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July
30, 2004
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Lab
Experiments Simulate House-to-House Fire Spread
 |
| In
a recent NIST lab test, flames from a simulated house with
combustible exterior walls ignite a similar "house"
six feet away. The numbers in the corner are the time (in
minutes) since the start of the test. |
In
a recent series of full-scale laboratory experiments at the
National Institute of Standards and Technology (NIST), it took
less than five minutes for flames from a simulated house with
combustible exterior walls to ignite a similar “house”
six feet away.
The experiments were conducted July 19 at the NIST Large Fire
Facility. The tests, along with additional tests conducted on
July 27 with more fire-resistant structures, are part of a program
to develop computer models for predicting the spread of fire
in residential communities.
As land prices continue to rise, homes are being built closer
together, many without fire-resistant materials. Building officials
need information about the rate of fire spread in communities
under various house spacing, construction methods and materials,
and weather conditions. Fire departments also have to understand
the time required for fire spread from one house to another
in order to provide adequate response.
Each
experiment conducted at NIST involved two 16-foot structures
clad in vinyl siding that simulated neighboring houses. The
outside walls for each structure included windows. In the July
19 test, typical home furnishings were ignited in one “home”
and the fire spread was recorded, along with heat release rates
and other data. In less than five minutes, flames shattered
the window of the home with the original fire, spread across
the gap, and ignited the exterior of the second structure.
The
July 27 experiment measured the effects of a fire-resistant
barrier in the exterior wall. Flames from the first structure
again reached the second in about four minutes, but this
time, the gypsum barrier
prevented the fire from significantly damaging the simulated
home.
NIST
plans to summarize its results once an analysis of the tests
is complete. Officials considering house separation regulations
and/or the inclusion of fire-resistant barriers on exterior
walls should find such fire spread data useful.
Media
Contact:
John
Blair, (301) 975-4261
Trade
Center Analysis Classifies Victims’ Locations in Towers
As
part of its building and fire investigation of the World Trade
Center (WTC) disaster, the National Institute of Standards
and Technology (NIST) released an interim analysis on July
20 of the location of the 2,749 victims that classifies the
decedents as being at/above or below the floors of impact
and specifies the number of victims found in each of the WTC
towers.
The
analysis categorizes all names provided by the City of New
York as decedents. It also identifies types of first responders
who perished in the disaster. The analysis does not specify
the names or exact locations of decedents.
Knowing
the location of victims assists NIST in better understanding
occupant behavior, evacuation and emergency response operations
after terrorists flew two aircraft into the WTC towers, including
the effects of aircraft impact, ensuing fires and overall
building collapse. It also helps NIST to recommend possible
changes in building design, construction, maintenance and
operation that would improve the safety of occupants and first
responders.
To
identify locations, NIST relied on more than 300 face-to-face
interviews and 800 telephone surveys, various Web sites maintained
by survivors or victims’ families and colleagues, several
media outlets’ reports, and a badge list maintained
by the Port Authority of New York and New Jersey.
For
further information, see: http://www.nist.gov/public_affairs/releases/wtc_victims_location.htm
Media
Contact:
Michael
E. Newman, (301) 975-3025
New
Way of 'Seeing': A 'Neutron Microscope'
 |
The
neutron micrograph at right (b) of a rat's foot uses
false
color to show differences in the number of neutrons penetrating
the sample and hitting a detector. Black areas represent
areas with the fewest neutrons; red areas have the most.
With future improvements in resolution, such microscopes
may provide details about internal structures.
Credit: Adelphi Technology Inc. |
A
prototype microscope that uses neutrons instead of light to
“see” magnified images has been demonstrated at
the National Institute of Standards and Technology (NIST).
Neutron microscopes might eventually offer certain advantages
over optical, X-ray and electron imaging techniques such as
better contrast for biological samples.
Described in the July 19 issue of Applied Physics Letters,*
the imaging process involves hitting a sample with an intense
neutron beam. The neutrons that pass through—whose
pattern reflects the sample’s internal structure—are
directed into a row of 100 dimpled aluminum plates. Each
dimpled plate
acts like a weak focusing lens for neutrons, diverting the
neutrons’ path slightly at each interface. The image
then is projected
onto a detector. Adelphi Technology Inc. of San Carlos, Calif.,
designed and demonstrated the microscope
with the help of NIST scientists, who routinely use multiple
lenses to focus neutron beams for other research.
In
principle, neutrons could provide better image resolution
than visible light because they have shorter wavelengths—as
short as 1 nanometer (nm) compared to 400-700 nm. In this
demonstration at NIST’s Center for Neutron Research,
the microscope produced a resolution of only 0.5 millimeters
and a magnification of about 10. However, Adelphi hopes to
substantially improve image resolution through research to
reduce lens aberrations. The company also hopes to build a
compact, laboratory-scale neutron source.
Moreover,
neutrons offer some unique advantages. Unlike other imaging
methods, neutrons interact strongly with hydrogen, an
important
component of biological samples composed mostly of hydrocarbons
and water. And neutrons easily penetrate samples, thereby
reducing artifacts produced with other techniques requiring
thin
slices,
staining or fixing.
Stanford
University also participated in the research, which was supported
in part by the U.S. Department of Energy.
Media
Contact:
Laura
Ost, (301) 975-4034
*Biological
imaging with a neutron microscope. 2004. J.T. Cremer,
M.A. Piestrup, C.K. Gary, R.H. Pantell and C.J. Glinka.
Applied Physics Letters, 85(3):494-496.
Something’s
Fishy About New NIST Food Standard
A
ccurately measuring exactly
what’s in the food we eat, before we eat it, is a surprisingly
difficult job. The latest effort by the National Institute
of
Standards and Technology (NIST) to make the process both easier
and more accurate is Standard Reference Material (SRM) 1946,
which is a set of five bottles of frozen, homogenized trout
from Lake Superior.
With carefully measured values for about 100 chemical constituents,
the SRM will help food industry and environmental researchers
assure that measurements of both healthful ingredients and contaminants
in fish and similar foods are accurate. Laboratories can validate
their analytical methods and instrument performance by using
them to analyze the SRM and comparing their results to the NIST
values.
This
is the first NIST SRM with certified values for three
of the
more toxic varieties of polychlorinated biphenyls (PCBs). SRM
1946 also has a certified concentration for methylmercury,
a
neurotoxin that tends to accumulate in fish and has been the
subject of federal advisories warning pregnant women to
avoid
eating certain fish. The level in the SRM is near the U.S.
Environmental Protection Agency’s maximum advisable
concentration in freshwater/estuarine fish tissue.
This
also is the first NIST food-matrix SRM with values for omega-3
fatty acids, which have been shown to reduce the risk of cardiovascular
disease. Other components included on the SRM’s certificate
include nutritionally significant mono-, poly- and unsaturated
fatty acids.
The
new SRM will help the food industry comply with nutritional
labeling requirements and help other researchers conduct risk
assessments regarding consumption of commercial fish. More than
40 federal, state, academic, industrial and foreign labs performed
measurements that contributed to the assigned values for the
SRM.
Media
Contact:
Laura
Ost, (301) 975-4034
Tackling
Tough Problems with Reliable Computer Grids
By
connecting hundreds or even thousands of computers together
to work on a single project, computer scientists are more frequently
using a technique called grid computing to do previously
intractable
computations.
Grid computing takes advantage of “down time” when
computers are not using their full processing power to provide
quick answers to problems in fields such as genomics, engineering
design and financial services. While parallel processing typically
involves tying together multiple computers at a single site—all
using one piece of software—a computer grid may be much
more geographically dispersed, composed of many heterogeneous
computers whose availability may change over time.
Computer
scientists at the National Institute of Standards and Technology
(NIST) recently launched a new project to improve understanding
of how computer grids react to volatile conditions. A computer
grid’s strength—the teaming of many computers—also
makes it more vulnerable to failures, viruses, sudden changes
in workload and cyber attacks such as denial of service. NIST
researchers are developing computerized models that will help
establish how vulnerable grid networks are to failure. They
hope to create ways to detect failure quickly and then fix the
problem.
Originally
developed as a way to connect supercomputers working
on extremely
complex problems like climate modeling, grid computing is rapidly
finding commercial applications. Already some investment
companies are using grid
computers to analyze shifts in financial markets in real time.
And pharmaceutical companies are beginning to use them
to overcome
the computational challenges of developing new drugs.
As
commercial applications grow, protecting such networks
and ensuring their reliability will become
more critical. The NIST
researchers hope to complete their models by early next year.
Media
Contact:
Philip
Bulman, (301) 975-5661
Two
National Institute of
Standards and Technology (NIST) Finalists for Service
to America Awards
Two
NIST employees, John Butler of Gaithersburg, Md., and
Deborah
Jin of Boulder, Colo., have been named finalists
for the 2004 Service to America Medals, a national awards
program
that
honors the outstanding accomplishments of America’s
public servants. A total of 28 finalists in seven different
categories were announced recently. Recipients of the awards,
sponsored by the Atlantic Media Company and the Partnership
for Public Service, will be announced this fall.
Butler
was cited for his development of new techniques to improve
DNA identification and for crafting texts and establishing
guidelines used internationally to ensure accurate DNA testing.
He also was recognized for helping identify the remains
of additional victims of the World Trade Center attacks.
Jin
was selected for creating a new form of matter that
could
potentially unlock the key to superconductivity, a phenomenon
with the potential to improve energy efficiency dramatically
across a broad range of applications.
For
further information, see www.govexec.com/pps/.
Comments
Sought on Withdrawal of Old Encryption Standard
The
National Institute of Standards and Technology (NIST) has
determined that a single Data Encryption Standard (DES)
algorithm is no longer sufficient to adequately protect
federal government information. As a result, NIST proposes
to withdraw Federal Information Processing Standard (FIPS)
46-3, which specifies the DES, and two related standards.
A notice in the July 26, 2004, Federal Register
(go to www.gpoaccess.gov/fr/index.html
and enter the docket number, 040602169-4169-01, in the search
engine) seeks comments on this proposal. The notice also
states that federal agencies only be permitted to use the
Triple Data Encryption Algorithm (TDEA) as described in
NIST Special Publication 800-67 (go to http://csrc.nist.gov/publications/nistpubs/800-67/SP800-67.pdf).
TDEA may be used for the protection of federal information;
however, NIST encourages agencies to instead implement the
faster and stronger algorithm specified by FIPS 197 (go
to http://csrc.nist.gov/publications/fips/fips197/fips-197.pdf),
the Advanced Encryption Standard (AES). Comments on the
proposed withdrawal of FIPS 46-3 must be received
on or before Sept. 9, 2004, by the contact listed in the
Federal Register notice.
(Return
to NIST News Page)
Editor:
Gail Porter
Date
created: 07/30/04
Date updated:07/30/04
Contact: inquiries@nist.gov
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