Darpa has come up with a way to put out fires with sound waves | Hacker News Reader

Darpa has come up with a way to put out fires with sound waves

noisemademedoit.com

50 pointsmactac15 comments

Some of us believe in historical determinism. I'd argue that sound waves would be putting out fires in 2012 whether or not the government put money into it.

Edit: I'm sorry, this was a poor attempt to joke about some of the sentiments seen in the recent Vint Cerf thread regarding the article in the WSJ

http://news.ycombinator.com/item?id=4295786

On what basis? Who else is working on this?

but this is bullshit, in almost all of the sciences we advanced because of someone who had more insight then anyone else, if any one of those stumbled we might not of gotten anywhere close to what we have today.

what if edison has succeded and we built a bunch of dc waystations across the entire country would we ever consider switching to AC? what if all the railway/trolley companies werent destroyed by the car/oil companies? what if we recounted bush vs gore would 9/11 still have happened? if Hitler's mom aborted would Germany still have turned out militant? what if einstein died in the holocaust and no one figured out general relativity till 50 years later? what if sony never broke with Nintendo and we ended up with a console monopoly by Nintendo?

historical determinism is bullshit spewed by people who cant create and try to bring down the accomplishments of others. just because you cant contribute shit doesn't mean other people wont.

edit: sorry, people that actually believe historical determinism piss me off

If Hitler hadn't been born, you would still have Mussolini and Stalin.

If Edison had succeeded, we could never have had anything like a national grid because DC transmission was too inefficient until long after the invention of the transistor.

Einstein was only one of several scientists working on theoretical physics near the turn of the 20th century; he didn't go from cave painting to special relativity all on his own.

The rest of your examples have nothing to do with scientific advancement.

You should read What Technology Wants. The first chapter or two contains a few leaps of logic, but the rest of the book makes a compelling case for emergent behavior leading to most of our scientific results.

but no holocaust and Mussolini/stalin were fuck ups, stalin only got power because of sheer population and being on the winning side.

EXACTLY we would of had a shitty inefficient grid because edison had a stranglehold at the time, this would of pushed back everything.

when einstein came up with special reliativity it was dubbed only 3 other people could understand it and no one else could of came up wit hit, he sped up the field by who knows ho many years.

so many of the world events were based on little things, and if we kept using electrical trolleys are knowledge of systems like that would of been much better.

Wonder if they use a similar technique to putting out oil well fires, albeit on a much smaller/controlled scale. "Typically high explosives, such as dynamite, are used to consume all the local atmospheric oxygen and snuff the flame out." [1] Granded, they are not using dynamite, but if they can duplicate the displacement of oxygen it could probably work.

[1] http://en.wikipedia.org/wiki/Oil_well_fire#Extinguishing_the...

I wondered the same thing, and then I started wondering if you set up an infrasonic standing wave, what sort of pressure differential could you maintain? Could you drop the pressure in the nodal low spots down by a millibar? 10? 20!?

That started me down the path of trying to figure out how much energy transfer was there in a standing wave and rather than run down the physics rabbit hole yet again, went back to work.

Don't you, by definition, have to drop the pressure by exactly as much as your raise it?

Meaning just use the DB of the sound, and calculate the sound pressure.

No, that is different. You need three things to get a fire:

- something to burn

- oxygen

- a sufficiently high temperature to ignite stuff.

You only need to take any of the three away to extinguish a fire.

According to the description, this spreads the flame over a larger area and decreases the depth over which burning can occur. So, it works by lowering the temperature.

The "high explosives" method works by taking away the oxygen.

This is actually a problem in land based gas turbines that are used for power production. A neat application to putting out sound waves.

I wonder, what's the biggest fire that this could put out? And how much the placement of speakers matters?

I can imagine in 20 years, fire departments having pick-up trucks with huge speaker cones driving around to put out fires.

Or not having fire departments at all; speakers in your home for your home automation system (with Siri and Google Now plugged) would be used to put the fire out from the inside.

Your home is going to be like a deck on the Enterprise sooner than you think.

Sure, but that won't help put out car fires, etc.

I do look forward to having fire-proof homes that incidentally have amazing sound systems built into the walls.

i can already see sysop geeks setting up budget for massive sound systems in the dc. y'know, for fire protection...

And it was called the Sonic Screwdriver.

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