Research
Highlights...
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Maria
Ghirardi studies chlorophyll.
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Number 86 |
July 30, 2001 |
Are the
digits of pi random?
Pi, the
familiar constant whose first few digits are 3.14159, is irrationalits
expansion goes on literally forever and never cyclesbut
are its digits really random? Or in more precise mathematical
terms, is pi "normal?" No natural constant has ever been proved
normal. Now David
Bailey of the National Energy
Research Scientific Computing Center (NERSC) at Lawrence
Berkeley National Laboratory and his colleague Richard Crandall
of Reed College have proved that pi and some other constants are
indeed normalIF a certain plausible hypothesis from chaotic
dynamic theory is valid. Their work may have application in generating
unbreakable pseudorandom keys in cryptography.
[Paul
Preuss, 510/486-6249,
paul_preuss@lbl.gov]
DNA-based
system spots plague's presence
Disappearances of
prairie dog colonies in northern Arizona often signal an outbreak
of plague - even though tests have usually required seven to
ten days to confirm the disease's presence. But no more. In
May, a team of Northern Arizona University researchers, using
a DNA-based detection system developed by Lawrence
Livermore National Laboratory biomedical scientists, confirmed
the presence of plague within four hours. The finding, by a
team led by NAU microbiology professor and plague expert Paul
Keim, represents the first time the LLNL system has been used
to detect a public health disease in the environment.
[Stephen Wampler,
925/423-3107,
wampler1@llnl.gov]
Remote
systems link technology
DOE's Idaho
National Engineering and Environmental Laboratory and Russian
scientists combined technologies to show the potential for improving
decontamination and decommissioning operations at the INEEL.
Those improvements could include increased worker safety, reduced
costs and shorter project schedules. The technologies link an
INEEL robot with a Russian-developed Gamma Locating Device and
Isotopic Identification Device. All three systems are controlled
remotely and the information collected can be used to plan decontamination
and decommissioning work while keeping worker exposures to radiation
to a minimum. The technology demonstration was sponsored by
DOE's Environmental Management International Program and funded
and managed through the National
Energy Technology Laboratory in conjunction with DOE-Idaho.
[John
Walsh, 208/526-8646,
jhw@inel.gov]
Solid-state
optical limiter saves eyes from lasers
Working with academic,
commercial and military partners, scientists at DOE's Los
Alamos National Laboratory have developed a device for protecting
human eyes from dangerous laser light. The optical limiter,
which resembles a plain, lightly tinted lens, can reduce the
intensity of laser beams as much as 400-fold. The solid-state
device works much like photochromic eyeglass lenses, which automatically
darken or lighten in response to changing daylight conditions,
but has a reaction time of less than a picosecond. The Army
Research Office funded the work under a Small Business Technology
Transfer grant . The technology recently won a 2001 R&D 100
Award.
Strobe
may keep fish from dam turbines
Researchers at
DOE's Pacific Northwest National
Laboratory are testing an underwater strobe light system
at Washington
state's Grand Coulee Dam this summer to see if it will
deter fish - including kokanee and rainbow trout - from entering
turbines. More than 400,000 fish are killed each year at Grand
Coulee's turbines. If successful, the technology ultimately
could be an effective tool for enhancing resident fish stocks
without affecting hydropower generation, which is an important
source of energy in the Northwest. PNNL scientists have studied
strobe light impacts on fish behavior previously and also
used hydroacoustics to track fish behavior near surface bypass
collectors at other Northwest dams. The five-week test is
being conducted for the Bonneville Power Administration and
includes scientists from the Confederated Tribes of the Colville
Reservation, PNNL, the U.S. Geological Survey and Bureau of
Reclamation.
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Study
of photosynthesis a
researcher's dream
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Maria
Ghirardi studies chlorophyll. |
Using
algae to separate hydrogen from water is a potentially efficient
source of clean, renewable energy. However, practical implementation
of hydrogenase catalyzed photosynthetic algal hydrogen production
has been hampered by the extreme sensitivity of the hydrogenase
enzyme to oxygen, one of the byproducts of photosynthesis.
Maria
Ghirardi, a principal investigator with DOE's National
Renewable Energy Laboratory is looking for a way around
this roadblock by bioengineering the algal hydrogenase to make
it more tolerant of oxygen. "I've been interested in photosynthesis
my entire college life," Ghirardi said. Ghirardi earned her
Ph.D. at the University of
California at Berkeley and searched for a project that would
give her the chance to study the ability of plants to extract
energy from sunlight. She came to NREL in 1991 to work as a
post doc after three years at the Department of Agriculture.
While there, Ghirardi studied the turnover of proteins involved
in photosynthesis. "Coming to NREL allowed me to develop skills
other than the ones that I had been using at the USDA, " Ghirardi
said.
In 1995,
Ghirardi received funding from the DOE Hydrogen Program for
a feasibility study on algal hydrogen production, a project
expanded in 1998 to include a new process developed jointly
by NREL and Berkeley.
This
new process involves partial inactivation of the photosynthetic
oxygen evolution capacity of the algal cells by depriving them
of sulfur. Such inactivation is followed by establishment of
anaerobic conditions in the reactor, leading to the synthesis
of the hydrogenase enzyme and production of hydrogen on a continuous
basis.
"At
this point, not enough hydrogen is produced to make the process
commercially viable but, this is one aspect that we are currently
addressing in our research," Ghirardi explained.
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