laser light as tweezers and a scalpel, scientists from the National
Institute of Standards and Technology (NIST) have demonstrated
the use of artificial cells as nanovials for ultrasmall volume
chemistry. The approach may be useful for faster, cheaper identification
of new pharmaceuticals and for studying cellular-level processes.
The researchers will report their results in the Sept. 30 edition
Fluorescent images show two liposomes, one
filled with dye and
another filled with calcium ions.
Bottom: After fusing, the contents of the
liposomes mix and react producing an increase in
artificial cells, called liposomes, are tiny spherical
containers that self-assemble from natural fats (phospholipids
and cholesterol). Measuring micrometers in diameter, the
membranes are currently used in cosmetics and for drug delivery.
NIST team developed an improved method for using liposomes
tiny test tubes for mixing chemicals with volumes measured
in trillionths of liters. Their experimental setup allows
trapping of two liposomes without deforming or stressing their
membranes, a problem with some other techniques. They
of infrared lasers ("optical tweezers") to bring
two liposomes into contact and a single ultra-violet laser
(the "optical scalpel") to fuse the two cells together.
Once fused, the contents of the two cells mix and react. One
liposome in each pair contained fluorescent dye, and the other
contained calcium ions. After the cells merged, fluorescence
increased as a result of the reaction between the dye and the
optical scalpel achieves cleaner fusion and less leakage of
contents than the typical technique using pulsed electric fields.
The liposomes fully enclose their reactant chemicals, minimizing
evaporation. Consequently, the technique also may be useful
for quantitative studies of chemical reactions involving samples
in the quadrillionths of liters.
Contact: Laura Ost, (301) 975-4034
Rating the Performance of Residential Fuel Cells
fuel cells sound almost too good to be true. Take a hydrocarbon
fuel such as natural gas, use a catalyst to extract hydrogen
from it, react the hydrogen with air and, presto, you have
a home power plant!
As the hydrogen
and the oxygen in the air combine, they produce electricity.
The primary “waste products” of the whole process
are water and heat. But that’s not all! The "waste"
heat can be captured to provide space or water heating for the
fuel cell systems can produce about five kilowatts of power
or 120 kilowatt-hours of energy a day—more than enough
to operate the average household. But a lack of performance
data on how well fuel cells work under different conditions
is one of several factors slowing marketplace acceptance of
the new technology.
at the National Institute of Standards and Technology (NIST)
have just launched an effort to supply the needed information.
They are studying how changing electrical and heating demands,
outside temperatures, humidity and power systems affect the
efficiency of fuel cells made by different manufacturers.
will submit its draft fuel cell test procedures and rating
methodology to a standards committee composed of industry,
independent standard organizations, government and academic
With consensus procedures in place, fuel cell manufacturers
should be able to evaluate and improve the electrical and
efficiency and output of their products. Ultimately, consumers
will be able to use NIST-developed performance ratings to understand
the financial costs and benefits of fuel cells operated in
specific geographic and climate conditions, at different
times of the
year, and for different purposes such as heating or electricity
Blair, (301) 975-426
Dual Microscopes Illuminate Electronic Switching
of semiconductor devices are like downhill skiers—they thrive
on speed. And achieving speed in the semiconductor business is
all about the stuff you start with. While silicon is still the
mainstay of the industry, circuit designers also would like to
put materials like gallium nitride and silicon carbide into wider
use. Such advanced semiconductor materials can operate at higher
voltages and provide faster switching speeds, an important characteristic
in determining how fast a semiconductor circuit can process information.
in the Sept. 22 issue of Applied Physics Letters, a National
Institute of Standards and Technology (NIST) researcher and a
Korean guest researcher describe a new method for scanning semiconductors
for defects that may help accelerate the market for these newer
materials. The duo combined an atomic force microscope with a
scanning capacitance microscope and then added custom software
and a simple on/off switch for the AFM’s positioning laser.
result is an instrument that can measure how fast a material
generates electrical charges and then map those
speeds in sections (at least for gallium nitride) that are only
about 100 nanometers square. Current methods for measuring switching
speed (carrier lifetime) produce only bulk averages.
to NIST co-developer Joseph Kopanski, the system allows quick
scanning of semiconductor wafers for defects that otherwise may
not be found until an expensive device has already been built
on the material. Most defects in semiconductors (i.e. sections
with missing atoms) are presumed to slow down the speed that charges
move through a material. Kopanski says further research using
the new technique should determine if this assumption is correct.
A patent application is pending on the technique.
Phil Bulman, (301) 975-5661
post doctoral research fellow Mark Iadicola examines
a sample of sheet metal that has been tested with NIST's
new formability testing station.
receive a high-resolution version of this image, contact Gail
Stamping Project Aims
At Cutting Manufacturing Costs
new, one-of-a-kind test equipment, National Institute of Standards
and Technology (NIST) researchers aim to stamp out costly, delay-causing
errors in the design of dies used to make sheet-metal parts ranging
from car hoods to airplane wings to pots, pans and cans.
The U.S. auto industry alone is estimated to spend more than $700
million a year on designing, testing, and correcting new dies
for its latest models, each containing about 300 stamped parts
shaped by dies and presses. About half of the total goes for remedying
as wrinkles, splits, excessive thinning or other defects.
fitting NIST's metal-stamping test station with an X-ray stress
measurement system, the Institute’s materials scientists
now can make detailed maps of stresses and strains as sheets of
steel and other metals are punched, stretched or otherwise shaped
to achieve the desired part geometry. According to project leader
Tim Foecke, the system can measure stress and strain behavior
in many different directions while the sheet is being stretched
in two directions simultaneously, a condition most commonly seen
in forming operations. Current methods extrapolate from strain
measurements taken from tests that stretch the sheet in only one
direction. As a consequence, newly designed dies often must undergo
successive rounds of refinement to correct for these simplifications
in computer models.
automakers and producers of steel, aluminum and other metals,
including developmental ones, are supplying Foecke’s team
with samples for testing and evaluation. The project will result
in a novel database of materials’ properties that designers
can feed into computer models for predicting whether would-be
dies can form particular metals into specified shapes, within
tolerances. Project findings might point the way to new metal-forming
Note: Color photo available
Protect Cherished Documents From Hurricane Isabel
a day after their debut at the National Archives, new high-tech
encasements for the nation’s most cherished documents—the
Declaration of Independence, Constitution and Bill of Rights—were
locked in a “battle of the bulge” with Hurricane Isabel.
Designed and built by researchers at the National Institute of
Standards and Technology (NIST), the hermetically sealed, titanium-framed
encasements were commissioned by the National Archives to preserve
the nation’s “Charters of Freedom” for future
The significant drop in atmospheric pressure (about 23 millibars)
due to Hurrican Isabel, caused the glass covers of the precision-machined
encasements to deflect outward by an estimated 2.4 millimeters.
No problem. The bulge was well within the limits set by the NIST
team, who factored in the potential for the most severe hurricane-caused
pressure drops conceivable into their design. The encasements
were unveiled on Constitution Day, Sept. 17. For more on the encasements,
go to: www.nist.gov/public_affairs/Charter/charters_of_freedom_project.htm.
Blair, (301) 975-426
Free CD Demystifies Complex Standards System
new CD from the National Institute
of Standards and Technology (NIST) can help steer engineers, novice
trade-association representatives and new government staffers
through the thicket of organizations, activities, policies and
laws related to standards and measurement in the United States.
an easily digested helping of technical detail, the free electronic
primer* provides an integrated view of major public and private-sector
components of the nation’s measurement and standards system.
These elements are sized up from several key perspectives, including
global trade and regulatory affairs.
descriptions are supplemented by pointers to copies of trade agreements,
federal laws and other background documents. Links to relevant
Internet resources, such as Web sites of standards development
organizations and regional measurement alliances, are found throughout.
For example, the section on conformity assessment (the umbrella
term for testing and other means of assessing whether a product
meets regulatory and customer requirements) contains pointers
to copies of international agreements and other efforts to harmonize
such formal requirements. It also features links to multinational
organizations working to eliminate duplication or needless variation
in the standards and regulations of trading partners.
major sections survey relevant topics and activities in the
areas of measurements, standards, conformity assessment,
regulations and global activities. An additional section
NIST, its programs, and its supporting technical roles
get a copy of the compendium-like CD, contact the editor, Elisabeth
(301) 975-3089; or firstname.lastname@example.org.
Note: (added 3/31/04) Current supplies of the CD are exhausted.
Additional copies are expected in a few months.
Mark Bello, (301) 975-3776
Overview of the U.S. Approach to Standards, Conformity Assessment,
and Metrology (NISTIR 6978)
Trade Center Information Needed—The National
Institute of Standards and Technology (NIST) recently detailed
its plans to collect first-person data to study occupant behavior
and evacuation, and emergency response as part of the federal
building and fire safety investigation of the World Trade Center
(WTC) disaster following the terrorist attacks of Sept. 11,
2001. Survivors, first responders (including retirees) and
family members who communicated with victims after the aircraft
impacts also are being asked to contact NIST
toll-free at (877) 221-7828 to learn if and how they can volunteer
to participate. For more information, go to http://wtc.nist.gov/media/provide_info.htm.
Radiation—The 12th annual meeting of the Council
on Ionizing Radiation Measurement and Standards will be held at
the National Institute of Standards and Technology (NIST) in Gaithersburg,
Md., on Oct. 27-29, 2003. Topics covered will include: traceability
in measurement standards for medical applications; homeland security;
occupational, public and environmental radiation protection; and
industrial applications and materials effects. For further information,