Piezoelectric Generators

Teahouse writes: "The U.S. Navy has developed this polymer "eel" that they dump in the water and get a trickle charge back. The biggest application for this would be for deep sea bouys that track weather across the pacific. This could extend accuracy, and lifespans...and save a few lives along the way. Here is the story." NOAA uses buoys that are solar powered and are left out for a year or more at a time, but I imagine that if this worked they'd be interested, too.

Comments

Repeaters for undersea cables?

[Cy Guy]

If these thins can work at extreme depths, then maybe they could be used for undersea cables. In an ideal situation, perhaps the cable itself could be coated with or paralleled with a series of these to generat significant amounts of current.

Another application might be for space tethers is the could be hung like flags off the length of the tether to provide power for warning lights.

Great reading here!

[Natalie's Hot Grits]

I have been doing a reserch paper on this stuff, some great resources also found at:

http://www.piezo.com/kgs.html
http://www.avxcorp.com/prodinfo_productdetail.asp? I=331&ParentID=146
http://www.ndt.net/article/yosi/yosi.htm
http://www.tokin.com/Tokin_America_Products/37/p37 /p37.html
http://www.biospec.com/HomePage/Review.html
http://www.morganelectroceramics.com/pzmat1.html

Have fun...

SOSUS

[John Jorsett]

I suspect that the Navy really developed this as a way to expand the SOSUS (SOund SUrveillance System) sonar network, which presently uses long undersea cables to connect the sensors to the monitoring point. Being able to drop buoys wherever and immediately start collecting data would be a great boon. There have been earlier unattached buoys used by the Navy, but they were typically deployed against a specific threat and died quickly. A perpetually self-powered one that didn't have to poke a large solar array above the water and betray its presense would be far better. It would certainly be much less vulnerable to having the enemy (and the occasional accident) cut the sensor cables.

Re:SOSUS

[DerekLyons]

SOSUS and sonobouys serve two very different purposes.

SOSUS is used for [extremely] long range tracking, but is not all that accurate. [Hey, there's a submarine out there, about 250 miles north of Bermuda! Great for getting count's and rough positions to vector a hunter-killer, but not for targeting a weapon.] To get even that level of precision requires huge fixed arrays. [To know where a target is, you have to know where your sensor is. Your long life bouy would have to be moored to be useful, and mooring cables can be cut as well.]

Sonobouys on the other hand, as you point out, are used against to prosecute a specific threat. They die relatively quickly by design, otherwise the airwaves would be jammed by bouys which are no longer required. The platform that dropped them knows where they are and thus can use that information to prosecute the contact.

There would be very little use for a drifting long life bouy. Such a bouy's sonar would be fairly short ranged, and the contact is likely to move easily beyond that range.

Football scarves

[Chuck Flynn]

A football scarf is a long (5-9ft) knitted scarf displaying the names of footballers (soccer-club players). They look like this. They're popular among football (soccer) fans in cold European climates: they let you root for the home club without having to take off your warm coat.

Rule of thumb regarding the ocean...

[Anonymous Coward]

...if you stick something in the ocean, one of
three things will happen:

1 - something will grow on it
2 - something will try to eat it
3 - it will corrode

There are *no* exceptions to this rule.

Re:Artificial lure?

[rtscts]

"we need a bigger buoy"

Re:think of what this could to for the spy game...

[karlm]

The drag caused by these is greater than the energy they put out (see the 2nd law of thermodynamics). Thus, they aren't useful if you're actively moving the object to which they're attached.

If you want these to be practical on a spy craft, you need to use a "free" source of propulsive power. That way, the efficiency losses don't matter. Of course, your craft goes slower, but you don't waste your power source.

There are some "free" sources of propulsive power in the ocean. For instance, somebody worked on a craft that used the thermal expansion of contration of a glycol solution to cause the craft to rise and fall through thermal gradients. Put wings on such a craft and you can use this vertical motion to create horizontil motion. The thermal gradients provide the energy.

Karl

I'm a slacker? You're the one who waited until now to just sit arround.

Re:think of what this could to for the spy game...

[the eric conspiracy]

The drag caused by these is greater than the energy they put out (see the 2nd law of thermodynamics).

All the second law says is that the entropy of a closed system doing irreversible work is increasing. A raft with one of these things hanging in the ocean is NOT a closed system.

Back when I was a grad student (early 70's) one of the students in my department developed a device that we called a collagen engine that worked on the same princlple. Collagen is a natural polymer that contracts is salt water, and expands in fresh water (simply taking advantage in the difference of chemical potential between water in both systems) much like the synthetic polymer described here. With this contraction, and winding the collagen fiber around a couple of tapered spindles it is possible to turn the contraction into mechanical work (which could be used to drive just about anything).

In the middle of the ocean the power source is obviously fresh water, which will gradually become contaminated by salt. When the concentration of salt in the fresh water equals that of ocean water there is no potential energy left that can be converted to kinetic energy, and the machine stops.

i'm an eel

[vsync64]

twitch twitch! really! can't you see?

--

Great for Pool Parties!

[danpbrowning]

This would be great for the neighborhood pool party. Just drop a few of these suckers in during a game of water polo. Bzzzap.

Artificial lure?

[silicon_synapse]

I wonder what sharks and other predators will think of this thing waving around in the water. It looks like a big artificial worm or something. Will these things have any predator repellant of any sort?

think of what this could to for the spy game....

[brad2600]

to me this seems like the perfect power source for some form of small submarine style spy tool. add a radar/sonar device, possibly a camera of sorts, a microphone maybe? these things are probably small enough to not get picked up by radar, and could be sent long distances without running out of power.

im sure you guys can think of a few uses for devices like this for use in large bodies of water as well as inside pipes and other common places you wouldnt expect survailence devices...

nifty, yet scary.....

.brad

Drink more tea
organicgreenteas.com