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Tech Beat - April 3, 2013

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Editor: Michael Baum
Date created: April 3, 2013
Date Modified: April 3, 2013 
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Don’t Call It Vaporware: Scientists Use Cloud of Atoms as Optical Memory Device

Talk about storing data in the cloud. Scientists at the Joint Quantum Institute (JQI) of the National Institute of Standards and Technology (NIST) and the University of Maryland have taken this to a whole new level by demonstrating* that they can store visual images within quite an ethereal memory device—a thin vapor of rubidium atoms. The effort may prove helpful in creating memory for quantum computers.

This brief animation (click link to launch mp4) by the NIST/JQI team shows the NIST logo they stored within a vapor of rubidium atoms and three different portions of it that they were able to extract at will. Animation combines three actual images from the vapor extracted at different times.

Their work builds on an approach developed at the Australian National University, where scientists showed that a rubidium vapor could be manipulated in interesting ways using magnetic fields and lasers. The vapor is contained in a small tube and magnetized, and a laser pulse made up of multiple light frequencies is fired through the tube. The energy level of each rubidium atom changes depending on which frequency strikes it, and these changes within the vapor become a sort of fingerprint of the pulse's characteristics. If the field's orientation is flipped, a second pulse fired through the vapor takes on the exact characteristics of the first pulse—in essence, a readout of the fingerprint.

"With our paper, we've taken this same idea and applied it to storing an image—basically moving up from storing a single 'pixel' of light information to about a hundred," says Paul Lett, a physicist with JQI and NIST's Quantum Measurement Division. "By modifying their technique, we have been able to store a simple image in the vapor and extract pieces of it at different times."

It's a dramatic increase in the amount of information that can be stored and manipulated with this approach. But because atoms in a vapor are always in motion, the image can only be stored for about 10 milliseconds, and in any case the modifications the team made to the original technique introduce too much noise into the laser signal to make the improvements practically useful. So, should the term vaporware be applied here after all? Not quite, says Lett—because the whole point of the effort was not to build a device for market, but to learn more about how to create memory for next-generation quantum computers.

"What we've done here is store an image using classical physics. However, the ultimate goal is to store quantum information, which a quantum computer will need," he says. "Measuring what the rubidium atoms do as we manipulate them is teaching us how we might use them as quantum bits and what problems those bits might present. This way, when someone builds a solid-state system for a finished computer, we'll know how to handle them more effectively."

*J.B. Clark, Q. Glorieux and P.D. Lett. Spatially addressable readout and erasure of an image in a gradient echo memory. New Journal of Physics, doi: 10.1088/1367-2630/15/3/035005, 06 March 2013.

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

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Experts Propose Research Priorities for Making Concrete ‘Greener’

The challenge of making concrete greener—reducing its sizable carbon footprint without compromising performance—is just like the world's most ubiquitous manufactured material—hard!

Hungry Horse Dam
Hungry Horse Dam, on Montana’s Flathead River, helped to pave the way for using fly ash in concrete. Completed in 1953, the dam was built with 120,000 metric tons of fly ash. It is one of the largest concrete-arch dams in the nation.
Credit: Bureau of Reclamation
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But, according to a new report* from the National Institute of Standards and Technology (NIST), the potential engineering performance, energy-efficiency and environmental benefits make it a challenge worth tackling.

Many factors determine the overall energy and environmental impact of concrete.  However, reducing the amount of portland cement, which reacts with water to bind all the sand, stone and the other constituents of concrete as it hardens, provides the biggest opportunity.  Depending on the particular concrete formulation that is used, portland cement accounts for approximately one-quarter of the total mass, and it is the product of a very energy-intensive process.

Nearly a kilogram of carbon dioxide, the main greenhouse gas, is produced for each kilogram of concrete that is constructed.  Portland cement manufacturing accounts for more than 5 percent of U.S. industrial carbon-dioxide emissions, according to the report.  In addition, the U.S. cement industry consumes 400 gigajoules of energy annually.  That's equivalent to the energy required to power more than 3 million homes each year.

The output of a workshop of experts drawn from industry, academia, and state and federal government, the report identifies barriers to acceptance and use of concrete in which greater fractions (30 percent or more) of the portland cement have been replaced by fly ash from electrical power plants and other industrial byproduct materials.  The measurement science barriers are identified, along with high-priority topics for research.

Before broad acceptance of green concrete can occur, the report says, "overly-restrictive prescriptive-specifications need to be overcome, and the performance of green concretes must be demonstrated to be either equivalent (to concrete using portland cement) or sufficient for the intended application, which may require performance beyond that of portland cement concrete."

Consensus high-priority research topics identified by the experts include:

  • Developing tools and metrics for quantifying the advantages and disadvantages of using different materials in concrete.
  • Developing and validating computer models that can predict the performance of green concrete mixtures, both during construction and over the long term.
  • Improving test methods for characterizing materials such as fly ash, glasses, and minerals and other portland cement substitutes to determine whether they will perform as required.
  • Developing a more complete understanding of the water-driven chemical interactions that occur as industrial byproduct materials and other components are incorporated into concrete.

The report also highlights the importance of stakeholder education to increase industry awareness and understanding of the performance and capabilities of alternative concrete mixtures.

Meeting the challenges identified at the experts workshop will require new "measurement science" the report says, "for quantifying and ensuring the short-and long-term performance of green concrete."

* K. A. Snyder, D. P. Bentz, J. W. Bullard, C. F. Ferraris, N. Martys and P. E. Stutzman, Measurement Science Needs for the Expanded Use of Green Concrete: Workshop Summary Report {NIST Technical Note 1783]. February 2013.  Available at: http://www.nist.gov/manuscript-publication-search.cfm?pub_id=913076

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

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Smart Grid R&D Opportunities Outlined in Two New NIST Reports

The nation's aging power grid is evolving into a modern, "smart" energy distribution network, and with these changes comes a host of challenges for the research and development community, as outlined in two new reports* issued by the National Institute of Standards and Technology (NIST). The documents provide valuable perspective to power company system planners, industrial and academic researchers, and senior decision makers concerned with development of the smart grid.

report covers
Credit: NIST
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Both reports –Technology, Measurement, and Standards Challenges for the Smart Grid and its companion, Strategic R&D Opportunities for the Smart Grid – identify the most important technical issues in the smart grid arena, and prioritize impediments and R&D areas that must be addressed for successful deployment of the smart grid. The latter publication, especially, should prove useful to a broader audience, according to NIST Engineering Laboratory Director Shyam Sunder.  

"While other high-level documents, such as the 2012 NIST Framework and Roadmap for Smart Grid Interoperability Standards, Release 2.0,** were written for the smart grid technical community, the Strategic R&D Opportunities for the Smart Grid report, in particular, will be understandable by non-technical audiences," Sunder says.  We are using this latter report to reach out to industry and government leaders so they know what the most important challenges to smart grid development are."

The two reports are the product of a workshop held in August 2012 in Boulder, Colorado, for more than 90 leading technical and industry experts in the smart grid community. The workshop was a collaborative effort of NIST and the Renewable and Sustainable Energy Institute (RASEI), a joint institute of the University of Colorado Boulder and the National Renewable Energy Laboratory (NREL). The documents reflect the near-consensus opinions of the attendees, and are intended to be of particular value to industry.

*For copies of both reports, visit http://www.nist.gov/smartgrid/.
**The Framework 2.0 document is available at http://www.nist.gov/smartgrid/upload/NIST_Framework_Release_2-0_corr.pdf

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

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NIST Goes to the End of the Earth for Measurement Science

NIST Boulder researcher Johannes (Hannes) HubmayrNIST Boulder researcher Johannes (Hannes) Hubmayr recently spent several weeks at the South Pole Telescope, where he optimized the performance of a NIST camera delivered to the telescope in 2011. The camera measures signals generated fractions of a second after the Big Bang to help scientists learn about the conditions and evolution of the early universe. The instrument is performing remarkably well. Hubmayr’s tasks included snowmobiling across the Antarctic tundra to set up equipment and climbing on top of the telescope to sweep snow away from the dish.

Take a look: https://www.facebook.com/media/set/?set=a.10151535047340365.1073741825.211075745364&type=1&l=fac06dd746

To learn more about the NIST project that is contributing to South Pole Telescope effort, go to: http://www.nist.gov/pml/div686/devices/sensors.cfm.

Photo Credit: NIST

Media Contact: Laura Ost, laura.ost@nist.gov, 303-497-4880

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