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NASA'S CHANDRA X-RAY OBSERVATORY DISCOVERS ANCIENT EXPLOSION
NASA's Chandra X-Ray Observatory has detected relics of an
ancient eruption that occurred in a cluster of galaxies, suggesting
that the clusters are home to enormously energetic and recurring
explosions. According to Brian McNamara of Ohio University,
Chandra's image revealed vast regions in the galaxy cluster
Abell 2597 that contain almost no x-ray or radio emission.
"We call them ghost cavities," he added. "They appear to be
remnants of an old explosion where the radio emission has
faded away over millions of years."
The ghost cavities seem to have been created by powerful
explosions that resulted from material falling toward a black
hole millions of times more massive than the sun. As the material
swirled around the hole, it generated enormous electromagnetic
fields that sucked material from the vicinity of the black
hole at high speeds.
The researchers also found evidence that the explosion was
not a one-time event. Near the center of the cluster was a
bright radio source that indicated that a new explosion had
occurred recently. Chandra observed Abell 2597 with the Advanced
CCD Imaging Spectrometer (ACIS) instrument. NASA's Marshall
Space Flight Center manages the Chandra program. For more
information, Contact Megan Watzke of the Chandra X-Ray Observatory
Center at 617-496-7998 or Judy Pettus at judy.pettus@msfc.nasa.gov.
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TECHNOLOGY OF THE MONTH:
MINIATURE SELF-ILLUMINATING-CHIP PLASMA DISPLAY
Patent number 5,990,620 describes a pressurized plasma display,
a miniature high-resolution display suitable for integration
on a semiconductor chip in combination with other circuitry.
It is comprised of two crossed sets of conductors arranged
on the first substrate to form an array of crosspoints. An
array of vertical tubes in a second substrate is spaced so
as to correspond to the array of crosspoints. The tubes and
cavities are filled with a pressurized gas. When a sufficient
voltage is applied across the cavity at a crosspoint, a plasma
is created. The charged particles in the plasma combine within
the tube to generate light.
Get the complete report at: http://link.abpi.net/l.php?20020114A3.
The Technology of the Month describes inventions available
for license through the yet2.com marketplace. Search over
$2.5 billion of licensable technologies at www.nasatech.com/techsearch.
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OPTOELECTRONIC PARTICULATE MONITORS SHRINK IN SIZE
A team at NASA's Johnson Space Center is developing optoelectronic
instruments for use in measuring the concentrations and sizes
of microscopic particles suspended in air. They could detect
smoke, explosive dust in grain elevators, or toxic dusts in
industrial buildings. Like older monitors, these instruments
are based on diffraction of light by particles. But they are
much smaller: they are compact, handheld units.
For the complete brief, titled "Hand-Held Optoelectronic
Particulate Monitors," see page 6a of the Photonics Tech Briefs
Supplement to the January issue of NASA Tech Briefs.
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STOCKERYALE TO INTRODUCE QUARTZ AND GLASS FIBER AT PHOTONICS
WEST
StockerYale is poised
to introduce glass and quartz bulk fiber at the Photonics
West show in San Jose later this month. The company's quartz
polymer- clad silica (PCS) fiber offers a hard coat cladding,
and unlike traditional soft-clad fiber, has a larger exit
angle and better bend radius. StockerYale says this results
in ten percent more illumination output than glass fibers
over the visible range.
StockerYale says its glass fibers have a premium borosilicate
cladding that can withstand temperatures as great as 1100
degrees F, for use in areas such as combustion engineering.
The light from its glass fiber appears whiter, the company
says, because it extends into the UV range down to 400 nm.
It also transmits light into the infrared range, up to 2000
nm.
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