rought tolerance of various species of poplar trees (Populus) and their hybrid offspring is the subject of a cooperative research and development agreement recently signed by Energy Systems and Boise Cascade Corporation. The purpose of the CRADA is to verify that certain biochemical indicators can be used to predict the clones of poplar that best survive episodic periods of little or no rain and remain productive.
Principal investigators of the CRADA at ORNL are Tim Tschaplinski and Jerry Tuskan, both members of the Environmental Sciences Division (ESD). They are also researchers in ORNL's Biofuels Feedstock Development Program.
Scientists have shown that some individual plants and plant species tolerate water shortages by maintaining or accumulating high concentrations of dissolved compounds, including nutrients. Such solutes may serve as biochemical indicators of drought tolerance. Mechanisms of drought tolerance vary among species and individuals.
The ORNL researchers published two papers in the Canadian Journal of Forest Research that describe their earlier research detailing the biochemical basis of drought tolerance in six poplar clones. They isolated 60 to 80 plant compounds, or metabolites, that may be involved. High concentrations of several metabolites were found in poplar tree species identified as drought tolerant.
For the CRADA, ORNL researchers will validate the use of these plant metabolites as biochemical indicators, or molecular selection criteria, for drought tolerance in poplar trees. Boise Cascade will grow 2-year-old hybrid Populus trees from seven clones under six levels of moisture stress at each of two sites in their drought-stress facility in eastern Oregon and Washington. ORNL will collect leaf samples from these trees, measure the total amount of solutes, and analyze the samples to determine the concentrations of the most abundant solutes that may be indicators of drought tolerance.
In work related to the CRADA, ORNL researchers will screen 60 genotypes--individuals sharing a unique genetic makeup--to assess the validity of using metabolites as drought-tolerance indicators in large-scale field trials. Molecular markers that prove to be correlated with drought tolerance will be mapped on the Populus genome.
The ability of Populus clones to tolerate drought is critical to short-rotation hardwood culture for the production of wood fiber. Because much of the hardwood fiber will be grown under irrigation to maximize production, the identification of drought-tolerant genotypes will enable industry to manage water resources more efficiently. Boise Cascade, a major U.S. producer of Populus fiber, hopes to use the technology to maintain improved growth rates in hybrid Populus while minimizing use of irrigation water.
If the biochemical and molecular markers are validated, Populus clones found to be most drought tolerant may be used as dedicated energy feedstocks--sources of wood used for production of liquid transportation fuels--in a renewable energy industry. The ability to use biochemical and molecular markers will reduce the amount of time, money, and effort needed to identify and test drought-tolerant genotypes.
One of the goals of the Energy Policy Act of 1992 is to demonstrate the commercial use of renewable energy and dedicated energy feedstocks. The development and selection of drought-tolerant Populus clones and the large-scale field testing of such genotypes will help the Department of Energy meet its goals.
The development work was funded by DOE through ORNL's Buildings Technology Program, and the technical monitor for the project was Robert C. Devault and his colleagues in ORNL's Energy Division.
DOE is forming a new partnership in which the Gas Research Institute, American Gas Cooling Center, Carrier Corporation, and ORNL will work together to support final development and commercialization of the generator-absorber heat exchange (GAX) technology pioneered by Phillips Engineering under ORNL's guidance.
The goal of the new National GAX Heat Pump Program partnership is to introduce GAX heat pump products into residential and commercial markets. The GAX cycle represents a revolutionary advance over the absorption technology used in the gas-fired absorption air-conditioning market of the 1960s and 1970s.
ORNL will provide technical support and program guidance in an effort to achieve even higher heat pump efficiencies. DOE will provide funding for the partnership through its Building Equipment Division's Office of Energy Efficiency and Renewable Energy; the DOE program manager for the partnership is Ronald J. Fiskum.
A major advantage of the GAX cycle is its use of ammonia and water as working fluids, rather than chlorofluorocarbons or hydrochloro-fluorocarbons, refrigerants that contribute to ozone depletion and global warming.
For utilities, GAX technology is desirable because it uses gas and is more efficient than current heating and cooling systems. Hence, it reduces peak demands for electricity in summer and gas in winter, thus leveling annual energy use and reducing the need for more power plants. For consumers the cycle's higher efficiency translates into lower monthly energy bills.
The GAX technology is also envisioned to make the United States more competitive in world markets, fostering economic growth--a goal of DOE's strategic plan. Energy efficiency and security, global economic opportunities that create U.S. jobs, and environmentally sound technology all are considered benefits from the cooperative pursuit of this new technology.
Inexpensive car crash simulations that give about the same information as an actual car crash have been performed in a few days to a few weeks on supercomputers. But at ORNL, a car crash can be simulated and analyzed on the Intel Paragon XP/S supercomputer in 8 hours at an even lower cost. The ORNL supercomputer consists of 512 parallel processors that can work on many parts of the same problem at the same time.
"Using data supplied by the U.S. Department of Transportation, we have done a half-day analysis of a 4-door sedan crashing into a lamppost at 35 miles per hour and of a head-on collision between two cars," says Thomas Zacharia, a group leader in ORNL's Metals and Ceramics Division.
Zacharia is currently serving as acting director of the new Computational Center for Industrial Innovation in ORNL's Center for Computational Sciences. This new center will be a focal point for ORNL's interaction with industry on high-performance computing.
Zacharia is also ORNL's representative to the Supercomputing for Automotive Applications Partnership of the U.S. Consortium on Automotive Research (USCAR). Other representatives on this committee are from Chrysler, Ford, and General Motors and from Argonne, Livermore, Los Alamos, and Sandia national laboratories.
USCAR is one of the chief participants in the Clean Car Initiative announced by President Clinton in 1993. The goal of this initiative is to design new cars that emit less pollution and are safer and more efficient than current vehicles. To make cars that travel 60 to 75 miles per gallon of fuel (compared with 20 to 30 mpg in today's cars), the engine system must be redesigned for more efficient combustion and lighter materials must be used.
"ORNL is a leader in using massively parallel supercomputing for simulating car crashes and modeling materials and manufacturing processes for cars," Zacharia says. "The information generated can be used to analyze the efficiency and safety of new car designs for the automotive industry."
Lighter-weight materials--aluminum alloys, magnesium, and polymer composites--will be used in new cars to make them more energy efficient. Parallel supercomputing, Zacharia notes, will help the automotive industry design next-generation vehicles using lighter materials while meeting safety standards.
Zacharia, who came to ORNL 7 years ago to do process modeling, first used parallel computers to model the impacts of dropping or crushing a radioactive waste container during a truck or train crash. This work was performed in collaboration with Gus Aramayo of the Engineering Organization of Martin Marietta Energy Systems, Inc. Then, with support from the Laboratory Director's Research and Development Fund, Zacharia showed the same code could be used to simulate the results of car crashes.
Zacharia and his group are working with USCAR and in a project under a cooperative research and development agreement involving DOE national laboratories called Materials by Computational Design. The results of these collaborations, he says, will likely influence the designs and choices of lightweight materials for American cars of the future.
In car crash analysis at ORNL, the processors calculate the local deformation and the energy absorbed during a car crash for each of 56,000 points, or finite elements. These include 3000 spot welds as well as 248 different structural materials. Zacharia, his research group, and Ross Toedte of Energy Systems' Visualization Laboratory have produced colorful still and animated images of smashed cars, showing the dramatic impacts of collisions, including the sequence of images depicting a head-on collision shown below.
Zacharia and his colleagues also have used parallel computing to simulate shape changes during the forming of superplastic aluminum components. This lightweight material, which is as stretchable as chewing gum, is a candidate for car hoods and doors. The capability to form superplastic aluminum was developed at the Oak Ridge Y-12 Plant for use in weapons components.
"Strains in superplastic aluminum have been modeled on the Y-12 Plant serial computer in a month," Zacharia says. "We did this modeling on 128 processors of the 512-processor Intel Paragon in 6 hours."
Zacharia says he and other DOE national laboratory scientists are working on developing the next-generation computer codes for car crash analysis and engine combustion analysis.
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