Fusione fredda Renzo Mondaini—trascrizione

I managed to extend a remaining coiled tungsten wire section that I thought would be too short, allowing another test. I used, as previously, about 36 ml tap water + about 1g acetone + 1ml 0.1M KOH solution

Below is a video of the last few minutes of testing with it. Current readings from the multimeter were highly unstable. The bright white flashes were associated with strong EM noise that could be heard on loudspeakers nearby. This time the wire seemed to perform well until the very last few moments when a large section vaporized, ending the test.

magicsound

I think so; that likely came from the test performed a few hours ago with the short tungsten wire section of which I previously posted a gif animation. The jar was clean before that and I haven't made tests with other wires in the interim.

Alan Smith

I was thinking about bringing it back in operation, but I'm not sure of where to put it. I have a fan in the area blowing air on the HV power supply to keep its temperature low during the tests. In the past I observed a far too high sensitivity of that Geiger counter to air flow, probably due to radioactive dust in the environment (radon, etc). This seems to be a general characteristic of Geiger counters and has been reported by others in the past as well with different models.

The background gamma level is also relatively high in my place (85–100 CPM or more on average depending on the exact location) and with significant daily variation, so relatively small and brief signals might be difficult to discern from it.

The USB RF receiver I recently got, on the other hand, at the minimum gain setting basically only sees noise produced by the plasma reaction (although in the past few days I've been mostly rather crudely gauging the intensity by how much noise could be induced on nearby loudspeakers).

To be honest, I'm generally more concerned about not getting zapped by the high voltage applied to the manually operated electrode and not breathing too much metal dust or gases emitted from it, or causing chemical explosions. At higher electrolyte concentrations (which seem counterproductive with my power supply, I eventually found) hearing protection is also required.

I added a Geiger counter inside a clear plastic box at about 30 cm distance from the test setup. The Geiger counter is partially shielded from background radiation with a small VRLA battery and a 1-mm thick steel sheet, but the Geiger tube faces the setup without significant obstructions.

Using the same electrolyte solution prepared yesterday (which might have lost some acetone although it retained the odor), I made a few tests with 28ga Ni200 wire, 26ga Kanthal A1 wire, 1mm tungsten rod, trying to maximize the RF output with a small antenna located close to the Geiger counter. Testing was performed throughout the period highlighted in the graph below with red color.

The 1mm tungsten rod seemed to perform the best and produced low-level continuous crackling noise from nearby speakers, but only when trying to cause a plasma just below the water surface, with the tip somewhat incandescently heated. The Kanthal wire did not seem to produce anything despite glowing brightly. I could not get it to glow bright below any significant depth. The Nickel wire melted easily and did not seem to produce as strong RF as the tungsten rod, no matter how thick (from melting) or hot I could get it, oddly.

I didn't get the impression that the Geiger counter reacted positively to the reaction and if anything readings appeared slightly lower during the tests. However from the data it appears they were about on average, and in any case within noise margins.

The most significant observation perhaps is that—although it's kind of obvious—it became clear that the RF noise is strictly related to the current instability observed with a multimeter.

I will keep the Geiger counter active for the next tests.

I got 28AWG titanium wire, but unfortunately it did not seem to perform very well.

Out of the box it appeared like a rather dull metal with no obvious indication that it was composed of titanium. The wire is easy to bend.

However upon testing, it clearly behaves differently than the wires tested so far. Under cathodic electrolytic action, it tends to turn into a brittle blue-black material. This is probably titanium hydride, but some non-stoichiometric oxide may be present too.

The ball shape is formed because when it gets hot the wire appears to start combusting at very high temperatures. This process cannot be stopped easily by immersion in water (i.e. it will combust under water).

The remaining surface is still conductive, at least the voltages used. Sometimes it turns into a light green/gray, irregularly-shaped compound that looks like this. It's conductive in this form:

Other times this combustion eats up large portions of the wire at a time, like here, but strangely slowly compared to copper or molybdenum. Note the 'ghostly' appearance of the bottom portion of the wire (EDIT: perhaps it was a low-current arc?):

The "combusted" wire can be used on the top of the water level for a kind of plasma heating reaction (from atmospheric glow discharge), but it cannot be immersed too much in the electrolyte without immediate quenching. It appears to slowly vaporize and form residues (possibly TiO2) in its immediate surrounding when kept at high temperature like this.

Overall, in any case, performance for the plasma electrolysis experiments described in this thread seems rather poor, perhaps even less performing than the Kanthal wire I got a while ago. Keeping the plasma going on for more than a few millimeters under the water level does not seem feasible. Since this behavior is similar to that of the Kanthal wire, it's probably mainly the fault of the oxide layer formed on the surface, and possibly the high resistivity.

No change observed with the Geiger counter. RF emissions were rather low too, together with the current instability effect observed earlier, also after adding about 1g acetone and 1 ml 0.1M KOH solution as for the previous tests.

I'm wondering if in general terms the suitability for the plasma electrolysis reaction has to do with the reactivity series of the elements.

Putting aside that copper would probably perform very well if it wasn't for its low melting point, subjectively speaking, the relative performance observed with the materials tested so far seems to more or less reflect the position on the table.

Al (FeCrAl) = Ti < Fe (carbon steel) < Ni < Cu < W

If this was the case, precious metals would work best, although the tests could end up being very expensive under the testing conditions I'm using.

Gupta et al in this paper (EDIT: paywalled) suggest that among Pt, Ta, W, graphite, Pt worked best, so it could be roughly consistent with the above idea. They do point out however that factors like oxide thickness, porosity and so on may be affecting the results.

In any case, in 10-14 days I should have some 0.35mm tungsten wire. The last test made with the 0.25mm one from a broken halogen lamp, and the apparent performance of the 1mm rod in producing RF emission compared to other materials are worth a further check.

Just wanted to report that following a brief test with a rather diluted HCl solution (just a few small drops in about 50ml water, but no acetone addition) using a Ni cathode it appears that oxidation in general and not just the material, makes the intense RF emission associated with current instability more difficult to observe.

Initially the fresh 28ga Ni wire seemed to work rather well, producing continuous noise on nearby equipment (loudspeakers), but as soon as it started becoming incandescent from the reaction, oxidizing in the process, the effect disappeared. With HCl this was clearer, because it leaves chloride residues on the surface that seem to strongly increase oxidation especially after drying in the atmosphere. A more or less uniform, visibly light green NiO layer was formed on the cathode.

Assuming—of course—that this RF emission is actually the desired outcome and that I'm not getting sidetracked toward a fruitless path, then it is clear that metals that do not readily oxidize nor form a strong oxide layer will work better in general, following what I mentioned in my previous comment on the reactivity series of the elements.

Similarly, conditions that prevent oxidation—e.g. 2–3 wt% acetone addition—will also promote the effect.

As for gamma emission, so far with my setup I haven't observed statistically significant departures from background levels that could be ascribed to the testing performed.

LeBob

The performance appears to be mostly determined by the conditions at the interface between the electrolyte solution and the immersed active electrode. I don't think an argon atmosphere above the water surface on its own would be particularly helpful here unless perhaps the gas was finely bubbled in the solution. However, perhaps running the experiment at a reduced pressure could help water evaporate faster and make the reaction easier to observe; or possibly ultrasonic agitation could help forming a gas sheath around the electrode and starting the reaction quicker too.

For clarity, by the way, what I'm seeking is not simply the electrolytic glow plasma reaction commonly observed, but conditions where strong(er) RF emissions are produced. Oxidized electrodes do work to varying extents in producing a plasma reaction, but not in producing intense RF emission, not even when incandescent. I should point out however this could be a peculiarity of the power supply I'm using.

Sometime this week I should be receiving 0.35mm tungsten wire to test, by the way.

LeBob

For what it's worth, this researcher observed a lower power consumption during anodic electrolytic plasma after injecting air in the solution. I haven't read the papers in detail yet, but my guess is that similar methods may work for cathodic plasma as well, and with other gases:

• https://www.researchgate.net/p…_dye_wastewater_treatment
• https://www.researchgate.net/p…_Radicals_at_Plasma_Anode
• https://www.researchgate.net/p…_method_and_air_injection
• https://www.researchgate.net/p…jection_and_NaCl_Solution
• https://www.researchgate.net/p…f_microbubble_and_Fe2_ion

Personally I think it could be interesting to see the effect of ultrasonics on the reaction, but at the moment I have no idea of where to start in order to assemble a cheap system to test this.

There's a risk however that the ultrasonic transducer could emit much stronger RF than the actual reaction, and that it might cause acetone (which appears to be beneficial in small amounts) to outgas quickly from the solution.

Curbina

Here I am only thinking that the microbubbles produced by ultrasonic agitation could possibly make the plasma reaction much easier to start, since what is normally required for it to start is the formation of a gas/water vapor sheath around the active electrode (this implies that with cold water it will not work very well, or not work at all). Cavitation must be likely already occurring to some extent close to the electrode, particularly when it gets incandescent.

As for pH: during electrolysis or electrolytic glow plasma, positive charges/ions may accumulate in large amounts close to the cathode (and viceversa); possibly this could affect local measurements. While looking for a reference for this I found this paper which also mentions about OH^. radical production as loosely suggested by Mondaini. The authors employ a variation of the plasma experiments described in this thread, however (plasma above the electrolyte surface):

https://www.ispc-conference.org/ispcproc/ispc21/ID331.pdf

Quote

We experimentally investigated some of initial reactions in liquid induced by electron or positive ion irradiation from atmospheric pressure dc glow discharge in contact with liquid. The local change of pH in the solution was visualized using pH indicator. OH radical generation yield in liquid was observed by chemical probe method. Possible reaction process was qualitatively discussed.

I finally received tungsten wire for more testing with cathodic contact glow discharge electrolysis (CGDE). It turned out to have a diameter of 0.45mm rather than 0.35mm. Out of the box it appears as a dark but shiny wire. It's a rather hard material which takes some effort to cut. The best way to use electrically connect short sections of such rigid wires in my case has been wrapping copper wire around it and the supporting welding rod.

Compared to 28ga Ni200 wire, which already seemed to perform well, this tungsten wire appears to produce strong RF noise right away. A condition for this to happen is that the wire becomes incandescent. I used the same solution I prepared last time, which initially had about 50 ml of tap water, 1 ml of 0.1M KOH solution and 2% weight acetone. These values have likely changed with use but they are not critical.

With this solution the immersed tungsten wire portion remains quite clean, while the portion above the water surface slowly oxidized and becomes dark. Below is after a brief test:

The higher the temperature, the stronger the RF, but at very high temperature the wire appears to get eroded very quickly. The tip becomes very sharp in the process:

When the wire is allowed to reach very high temperatures (e.g. by increasing current density), it starts blinking bright white as observed earlier on, but it also gets eroded very quickly in the process. So this mode of operation is probably best avoided.

I haven't made very extensive tests yet, but in the past hour (since I began testing) I have not noticed any serious increase in background gamma emissions.

Below is a video of a testing session of a few minutes. At about 1:54 I set the camera exposure to a fixed setting: