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 ")
China Steals Strato Airship Design From Google App Engine
'...war-balloons, or, as it would be more correct to call them, navigable aerostats.' - George Griffith, 1893.
Biohybrid Jellyfish Explore The Ocean
As predicted, and detailed, by science fiction writers!
3D-Printed Exoskeleton Learns From Your Hand
'...small electric motors at the principal joints worked the prosthetic framework by means of steel cables...' - Fritz Leiber, 1968
Smartwatch Powered By Slime Mold
'Living protoplasm incorporated into the Ampek F-a2 recording system...' - Philip K. Dick, 1966
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
RoboBallet The Dance Of Cooperative Robots
'...an integrated seven-unit robot team.'
Chrysalis Generation Ship to Alpha Centauri
'This was their world, their planet —
this swift-traveling, yet seemingly moveless vessel.'
Alexa+ And Its AI Brain Improvements
'What's it do?' he asked. 'It amuses.'
Does CloneRobotics Offer A True Android?
Is this What Little Girls Are Made Of?
Brain Implant Is Able To Capture Your Inner Dialogue
'So you see, you can hide nothing from me.'
Are AIs Going Rogue Like Hal 9000
'I know that you and Frank were planning to disconnect me...'
Animated Tumblebugs On Astounding Cover!
'Gaines and Harvey mounted tumblebugs, and kept abreast of the Cadet Captain...'
LingYuan Vehicle Roof Drones Now Available, ala Blade Runner 2049
Accompanied by a small selection of similar ideas from science fiction.
China Steals Strato Airship Design From Google App Engine
'...war-balloons, or, as it would be more correct to call them, navigable aerostats.'
The First Space Warship For Space Force
'Each of the electrical ships carried about twenty men...'
Biohybrid Jellyfish Explore The Ocean
As predicted, and detailed, by science fiction writers!
Should AIs and AI Robots Demand Rights?
'This robot is a creature... It is a manlike being. Therefore, like any other talking, thinking man, he is entitled to a court trial!'
Robot Learns Human Tool Usage By Imitation Learning
'I got one of those new electronic cameras...'
Companion Caregiver ChatGPT Dolls
'Every Artificial Friend is unique, right?'
'Pregnancy Humanoids' From China Replace Moms
'A great many of these synthetic babies were made...'
Man Builds 200 Foot Basement Firing Range
'The basement was huge... carved deep into the rock.'
