Cold fusion

[matrixscarface]

Has anyone heard of cold fusion? people say its a hoax, people say its gods gift to free energy..but if it is true it is a low energy nuclear reaction and also a chemically assisted nuclear reaction.. does anyone know how to make this?!? i dought this is real. what are your thoughts?

[Buffy]

There's a news brief in this month's Scientific American. Briefly, although conspiracy theorists have tried to claim that the government is trying to supress the "truth" about cold fusion, about the only places funding it have been the DOE and the Office of Naval Research. The results have been "inconclusive" Tests show "something" happening, although not very much in the way of net energy is produced, and no one has been able to show that the energy is not produced by simple chemical reactions as opposed to nuclei actually "fusing" which ought to produce a *lot* of energy.

 

Cheers,

Buffy

[C1ay]

Has anyone heard of cold fusion? people say its a hoax, people say its gods gift to free energy..but if it is true it is a low energy nuclear reaction and also a chemically assisted nuclear reaction.. does anyone know how to make this?!? i dought this is real. what are your thoughts?

 

Sure, back in 1989 2 scientists claimed to have discovered a way to produce it. Their research was in error though and their peers in the scientific community quickly disowned them. No one has done much work on it since but there has been a recent increase in interest. There are a half dozen or so experiments around the world searching for it, but so far it has not materialized.

[TeleMad]

Cold fusion has more than one meaning. Using one it is a scientific fact. For example:

 

“Step aside, element 114; there's a new heavyweight champ. Physicists at the Lawrence Berkeley National Laboratory in California announced earlier this week that they have created two new superheavy elements, tipping the scales at 118 and 116 protons. The new heavyweights come as something of a surprise, as standard theories had suggested that the [cold fusion] technique used to create them--fusing two medium-weight nuclei at a relatively low energy--should top out at 112.

 

…

 

Although the [element] 114 work has yet to be duplicated, the success marked an unexpected renaissance for a previously successful technique known as hot fusion, in which a beam of light isotopes is smashed into a heavier target, such as plutonium. Prior to that success, the technique of choice had been cold fusion, a gentler collision of medium-sized isotopes. Researchers at the Institute for Heavy Ion Research (GSI) in

Darmstadt, Germany, used the technique to lay claim to five elements from 107 to 112 since the early 1980s. Conventional theories suggested that neither technique [neither hot fusion nor cold fusion] would be able to form elements as big as 118 without them instantly breaking apart, or fissioning.

 

The Berkeley team's big break came at the prodding of Robert Smola«nczuk, a visiting theorist from the Soltan Institute for Nuclear Studies in Poland, who suggested that there may still be a little warmth left in cold fusion. His calculations suggested that bombarding a lead target with krypton ions would have reasonable odds of producing a few atoms of 118 after all: The compound nucleus, he found, was less likely to fission than previously thought. “ (Robert F. Service, Berkeley Crew Bags Element 118, Science, Volume 284, Number 5421, Issue of 11 Jun 1999, p. 1751)

[Qfwfq]

A link with maybe a brief excerpt or two would hog less space TeleMad. A part from that instance of CF, which isn't exothermic, there has been another around for a long time that fails to break-even by a rather small effect.

 

I'm talking about muon catalysis. The fusion certainly occurs and there's not a shadow of doubt about that. The hitch is:

 

How do you get the mus? At what cost for each mu? How many fusion events will you get for each mu?

 

Answers: You can get them quite for free, manna from heaven, but not many of them unless you find a practical way of concentrating them from a wide part of the sky into a bit of deuterium. You can also produce them easily but at a cost, at the very least an electron + 100 or so Mev. Each mu decays back to an electron after an average of 2.2 microseconds and a good bit of those Mevs go into elusive neutrini. 2.2 microseconds is quite a long time, actually. It could be time enough for the same mu to catalyse many fusion events for a total output exceeding the cost of the mu. Unfortunately, in about 1% of the fusion events, the precious mu is carried away by the absent-minded new-born He atom and this truly removes it from the production line. One (1) percent is a low figure but it is the figure for each single event and we need an average of many events for each mu. Hence that measley 1% fiercely chops down the average output for each mu. Count in that the 100 or so Mev/mu cost is the lower limit and certainly not the average cost in practice.

 

... as opposed to nuclei actually "fusing" which ought to produce a *lot* of energy.

How much it ought to produce depends on how many nuclei fuse. :naughty:

[TeleMad]

... into elusive neutrini.

 

Neutrini?

 

Qfwfq: How much it ought to produce depends on how many nuclei fuse. :naughty:

 

No, it depends on how much mass is converted into energy in the fusion process. Since different amounts of mass are converted for different nuclei, a mere counting of nuclei isn't sufficient.

[TeleMad]

... into elusive neutrini.

 

Neutrini?

 

Qfwfq: How much it ought to produce depends on how many nuclei fuse. :naughty:

 

It depends on how much mass is converted into energy in the fusion process. Since different amounts of mass are converted for different nuclei, a mere counting of nuclei isn't sufficient.

[Qfwfq]

The decay of the mu is a weak interaction. I can't remember the Feynman diagrams offhand but, as well as gamma, the decay is bound to produce at least a neutrino and energy would likewise be lost in producing the mu. I'll look it up when I can.

 

Without getting into too much technicality, including calorimetry effeciency, an order of magnitude estimate will primarily be based on the number of events. Then, of course, one must reckon on a few factors as well.

[matrixscarface]

and how would you start your own cold fusion project? can we do it in our basement? i hear tell about it being possible to do that? whats needed and how do you do it?

[Qfwfq]

can we do it in our basement?

Well, not so easy... You could capture a few mus instead of using homegrowns, a good layer of lead slows them and catches them, but then you've gotta channel them into your deuterium at as high a concentration as possible, replacing electrons in deuterium molecules. Easier if you can produce a mu beam.

 

Providing enough mus coming into your deuterium, it's easy, the reaction is catalysed. What's hard to beat is that 1% of thief He atoms that grab the mu despite the recoil. Research has been done on it but a break-even hasn't yet been found. Not all that terribly much funding went into it and, when the news broke about the bogus cold fusion, there were some justly angry people around, indignant at it receiving such greater coverage. Journalists and politicians go for whatever seems coolest at the moment, even when it comes to cool fusion.

[UncleAl]

Pons and Fleishman; old as the hills; beaten to death by the Japanese amongst others. In short, deuterium nuclei were to closely approach and fuse by quantum tunneling, their charge repulsion compensated by the palladium lattice. MeV nuclear events were to be modulated by eV chemical events.

 

In practice, the thing is totally irreproducible if it does anything at all. No radiation release and no fusion products are validly detected in any case. Absent LiOH electrolyte, nothing at all happens aside from the occasional explosion of D2/O2. Exotherms are caused by an Li-rich Li/Pd rind violently alloying with bulk Pd. Li/Pd braze alloys are common. Li dissolving in Pd outputs a purely amazing amount of heat plus a mjaor depression in melting point, alloy vs. Pd metal. Sodium dissolving in mercury also has a huge exotherm - enough to boil the mercury even at low Na final concentrations.

[Qfwfq]

Pons and Fleishman

That's what those names were! I couldn't remember them. They made the bogus claim that got so much more resonance than mu catalysis, which is on perfectly reasonable grounds.

[BlameTheEx]

I posted on this topic before here:

 

http://hypography.com/forums/showthread.php?t=649&highlight=cold+fusion

 

The gist of my post was a link to this article which suggests that Cold Fusion may not be quite the "Junk Science" we have all assumed:

 

http://www.spectrum.ieee.org/WEBONLY/resource/sep04/0904nfus.html

 

There is a very short article here which suggests to me a possible mechanism. Could collapsing bubbles provide the necessary temperature and pressure?:

 

http://www.eurekalert.org/pub_releases/2005-03/uoia-tic022805.php

[Qfwfq]

Your second link talks of temperature four times that of the sun's surface and presumeably more inside. The temperature in the centre of the sun is far greater than at the surface. I'm a bit skeptical about a collapsing bubble being sufficient for causing fusion.

 

Actually, 20,000 Kelvin is a little over three times the surface of the sun and anyway I'm a bit doubtful of it being reached in the collapsing bubble.

[BlameTheEx]

Qfwfq

 

Doubt all you want. It can't be concidered better than a long shot - but it is valid science.

More links here:

 

http://www.physicstoday.org/vol-55/iss-4/p16.html

http://www.nature.com/news/2005/050228/pf/050228-7_pf.html

[Qfwfq]

I don't rule out that a tiny amount of plasma may form in a collapsing bubble but 15 or 20 thousand K isn't nearly enough to cause fusion, afaik.

but it is valid science.

What do you mean by "valid science"? Some of the things these articles say don't seem to match up. In particular, I smiled at the notion that "only in a plasma" could an oxygen molecule become ionized without breaking up.

 

In any case, considering the way they induce the phenomenon, I think we'll be waiting a while before we see a breakeven.

 

Wouldn't it make more sense, to research purposes, for them to take a saturated solution of deuterium in pure heavy water and see if any helium was produced?

[BlameTheEx]

I would call it valid science because valid scientists are co-operating in research on this and publishing results. There is apparently theoretical reason to believe that bubble fusion is possible. Only possible mind you, not probable or certain. Given the benefits of success that is good enough reason for scientists to research the matter.

 

Sadly I am not an expert on bubbles collapse to tell you if heavy water would have been a better bet.