified as the one whose failure on 9/11 started the progressive collapse—would still have led to a complete loss of the building if fire or damage from the falling debris of the nearby WTC 1 tower were not factors. The investigation team concluded that the column’s failure under any circumstance would have initiated the destructive sequence of events.

With the release of the final WTC 7 report, NIST has completed its federal building and fire safety investigation of the WTC disaster that began in August 2002. A three-year study of the collapses of the WTC towers (WTC 1 and 2) was completed in October 2005. More than 20 changes in the U.S. model building and fire codes have already been adopted based on the findings and recommendations from the investigation.

NIST will now work with various public and private groups toward implementing additional changes to the U.S. model building and fire codes including those based on the 13 recommendations from the WTC 7 report (one new and 12 reiterated from the towers investigation).

A new testing procedure just published by the American Society of Mechanical Engineers (ASME) represents the final step in a decade-long effort led by the National Institute of Standards and Technology (NIST) to unite the United States with the rest of the world in evaluating the performance of coordinate measuring machines (CMMs).

CMMs, which make precision measurements of the dimensions of objects, are critical in such industries as aerospace, automobile and heavy equipment manufacturing to ensure that parts match blueprints, and for performing reverse engineering and managing process control. The United States has been the only major country with its own national standard for CMM performance evaluation because U.S. standards developers were concerned that the current version of international standard, ISO 10360-2, left major error sources unevaluated and contained ambiguities in the interpretation of the performance specifications. For a decade the U.S. team on the International Standards Organization CMM standard committee, led by NIST, worked to revise the international standard to correct these deficiencies and to develop a U.S. version that also added tutorials and optional tests to address concerns specific to the United States.

The new U.S. document has been published by the ASME as B89.4.10360.2, while its ISO counterpart is currently out for final approval by the international standards community. ASME B89.4.10360.2-2008 “Acceptance Test and Reverification Test for Coordinate Measuring Machines (CMMs) Part 2: CMMs Used for Measuring Linear Dimensions” may be obtained from ASME at http://catalog.asme.org/home.cfm?SEARCH=B89.4.10360.2.

The National Earthquake Hazards Reduction Program (NEHRP) has just published a new strategic plan to guide the activities of the four federal agencies that participate in the program for the next five years. NEHRP’s goal is to reduce earthquake losses through better understanding of earthquake generation and propagation processes, improved design and construction techniques for new and existing buildings and lifelines, monitoring and early-warning systems, and assisting states and localities in developing coordinated emergency preparedness plans and public education.

The National Institute of Standards and Technology (NIST) is the lead agency in NEHRP. Other participants include the Federal Emergency Management Agency (FEMA), the National Science Foundation (NSF) and the United States Geological Survey (USGS). These agencies partner with state and local governments, private enterprise, professional organizations and academia.

The NEHRP plan was originally published for comment last spring (see “Comments Requested on Draft Earthquake Hazards Plan,” Tech Beat, April 14, 2008). The final plan lists nine strategic priorities important to understanding earthquake phenomena, developing cost-effective measures to reduce impacts on individuals, society and construction, and improving rapid community recovery from earthquakes. Some of these include fully implementing the Advanced National Seismic System for impact notification, deployment of response, hazard assessments and research; developing cost-effective techniques and tools to design new earthquake-resistant buildings and improve the survivability of existing buildings; creating realistic earthquake scenarios to help communities and businesses better understand and plan for earthquake consequences; and designing earthquake-resilient infrastructure to end vulnerabilities and possible cascading failures in critical, interconnected transportation, ports, energy, water, sewage, communications and industrial production systems. The plan can be found at www.nehrp.gov/pdf/strategic_plan_2008.pdf.

NIST physicist David Wineland will receive the inaugural Herbert Walther Award in recognition of his “seminal contributions to quantum information physics and metrology, and the development of trapped ion techniques for applications to basic quantum phenomena, plasma physics and optical clocks.” The award is made jointly by the Optical Society of America (OSA) and the Deutsche Physikalische Gesellschaft (the German physical society) and will be presented by each society in alternate years. The OSA will present Wineland’s award in June 2009 at a meeting in Germany.

The award is named in honor of Professor Herbert Walther, a founding director of the Max Planck Institute of Quantum Optics and former chair of physics at Ludwig Maximilian’s University, both in Germany, for his innovations in quantum optics and atomic physics as well as leadership in the international scientific community. For more information, see www.osa.org/News/pressroom/release/11.2008/WaltherAward.aspx.

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Editor: Michael Baum

Date created: November 25, 2008
Date updated: November 25, 2008
Contact: inquiries@nist.gov