Slashdot Mirror
More Evidence for Tabletop Fusion
heptapod writes "Researchers at Purdue University have statistically significant evidence that their tabletop fusion experiments were successful. Yiban Xu's experiment different from an earlier Oak Ridge experiment using a different and cheaper source of neutrons than Oak Ridge's pulse neutron generator. Surpassing break-even point still eludes the grasp of science."
Statistical evidence of fusion at this level is indeed impressive; however, while fusion experiments such as this others remain below the break-even point, they shall yet be little more than a labtable source of neutrons. We await developments from the latest in the field.
Are they counting break-even as getting back more energy than needed to operate the ultrasound source ou they did count also the expense of producing the deuterated acetone and their expendable neutron source?
It reminds me of when people say hydrogen burning cars will solve all emition problems because they produce water. They don't count the emissions that may be needed to produce, compress and ship the hydrogen to the nearest gas station.
http://www.dieblinkenlights.com
It reminds me of when people say hydrogen burning cars will solve all emition problems because they produce water. They don't count the emissions that may be needed to produce, compress and ship the hydrogen to the nearest gas station.
The trick with this one is in the may.
Maybe someday we'll find a technology that's clean-burning and energy-efficient to the point where oil is no longer the most cost-effective way to make energy. Say, maybe nuclear fusion. Or maybe oil will eventually get so expensive that other energy technologies start to look not so bad by comparison. But if we ever reach this point, because of the massive installed base and economies of scale of oil systems, especially the ones in cars, we and our economies will still be dependent on oil. So it won't matter that the newer technology is better, we'll keep using oil anyway. That's bad.
Hydrogen may at first be ultimately dependent on "dirty" oil and coal to make the hydrogen in the first place, but because it decouples energy production from energy use, in the long run it gives us the capacity to move on to better energy sources. It's like a nicotine patch, okay, it technically doesn't address the addiction but the thing is eventually you get to take the nicotine patch off.
On top of this, there are situations where if you can't eliminate emissions, moving the emissions is a desirable second best thing. Like, of course we're not making advances in our contribution to global CO2 levels if all these cars in the city burning oil are replaced with a bunch of cars burning hydrogen [PLUS] one huge smoke-belching oil-burning hydrogen plant. But, well, if the city is Los Angeles, and the city is basically one huge smog-trapping bowl surrounded by mountains, and the smoke-belching hydrogen plant is on the other side of the mountains, then never mind the global CO2 levels, you've still made Los Angeles a significantly more pleasant place to live.
Irritable, left-wing and possibly humorous bumper stickers and t-shirts
Where's the nuclear powered car we were promised back in the 1950s?
Some genius figured out that providing every man, woman, and child with sufficient nuclear material to create an atomic pile wasn't such a good idea?
From a technology perspective, there were a few other problems as well. Off the top of my head:
- Radiation: You need a lot of shielding to stop the "hard" stuff like Gamma, Neutron, and X-Ray bursts from escaping a functioning pile.
- Weight: All that shielding results in a lot of extra weight.
- Inefficiency: A "simple" atomic pile may be relatively safe (from a runaway reaction perspective), but it's not particularly efficient, nor can it be actively controlled.
In any case, the Ford atom car was never seriously developed. It was just an "Atoms for Peace" idea that was kicked around as a promotional gig.
A far better use for nuclear tech is in Merchant ships. Today's merchies pay extraordinary amounts for diesel fuel, have limited range, and burn fuel at the rate of gallons per feet. Nuclear reactors could provide these ships with more cargo space (no fuel tanks!), greater speed, longer endurance, and better turn-around times.
Unfortunately, the case of the NS Savannah turned off the private sector to the idea of a nuclear merchant ship. There was no real problem with the ship herself, but rather the fact that she was ahead of her time (crude was still VERY cheap back then) and one of a kind (no infrastructure to support her) meant that she couldn't compete in the market.
The equation today is a very different one from the equation back then, but concerns related to the control of reactors and nuclear fuels have placed road-blocks in the way of reviving the idea.
Javascript + Nintendo DSi = DSiCade
However, as a geek, I know that the Dark Ages were as much caused by the change in the fuel economy from wood to coal as the retreat of the Roman Empire.
However, as a pastry chef, I know that the Krebs cycle causes metal fatigue in steel structural support beams.
However, as a ballerina, I know that the Pythagorean theorem causes the release of neutrons from radioactive material.
However, as a professor of French literature, I know that penicillin causes cost overruns in long-haul LTL shipping.
All employees must wash hands before seeking equitable relief.
Not only that, but fuel for very large diesel engines contains lots of residual oil, and is very high in sulfur. 5000 ppm plus. I understand that England recently traced the source of some acid rain problems to maritime activity. They've practically eliminated their sulfur output from coal power plants, etc, so boats are now the biggest producer.
That heavy diesel fuel is nasty stuff. Basically, its what's left over after they boil off all of the gasses, gasoline, kerosene, road use diesel fuel and the lower grade heating oils. They have to pre-heat it quite a bit to get it to burn in an engine, otherwise it's about as good as filtered crude oil--slightly less viscous.
Nuclear power would be a huge step forward in this area... I can't agree more. Throw in some modern reactor and propulsion designs and you'd have a terribly efficient and manuverable ship. Might even make fuel a bit cheaper for the rest of us if it caught on... Bonus.
Constitutional rights may be respected, repealed, or modified; but they must never be ignored.
You can get tabletop fusion with a TV high voltage supply, a glass bulb, some wire, and deuteriums gas. That's been known for decades and is used as a neutron source commercially. People build those things for science fairs. It's called the "Farnsworth Fusor" (I know, in light of Futurama it sounds like a joke, but the fictional character was named after the real one).
Why don't we all have flying cars, then? Because you can't get a net energy gain with the Farnsworth Fusor--it seems to be impossible in general to do so, the numbers just don't work out.
Of course, even if you do make it efficient, it's not exactly "clean energy": even with so-called aneutronic fusion, a few percent of the fusion reactions will generate neutrons, which, for realistic power generation, results in a neutron flux that causes the power generation to be quite dirty. Not as dirty as fission--disposal should be easier--but don't expect something harmless you can just run in your basement.
So, tabletop fusion isn't really anything impressive: there are probably lots of ways of getting fusion on your tabletop. The question is how you make it efficient enough to useful amounts of energy out of it. And cavitation seems no more promising there than inertial confinement in the Farnsworth Fusor. But maybe if enough people keep playing around with this, someone will get lucky and find something that works.
There was a BBC Horizon documentary on this nuclear fusion sonoluminescence phenomenon that casts strong doubt on the validity of previous work conducted by this researcher. The acid test for the occurence of fusion is the release of a neutron at the exact instant that the flash of light from sonoluminescence occurs. The Horizon team used a detector that can record the neutron releases at the required instant in time. After recreating Taleyarkhan's experiment according to his published journal papers, results were disappointing. None of the neutrons that were detected occurred at the same instant of any of the sonoluminescence flashes. The extra neutrons were explained away as originating from the emitter used to generate bubbles, or from external sources. No doubt rivals will challenge the statistically significant tritium claim. Tritium does occur naturally in significant quantities in any mass of heavy water (deuterium oxide).