This issue...

  Brieflies

  View from the Inside

  Sandia Sells Seashells

  Asymmetric Dancing Partners

  Working Science

  People

  Site Seeing

  E-mail Reminder






















This issue...

  Brieflies

  View from the Inside

  Sandia Sells Seashells

  Asymmetric Dancing Partners

  Working Science

  People

  Site Seeing

  E-mail Reminder

Brieflies ...

Better than a Donut: The National Spherical Torus Experiment (NSTX) began operations in February this year at the Princeton Plasma Physics Laboratory's (PPPL's) D-Site, taking advantage of some of the existing equipment and infrastructure that supported the Tokamak Fusion Test Reactor. NSTX will produce a plasma that is shaped like a sphere with a hole through its center, different from the "donut" shape of the Tokamak. This spherical configuration may have several advantages—a major one being the ability to confine a higher plasma pressure for a given magnetic field. Since the amount of fusion power produced is proportional to the square of the plasma pressure, the spherical torus concept could play an important role in the development of smaller and more economical fusion reactors.

"NSTX was designed and built on knowledge generated over the last decade, including from experiments on the Tokamak Fusion Test Reactor (TFTR)," says NSTX project director Masayuki Ono. "TFTR demonstrated that fusion works, that it gives off power and functions as expected. We now need to demonstrate that fusion power can be generated more efficiently, so that it can become a practical energy source."

The NSTX was designed and built in a collaborative effort between PPPL, Oak Ridge National Laboratory (ORNL), Columbia University, and the University of Washington in Seattle. A national team of scientist from 14 institutions was formed recently to carry out research on NSTX, which is supported by the Office of Fusion Energy Sciences.

Contacts: Project Director Masayuki Ono, PPPL, (609) 243-2105, mono@pppl.gov; and Program Director Martin Peng, ORNL, (609)243-2305, mpeng@pppl.gov. For photos and more information, see the NSTX project website: http://fileroom.pppl.gov/nstxhome/index.shtml

Metal in the Petals: Horticulturists have known for years that silver nitrate treatment of cut flowers prolongs their lives, but they didn't understand the process involved. Using the model Arabidopsis thaliana plant, Dr. Anthony Bleecker's research team at the University of Wisconsin-Madison, was able to confirm a hypothesis that a plant's ability to detect minuscule environmental and development cues depends on a transition metal. That metal was discovered to be a copper ion that allows a plant to detect minute whiffs of ethylene, a gaseous plant hormone that tells fruit when to ripen or flowers to fall off. This discovery begins to solve the mystery of how plants can sense a very small molecule and reveals the key that permits the ethylene to gain access to plant cells and their fruit. Understanding the mechanisms of signaling in plants may help scientists develop applications for agriculture such as the ability to regulate ripening, delay abscission (dropping of leaves, flowers, and fruits), and delay senescence (aging).

This research is supported by SC's Office of Basic Energy Sciences/Energy Biosciences.
Contacts: Sara E. Patterson, University of Wisconsin - Madison, spatters@facstaff.wisc.edu; and Fernando Rodriguez, firodrig@students.wisc.edu.

Boom-Box Technology Helps Detect Toxic Radioisotopes: Widespread environmental release of strontium-90 by the Chornobyl reactor accident has focused attention on the need for rapid detection of this highly radiotoxic isotope. Researchers at Pacific Northwest National Laboratory (PNNL) have developed a laser-based technique that allows near real-time detection of this dangerous isotope in the environment. Solid-state diode lasers, similar to those used in compact disc players, are the key to detecting even very small quantities (10-15 gram) of strontium-90 within a few minutes. The traditional radiochemical decay counting methods require several weeks. The lasers have high spectral purity, allowing them to selectively ionize the radioactive isotope of strontium while not affecting the more common stable isotopes. The ionized atoms are then detected with a mass spectrometer. For example, a 100-ml sample of water taken from a well or a river is run through an ion-exchange resin, which preconcentrates the strontium. The sample is then loaded into the laser mass spectrometer for analysis. Continued research in this area includes seeking lasers that will selectively ionize other environmentally harmful radioisotopes.

This research is supported by the Office of Basic Energy Science/Chemical Sciences. Contact: Bruce Bushaw, PNNL, (509) 375-2209, bruce.bushaw@pnl.gov.

Circuit-Etchers May Soon Be Jobless: Miniaturized electronic devices—such as a pacemaker the size of a thumbnail—require very fast, very tiny electronic circuits. Currently, circuits must be etched onto a surface, generally by a light source such as a laser. Circuit-etching techniques are cumbersome, from the miniaturization perspective, despite technology that creates circuit features less than 0.25 micrometers wide (400 times narrower than a human hair). To create subtler, smaller circuit features, researchers are studying self-assembling nanostructures that would, in essence, create the circuit pattern within the material of the circuit itself like the ordered design in a quilt in which the figures used to make the pattern can be altered within the same regular layout. Researchers from Sandia and Brookhaven National Laboratories found that an astoundingly regular self-assembling pattern occurred when they distributed sulfur onto a single-atom sheet of silver overlaying a ruthenium substrate. As the corrosive sulfur atoms grouped together they displaced the silver, causing the underlying ruthenium to buckle directly beneath the sulfur "islands" and creating a uniform pattern of holes in the silver sheet. The research team used a scanning tunneling microscope with such fine resolution that they were able to watch the holes form—a remarkable feat, given that the holes measure about 34 Angstroms (1 Angstrom is the width of an atom). Continuing research will examine whether this phenomenon occurs with other substances and substrates, what patterns occur, and whether the self-assembly can be manipulated to create the precise patterns electronic circuitry requires.

This research is supported by SC's Office of Basic Energy Sciences, Division of Materials Sciences and Chemical Sciences. Contact: Robert Q. Hwang, SNL, (925) 294-1570, e-mail rqhwang@sandia.gov

Related Information: Nature, Jan. 21 1999, Vol 397 p. 238.

The Next-Generation is Here: The National Energy Research Scientific Computing Center (NERSC), which marks its 25th anniversary this year, announced on April 28 that it had selected an IBM RS/6000 SP system for its Next-Generation SuperComputer. The final system will have 2,048 processors and a peak speed of 3 teraflops (three trillion calculations per second). The IBM system was chosen based on its ability to handle actual scientific codes and other tests designed to ensure the computer's capability as a full-production computing system in NERSC. These tests indicated that the system, when fully installed, will provide four to five times the total current computational power of NERSC, already one of the most powerful supercomputing sites in the world. The new system, which will incorporate IBM's newest processor and interconnect technology, will be installed in two phases: the first phase in June 1999, and the second phase no later than December 2000.

NERSC, at Lawrence Berkeley National Laboratory, provides high-performance scientific computing and data storage resources to approximately 2,500 researchers at national laboratories, universities, and industry across the Nation who are working on DOE-funded programs such as combustion, climate modeling, fusion energy, materials science, and computational biology. NERSC's seven supercomputers, the largest of which is currently a 640-processor Cray T3E-900, are utilized 24 hours a day, 7 days a week, and are up and running more than 95 percent of the time. NERSC will soon be accepting applications for allocating resources for FY2000.

The NERSC is supported by the SC's Office of Mathematics, Information, and Computational Sciences Division of the Office of Advanced Scientific Computing Research.

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