Science Fiction
Dictionary
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
 |
Bio Acoustic Fish Fence May Protect Great Lakes
A bio acoustic fish fence (BAFF) is being tested on a tributary about 200 miles from Chicago by ecologist Gregg Sass. The BAFF is basically an underwater sonic fence; a barrier created by outputting sounds into a wall of bubbles.
The intent is to stop invasive Asian carp species from swimming up the Illinois river and reaching the Great Lakes, which already have enough problems.
Physically, the BAFF comprises a pneumatic sound transducer coupled to a bubble-sheet generator, causing sound wave to propagate within the rising curtain of bubbles. The sound is contained within the bubble curtain as a result of refraction, since the velocity of sound in a bubble-water mixture differs from that in either water or air alone.
It uses an air bubble curtain to contain a sound signal which is generated pneumatically. Effectively, this creates a "wall of sound" (an evanescent sound field) field that can be used to guide fish around river structures by deflection into fish passes.
(An effervescent wall for fish)
1. Inside a shed on the riverbank, a signal generator emits eight chirps at varying intervals and varying frequencies up to 2,000 Hz. Two 400-watt amplifiers pump up the beeps to carp-deafening levels.
2. A compressor pushes a continuous stream of air through a rubber pipe riddled with small holes. The pipe, housed in an open steel chassis, runs across the bottom of the riverbed.
3. The pipe releases a sheet of bubbles illuminated by strobe lights flashing 200 to 400 times per minute. Alongside the pipe, 16 hundred-watt sound projectors shoot the chirping sounds into the fizz, where the noise is concentrated.
4. Native fish like trout and salmon can't hear frequencies above 400 Hz and swim through the bubbles unfazed. Carp, which perceive sound as high as 2,000 Hz, hit the piercing noise and turn back.
The first place I read about this idea was in Roger Zelazny's 1976 novel My Name is Legion; he refers to sonic curtains that can be used to keep sharks out of selected areas in underwater parks. Amusingly, dolphins can be taught to use it, and in turn teach other dolphins.
From Wired via Neatorama. See also this article on the fish fence.
Scroll down for more stories in the same category. (Story submitted 8/16/2009)
Follow this kind of news @Technovelgy.| Email | RSS | Blog It | Stumble | del.icio.us | Digg | Reddit |
Would
you like to contribute a story tip?
It's easy:
Get the URL of the story, and the related sf author, and add
it here.
Comment/Join discussion ( 0 )
Related News Stories - (" Engineering ")
Moonwalkers AI-Controlled Electric Shoes
Now that's power walking that Hugo Gernsback would have approved.
Electric Catamaran 'Explorer Eco 40m' Has 'Solar Skin'
'On went the electric-yacht faster and still faster.' - John Baker Hopkins, 1885.
Harvest Power From Tears And Blinking With Smart Contact Lens
'...he realized that it was not quite a clear lens. Speckles of colored brightness swirled and gathered in it.' - Vernor Vinge, 2001.
AI Enhances Images Your Brain Sees
'I could have sworn the psychomat showed pictures almost as sharp and detailed as reality itself' - Stanley Weinbaum, 1935.
Technovelgy (that's tech-novel-gee!) is devoted to the creative science inventions and ideas of sf authors. Look for the Invention Category that interests you, the Glossary, the Invention Timeline, or see what's New.
Science Fiction
Timeline
1600-1899
1900-1939
1940's 1950's
1960's 1970's
1980's 1990's
2000's 2010's
Current News
SpaceX Wants A Moonbase Alpha
'And he had been sent with troops, supplies and bombs to command Russia's most trusted post, the Moonbase.'
Vast Apartment Living Will Get Even More Vast
'What is your population', I asked. 'About eighty millions.'
NASA Wants Self-Driving Or Remote-Controlled Vehicles For Lunar Astronauts
'THE autobus turned silently down the wide street of Hydropole. Robot-guided, insulated from noise and cold...'
Elon Musk Says Robotaxis Will Be Ready This August, 2024
'The car had no steering wheel, and no one drove!'
Moonwalkers AI-Controlled Electric Shoes
Now that's power walking that Hugo Gernsback would have approved.
Steve Jobs: 'Capture The Next Aristotle - With AI'
'It was disturbing to think of the Flatline as a construct...'
No Tips! Robotic Food Delivery In Phoenix
'...he rewired the delivery robot so that it would serve him midnight snacks.'
Electric Catamaran 'Explorer Eco 40m' Has 'Solar Skin'
'On went the electric-yacht faster and still faster.'
Orbital Mechanics, The Liftoff, The Turnover, The Retrograde Burn
'...the huge vessel had spun, with a sickening lurch, through a complete half-circle, the instant the power was reversed.'
Harvest Power From Tears And Blinking With Smart Contact Lens
'...he realized that it was not quite a clear lens. Speckles of colored brightness swirled and gathered in it.'
Europa Clipper Plate Carries A Special Message
'...a universal cryptogram — yet it is one which can be interpreted by any intelligent creature on any planet in the Solar System!'
Micro-Robots Are Smallest, Fully Functional
'With a whir, the Scarab shot from the concealing shadows of the corner where it had hidden itself.'
AI Enhances Images Your Brain Sees
'I could have sworn the psychomat showed pictures almost as sharp and detailed as reality itself'
Illustrating Classic Heinlein With AI
'Stasis, cold sleep, hibernation, hypothermia, reduced metabolism, call it what you will - the logistics-medicine research teams had found a way to stack people like cordwood and use them when needed.'
Deflector Plasma Screen For Drones ala Star Wars
'If the enemy persists in attacking or even intensifies their power, the density of the plasma in space will suddenly increase, causing it to reflect most of the incoming energy like a mirror.'
DIY Robotic Hand Made After Loss Of Fingers
'I made them... with the fine work of the watchmaker...'
