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Micrograph
of NIST sensor device used to detect toxic gases. Colors
reflect slight variations in thickness of the sensing film.
The
suspended microhotplate in the center measures about 100
micro-meters square.
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Detecting
Chemical Threats With "Intelligent" Networks
Prototype
microsensor arrays connected to artificial neural networks—computer
models that “learn”—can reliably identify
trace amounts of toxic gases in seconds, well before concentration
levels become lethal, National Institute of Standards and
Technology (NIST) scientists and a guest researcher reported
Sept. 7 at the American Chemical Society annual meeting in
New York City. The system has the potential to provide cost-effective
early warning of chemical warfare agents.
Lab
experiments show that the sensors, which use NIST-patented
microheater
technology, can detect compounds such as sulfur-mustard
gas and nerve agents (tabun and sarin) at levels below 1
part per million. The neural networks, which currently
run on a
personal computer, were added recently to process signals
from the sensor arrays. The networks enable the system
to rapidly
distinguish among the gases and predict their concentration
in the ambient air.
The
microheaters, which are coated with metal oxide films,
can be programmed to cycle through a
range of temperatures.
Airborne chemicals attach to the film in characteristic
ways depending on factors such as temperature and film
material,
causing changes in the flow of electricity through the
microsensors. These changes serve as a “signature” for
identifying both the type and concentration of the gas
in the ambient
air.
The
neural networks were trained to detect subtle variations
in these signatures. An array of four microheater sensors
programmed to quickly sample 20 temperatures produces
as much data as 80 different sensors.
Research
is ongoing to more fully assess the impact of background
interference as a means
of avoiding false positives,
and
to enhance the robustness of the sensors with repeated
use. The
research is funded by NIST and the Defense Threat Reduction
Agency.
Media
Contact:
Laura
Ost, (301) 975-4034
From Movies to Minutia: DVDs Eyed for Archival
Uses
The
U.S. Geological Survey has compiled massive amounts of information
about the Earth, and wants to hold on to it indefinitely. The
National Archives is the official depository for information
about the federal government and wants to protect its digital
treasures.
However,
before these government agencies and others start replacing
their bulky paper files or compiling information
on newer technologies like DVDs, they want to be sure that
the new storage disks have staying power. Computer scientists
at the National Institute of Standards and Technology (NIST)
are launching an effort to develop specifications for “archival
quality” CD and DVD media that agencies could use to
ensure the procurement of sufficiently robust media for their
long- term archiving needs (i.e., 50 years and longer).
NIST
is spearheading the standards effort under the auspices
of the Government Information Preservation Working Group,
a newly formed group that includes representatives from
a
variety
of agencies. The working group shares information and best
practices concerning the use of DVD and related technologies
in the federal government. It will identify the needs of
the federal community in relation to the durability of
storage media and work with industry to develop suitable
archival
grade
specifications.
NIST has
developed test and evaluation facilities that the group will
use. The test facilities have systems
that
can
rapidly assess disk quality by detecting flaws. Also
included are enclosed
chambers that use temperature and humidity changes to
artificially age the media some 20 years in only six weeks.
Media
Contact:
Phil
Bulman, (301)
975-5661
Software Opens the Door For Natural Ventilation
A lack
of rigorous design methods and comprehensive performance data
has slowed U.S. acceptance of natural ventilation technology,
which proponents argue can increase energy efficiency in commercial
buildings as well as improve indoor environmental conditions.
The National Institute of Standards and Technology’s
(NIST) new LoopDA 1.0 software program (for Loop Design and
Analysis) helps fill this critical information gap.
The
LoopDA simulation tool enables building designers and engineers
to
determine the size of natural ventilation openings needed
to provide desired airflow rates. Previously, building designers
have had to make decisions using trial and error or based on
past experiences. Although LoopDA 1.0 provides “first-cut” estimates
rather than final results, it is a great improvement over the
former “more art than science” approach, according
to NIST developer Stuart Dols.
As described at a recent technical
conference in the Netherlands* LoopDA allows users of the computer
program to sketch rooms and
vertical sections of a building, the location of natural ventilation
openings (e.g., windows, doors and ducts) and the paths the
air should take through the building (i.e., pressure loops).
The
program then enables designers to determine the size of the
natural ventilation openings needed to control indoor air quality
and
thermal comfort using an engineering-based design process.
For
more information on LoopDA 1.0 go to www.bfrl.nist.gov/IAQanalysis/LOOPDAdesc.htm.
Media
Contact:
John
Blair,
(301) 975-4261
*Steven
J. Emmerich and W. Stuart Dols "LoopDA—A
Natural Ventilation System Design and Analysis Tool" Proceedings,
Building Simulation 2003 for Better Building Design Conference,
Eindhoven, Netherlands, August 11-14, 2003.
Sensor
Company Flies High With Extension Center Help
Ascension
Technology Corp. (ATC) manufactures high-tech motion tracking
sensors that are helping to train military pilots to fly or
guide doctors through delicate surgery faster and safer. Combined
with 3-D computer graphics, motion trackers are revolutionizing
areas such as animation,
medical imaging and treatment, biomechanics, virtual reality,
and military simulation and training.
ATC
now has 40 employees but that wasn’t always the case.
Founded in 1986, the Milton, Vt., company was struggling with
excessive inventory levels and chronic parts shortages. In June
2002, ATC managers asked for help from the Vermont Manufacturing
Extension Center, an affiliate of the National Institute of Standards
and Technology’s (NIST) Manufacturing Extension Partnership.
VMEC’s Manufacturing Business Advisors drafted a comprehensive
improvement plan for the company including lean manufacturing
initiatives, quality improvements and new inventory control
and replenishment systems.
To date, ATC has cut the time to manufacture and
ship from an average of 36 days to one to two days. As a result,
the company has been able to increase its sales, save money,
and create new jobs.
Media
Contact:
Jan
Kosko, (301) 975-2767
Quick
Links
Advanced
Technology Awards—The National Institute
of Standards and Technology has announced 44 new awards from
its Advanced Technology Program (ATP). The funding will assist
35 companies and nine joint venture partnerships in developing
novel technologies such as brain stimulation technology to reduce
the likelihood of severe epileptic seizures, a computer network
firewall that uses artificial intelligence, a low-cost system
for fabricating electronic devices that are as thin and flexible
as paper, and three-dimensional laser-scanning technology for
faster and more reliable inspection of manufactured parts and
products. The new awards represent a total of up to $104.5 million
in ATP funding and an industry share of up to $74.5 million,
if all projects are carried through to completion. For details
see: www.nist.gov/public_affairs/releases/atpaward09-03.htm.
Building
Investigations—The
National Construction Safety Team (NCST) Advisory Committee,
a panel of 10 building and fire experts who advise the NIST
director on carrying out investigations of building failures
conducted under the authorities of the NCST Act, met for the
second time on Aug. 26-27, 2003. Presentations from that meeting
are now available online that detail the status of NIST’s
ongoing technical investigations of the Sept. 11, 2001, World
Trade Center disaster and the Feb. 20, 2003, Rhode Island nightclub
fire. Go to www.nist.gov/ncst.
Statistics
for Everyone—The NIST/Sematech e-Handbook of
Statistical Methods, which provides modern statistical techniques
and updated case studies for non-experts who want to use statistical
tools, is now available for free on CD-ROM. The CD-ROM complements
the Web-based guide that came out in July 2002. To receive
the CD version send a request to handbook@nist.gov. Remember
to include your postal address (not just an e-mail address).
The e-Handbook Web version may be found at www.nist.gov/stat.handbook.
Network
Security Workshop—A workshop on “Securing & Auditing
Virtual Office Networks” will be held at the National
Institute of Standards and Technology in Gaithersburg, Md.,
on Sept. 24-26. The workshop will explore authentication mechanisms,
enterprise authentication systems, remote access server configuration,
session-level encryption, virtual private networks, and wireless
application security, among other topics. Go to: www.nist.gov/public_affairs/confpage/new030924c.htm.
Tissue
Engineering Symposium—On Oct. 14-15, the National
Institute of Standards and Technology will host a symposium
in Gaithersburg, Md., on “Metrology and Standards for
Cell Signaling: Impact on Tissue Engineering.” The meeting
will identify advancements in measurements, reference materials
and standards that will be required to foster understanding
and control of cell response, as well as enable the development
of new products and approaches for tissue engineering and regenerative
medicine. Go to: www.nist.gov/public_affairs/confpage/new031014.htm.
