Another one, with an image
Another article, telling something moreNote to journalists: Please report that this research was presented at a meeting of the American Chemical Society
ANAHEIM, March 27, 2011 — A curtain of flame halts firefighters trying to rescue a family inside a burning home. One with a special backpack steps to the front, points a wand at the flame, and shoots a beam of electricity that opens a path through the flame for the others to pass and lead the family to safety.
Scientists today described a discovery that could underpin a new genre of fire-fighting devices, including sprinkler systems that suppress fires not with water, but with zaps of electric current, without soaking and irreparably damaging the contents of a home, business, or other structure. Reporting at the 241st National Meeting & Exposition of the American Chemical Society (ACS), Ludovico Cademartiri, Ph.D., and his colleagues in the group of George M. Whitesides, Ph.D., at Harvard University, picked up on a 200-year-old observation that electricity can affect the shape of flames, making flames bend, twist, turn, flicker, and even snuffing them out. However, precious little research had been done over the years on the phenomenon.
“Controlling fires is an enormously difficult challenge,” said Cademartiri, who reported on the research. “Our research has shown that by applying large electric fields we can suppress flames very rapidly. We’re very excited about the results of this relatively unexplored area of research.”
Firefighters currently use water, foam, powder and other substances to extinguish flames. The new technology could allow them to put out fires remotely — without delivering material to the flame — and suppress fires from a distance. The technology could also save water and avoid the use of fire-fighting materials that could potentially harm the environment, the scientists suggest.
In the new study, they connected a powerful electrical amplifier to a wand-like probe and used the device to shoot beams of electricity at an open flame more than a foot high. Almost instantly, the flame was snuffed out. Much to their fascination, it worked time and again.
The device consisted of a 600-watt amplifier, or about the same power as a high-end car stereo system. However, Cademartiri believes that a power source with only a tenth of this wattage could have similar flame-suppressing effect. That could be a boon to firefighters, since it would enable use of portable flame-tamer devices, which perhaps could be hand-carried or fit into a backpack.
But how does it work? Cademartiri acknowledged that the phenomenon is complex with several effects occurring simultaneously. Among these effects, it appears that carbon particles, or soot, generated in the flame are key for its response to electric fields. Soot particles can easily become charged. The charged particles respond to the electric field, affecting the stability of flames, he said.
“Combustion is first and foremost a chemical reaction – arguably one of the most important – but it’s been somewhat neglected by most of the chemical community,” said Cademartiri. “We’re trying to get a more complete picture of this very complex interaction.”
Cademartiri envisions that futuristic electrical devices based on the phenomenon could be fixed on the ceilings of buildings or ships, similar to stationary water sprinklers now in use. Alternatively, firefighters might carry the flame-tamer in the form of a backpack and distribute the electricity to fires using a handheld wand. Such a device could be used, for instance, to make a path for firefighters to enter a fire or create an escape path for people to exit, he said.
The system shows particular promise for fighting fires in enclosed quarters, such as armored trucks, planes, and submarines. Large forest fires, which spread over much larger areas, are not as suitable for the technique, he noted.
Cademartiri also reported how he and his colleagues found that electrical waves can control the heat and distribution of flames. As a result, the technology could potentially improve the efficiency of a wide variety of technologies that involve controlled combustion, including automobile engines, power plants, and welding and cutting torches, he said.
The Defense Advanced Research Projects Agency (U.S. Department of Defense) and the U.S. Department of Energy funded this study.
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The American Chemical Society is a nonprofit organization chartered by the U.S. Congress. With more than 163,000 members, ACS is the world’s largest scientific society and a global leader in providing access to chemistry-related research through its multiple databases, peer-reviewed journals and scientific conferences. Its main offices are in Washington, D.C., and Columbus, Ohio.
Why do I feel the urge to sing Ghostbuster's Theme?Since the time humans first began to control fire around 400,000 years ago we have had just a few simple tools to douse the flames.
Now some Harvard University chemists believe they have found a way to bring fire suppression into the digital age by controlling flames with electricity.
During a series of experiments to study the chemical nature of fire, scientists were surprised to learn that by applying an electrical field to a burning flame it easily went out. All they needed to do is wave a wand-like, electrified metal wire near the flame.
'What did I do wrong?'
"As a scientist you find it fascinating, but you have to control your emotions and ask how nature is trying to deceive you," Ludovico Cademartiri recalled about the experiment. "I was thinking, 'What is wrong with this experiment? What did I do wrong'"
As it turns out, he and other chemists in the lab of Harvard chemist George Whitesides had done nothing wrong.
Nearly all previous study of flames and electric fields involved those generated by direct current, or DC, instead of alternating current.
"What we discovered is that by applying an oscillation field, AC voltage, the effects are completely different," Cademartiri said. He reported the findings Sunday at the national meeting of the American Chemical Society.
In their experiments the researchers used a 600-watt power source — about the same as a modest home-theater stereo — to create an electric field near flames as large as 18 inches tall.
They found the field created an organized "flow" of charged particles inside the flame, and that the flame was literally pushed away from the burner and put out.
It's too early to say how well the effect will scale to larger flames. Cademartiri said he and his colleagues have begun collaborating with the U.S. Naval Research Laboratory in Washington, D.C., which has facilities devoted to the study of fire.
"I'm very optimistic that something very relevant is going to come out of this new capability," he said.
More efficient energy?
The most obvious effect is fire suppression. But there are other applications as well. The world still derives about 90 percent of its energy from burning coal, natural gas and other products.
The potential to better control the internal flow of combustion could lead to more efficient energy production, among other benefits.
"Our hypothesis was that if we could find any new way to control flames in a novel way, we have a real chance to make a real big impact," Cademartiri said. "This is our hope."
Anyway, I'd love to find the paper for this research, but Google is saying "nono".
Anyone can help?
