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Looking to jellyfish to solve human jams

Whittier Daily News, The (CA) - July 2, 2006
Author: Elise Kleeman Staff Writer
PASADENA - "Jellyfish are going to save the world in three different ways," Caltech engineer John Dabiri said as he sat at his desk last week.

Maybe he's exaggerating just a bit, but Dabiri has high hopes for what he can learn from these delicate sea creatures.

By watching how they propel themselves through the water, he said, he and his colleagues can learn about how to diagnose an ailing human heart, how to build the next generation of vehicles and how to extract energy from the oceans and the air.

If it sounds like a big undertaking, it is.

Only recently did researchers start understanding the physics of jellyfish motion.

In doing so, they've found the creatures move through the sea very efficiently, creating swirling currents of water - similar to a cigar smoker's smoke rings - as they open and close their bell-shaped bodies.

"What the animals do is push off these in order to swim," Dabiri said.

Their unconventional but ancient method can make them both highly maneuverable and speedy, all the while using very little energy.

"Jellyfish can go for days without nourishment and still continue to function," Dabiri said.

The trick now is to understand how to apply the jellyfish model to other uses.

One of the first successes has been with the human heart, which fills with blood using currents similar to the ones jellyfish create.

"As a person goes through various stages of heart disease, those currents change," Dabiri said.

A healthy heart pumps like a slowly moving jellyfish, while a sick heart has the blood flow of one that quickly darts around.

Dabiri and his Caltech colleague Mory Gharib showed that such differences can be easily observed using ultrasound, making them a potentially powerful and non-invasive tool for diagnosing heart disease.

For his next project, Dabiri has turned to an even tougher challenge - building boats based on jellyfish.

But just as people never learned to fly by strapping on wings and imitating birds, he said, "the goal isn't necessarily to have technology that look like jellyfish, but to come up with engineering designs that create the same type of flows."

"I'm convinced that just trying to make devices that look like jellyfish is almost silly," he said. "We're going to have to work a little bit harder than that."

Even imitating jellyfish material, which is 95 to 98 percent water, is an unsolved challenge, Dabiri said.

Indeed, one his earliest prototypes, which he built as a grad student during his free time, looks nothing like the squid on which it was based. A book-sized floating platform of thick plexiglass holds motors and batteries, and underneath, a curved pipe jets water backward to push the whole machine forward.

It might not be much, but Dabiri is confident that in the next five years he'll have working prototypes of craft the size of a briefcase or small table to test in the 40-foot-long tank in his laboratory's basement.

The tank will also be the home for future research with squid (which use a similar propulsion system, but also use fins for maneuverability) and for capturing renewable energy from tiny ocean and air currents - another jellyfish ability.

"Its always important ... as scientists for us to work on problems that are important to people around us and not necessarily just cool," he said. "And I think this is one that's both, so I think we get the best of both worlds."

elise.kleeman@sgvn.com

(626) 578-6300, Ext. 4451
Section: News
Record Number: 4006651
(c) 2006 The Whittier Daily News. All rights reserved. Reproduced with the permission of Media NewsGroup, Inc. by NewsBank, Inc.