June 22, 2006

	In This Issue:
	Rooftop PV Data for Better Energy Prediction Models
	Soft Materials Buckle Up for Measurement
	Improved Rating for Residential Fuel Cells
	Noise Measurement May Boost Cell Phone Performance
	U.S., Singapore Act to Simplify Telecom Trade
	Quick Links
	Draft Guide Will Help Make WLANs More Secure
	Seventy-Six Apply for Nation’s Top Honor for Excellence
	NIST’s FISMA Team Receives AFFIRM Leadership Award

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Rooftop PV Data for Better Energy Prediction Models

NIST’s new Roof Photovoltaic Test Facility duplicates real-life conditions to monitor photovoltaic (PV) systems blended into concrete tile, slate and asphalt shingle roofs. Data from PV embedded systems and other framed PV roof modules systems will be used to validate or improve energy prediction models. Credit: NIST Click for hi-resolution image

New generations of photovoltaic (PV) roofing products utilize designs that allow them to be integral parts of the roof, providing both electricity and shelter from the elements. But how effective would they be on your roof? This month the National Institute of Standards and Technology (NIST) began a 15-month research project to help resolve such basic costs concerns.

At its new Roof Photovoltaic Test Facility, NIST is monitoring the electrical performance and thermal performance of seven different residential systems designed for sloped roofs and two commercial building units designed for flat, industrial roofs. The data will be used to evaluate and improve computer algorithms for software simulation programs that predict the installed energy production of photovoltaic roof installations.

The test photovoltaic systems are blended into concrete tile, slate and asphalt shingle roofs for residential applications and in raised, unframed modules for commercial applications. Each of the nine photovoltaic systems fall within the three general categories of photovoltaic cell technology—single crystalline, polycrystalline and amorphous silicon—with each unit representing different manufacturing processes, materials and design features.

Current, voltage and power output are sampled four times a minute for each test specimen. Ambient temperature, wind speed and the temperature of the test specimens also are measured at numerous locations because the operating temperature of photovoltaic modules affects the conversion efficiency of the units. Finally, the researchers are taking solar radiation measurements at the various planes of the installed roofing projects. Comparative analysis of the solar radiation data will allow NIST researchers to determine the accuracy of solar radiation models that take the horizontal radiation  measurements, normally available at airports, and compute the quantity of solar radiation on surfaces at various tile angles.

The results will be published in the open literature. Some intermediate results may be published prior to the end of the 15-month study. Ultimately, consumers could have access to a new generation of simulation models developed or validated with NIST data that will be useful in any given geographic location, building orientation and with any photovoltaic cell technology.

For more information, go to www.bfrl.nist.gov/863/bipv/roof.htm.

Media Contact:
John Blair, john.blair@nist.gov, (301) 975-4261

 

Soft Materials Buckle Up for Measurement

NIST researchers developed a new high-speed method for measuring the stiffness of soft-polymer materials like those used in contact lenses. The test material is covered with a sensor film, and the combination is compressed until it buckles. The resulting pattern of ridges is the key to determining stiffness, an important material property. Credit: NIST Click for hi-resolution image

Buckling under pressure can be a good thing, say materials scientists at the National Institute of Standards and Technology (NIST). Writing in the June 13 issue of Macromolecules,* they report a new method to evaluate the mechanical properties of soft polymers and gels, such as those used in contact lenses and as tissue-engineering scaffolds. For such applications, stiffness is an indicator for key material performance qualities, such as comfort and durability, and it is important to controlling cell adhesion.

The new method uses “sensor films” with known properties to report the stiffness (or “modulus”) of the soft substrates to which they are attached. Compressing the sample causes the sensor film to buckle, resulting in patterns of repeating ridge-like features, akin to corrugated cardboard. The ridge spacing is related to the modulus ratio between the film and the soft substrate. Since the mechanical properties of the sensor film was known, the researchers could calculate the stiffness of the soft material underneath.

In the journal article, the team focuses on results achieved with model soft specimens, such as silicone polymer, and more challenging “hydrogel” specimens (networks of polymers swollen with water). In each case, the researchers tested “gradient” specimens that changed in their mechanical properties across the lengths of a sample. With the sensor film, they could track and measure changes in stiffness in the underlying materials.

This capability makes it possible to “map” spatial variations in rigidity in complex materials and devices. Accordingly, the new method may be a powerful tool to test for flaws or weak regions in soft materials products, the researchers suggest.

Another key aspect of the technique is its speed. The NIST team is working with industrial partners to harness this method as a high-throughput measurement tool for rapidly testing large numbers of soft polymer products. For more information on this aspect of the research, see the NIST Combinatorial Methods Center Web site (www.nist.gov/combi).

* E.A. Wilder, S. Guo, S. Lin-Gibson, M.J. Fasolka, and C.M. Stafford. Measuring the modulus of soft polymer networks via a buckling-based metrology. Macromolecules. 2006, 39, 4138-4143.

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

 

Improved Rating for Residential Fuel Cells

A new performance rating system for residential fuel cells developed at the National Institute of Standards and Technology (NIST) can help prospective buyers assess the economic value of alternative fuel-cell technologies.

Residential fuel cells now being developed combine hydrogen from natural gas or propane with oxygen from the air to produce electricity. Homeowners might be able to meet all of their energy needs with a residential fuel cell and, in some cases, even sell excess energy to a utility. Currently, PTC 50, an ASME standard, is used to measure fuel cell system performance, but it does not take into account either seasonal changes in heating and cooling requirements, or a residence’s quickly changing demands for electricity.

To bridge the gap between the PTC 50 standard and the information that consumers will need to make economic decisions on installing a fuel cell, NIST researchers have published proposed test and rating methods* that will help consumers assess the economic feasibility of four different types of residential fuel cells under different climate conditions in six different geographic locations. The rating will provide the annual electrical energy produced, fuel consumed, thermal energy for domestic water heating and space heating delivered, and water used by the residential fuel cell system.

The four fuel cell types studied include systems that operate independent of the power grid with all generated power used by the residence itself; systems connected to the grid, in which electrical power output remains constant and excess electricity is sold to the utility; systems for thermal space and domestic water heating similarly connected to the grid to supplement the fuel cell power when needed; and similar but smaller systems used primarily for water heating.

The NIST test methodology and performance rating procedure uses building energy simulation results for three days, one each for winter, spring/fall, and summer for a prototypical house located in a representative city within six Department of Energy (DOE) designated climate zones, including Jacksonville, Fla.; Charleston, S.C.; Memphis, Tenn.; Pittsburgh, Pa.; Minneapolis, Minn.; and Astoria, Ore.

The NIST researchers expect to present their test methodology and performance rating procedures to standards organizations this summer. Several manufacturers have provided input on the rating methodology.

*M.W. Davis, M.W. Ellis and B.P. Dougherty. Proposed test methodology and performance rating standard for residential fuel cell systems, NISTIR 7131, June, 2006. Go to www.bfrl.nist.gov/863/heat_transfer_group/pubs/NIST_IR_7131.pdf (.pdf; download Acrobat Reader).

Media Contact:
John Blair, john.blair@nist.gov, (301) 975-4261

 

Noise Measurement May Boost Cell Phone Performance

Researchers at the National Institute of Standards and Technology (NIST) and industry collaborators have developed improved methods for accurately measuring very faint thermal “noise”—caused by random motion of electrons—in electronic circuits. The technique may help improve the signal range, data rate and battery life of cell phones and other wireless communications devices.

Low background noise typically translates to better performance in electronics, such as longer ranges and clearer signals or higher information-carrying capacity. However, noise too low to measure means that circuit designers cannot tune the system for optimal performance. The NIST research focuses on CMOS (complementary metal oxide semiconductor) transistors, which are inexpensive and widely used in integrated circuits for wireless devices. Noise levels for CMOS transistors have, until now, been too low to measure accurately in much of their signal frequency range (1 – 10 gigahertz), and as a result CMOS circuits may be poorly matched to wireless transmission systems, resulting in significant signal loss.

In a collaboration with IBM Semiconductor Research and Development Center (Essex Junction, Vt.) and RF Micro Devices (Scotts Valley, Calif.), NIST has developed and demonstrated the capability to reliably measure the noise in CMOS devices before they are cut from silicon wafers and packaged. This is believed to be the first method for on-wafer noise measurements directly linked to national standards for thermal noise power. The new measurement methods were described June 12* at the IEEE Radio Frequency Integrated Circuits Symposium in San Francisco.

The team also demonstrated the use of “reverse” noise measurements—focusing on noise emitted from the input of the transistor when incoming signals are reflected and scattered—as a tool for checking overall noise parameters. This method can improve precision, particularly of the optimal impedance properties needed in transistors to minimize noise, the team found. Reverse noise measurements also may help improve modeling of CMOS transistors.

*J. Randa, T. McKay, S.L. Sweeney, D.K. Walker, L. Wagner, D.R. Greenberg, J. Tao, and G.A. Rezvani. 2006. Reverse noise measurement and use in device characterization. Presented June 12 at the IEEE Radio Frequency Integrated Circuits Symposium, San Francisco, Calif.

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

 

U.S., Singapore Act to Simplify Telecom Trade

On June 2, new, streamlined regulatory approval procedures came into effect in the United States and Singapore, allowing U.S. makers of telecommunication equipment to certify their products at home and ship directly to the $1.3 billion Asian market, and eliminating the need for often-duplicative testing.

The delay-ending, cost-saving simplification is the latest bilateral step in carrying out a 1998 trade agreement among members of APEC, the Asia-Pacific Economic Cooperation. The National Institute of Standards and Technology (NIST) designated four U.S. organizations as “certification bodies,” and they now have been recognized by the Singapore government as qualified to determine whether shipments of telecommunications products—including wireless equipment—comply with that country’s required standards.

In a parallel action, the Federal Communications Commission (FCC) has recognized a certification body designated by the Infocomm Development Authority of Singapore. This permits Singapore telecommunication exports to be tested and certified as conforming to FCC regulations before shipment to the United States. The FCC is the U.S. regulator of interstate and international communications. Two-way trade of telecommunication products between the two nations totaled about $1.1 billion in 2005.

The joint action nearly completes the second phase of the 1998 APEC Mutual Recognition Arrangement on Telecommunication Equipment, intended to reduce technical barriers to markets. Since 2001, under the first phase, manufacturers could furnish test results from approved U.S. laboratories as evidence of compliance, but Singapore officials continued to perform the final evaluation and certification of products. Before then, procedures for certifying U.S. telecommunications exports were performed entirely by Singapore organizations.

The four Singapore-approved certification bodies include the Bay Area Compliance Laboratory Corp. (Sunnyvale, Calif.); Underwriters Laboratories, Inc. (San Jose, Calif.); CKC Certification Services (Mariposa, Calif.) and Compliance Certification Services (Morgan Hill, Calif.)

After Canada, Singapore is only the second APEC member with which the United States has progressed to full implementation of the MRA. The first phase has been implemented with Australia, Canada, Chinese Taipei (Taiwan), Hong Kong, Korea and Singapore.

U.S. certification bodies are evaluated by the NIST-recognized accreditation services of the American National Standards Institute (ANSI). After an audit and review, in 2005, NIST recognized ANSI to be the accreditor of U.S. “certification bodies” for evaluating telecommunications equipment for compliance with Singapore requirements. Further information on the Singapore-approved laboratories and certification bodies, and the MRA can be found at http://ts.nist.gov/ts/htdocs/210/gsig/mra.htm.

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

Quick Links

Draft Guide Will Help Make WLANs More Secure

The National Institute of Standards and Technology is requesting comments on a new draft guide that is intended to help organizations make wireless local area networks (WLAN) more secure. The draft document, Guide to IEEE 802.11i: Robust Security Networks, explains the security features of the Institute of Electrical and Electronics Engineers’ 802.11i standard and provides specific recommendations to ensure the security of the WLAN operating environment. The previous IEEE 802.11 security method, Wired Equivalent Privacy (WEP), has several well-documented security deficiencies. IEEE 802.11i introduces a range of new security features that are designed to overcome the shortcomings of WEP. The document complements, but does not replace, NIST Special Publication 800-48, Wireless Network Security: 802.11, Bluetooth and Handheld Devices.
 
Special Publication 800-97, Guide to IEEE 802.11i: Robust Security Networks is available at http://csrc.nist.gov/publications/drafts.html#sp800-97. Send comments by July 7, 2006, to 800-97comment@nist.gov with "Comments SP800-97/802.11i" in the subject line.

 

Seventy-Six Apply for Nation’s Top Honor for Excellence

Seventy-six organizations have sent the National Institute of Standards and Technology (NIST) their applications for the 2006 Malcolm Baldrige National Quality Award, the nation’s Presidential award for excellence. In addition to the 76 regular applicants, an additional 10 non-profit organizations applied to a pilot application program this year in preparation for 2007 when non-profit organizations will be eligible to apply for the award. While no awards will be presented to non-profits during the pilot phase, a private-sector team of examiners will review the applications and, like the other 2006 applicants, they will receive feedback on strengths and opportunities for improvement. The other applicants include three manufacturers, four service companies, eight small businesses, 16 education organizations, and 45 health care organizations. Over the next six months, teams of specially trained examiners will evaluate these 86 organizations. The 2006 Baldrige award recipients are expected to be announced in November. For more information on the Baldrige award program, see http://baldrige.nist.gov/.

NIST’s FISMA Team Receives AFFIRM Leadership Award

The Association for Federal Information Resources Management (AFFIRM) recently awarded a team of NIST employees the Leadership in Service to the Government IT Community award for its outstanding achievements in developing a suite of security standards and guidelines in support of the Federal Information Security Management Act  (FISMA). Team members include Curt Barker, Joan Hash, Peggy Himes, Arnold Johnson, Stu Katzke, Ron Ross, Ray Snouffer, Marianne Swanson and Pat Toth. For more information on AFFIRM, see www.affirm.org; for information on FISMA, see http://csrc.nist.gov/sec-cert.

 

 

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Editor: Michael Baum

Date created: 6/21/06
Date updated: 6/221/06
Contact: inquiries@nist.gov