Media
Contact:
Michael
Baum, (301) 975-2763
Physics
Idaho
Educator Learns On the Job About Environmental Monitoring
Linda
Selvig, an earth science teacher at Centennial High School in Meridian,
Idahos Joint School District No. 2, is now working at the
National Institute of Standards and Technology (NIST) under the
auspices of the Albert Einstein Distinguished Educator Fellowship
Program. The program offers elementary and secondary science and
mathematics teachers year-long fellowships to serve on Capitol Hill
and in federal agencies. It is administered by the U.S. Department
of Energy and the Triangle Coalition for Science and Technology
Education.
Selvig,
a resident of Boise, Idaho, and a past president of the National
Earth Science Teachers Association, has a strong interest in issues
involving radioactivity and the environment. Her classes over the
years have included studies on how the environment can become contaminated
with radioactivity and the potential paths by which that contamination
might reach the public.
During her year at NIST, Selvig will work with the NIST Radiochemistry
Intercomparison Program (NRIP). The NRIP is responsible for making
precise measurements of low-level radioactivity in a variety of
samples (water, soil, sediment, air filter, synthetic feces and
synthetic urine) and then having university, federal, national,
interest group and contract laboratories assess their measurement
capabilities using the NIST values.
Selvig
will learn how to prepare environmental test samples (primarily
water) and take measurements; conduct statistical evaluations of
the measurement data; and report on her findings. She also plans
to tie in her interest in geology by working on the Radionuclide
Speciation Project, where she will investigate the uptake of radioactive
materials in the minerals found in soils and sediments.
Information
about the Einstein Fellowships is available at www.triangle-coalition.org/ein.htm.
Media
Contact:
Michael
E. Newman, (301) 975-3025
Economics
Study Finds NIST
Gas Standards Yield Substantial Benefits
Accurate,
real-time monitoring of polluting gases emitted by electric utilities,
automobiles and other sources depends heavily on equipment calibration
standards made by or traceable to the National Institute of Standards
and Technology (NIST). A new study now available from NIST, The
Economic Impact of the Gas-Mixture NIST-Traceable Reference Materials
Program (NIST Planning Report 02-4), found that the gas-mixture
NIST-Traceable Reference Materials (NTRM) programan innovative
mechanism for meeting a high demand for standardsreturns between
$21 and $27 in benefits for every dollar spent, with substantial benefits
extending into the future.
The
NTRM program was created in the early 1990s by NIST, the U.S. Environmental
Protection Agency (EPA), and specialty gas companies to increase the
availability of NIST-certified reference materials needed to monitor
compliance with environmental regulations. Most EPA regulations for
stationary source, mobile source and ambient air monitoring require
that measurements be traceable to NIST. Under the program, gas companies
manufacture standards according to NISTs technical specifications
and submit these mixtures to NIST for certification. (NIST also produces
a smaller number of its own gas-mixture Standard Reference Materials,
the benefits of which were not evaluated in the study.)
In
addition to greatly increasing the supply of gas-mixture standards,
the NTRM program, after an initial start-up investment by NIST, minimizes
on-going costs to taxpayers because it is now supported by industry
fees. According to the study, benefits of the program include reduced
measurement uncertainty, helping users of the reference materials
to avoid some operations and maintenance costs and reducing credit
expenditures in emissions trading (an innovative approach to environmental
regulation that is generally believed to reduce total pollution-abatement
costs). The program enables NIST to meet the needs of these impacted
industries, while freeing up its resources to solve other critical
standards issues.
Copies
of NIST Planning Report 02-4 are accessible at www.nist.gov/director/prog-ofc/report02-4.pdf,
or in printed format by sending a request to denise.herbert@nist.gov.
Media
Contact:
Michael
E. Nemwan, (301) 975-3025
Fire Research
NIST
Gets the Drop on Fire Quenchers
The
behavior of tiny droplets of new liquid fire suppressants may play
a big role in fire-fighting effectiveness. The new suppressants are
proposed to replace halon suppressants now being phased out because
they cause damage to stratospheric ozone.
The effectiveness
of a suppressant depends on many factors. Do the droplets evaporate
quickly or cling to a hot surface? Do they spread, shrink, splash
or levitate? Liquid droplet interactions with surfaces have been studied
for more than 100 years, but the complicated fluid mechanics process
is still not well understood. Moreover, few studies have addressed
what happens to water droplets containing fire-suppressing additives.
National Institute
of Standards and Technology (NIST) researchers are studying the collision
dynamics of single droplets, about 2.7 millimeter (0.1 inch) in diameter,
as they strike a heated stainless steel surface. In one set of experiments,
the behavior of pure water was compared to that of a solution with
salt-containing additives (30 percent sodium acetate trihydrate).
The researchers recorded what happened to the droplets at different
impact energies and at different surface temperatures using a high-speed
digital camera.
Among the findingsfor
both water and additive-containing dropletsthe disk-shaped liquid
film formed on the surface after impact grew in diameter at higher
impact velocity, possibly providing increased surface cooling. The
presence of the additive influenced the collision dynamics greatly
at low impact energy, but less so as the velocity increased. This
suggests that for high-velocity impact, knowing the evolution of liquid
film diameter for water impact may be sufficient to determine the
amount of surface cooling. These findings are important in fire suppression
because droplets impinging on surfaces from sprinklers and pressure
nozzles are expected to have relatively higher impact energies.
For more information,
contact Samuel Manzello, (301) 975-6891, samuel.manzello@nist.gov.
Media Contact:
Jan
Kosko, (301) 975-2767