Subject: Viridian Note 00216: Piezoelectric EelBruce Sterling [email@example.com]
Attention Conservation Notice: Kind of a Viridian gizmo Christmas toy knickknack military blobject thing.
"Reinventing the eel
"AN ARTIFICIAL eel that can harvest energy from the
currents of the ocean, a river or even a sewer is being
developed by engineers in the US. (((Electronic sewer
apps are a big trend lately.))) The eel's tail thrashes
around in turbulent underwater flows, flexing to produce a
current that charges a battery.
"The idea is to provide long-term power for remote-
sensing and surveillance devices that the US Navy drops
into the sea. Currently, these use small dynamos to
generate power, but their turbines clog quickly, rendering
"'We have built a prototype that works well and we're
now developing a larger-scale version,' says Sean Kammenn,
chief engineer on the project at Ocean Power Technologies
in Pennington, New Jersey.
"The prototype eel is essentially an underwater flag
the size of a football scarf. It's made of a
piezoelectric polymer called polyvinylidene fluoride
(PVDF), which produces a small current when flexed. The
flag is only a couple of millimetres thick and so
flutters easily when it is anchored in a turbulent flow.
(((Cut to the chase and make that scarf into a wearable
couture item. PVDF might also make great aquatic galoshes
to go with your piezoelectric Gershenfeld jogging
"The energy this produces trickle-charges a battery.
'The prototype produces about 10 milliwatts, but the eel
we are developing for the US Navy will produce about 1
watt of usable power,' says Kammenn.
"The navy plans to use the eel to power sensors
dropped in remote ocean locations. These will measure
factors such as sea temperature and salinity for weather
forecasts and broadcast the data via a satellite to the
mainland. (((Wow! A fabulous Greenhouse app!))) The eel
may also power underwater microphones for listening to
underwater traffic. 'The Navy drops lots of sensors that
are only able to broadcast data for about an hour because
of battery limitations. However, the eel should produce
power for at least a year,' says Kammenn. ((("Kids! Buy
your own Navy-Surplus Slimy Spy Eel!")))
(...) "The team has already carried out trials in the
lab and is hoping to begin ocean testing in a tidal
estuary sometime during 2001. 'We're looking for a
suitable site right now,' says Smits.
"The eventual objective, however, is to make an artificial eel that can swim. By reversing the flow of current to the piezoelectric material, the researchers believe it should be possible to make it flex in a way that drives it through the water like a real eel. The idea is that an eel carrying surveillance equipment and a fully charged battery would be dropped into an enemy sewer or storm drain, stopping to recharge whenever necessary." (((Those of you who read the Viridian issue of TIME DIGITAL (Jan-Feb 2001/2026) probably thought we were making it all up about those sewer-based "jellybot" surveillance devices. Another "Viridian Imaginary Product" swims gamely toward real-world existence!)))
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