Slashdot Mirror
Fusion In Sonoluminescence (Again)?
srhuston writes "According to a story at the NY Times (first born child req'd, yadda yadda), 'Scientists are again claiming they have made a Sun in a jar, offering perhaps a revolutionary energy source, and this time even some skeptics find the evidence intriguing enough to call for a closer look.' This has been covered here before (First, second, third) but it looks like they claim that the latest round of experiments, using better detectors, 'offer more convincing data that the phenomenon is real'." The scientists involved come from Rensselaer Polytechnic Institute, Purdue University, Oak Ridge National Laboratory, and the Russian Academy of Science; here's their press release.
So, the problem with extracting energy from this is still sustainability combined with total output right? The amount of energy invested in the system will have to be exceeded by the energy produced or else it is for naught. The things about traditional plasma fusion is that energy output is extensive, but the reaction cannot be sustained. Bubble fusion appears to be sustainable, but likely does not produce significant caloric heat......
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*cough*google link*cough*
All I want to know is when I can throw garbage in the gas tank of a DeLorean to fuel it.
It's better to vote for what you want and not get it than to vote for what you don't want and get it.
- E. Debs
This is news? We've had canned sunshine in our gift shops here in Florida for years!
666-607: 6th floor apartment of the beast
A SUN in a jar? If you think Darl is bad, just wait to see the look on Scott McNealy's face once everyone starts creating his server in their mayonaise jars.
Don't blame Durga. I voted for Centauri.
Sigmentation fault - core dumped
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Do you have Wireless-Enabled Hosting(tm)?
Well, at least this finally fills that ugly hole on Wednesday in the Slashdot weekly schedule:
Monday: Patch Windows
Tuesday: Stop SCO's latest plan
Wednesday: Invent Fusion
Thursday: Patch Linux
Friday: Watch LoTR while patching Windows
Since they got Fusion out of the way early today, I think I have a little time to go bash Infinium Labs some more. Tally ho!
Without understanding all the physics here, I think there may be something to this. One of the reasons chemists are kind of intrigued with sonochemistry (chemistry facilitated by sound) is that ultrasound generates "bubbles" (for lack of a better word) where the local temperatures can reach into the thousands of degrees of Celsius. You can do some really amazing chemical syntheses using ultrasound all because of the extremely high local temperatures generated. The same idea extends to using microwave ovens for chemistry. You can do lots of reactions in a microwave because of the intense and neatly condensed amount of heat generated.
So, there may really be something to this. It would be great if it did work out.
No trees were harmed in the composition of this; however, numerous electrons were inconvenienced.
...people standing around said jar start dieing.
I was so hoping this was an item about "the son of Jar Jar". My bad. "Meesa so sorry."
I've done a bunch of work in sonoluminescence. It's deeply cool, don't get me wrong. But the highest temperature we were able to measure was about an order of magnitude too low for fusion. Even if our measuring had an error factor of two or three (not impossible, since we had to dope the water to get high enough brightness for using a spectrometer), I'm far from convinced.
I've had this sig for three days.
In other news today, Hell has frozen over. Satan responded to the sudden freeze by noting, "Oak Ridge National Laboratory and the Russian Academy of Science collaborating on nuclear research? Who would've thought it possible?"
Who do you get to be an expert to tell you something's not obvious? The least insightful person you can find? -J Roberts
>>>JasonF, a scientist at NCSU, has created a perpetual motion machine!
"In this house, we obey the laws of thermodynamics!" - Homer S.
Young lady, in this house we obey the second law of thermodynamics!
how the end always is
The claim is that the bubbles create temperatures high enough to create fusion.
--- Ban humanity.
... they squeezed tiny gas bubbles in the liquid so quickly and violently that temperatures reached millions of degrees and some of the hydrogen atoms in the solvent molecules fused, producing a flash of light and energy.
Please note that this is *NOT* cold fusion.
Iraq: war to save the U
From the press release, "The research team used a standing ultrasonic wave to help form and then implode the cavitation bubbles of deuterated acetone vapor."
Deuterium to fuse, acetone vapor to help it form gas bubbles.
It turned out that the secret to making this work was to use polywater as the liquid medium.
SIR, PUT THE BONG DOWN AND STEP AWAY PLEASE!
I know the stupid filter says "Don't use so many caps. It's like YELLING" but I AM YELLING!
here's a link from a local paper.
An interesting quote from the article:"Willy Moss has been trying to reach that brass ring for a long time, and he's had way more money than Taleyarkhan and way more facilities," George said. "And when Taleyarkhan said he had neutrons, (Moss) sort of chimed in and said, 'No, no you don't,' because he was hard on the trail trying to get there first."
Seems there is a bit of anonymity here. In the defense of the researcher(s):The evidence now is "far more compelling," he said. "This time around, before publication took place, I deliberately involved a series of highly acclaimed physicists to come down to the lab and review the experimental setup and the way we were obtaining data and look at the experimental data."
After receiving positive reviews from them, he took the findings to the management of Oak Ridge, which conducted its own internal review, making the forthcoming publication "perhaps the most peer-reviewed paper in the history of the Oak Ridge National Laboratory," Taleyarkhan said.
Don't we already have several technologies to replace oil? If this is working and could be used Great!
But when will it roll out and effect the everyday Joe?
Just curious why we're always pushing the limit higher, when we haven't pushed the bar up.
*DrugCheese rants*
if this particular discovery bears fruit, it might be really cool, as the cost for implementing it appears much lower than other attempted fusion experiments. But, how much would a true power plant cost? Or, how much would a "home unit" cost, since distributing the grid would probably be a better long-term solution to our power needs.
Then come the obvious questions about environmental impacts, as energy = heat, and here is an energy source without effective limits, hence limitless energy, and limitless heat. Perhaps they can use some of this limitless energy to pump the generated heat out of the planet? (ie, big heat radiators? Energy recycling? Something totally out of my depth?)
The cesspool just got a check and balance.
"Going Supernova" requires a certain amount of mass. Our sun is too small. For a star the size of our sun, the death is a gradual swelling of the outer layers and a contraction of the core, resulting in a nebula with a white dwarf in the middle.
A drinking-cup sized chunk of fusion wouldn't have much umph at all. Considernig the processes going on are completely different from the kind in hydrogen fusion bombs, I'd say the worst explosion is from overheating and overpressurizing of the chamber - something like a handgrenade.
=Smidge=
$discovery is really cool. Once again, $scienceFictionAuthor was a visionary when he wrote about this concept in $book. I hope that we can come up with some practical applications using $discovery soon.
$wittySig
Sonoluminescence: an Introduction
Single Bubble Sonoluminescence HOWTO
The liquid is deuterated acetone. AFAIK, this is essentially nail polish remover doped with deuterium. Probably as brain-rotting as normal nail polish remover, only a bit more dense.
As a separate point, I don't entirely buy the "less radioactive waste" argument of this press release or the fusion community in general - I used to work in a physics lab, and one of the PhDs there made what I thought was an excellent point - In order for fusion to be commercially viable, ultimately the reaction has to turn a generator somehow, probably via heat generated by fast neutrons. He couldn't see how fast neutrons from a fusion reaction could be any less nasty than fast neutrons generated by a conventional fission reaction.
Am I off in the weeds here, or is this correct? Anyone out there with nuclear physics experience care to weigh in with an opinion?
"The plural of anecdote is not data" -- Bruce Schneier
> ... but I've taken enough chemistry to know that what comes out must
> equal what goes in...
Well you had better go take a physics course if you wish to understand this topic because the proposition is that a non chemical process (fusion) is at work.
> What is this solvent?
Who cares at this early stage. If the process proves out the race will be on to find the ingredients/processes that produce the holy grail of fusion research; a net gain in energy. Until that happens it is only a labratory toy, even assuming fusion is actually occuring.
Democrat delenda est
I though Sunny Delight was "Sun in a jar"
Actually after a while the walls of a tokamak have to be changed because neutrons makes them radioactive on the long run.
So yes this would produce radioactive material too, but a material less nasty and lesser material than a fission reaction.
Iraq: war to save the U
When scientists are sure of their data, the first thing they do does not involve a press release. I'll be more convinced once I've seen it in a reputable journal
Well, you better let it out! *click*
HOW'S MY POSTING? CALL 1-800-POSTING
Our setup is presumably somewhat different than ours, but here's the summary of the five-minute do-it-your-self sonoluminescence kit:
Take a spherical flask, around 100ml or so. Bigger will mean lower frequencies but higher amplitudes needed. Fill the flask with water from the tap, up until the mensicus is just at the neck of the flask (that is, the water body is as close to spherical as possible). Attach on opposite sides of the flask two speakers, and somewhere else (we just put it between the two speakers, 90 degrees from each, but it doesn't really matter) a microphone.
Hook up a frequency generator to your speakers. Hook up your mic to a 'scope. You'll see the frequency being generated being picked up, slightly muffled and distorted, by the microphone. Tune your frequency until you get resonance; it'll be really, really obvious as the peaks of the mic output become much sharper than the input frequency. The actual frequency depends greatly on the water volume, and is very sensitive to temperature; for our particular setup 48kHz - 52kHz seems about right.
Turn off the light. Allow your eyes about 10 minutes to adjust. With this setup, you'll have light about as bright as a 5th-magnitude star. Any stray light at all will limit your detection. Slowly pump up the amplitude of your input. As the amplitude goes up, resonance frequency changes slightly, so tune as needed. The total amplitude needed is not very high, but it's probably going to be in the top half of a non-amplified signal generator's range.
The gas in the bubble, in this case, is a combination of (some) water vapor and (mostly) outgassed dissolved gasses. That's why we used tap water, above. Bottled water has much less dissolved gasses, so will be much dimmer. Also, water that sits there outgasses, so if you don't change your water it'll get dimmer over time. But we can exploit the fact that it's this added gas that glows, if we want.
Drill a very small hole (seven mil, for us) in the exact bottom of your glass flask. Attach a capilary of the same ID, or a bit more. Attach capilary to a gas canister, and input a low flow rate of gas while running the experiment as above. The idea is to have a near-constant flow of extremely small gas bubbles. If the bubbles are too big, nothing will happen at all; the temperature doesn't get high enough. If there are too many bubbles, you disturb resonance something awful. If the bubbles don't pass through the center, they'll be ignored. But if you get it just right, you'll get a nice burst of light (0th or 1st magnitude) when each bubble goes through, appearing as a constant point of light to the naked eye.
Argon works really nicely for this. Nitrogen works too. You don't want to use anything that dissolves too easily, because it will saturate the water; too much gas outgassing results in bubbles too big to glow. And you'll have to chance the water quite often, because everything will dissolve too much eventually (although helium seems to either dissolve less or just outgas from the top of the flask more quickly).
I presume what they're using in this experiment is hydrogen/deuterium gas, either fed in ordissolved in the water.
Since I should be studying for a midterm, I'll cut off my tutorial now, but feel free to ask more!
I've had this sig for three days.
When I was an undergrad at BYU, I had a friend who was working in this field. He worked under a mountain (less background radiation from cosmic rays). Made measurements while running, and compared to background when not running. Sadly, back then ('96 or '97) there was less radiation when running than when not (*very* disturbing). I told him he should change his project from "fusion generator" to "radiation absorber". Of course, the field has had 7-8 years to develop since then, so hopefully things are better now. Still, you have to wonder if it could scale up to a useful level....
An order of magnitude too low is also within merely one order of magnitude of success. What actual quantity was in the range? Degrees Kelvin? Joules:m^3? Order of *decimal* magnitude, logarithmic, other? In a statistically distributed energy system, an average miss by 0.1% might mask hits in 1% of the material, balanced by farther misses in the other 99%. And if you were really only 33% off, considering a 2-3x error margin, might their experiment not have been more precise in efficiency, and in measurement, offering a hit at the threshold?
When fusion is industrialized, I expect that some processes will far exceed the fusion thresholds, for their own specific reasons. The threshold is not a bullseye, but rather a welcoming shore of a virgin territory. News of our drawing ever nearer is tantalizing, but not discouraging, as we prepare to colonize the territory.
--
make install -not war
Perhaps I should clarify. We got these results when attempting to reproduce these results, which is why I doubt them. Our results were also consistent with our earlier results trying to estimate the peak temperature possible by sonoluminescence in a given fluid (which is, theoretically, unique for any particular fluid); both results were roughly an order of magnitude smaller than needed for fusion.
I've had this sig for three days.
...tastes better than Bud.
ARG!! Must. Not. Answer...
A major difference between the sun and a large jar is mass and pressure. Stars must be larger than a certain mass threshold to be capable of a supernova event. At this time I forget what that threshold is but I do know that if Jupiter (sometimes considered a brown dwarf star) collapsed to become a true star it could not end its life in a supernova but it could produce nova events during its life span. The reason for this is that it does not have the mass to generate the inward pressure needed to suppress the outward pressure of the reaction. As the outward pressure builds up it will eventually become greater than the inward pressure, once it does it will become a nova. If the inward pressure is sufficiently powerful the star will begin to fuse higher elements (e.g. H+H=He, He+He=Li, etc.) and the outward pressure will exceed the inward pressure and in this case will result in a supernova destroying the star. A jar (or even an eventual facility based on this technology) simply is not massive enough to produce a supernova; this is what makes fusion as a power source so attractive. Without monitoring and adjustments the reaction simply ends. Our current fission systems do not require an artificial environment to make them function. I.E. the fission reactions have occurred naturally here on Earth and can have uncontrollable catastrophic results if not carefully monitored and adjusted.
NarratorDan
"If you're not confused by quantum mechanics, you really don't understand it." - Niels Bohr
If it can be used to subjugate the native population of Mars, I'll be happy. They need to be moved out so we have room for our steakfruit farms.
I thought they were not using gas. I thought they were just using acetone who's hydrogen had been switched with deuterium... And ( from an earlier slashdot story on this ) wasn't the acetone used to minimise the amount of gas emitted into the bubbles so that the point they collaped onto was smaller and so more energy intense?
Eat at Joe's.
http://scienceblog.com/community/article2389.html
Does anyone remember this sonoluminescence article:t this.asp?c lip=%2Farticles%2F20011006%2Fclip%5Ffob3%2Easp
http://www.sciencenews.org/scripts/prin
what I found particularly funny/interesting is the last lines of the article, which read:
"Cavitation bubbles in synovial fluid may even explain the sound of "cracking" knuckles, he ventures. And if that's the case, he says, "I'd be willing to bet pitchers of beer that cracking knuckles will also generate small amounts of luminescence."
Read up a bit on fusors.
Desktop fusion isn't very hard. Hobbyists do it with stuff they build in their garages.
A sustainable fusion reaction (i.e. one which pays for itself with the energy it produces) is the hard thing.
How ironic is it that I just started reading Voodoo Science last night, and the first chapter deals with Cold Fusion. The author notes that with the wide discreditaion of Cold Fusion, the new Fusion in a Jar proponents are coming up with similar things - but with different names - to Cold Fusion.
I have a few questions for this type of fusion (Those of you who have read the book, or are up on the cold fusion controversy will get this):
1) Can I have a cup of tea?
2) How many neutrons are emitted over the background noise?
3) How is the health of the lab assistant? (Related to question 2).
Try to hack my 31337 firewall!
Desktop fusion is no big deal, after all - the Farnsworth-Hirsch Fusor (
Here's a link ) does this.
The fusor operates by accelerating deuterons in a static electrical field towards a central locus ('juicy nugat center')(grin).
The trick to a fusor is that there's a lot of possible factors to setting one up:
among other factors. more info is at a homebrew club of amateur experimentors
I've been tempted to try this, but my wife has overruled all discussion of it. She has something against hot neutron sources in the house when we have 3 small kids. Alas. (Especially since this thing emits the particles in 3 dimensions, so shielding would be significant.)
SO: MY QUESTION FOR THE EXPERIMENTERS: WHAT IS THE TOTAL ENERGY (JOULES) PUT INTO THIS EXPERIMENT VS. HOW MUCH EMITTED? Is this going to be another wildly inefficient methodology, or does it have advantages over Fusor or Tocamak designs?
-- Kevin J. Rice
Unitarian Church: Freethinkers Congregate!
Please see my other postings in this thread.
Also, it's true, we didn't try to recreate the exact same conditions as in this latest paper, mostly because our work predates it; and I don't even know what there solvent is, so I can't even say for sure if we've tested that. But we did reproduce most of the earlier work that lead to the other fifty or sixty claims of 'fusion' in sonoluminescence, with consistent negative results; we also verified the (accepted) fact that solvent doesn't make a huge difference.
I've had this sig for three days.
Causing fusion is, in fact, not hard to do. Slash recently had such an article: College Freshman Builds Fusion Reactor. Unfortunately, it's getting the reaction to generate more energy than it consumes, is the problem. The bubbles may heat to 1 million degrees, but a few thousand atoms at a 1 million degrees will quickly lose its heat to the surrounding billions of atoms of matterial. This is why conventional reactors have been attempting to heat a large mass that is contained by magnets--the heat stays at those levels and hopefully enough heat can be tapped away to run some generators.
Bel, the mostly sane.. "Of course I can't see anything! I'm standing on the shoulders of idiots." -- Me
Now I am not a physicist or a chemist so this really exposes my ignorance but... what effects would doing this in a zero-g have? No need for a container to keep the spherical shape, this would aide in outgassing. Not sure how to supply the stream of bubbles, but if they could be introduced right to the center somehow, they would not move from there until they were 'ignited'.
Underloved Movies and Pub Quiz: donotquestionme.org
Fast neutrons hitting water and acetone give less heinous crap than fast neutrons hitting lead and above, basically.
Thanks for clearing up the solvent... makes sense. Acetone is good stuff for sono, and it has a decent density of hydrogen/deuterium. I'd like to know if they really found an effect they could obtain with acetone and not water...
I've had this sig for three days.
"Neutrons are slippery little rascals," he said. "They can fool you. They can bounce and show up around corners you don't expect."
Yep, ran into three of them on the way to lunch this afternoon at the corner of Hargett and Fayetteville St.........
Yep. Less gas gives you higher temperatures, less light. It's a tradeoff. But for show-and-tell, more light is better. It's also much easier to figure out temperature with more light, and then project how temperature increases as the amount of gas gradually decreases; with no extra gas at all, trying to get a reliable spectrum was the most difficult thing I've done, and even then the error bars were huge. (For reference, with no extra gas at all, and degassed water, our original setup, as described, ticked a photomultiplier tube less than a million times a second. That's essentially the number of photons emitted over a significant (1% or so) portion of the sphere. Our next setup was built specifically to make that case more managable, but it was still sketchy.)
I've had this sig for three days.
It's an interesting idea. The only complications I see are stabilizing the water sphere, mounting speakers or PZTs on the water sphere, and actually getting it in zero G.
Upon further thought, the rewards as a result of having no flask seem to shrink in comparison to the problems posed by the above points. Good thinking though - It would be a neat experiment to have the ability to carry out.
The stream of bubbles is for demo purposes, you don't want it in a real system. Bubbles are induced in the center by vaporization of the solvent, if no gas is present (actually, it may be that some minimal amount of gas is needed, but there's always /some/, so this is a none-issue).
Keeping the spherical shape, though, it going to either require a container or something close to magic. When you put sound waves through the sphere, it's going to distort, and resonance means that you're in a positive feedback loop. Unless you can apply sound energy equally across the surface of the sphere (from what I understand, applying x-ray energy evenly across a sphere was one of the bigger problems in thermonuclear weapons), a container is needed.
I've had this sig for three days.
Several years ago I did quite a bit of work with Sonoluminsecence for my high school's science and engineering fair. Made it to the State science fair (anyone interested - the parent's tutorial is a great place to start).
The bit I'm particularly interested in is the stream of bubbles being supplied to the flask. When we did our setup, we just used tap water and let the bubble form spontaneously (or in some cases visibly drawn downwards from the water's surface). Getting argon or some other gas artificially introduced is a great idea. I would just wonder how difficult is it to align the stream of bubbles.
I'm a science nerd, but this idea is almost enough for me to dust off the old apparatus and try again with this innovation.
And people said the same thing about electricity. Sure, it's neet and it makes these bulb things glow, but how will it heat my house, cook my food, suck dirt from my rugs, chill my milk, etc...
Producing the energy is just the first step. If this does actually work you can bet your testicles that someone will figure out a way to harvest the energy.
Boobies never hurt anyone. - Sherry Glaser.
Good News:
Piping hot coffee or soup in seconds.
Bad News:
Everything metal in kitchen becomes mildly radioactive from neutron bombardment.
Good News:
Rats, mice, cockroaches hate the sound of a sonofusor in operation, emptying cities of vermin.
Bad News:
Sound also drives dogs into a frenzy of mindless leg-humping. Except Boston Terriers, whose tightly sutured little skulls explode.
Good News:
Leads to development of ultra-efficient (but low thrust) rocket motor that uses water as a reaction mass.
Bad News:
All water outside of Mars orbit turn out to be owned by Capella OmniVolatile GMBH, who charge a heavy fee, payable in increasingly rare Boston Terriers.
Stefan Jones
The bitter lessons of a veteran coder: http://bitterprogrammer.blogspot.com
The liquid is deuterated acetone. AFAIK, this is essentially nail polish remover doped with deuterium. Probably as brain-rotting as normal nail polish remover, only a bit more dense.
As a separate point, I don't entirely buy the "less radioactive waste" argument [...] In order for fusion to be commercially viable, ultimately the reaction has to turn a generator somehow, probably via heat generated by fast neutrons. He couldn't see how fast neutrons from a fusion reaction could be any less nasty than fast neutrons generated by a conventional fission reaction.
They aren't. But the energy also comes out as fast helium, which has a charge and is easy to decellerate, liberating heat.
The point is that, for a given amount of heat energy produced, there's a LOT less radioactive crud produced with fusion than with fission.
= = = =
However:
Let's stuff in some boric acid instead of heavy acetone and see if THAT works. It's a LOT harder to light off. But B-11 + H-1 -> 3 He-4 + LOTS of free energy and NO neutrons.
You do get a small amount of neutrons from other reactions that might take place in an environment that could light that reaction, such as B-11 + He-4 -> N14 + slow neutron, but those are very few and (at least in this case) very low energy.
= = = =
Now I'd prefer to run that reaction in a near-vacuum, excited with pulses at a microwave rate. The three He neuclei come off at very well-defined energies (and thus velocities). So you can design a decellerator in the form of a klystron and extract the power as microwaves - some of which you can recycle to pump the ignition reaction directly, the rest to rectify into more convenient electrical power. NOT a heat engine and VERY efficient.
Some of your particles will hit the structure, so from those you mostly get heat (though you might also scavenge some electricity by taking advantage of the current from the particles themselves and the secondary emission produced by the collision and the resulting x-rays).
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
I think you're deep in the weeds.
Most radioactive waste from a fission power plant comes from decaying fission fragments - that is the left-over elements which are produced after the fissile material has split and released its energy in the form of the kinetic energy of the fission fragments which find themselves awfully close together with the same charge and not enough of the strong nuclear force to hold things together, plus the kinetic energy of the neutrons born from the fission process and some directly produced radiation.
These fission fragments then decay through a long decay chain up toward lead. Most of them have relatively long lives and produce high energy gamma so they create a problem.
Fusion power will also create fusion products - but those products tend to be more stable - grabbing neutrons from the stew and much more rapidly settling down into nuclides that are much less radioactive than those produced by fission.
Of course there ARE fast neutrons produced during the fission and fusion process. Neutrons born from fission are fast neutrons, very high energy. In all fission power reactors those neutrons have to be slowed into thermal equilibrium (lose a LOT of energy) by having elastic collisions with some material - say the hydrogen atoms in water (the material that slows the neutrons is called a "moderator") so they have a reasonable chance of interacting with another fuel atom and cause fission. U235 likes thermal neutrons to fission.
During the termalization process some neutrons will scatter out of the core, "leaking out" of the reactor core. And they interact with the primary shield. They make some things radioactive. The materials that go into reactor construction are choosen to reduce the nasty things that can get really radioactive - like, say, cobalt one of whose isotopes (Cobalt-60) decays giving off a very nasty gamma which lead doesn't shield particularly well. (another story).
So some materials will be irratdiated by the high energy neutron flux of a fission reactor and become radioactive. But the worst is done by the fission products of the reactor. Think one Curie of waste per watt of power at the end of core life as a thumb rule and remember that a Curie is one whale of a lot of radioactivity.
Firstly, is it something where they could have a whole vat of these bubbles being created and destroyed with sonic waves constantly and through this vat you could have water pipes that would create steam and drive a turbine?
This would not generate any extra energy. It is simply using energy to cause vibrations that heat up water and generate steam. The change in phase causes a high enough pressure to cause a turbine to generate electricity. In each of those steps, energy is wasted (it's the law!).
What the article is talking about is supplying enough energy to facilitate a reaction that could cause two hydrogen atoms to form a helium atom. When this occurs, the mass of the helium atom is slightly less than the sum of the two hydrogen masses. Since thermodynamics says the mass had to go somewhere, we account for the loss with an increase in energy (a la E=mc^2). The amount of energy released by this reaction is theoretically substantially greater than the energy used to force the two atoms together. At least, that's the gist of it.
Don't confuse fusion with free energy,however. Fusion comes at a price, and it's the coversion of mass into heat that leaves you with two less hydrogens and one more helium, so there still is a fuel that is 'burned'. Luckily, our favorite proton-electron duo is the most abundant element in the universe.
BUBBLE FUSION, the apparent generation of fusion energy through theviolent collapse of bubbles in a liquid tank, has been reported in apaper about to be published in Physical Review E (Taleyarkhan etal., upcoming, probably March 2004). The paper, a followup to acontroversial report published two years ago(http://www.aip.org/enews/physnews/2002/split/5 79-2.html), reports"statistically significant neutron and gamma ray emissions" aftersound waves and pulsed neutrons hit a chilled liquid acetone tankspiked with deuterium fuel. The researchers (Rusi Taleyarkhan,formerly at Oak Ridge but now at Purdue, 765-494-0198,rusi@purdue.edu ) report the observation of flashes of light(sonoluminescence) as well as the emission of neutrons with energiesof less than or equal to 2.5 MeV---what you would expect if pairs ofdeuterium atoms were fusing together to produce energy in theirsetup. While the researchers describe various improvements to theirexperimental setup, in response to comments received in theiroriginal paper 2 years ago, critics (including Aaron Galonsky,Michigan State, galonsky@nscl.msu.edu, 850-267-8976 by phone untilApril 1) still have a number of concerns. According to Galonsky,the data for neutron emissions is lumped together with data ofgamma-ray emissions. While separating neutron and gamma-ray signalsis challenging, it is necessary to have a clean neutron-onlyspectrum to have an unambiguous demonstration of nuclear fusion.Willy Moss of Livermore (925-422-7302, wmoss@llnl.gov) says"Although I believe that thermonuclear sonofusion [not to beconfused with cold fusion] may not be impossible...I am still notconvinced... I believe that additional tests need to be done andmany should have been performed and discussed in the paper, forexample...if neutrons are being generated, then how about moving thescintillator further away from the sample to see if the signaldecreases, due to the decreasing solid angle of the detector?"(Other experts, Richard Lahey, RPI, laheyr@rpi.edu , 518-276-6614, aco-author on the paper; Mike Saltmarsh, Oak Ridge, 865-576-6915,saltmars@mail.phy.ornl.gov, co-author of a paper that attempted toduplicate the initial results but reported a null result---seeShapira and Saltmarsh, Phys Rev Lett, 19 August 2002)
Attending purdue university i read this today in our campus paper. The link to the article is here: http://www.purdueexponent.com/interface/bebop/show story.php?Date=2004/03/03§ion=campus&storyid=n uclearfusion
We used "expensive" ($20 or so) piezo drivers with a really clean output in our (slightly ultrasonic) range for our original stuff. Our bigger setup ended up needing more power, so we went to fancier transducers, but they're not needed.
The mic is entirely for your own reading, if you're tuning frequency by hand. Anything that gives a clean output in the 60kHz range is fine, but, of course, this isn't a standard microphone.
I've had this sig for three days.
"and how did he manage to generate 1.21 gigawatts of electricity with only a steam engine? A giant capacitor?"
A FLUX capacitor.
DUH.
+++ATH0
I wonder if these results may lead to legitimacy for the claims of Grigg's hydrosonic pump -- a boiler-sized device that claims to generate over-unity heat generation from cavitation. The creator claims that it generates sonoluminescene which is its primary source of power.
Of course, as with any supposed "free energy" device, there's a lot of claims like, "Scientists have done tests that verify that it works," but I've never seen any published papers on the fact, and the device has been apparently known in the "free energy" fringe for over ten years, and supposedly there are buyers already using it to heat their water for much cheaper than usual.
(I keep meaning to look up this guy. He supposedly lives in my hometown.)
If it's for-profit but free, you're not the customer -- you're the product (e.g., the Slashdot Beta's "audience").
I don't know how it works but triboluinescence is distinct from nuclear fusion - it's probably a chemical reaction of molecules in crystals generated by mechanical energy that emits light. I don't believe triboluminescence results from nuclear fusion.
I don't know if the humor was intended or not, so excuse my humor detector if so...
Issuing a press release to the general public before peer review just reeks of pseudoscience. "Look what we did! It's so cool that the respected journal would have covered it up! In your face, respected journal!"
Sure, what they claim may be possible, but I'll be much less likely to believe it until I see it validated by other scientists.
*****
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Unlucky, however, is that most (all, afaik) man-made fusion reactions don't involve that proton-electron duo.
They involve heavy hydrogen (deuterium, hydrogen with a neutron) and heavy-heavy hydrogen (tritium, hydrogen with two neutrons), which is much more rare. The result, by the way, is not just one helium - it's a helium and a neutron for a net mass loss of about 2AU per reaction.
The activation cost of fusion using normal water is much, much higher than when using heavy water. There are processes to produce both of these isotopes (tritium can be produced as a side-reaction from the fusion, but deuterium must be filtered from water), but they're not especially capable of producing large quantities easily. But we've got to crawl before we can walk; once we get controllable, sustainable, and energy producing fusion, then we can worry about switching over to a fuel source that will actually make it practical to use for power.
Mod me down and I will become more powerful than you can possibly imagine!
What the article is talking about is supplying enough energy to facilitate a reaction that could cause two hydrogen atoms to form a helium atom. When this occurs, the mass of the helium atom is slightly less than the sum of the two hydrogen masses. Since thermodynamics says the mass had to go somewhere, we account for the loss with an increase in energy (a la E=mc^2). The amount of energy released by this reaction is theoretically substantially greater than the energy used to force the two atoms together. At least, that's the gist of it.
Grammatical nitpick: the atoms don't get together, check their new weight against the required weight of their new self, and discard the rest through energy in accordance with the regulations from the heavenly bureau of thermodynamics.
Other than that, seems spot-on to me.
I dont know if i am noticing it more now or it is because Indians are actually doing better on the global stage. Rusi Taleyarkhan, the key player in this discovery/invention, obtained a bachelor's degree in mechanical engineering from the Indian Institute of Technology in 1977. He came to the United States shortly afterward for graduate studies at Rensselaer Polytechnic Institute, located in Troy, N.Y. In addition, he obtained a master's degree in nuclear science and engineering in 1978 and a doctorate in the same field in 1982. In all this talk about foreign workers coming to the USA, their contribution to American and Global knowledge is left unmentioned. This I think is tragic. In my view USA provides the best platform in the world for intelligent, creative and hardworking people and by doing that US benefits and stays ahead of the pack of nations. How I wish India could emulate US of A and make the smart people across the world work in India.
Deuterated acetone is fairly cheap (and less viscous than heavy water, so it is a good medium for cavitation). What would realy convince me would be repeating this experiments with partialy tritiated deuteroacetone. This would be hugely expensive (tritium is one of the most expensive common radionuclides) and unpleasant(because of the radioactivity of T). But D+T reaction has so much lower activation energy than D+D and it produces plenty of neutrons, so the detection should be so much easier, orders of magnitude above what they see right now.
(All common fission nukes and the fission parts of thermonuclear nukes are boosted with about half a gramm of T mixed in with D, to generate enough neutrons for complete fission of plutonium before the explosion spills it apart. Hiroshima non-boosted bomb had only 20% of theoretical yield. The infamous "Neutron bomb" is just a small boosted plutonium fission nuke, overboosted with excess T+D mix and without a reflector shield, so that excess of neutrons is produced and allowed to escape)
I doubt that we will ever figure out - and I suspect that even if we did figure out we couldn't do much about it
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Of course that doesn't do too much. So you put a plutonium rod in the middle as a "spark plug." That gets some fusion going from the flood of neutrons, but most of what that does is just give more neutrons which would otherwise fly off and not contribute to the explosive force unless you surround the works with U-238, which fissions from the flood of neutrons.
And people call this a fusion device. This is relevant to the discussion of table-top fusion because even uncontrolled fusion is hard to get -- the original Teller idea of the "Super" which would be just sticking an A-bomb next to a tub of deuterium simply doesn't work, and it is a Good Thing because otherwise A-bomb explosions could start a fusion chain reaction in the Earth.