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Pressure-Cooking the Garbage into Real Goodies


Near Philadelphia, there's a bubbling, hissing plant that just might help solve the world's energy woes -- and help clean up pollution as well. At this test facility, Changing World Technologies Inc. (CWT) is flash-cooking solid waste, everything from sewage and old tires to pulverized electronics and industrial refuse, and turning it into valuable products.

The technology is simple. Ground-up waste is mixed with water, then heated under pressure. When the pressure is suddenly lowered, the water rapidly vaporizes into steam, releasing a wave of energy that snaps molecular bonds in the stew. Carbon molecules then float up, while heavier minerals settle. Further refining turns the carbon into oil or chemicals, and the mineral solids emerge purified, ready to be recycled.

In the past, similar attempts to reclaim organic waste were too costly because they didn't optimize the energy cycle, says Brian S. Appel, chairman and CEO of CWT. But the new method is 85% efficient, he says, because it reuses the steam and natural gas generated in the cooking process. And the proof is in the first commercial plant, built in Carthage, Mo., for ConAgra (CAG) Foods Inc. Launched in April, it's designed to turn tons of turkey offal into oil and fertilizer.

Appel figures that if America's annual output of 12 billion tons of solid waste were pressure-cooked, it would yield 5 billion barrels of oil for $10 to $15 each -- more than enough to replace the 4 billion barrels now imported each year. Technology for cutting air pollution from cars and trucks has made great strides. Now, scientists may be closing in on another form of pollution caused by all those vehicles: highway noise.

Purdue University has built a giant contraption, resembling a 12-foot-diameter doughnut, for measuring the sounds created by tires rolling on actual road surfaces. Current laboratory tire testers don't use real pavement because small rollers turning under the tire spin so fast that any pavement on them quickly disintegrates. Of course, engineers can listen to tires being towed over highways or test tracks, but that also has drawbacks, including sounds from other traffic and wind gusts. Purdue's $250,000 machine lets researchers eavesdrop, under lab-controlled conditions, on tires rolling over different surfaces at varying speeds. The rubber-meets-the-road sounds are now recorded with five microphones, but the researchers plan to boost data collection by embedding sensors in the pavement.

So far, results indicate that tire design and construction have little effect on noise, says Robert J. Bernhard, a mechanical engineering professor. Rather, he says, the porosity of the road surface is the key. If these findings hold up in further experiments, engineers will know where to focus to quiet our roadways. About this time last year, a scientific furor erupted over a hypothetical kind of nuclear fusion that might be achieved cheaply, not in some giant facility. Two teams from Oak Ridge National Laboratory ripped into each other in the same issue of Science: One announced it had found evidence of so-called sonofusion, the other denounced those findings. Now the battle is heating up again.

Sonofusion is the notion that fusion reactions could be triggered by a form of sonoluminescence, or blowing bubbles in a liquid with strong bursts of sound energy. The resulting tiny bubbles implode with great speed and force, generating extremely high temperatures. (This form of "table top" fusion contrasts starkly with the cold fusion theories that sparked controversy a decade ago.) Some researchers believe the bubble temperatures may be as high as the sun's nuclear furnace -- and might lead to backyard sources of almost limitless power.

At an Acoustical Society of America meeting in Nashville, both Oak Ridge teams reexamined the dispute -- without resolving it. But sono expert Seth J. Putterman at the University of California at Los Angeles boosted the outlook for sonofusion. He reported peak temperatures of 1 million C. in collapsing bubbles. While that's a 10-fold jump, another 10-times increase would be needed to sustain fusion. And D. Felipe Gaitan, chief scientist at Impulse Devices Inc. in Grass Valley, Calif., said his company is now building a much more powerful system, and it might produce solid evidence of fusion by yearend. Doctors are testing many cancer drugs that prevent tumors from spreading. But researchers from Seattle's Dendreon (DNDN) Corp. report they have developed a vaccine that, at least in mice, prevents cancer from developing in the first place. At a recent conference, Dendreon scientists said they have isolated abnormal peptides -- small bits of proteins produced by cells -- and these seem to be closely associated with subsequent tumor development. Antibody-stimulating vaccines derived from the peptides were given to 10 mice, which were then injected with breast-cancer cells. All of the vaccinated mice have remained tumor-free, while all 10 mice in a control set died of cancer within 35 days. Dendreon has applied for a patent on the technology.


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