NIST Tech Beat - Jan. 17, 2006

A laboratory method developed for making and analyzing cold, concentrated samples of a mysterious “floppy” molecule thought to be abundant only in outer space has revealed new data that help explain the molecule’s properties.

The advance, described in the Jan. 6 issue of Science,* is a step toward overcoming a decades-old challenge in chemistry—explaining reactions that occur within very cold clouds among the stars, and perhaps for developing new chemical processes. The paper combines experiments performed by David Nesbitt and colleagues at JILA, a joint institute of the National Institute of Standards and Technology (NIST) and University of Colorado at Boulder, with theoretical predictions made with Joel Bowman at Emory University in Atlanta, Ga., and Anne McCoy at The Ohio State University in Columbus, Ohio.

Most molecules have a rigid three-dimensional (3D) structure. The subject of the new study is “protonated” methane, which contains one carbon atom and five hydrogen atoms, one of which is ionized, leaving nothing but a proton (a particle with a positive charge). The five protons from the hydrogen atoms scramble for four bonds around the molecule as if playing a continuous game of musical chairs. In the process, the molecule classically vibrates and rotates in a bizarre manner, morphing between several 3D structures with nearly identical energy levels. Chemists have spent decades trying to explain why and how this occurs, a challenge that has seemed insurmountable until recently.

Protonated methane is a so-called “super acid.” This class of molecule has been shown to be more than a million times more powerful than conventional acids and is more effective in inducing reactions that produce solvents and many other important industrial products.

Many theories have been published on the puzzling behavior of this charged molecule (or ion), but experiments must be done to match the ion’s energy characteristics with its physical motions, and such data are difficult to collect and understand. In particular, scientists are interested in how the molecule absorbs different wavelengths of infrared (IR) light, which provides clues about nuclear motion and chemical bonds and structures. The JILA method generates concentrated amounts of the ion at cold enough temperatures to simplify the complex IR spectrum so it can be analyzed.

*X. Huang, A.B. McCoy, J.M. Bowman, L.M. Johnson, C. Savage, F. Dong, and D.J. Nesbitt. 2005. “Quantum deconstruction of the infrared spectrum of CH₅+”. Science. Jan. 6.

Simulation Program Predicts Resistivity in Nanodevices

A s nanoscale circuits continue to shrink, electrical resistivity increases in the wiring and limits the maximum circuit speed. A new simulation program developed by researchers at the National Institute of Standards and Technology (NIST) and George Washington University (GWU) can be used to predict such increases with greater input flexibility and model accuracy than other methods. The software program is expected to help the semiconductor industry design and test devices more efficiently and with greater cost-effectiveness.

On average, an electron can travel only 39 nanometers in pure, bulk copper at room temperature before it is scattered by thermal vibrations of the copper atoms. But, as the dimensions of the wiring shrink, additional scattering by surfaces and grain boundaries within the metal lead to undesirable increases in resistivity. The NIST/GWU computer program, described in a recent paper in Microelectronics Reliability,* enables users to examine how these additional mechanisms alter the resistivity of the thin, narrow metal lines that make up the circuit wiring.

As described in the journal article, NIST researchers used the simulation program to demonstrate that, at critical nanoscale dimensions, electron scattering from surfaces and grain boundaries have effects that are interdependent. This interdependence could not be predicted using methods previously available. The finding has implications for both achievable circuit speed and electrical measurements of the dimensions of thin, narrow lines.

For information about obtaining the software code and a forthcoming NIST technical report on the project, contact Richard Allen at (301) 975-5026 or richard.allen@nist.gov.

* A.E. Yarimbiyik, H.A. Schafft, R.A. Allen, M.E. Zaghloul, D.L. Blackburn. 2005. Modeling and simulation of resistivity of nanometer scale copper. Microelectronics Reliability. Posted online Dec. 19.

Media Contact:
Laura Ost, laura.ost@nist.gov, (301) 975-4034

Helping Small Firms Run Large Supply Chains

Big manufacturing jobs, especially those in the defense industry that involve management of extensive supply chains, often require resources and expertise that many believe are beyond the capacity of small and medium-sized enterprises (SMEs). Recent work by researchers at the National Institute of Standards and Technology (NIST) and colleagues at Pittsburgh’s Doyle Center for Manufacturing Technology, however, demonstrates the capabilities of simulation and visualization technologies for improving SME supply chain expertise.

The proof-of-concept test involved SME management of a 10-enterprise subassembly supply chain for a major aircraft engine component. The Doyle Center collected data for the simulation model often using questionnaires and personal visits to suppliers. NIST and Doyle researchers then adapted a commercial software program to build an accurate visualization and analytical simulation model for the supply chain enterprise.

The finished program allowed a small firm to know what would happen at any given time during the flow of material through the chain. Data inputs enabled it to use supplier production rates, inventory numbers and shipment times for components. The model identified prospective supply chain performance at “normal,” “surge” (twice normal) and “mobilization” (four times normal) production rates. When the program uncovered potential bottlenecks in the supply chain, the team used the program to evaluate potential impacts and to implement solutions to mitigate risks and reduce costs.

NIST presented a detailed description of the project at the 2005 Winter Simulation Conference in December. “Stress Testing a Supply Chain Using Simulation,” the NIST paper by Sanjay Jain and Swee Leong, is available at http://www.informs-sim.org/wsc05papers/203.pdf.

In an increasingly open environment of interconnected computer systems and networks, security is essential to ensure that information remains confidential, is not modified or destroyed and is available when needed. To help federal agencies protect sensitive, but unclassified information, the National Institute of Standards and Technology (NIST) has updated a set of guidelines for selecting and implementing cryptographic methods.

Originally published in 1999, Guideline for Implementing Cryptography in the Federal Government (NIST Special Publication 800-21-1) is intended primarily for federal employees who design computer systems and procure, install and operate security products to meet specific needs. The publication is one of a series of key standards and guidelines produced by NIST’s computer security experts to help federal agencies improve their information technology security and comply with the Federal Information Security Management Act (FISMA) of 2002. FISMA requires all federal agencies to develop, document and implement agency-wide information security programs and to provide security for the information and information systems that support the operations and assets of the agency. The act called upon NIST to develop the standards and guidelines needed for FISMA compliance.

This summer the National Institute of Standards and Technology (NIST) will again provide about 125 full-time undergraduate research fellowships for college students majoring in physics, chemistry, materials science, engineering, mathematics and computer science. Supported by the National Science Foundation, the program provides 12 weeks of paid employment and gives young scientists and engineers an opportunity to work in NIST research laboratories alongside some of the world's leading experts in science and technology. Positions are available in both Gaithersburg, Md., and Boulder, Colo., for the time period, May 22 to Aug. 11, 2006.

Students must be recommended by their departments and applications must be submitted from each college or university as a group by Feb. 15. Students interested in applying should contact the administrative office for their departments as soon as possible for instructions.

In operation since 1993 and known as the Summer Undergraduate Research Fellowship, or SURF, the program offers a unique, hands-on learning experience. Students work with mentors on NIST research projects using cutting-edge technology. Other benefits include regular seminars held on the NIST campuses throughout the summer on a broad array of current science and technology topics and the opportunity to meet peers from across the United States. A video that includes interviews with past SURF student participants is available at www.surf.nist.gov/gallery.htm.

For more information on the SURF program or to obtain a copy of the application, please visit www.surf.nist.gov/surf2.htm (Gaithersburg) or http://surf.boulder.nist.gov (Boulder) or contact Anita Sweigert, NIST, 100 Bureau Drive, Stop 8400, Gaithersburg, Md. 20899-8400.

The National Institute of Standards and Technology (NIST) announced Jan. 10 that John (Jack) R. Hayes Jr. has been appointed director of the National Earthquake Hazards Reduction Program (NEHRP) effective Feb. 5, 2006. NEHRP is the federal government’s program to reduce the risks to life and property from earthquakes. NEHRP consists of four federal agencies: the Federal Emergency Management Agency (FEMA), the National Science Foundation (NSF), the United States Geological Survey (USGS) and NIST. Congress designated NIST as the lead agency for NEHRP in 2004.

As director, Hayes will provide overall program management, coordination and technical leadership for NEHRP; strengthen program effectiveness by facilitating implementation of earthquake risk mitigation measures; and build and maintain effective partnerships with NEHRP program agencies and stakeholders in industry, academia and government.

Hayes joins NIST after serving since 1988 as leader of seismic and structural engineering research at the U.S. Army Engineer Research and Development Center’s (ERDC) Construction Engineering Research Laboratory (CERL) in Champaign, Ill.

The National Institute of Standards and Technology (NIST) announced Jan. 10 that Carol Hockert has been selected as the new chief of the NIST Weights and Measures Division. The division promotes uniformity in U.S. weights and measures laws, regulations, and standards to achieve marketplace equity.

Hockert, who will join NIST on Feb. 20, is currently director of the Minnesota Weights and Measures Division. She replaces Henry Oppermann who retired July 1, 2005. Hockert previously served as a technical expert for NIST’s National Voluntary Laboratory Accreditation Program (NVLAP) and as a vice president of NCSL International (formerly known as the National Conference of Standards Laboratories).

As chief of the Weights and Measures Division, Hockert will work with the National Conference on Weights and Measures (NCWM), and advise its Board of Directors. NCWM is a professional organization of state and local weights and measures officials and representatives of business that works to “advance a healthy business and consumer climate through fair and equitable weights and measures standards.”

Hockert also will oversee division programs that offer training for weights and measures officials and laboratory metrologists, develop test procedures for weighing and measuring devices, provide guidance on weights and measures laws and regulations, provide NIST input to the NCWM, coordinate U.S. input for international standards for legal metrology, and develop and publish NIST reports for weights and measures.

Further information on the NIST Weights and Measures Division can be found at www.nist.gov/owm.