ORNL Wins Two R&D 100 Awards

Two of the top 100 new technologies recognized in 1994 by R&D magazine were developed or co-developed by ORNL researchers. The total number of R&D 100 awards for Department of Energy plants in Oak Ridge is 84.

The winning ORNL technologies are an improved method of testing for polychlorinated biphenyls (PCBs), a significant environmental contaminant, and a computer software package called parallel virtual machine (PVM) that virtually turns computer workstations into supercomputers.

The developers of the PCB test strip are Tuan Vo-Dinh, Anjali Pal, Lorna Ramirez, and Tarasankar Pal, all of ORNL's Health Sciences Research Division. The ORNL co-developer of PVM software is Al Geist of the Engineering Physics and Mathematics Division. Collaborating with him on this development were V. S. Sunderam of Emory University in Atlanta, R. J. Manchek and J. J. Dongarra, both of the University of Tennessee (PVM) at Knoxville, and A. L. Beguelin of Carnegie-Mellon University in Pittsburgh.

R&D magazine has annually honored inventors and scientists around the world since 1963 by selecting the 100 most technologically significant new products and processes.

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The newly developed PCB test uses strips of chemically treated paper that glow under ultraviolet (uv) light if the environmental sample being tested is contaminated with PCBs. The improved process saves money by eliminating costly laboratory procedures and extra work time. Before Vo-Dinh's innovation, researchers had to collect samples on site and then transport them to a laboratory for chemical analysis to determine whether they were contaminated.

"The PCB strip test will cost ten times less than previous methods because it uses a simple process called photoactivated fluorescence, allowing quick analysis at the site," says Vo-Dinh, leader of the Advanced Monitoring Development Group at ORNL. "A user of the test can rapidly screen samples for PCBs and even measure the level of contamination."

When the patented process is developed fully for large-scale field use, testing a sample could cost only a few dollars. "However," Vo-Dinh notes, "the raw material for each sample run--the chemically treated paper test strip--costs less than a penny."

The research project was sponsored by DOE's Office of Health and Environmental Research, the Environmental Restoration and Waste Management Office of Technology Development, and the Environmental Protection Agency's Environmental Monitoring Systems Laboratory in Las Vegas.

PCBs were manufactured in the United States from 1929 to 1977. They were used in electrical equipment, such as transformers and capacitors, and in hydraulic fluids and lubricants for industrial equipment. Through such products, PCBs made their way into the environment.

The disposal of PCBs was not regulated until the late 1970s, when studies first showed that these toxic compounds persist in the environment and may cause cancer.

In the new test, a drop of liquid from an environmental sample is applied to a paper test strip coated with special chemicals that are activated by uv light if exposed to PCBs. UV light is then shone on the strip. If PCBs are present, the activator molecules on the test strip will absorb the uv energy, interact with the PCBs, and glow. The intensity of the glow is measured in a luminescence analyzer, which indicates the level of PCB contamination.

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The parallel virtual machine (PVM) computer software package developed by ORNL's Al Geist and others virtually turns computer workstations into supercomputers. The software allows organizations and individuals with computers to tap the power of several workstations simultaneously, thereby solving problems that would be too large or complex for a single workstation.

PVM is one of the first software systems to allow computers with widely different architectures and data formats to cooperate simultaneously on a single computational task. Their combined power can equal that of multimillion-dollar supercomputers, at a fraction of the cost.

PVM is particularly useful in linking several computer workstations during off hours to solve problems that normally would be submitted to a more powerful mainframe computer. Perhaps best of all, says Geist, the software is available free through an ORNL electronic mail network. "It's an example of your tax dollars at work," he says.

Geist notes that the PVM system could be viewed as "a poor man's supercomputer." By using it to tap the aggregate power of computer workstations whose combined cost is roughly $250,000, researchers have achieved computing speeds that rival those of $20 million supercomputers. The package has been applied to as many as 125 workstations. It can even be used to link supercomputers.

"The workload achieved," Geist says, "is limited only by the number and power of computers to which you have access."

The software also allows linking of several computer networks, such as Ethernet and Token Ring, to form a single PVM configuration.

PVM will be particularly beneficial to universities, most of which cannot offer courses in supercomputing because of the high cost of the hardware. "With PVM," Geist says, "universities can teach students how to write parallel programs that apply to supercomputing even though they could never afford a supercomputer."

PVM is being used at hundreds of sites worldwide by companies whose business ranges from aerospace, automotive, and chemical research to medicine and the environment. PVM is supported on more than 30 different types of workstations and supercomputers, including those manufactured by IBM, Hewlett Packard, DEC, Sun, Cray Research, Convex, Silicon Graphics, and Intel

Parallel computing using the PVM system may be the key to solving so-called computational grand challenges, such as modeling of the global climate, groundwater transport of hazardous waste, and the structure of superconductors.

"At this time, these problems can't be solved because of a lack of computer power," Geist notes. "One computer, even a supercomputer, simply has physical limitations. Parallel computers will be required to solve these problems."

PVM research is sponsored by the Applied Mathematical Sciences Research Program of DOE's Office of Energy Research.

Nuclear Physics Device for ORNL Accelerator

Although the Daresbury Laboratory in England was closed on March 31, 1994, one of its nuclear physics instruments will have a second life at ORNL. The large, multimillion-dollar instrument will be used with ORNL's upgraded heavy-ion accelerator facility to study nuclear reactions predicted to occur during the birth and death of stars.

On October 20, 1994, the Daresbury Recoil Separator, which has been donated to the Laboratory, was delivered to ORNL for use in its new Holifield Radioactive Ion Beam Facility (HRIBF), now being constructed in the Physics Division and expected to begin operation in the fall of 1995. HRIBF will be the only U.S. facility dedicated to producing and accelerating intense beams of radioactive nuclei.

The two accelerators that formed the heart of the Holifield Heavy Ion Research Facility from 1980 to 1992 are being reconfigured. One will be used to produce radioactive nuclei that do not occur naturally, and the second will be used to accelerate them. When radioactive nuclei bombard a target, particles called recoils are produced. The Daresbury Recoil Separator will direct these recoils to detectors while steering away radioactive beam particles.

"The ability of the Daresbury Recoil Separator to separate recoil products from projectile particles makes it a tremendous addition to our research program," says Jim Ball, acting ORNL associate director for Physical Sciences and Advanced Materials. "Combining this instrument with ORNL's unique radioactive beams will enable pioneering advances in our understanding of the explosive events that create and destroy stars."

The recoil separator came to ORNL from the Nuclear Structure Facility of the Daresbury Laboratory in Warrington, England. The facility was closed because of budget cutbacks in the United Kingdom. The Physics Division staff of the Holifield Heavy Ion Research Facility, which faced budget cutbacks of its own in 1992, was successful in securing a new role for the Holifield facility. Approved for construction in 1992, the new HRIBF will begin operating in 1995. The physicists will use these capabilities to study nuclear structure and to conduct nuclear astrophysics research.

"Radioactive beams at ORNL will be used to study nuclear reactions occurring in exotic stellar explosions such as novae, supernovae, and X-ray bursts," says Michael Smith of the Physics Division. "These incredibly energetic astrophysical events produce the majority of heavy elements in the universe and mark the dramatic end of the life of massive stars.

"Sophisticated computer models of these explosions," Smith continues, "require precision measurements of nuclear reactions involving radioactive nuclei like those that will be produced in our new radioactive ion beam facility. Such important measurements would not be possible without instruments such as the Daresbury Recoil Separator."

This separator generates magnetic and electric fields that selectively focus the recoil products onto detectors while steering away the projectile beam particles. The detectors generate information on the arrival time, position, and energy of the recoil products; these data are processed electronically and sent to a computer for storage and analysis. The information obtained may help scientists understand the structure of some 100 nuclei that cannot be produced with nonradioactive beams and targets.

The Daresbury Recoil Separator is 13 meters long and weighs about 90 tons. Its components include two 18-ton dipole magnets surrounding vacuum chambers containing high-voltage electrostatic plates. These components form two velocity filters that separate the radioactive beam particles from the recoil products based on differences in their direction and speed.

"The transfer of the Daresbury Recoil Separator from England to ORNL required the cooperation of researchers and technical staff from both laboratories," says Jerry Garrett, scientific director of HRIBF. "We anticipate that this cooperative spirit will continue through research collaborations between ORNL physicists and those from Daresbury Laboratory and sites throughout the United Kingdom. Such collaborations will greatly benefit research efforts in nuclear astrophysics, nuclear structure physics, and radioactive beam physics on both sides of the Atlantic Ocean."--Carolyn Krause

Cyclotron Reaches Goal for Radioactive Beam Facility

The Oak Ridge Isochronous Cyclotron (ORIC) has proven that it can still carry out its original mission--produce intense beams of light ions, such as charged atoms of hydrogen and helium. The difference today is that ORIC, the Laboratory's only cyclotron, is being used to produce radioactive rather than stable ion beams. A cyclotron is an accelerator in which charged particles are propelled, often in a circle, by an alternating electric field in a constant magnetic field.

On March 10, 1994, an important milestone toward developing ORNL's new Holifield Radioactive Ion Beam Facility was achieved. ORIC produced a 75-million-electron-volt beam of alpha particles (helium nuclei).

"This is the first time since 1983 that a beam was extracted from ORIC using the internal ion source," says Fred Bertrand, director of the Physics Division. "This achievement marks a major milestone in the Physics Division's development of a radioactive ion beam facility."

ORIC was built in 1964 to produce intense light-ion beams. But its mission changed in 1970 to the production of heavy ions, which were needed for nuclear physics experiments. From 1980 to 1992, the 25-million-volt tandem accelerator, the workhorse of the Holifield Heavy Ion Research Facility, took up the burden of producing heavy ions at ORNL. ORIC was used part-time to boost the energy of the heavy-ion beams emerging from the tandem accelerator.

Now, in a reversal of roles, ORIC will produce the radioactive beams and the tandem accelerator will accelerate them.

Just as many people switch careers at least twice, a cyclotron's role can also change more than once.--Carolyn Krause

Greenhouse Gases and Forests

Researchers at ORNL have created an experiment to test the effects of regional precipitation changes on forests. In the experiment, an oak forest is being manipulated to show the effects of drought, normal precipitation, and heavy precipitation on different tree species.

Scientists worldwide predict that the greenhouse effect will increase global temperatures and alter regional levels of precipitation. Temperature increases of approximately 3 to 5 degrees C (5 to 10 degrees F) could occur in 60 to 70 years--a short time compared to a mature tree's life span, which can be several hundred years.

The projected change in precipitation has led researchers in ORNL's Environmental Sciences Division to ask a key question: With some change in precipitation, will current forests be able to maintain current levels of growth and ecological diversity? Determining the sensitivity of forests to changes in soil moisture will provide information on one of the effects of increasing atmospheric concentrations of greenhouse gases.

The experimental site for the precipitation studies is a part of the Walker Branch Watershed on DOE's Oak Ridge Reservation, which has been used for ecological research for more than 25 years. The site was chosen for this experiment because the forest has not been disturbed by other experiments or heavy use. According to Paul Hanson, a project researcher in ORNL's Environmental Sciences Division , this project is the largest experimental manipulation of an oak forest.


The site, which is approximately the size of three football fields, consists of a wet plot, a control plot, and a dry plot of equal length and width. The amount of precipitation distributed to the wet and dry plots is controlled by a series of plastic, gutterlike troughs. Each trough is 0.3 meter (1 foot), and they are spaced 0.6 meter (2 feet) apart.

Approximately 2000 troughs intercept about 33% of precipitation falling onto the dry plot--a level chosen to reflect drought levels from the mid-1980s. The intercepted rainwater then flows to the wet plot. The control plot receives natural precipitation.

Trees are unlikely to die during the current three-year experiment, but researchers hope to see trends that will help them predict the plight of forests in several years or decades to come.

One prediction is that tall trees with deep roots may buffer themselves against short-term droughts because their roots will be able to reach deep water supplies. For example, oaks are considered to be more tolerant of droughts than are maples.

The data gathered by this experiment will be applied to other types of trees. However, the experiment cannot be generalized to all regions in the United States because each region's plant life is specifically adapted to that regionŐs climate.

The precipitation experiment is composed of four studies funded through the Program for Ecosystem Research, Office of Health and Environmental Research, Department of Energy. These four studies examine the ability of deciduous forest species to tolerate and survive periods of drought, observe changes in below-ground processes, and quantify alterations in forest productivity and water use under the manipulated conditions of changing moisture levels.

Several collaborators are conducting complementary research on the experimental site. Ted Leininger, U.S. Forest Service, and Johann Bruhn, University of Missouri at Columbia, compose one team studying how Armillaria, a pathogenic fungus, will affect oaks when precipitation levels change. Don Shure of Emory University is studying changes in insect feeding patterns in forests in response to precipitation changes.

Researchers hope that the watershed experiment will provide several ecological scenarios on which to base further research, and an understanding of how climate change, influenced by increasing atmospheric concentrations of greenhouse gases, will affect forests before the effects are irreversible.--Kimberly Baker

ORNL-Produced Isotope Treats Bone Pain

A therapeutic radioisotope recently approved in the United States for relieving cancer-induced bone pain is produced from a material enriched in a stable isotope by ORNL. The treatment, called Metastron, is manufactured and marketed by Amersham International in England. The company's division Medi-Physics, Inc., in Arlington Heights, Illinois, is distributing Metastron throughout the United States, where it is expected to have widespread use.

In the past seven years, Metastron has been used worldwide for more than 6000 patients to reduce metastatic bone pain--pain caused when breast and prostate cancer spreads, or metastasizes, to bone. Metastron was not employed in the United States for managing metastatic bone pain until recently, following its June 1993 approval by the U.S. Food and Drug Administration.(FDA).

Metastron, which consists of strontium-89 chloride, is used to treat bone pain because strontium-89 localizes in bone as a result of its chemical similarity to calcium and because its radioactivity reduces tumor growth in bone. Its effectiveness reduces or eliminates the need for chemotherapy or addictive narcotics to relieve pain. This nonsedating drug eliminates bone pain for up to six months with a single injection. It improves patient quality of life, especially mood, mobility, appetite, and sleep patterns.

According to the December 1993 issue of Reader's Digest, Metastron leaves patients alert, allowing them to participate in normal activities. "Dr. Ralph G. Robinson at the University of Kansas Medical Center has studied Metastron in more than 600 patients," the magazine states. "About 80% get relief," he says. "And for some, pain disappears completely."

The strontium-89 in Metastron is produced in five European reactors by neutron irradiation of targets enriched in strontium-88 by ORNL. The source of the strontium-88 is a set of calutrons at the Oak Ridge Y-12 Plant operated by ORNL's Isotope Enrichment Group headed by Joe Tracy. The calutrons, which separate isotopes electromagnetically, were originally used to produce enriched uranium for the Manhattan Project during World War II.

"Since the early 1980s," Tracy says, "ORNL's Isotope Enrichment Program has collaborated with Amersham in development of the Metastron product, and we continue to support Amersham in providing certified, high-quality strontium-88.

"The ORNL group does not certify isotopes for human consumption," Tracy says. "However, our quality-assurance documentation and certification of the starting strontium-88 played an important role in Amersham's obtaining FDA approval for Metastron."

By electromagnetically separating the isotopes of naturally occurring strontium in a single pass, an ORNL calutron produces materials enriched in more than 99.8% strontium-88 for fabricating strontium-88 carbonate targets. After neutron irradiation, these targets are converted to a strontium-89 chloride solution, which is injected into patients.

Tracy says the enrichment process almost completely eliminates the strontium-84 contaminant from the enriched target. Exposure of strontium-84 to neutrons in a reactor yields strontium-85, which emits penetrating gamma rays that could harm patients. Strontium-89, which has a half-life of 51 days, emits pure beta radiation, energetic electrons that have a very short range.


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