An improvised quick carbon arc experiment [result: inconclusive]

If cavitation is defined as caused by the rapid formation and collapse of water vapor bubbles, in addition to local pressure drops as with propeller blades it should also occur with a very rapid temperature rise followed by rapid quenching.

Given that during arc discharges the temperature must be locally in the order of a couple thousands °C to several thousands °C, I think it should not be too unexpected that it occurs, or at least that's my idea (which could be wrong).

I suspect there's a balance to be achieved with arc discharge size/energy to obtain this effect; it would probably not occur (or not occur as much) with the water vigorously bubbling, but I haven't researched on this topic in depth yet.

Eventually I found that laser-induced cavitation exists and uses rapid localized heating to achieve the effect, so the above hypothesis should be possible in principle.

http://www.laserfocusworld.com…microfluidic-systems.html

However, this would be a sort of unexpected side effect, not what I planned to actually do.

A related side-side effect: https://link.springer.com/chap…1007/978-3-319-21611-9_22

axil

I can't really do much with the equipment I have and the budget I decided to allocate to it. These ones I'm doing are rather small-scale experiments. I have a couple ideas for what I'm going to do next, but cavitation isn't the primary focus. However, that it might also happen during low power arc discharges under water is an interesting side effect.

I was already aware of LeClair's (and others') experiments, by the way.

I wanted to post a sample of the the metallic reverberating sound I mentioned yesterday, which can be perceived the most when arc discharges are the brightest and as soon as they are initiated, but I realized that it cannot be recorded properly. Significant broad-band electromagnetic interference arises, causing sound distortion even if the waveform isn't clipping. The brighter the discharge, the more distortion recorded. Continuous low-temperature (reddish, low-brightness) arc discharge that doesn't sound very metallic does not cause audio distortion.

Following this test I used a different (lower quality) battery-powered voice recorder. Although the recording spectrum is different, I still get a wide-bandwidth interference covering all frequencies. To be sure it wasn't due to interference by the PSU, I also placed the recorder next to it. The wide-bandwidth noise was still present, although at a lower volume. My take is that it's caused by the arc-discharge reaction.

I'm aware that electromagnetic interference from arc discharges is a known effect.

Since there might be a disconnect between the opening post, thread title and the experiments described in the latest comments, here is a condensed summary to explain what I was trying to do. Does it make sense to any of you?

"The objective of these experiments is to vaporize with an electric arc the materials composing the electrodes and form a short-lived plasma that will hopefully host the reaction. For this a high current density (A/cm²) is required, not necessarily a high voltage.

The consumable electrodes themselves may already include the active materials, or alternatively these may be provided in the form of dissolved ions or suspended particles in a water medium."

Alan Smith

I don't have access to an optical microscope, but in the case of carbon/graphite I noticed that with discharges in the atmosphere a very fine (nanometric?) soot is produced, while under water they agglomerate into larger particles. I think the so-formed larger particles might be quite porous.

Alan Smith

Did you mean that those larger particles are the interesting ones or that there are other interesting particles?

My experimental conditions are far from being controlled or repeatable (e.g. the graphite cores I used as electrodes from an old 4B pencil have worn off almost completely [from 25mm to 12mm length for the most used one] and I don't have an exact replacement), so I'm not sure how worth would it be to send samples for photos. Do you have some from material produced in your experiments?

On a related note, occasionally I stirred the water in the small jar to suspend the deposited carbon particles in the liquid. This caused them to absorb visible light and possibly UV radiation from the arc discharges, greatly attenuating their perceived brightness, although not the color. Sometimes producing arc discharges under these conditions would form a large(r) scale plasma.

Quote from Alan Smith

I have been playing with this recently. Not interested so much in transmutation products, but in the creation of nano-carbon/graphite spheres (known as onions) to use as a catalyst framework. A work in progress.

Quote from Alan Smith

There the interesting ones. Send me some if you would like to see them, photography might be possible.

Did you mean these particles:

Carbon Onions: Synthesis and Electrochemical Applications, by John K. McDonough and Yury Gogotsi

Properties of carbon onions produced by an arc discharge in water

Alan Smith

If metal-loaded carbon onions absorb hydrogen to any significant extent in the process, you could "blow them up" with arc discharges and obtain a reaction similar to what Randell Mills of Brilliant Light Power does in some experiments for producing what he calls Hydrino, with a larger energy release than normally possible with ordinary chemical reactions.

Actually I'm wondering if in some cases I observed effects that could be ascribed to these reactions observed by Mills.

EDIT: perhaps it's worth specifying once again that in my case I used graphite from an ordinary pencil, which contains clays (composed of silica and metal oxides), so a certain amount of metallic impurities would be already included. Harder pencils contain more of these impurities but do not conduct electricity as well and they tend to be brittle when applying heat. Also, it's not clear if onion formation would still occur with such graphite.

(Table from https://arxiv.org/ftp/arxiv/papers/1107/1107.1662.pdf)

Actual composition may vary greatly from manufacturer to manufacturer.

Alan Smith

I've considered that (even though I don't really want to start spending money for LENR experimentation). The main problem is that such electrodes are much more conductive than what I'm using right now. To handle the load I would also need a large 12V battery as a buffer. Right now I'm using a 450W computer power supply connected to the mains power which can only supply 28A on its 12V rails (in practice it might be less before short-circuit protections engage and switch it off).

Another problem is that to continue with these experiments I would probably need better safety equipment, and I don't mean radiation protection. To understand why, read the following report (from my notes) on another short testing round I did today to try to confirm a couple things.

______

I've harvested a new "electrode" from an HB graphite pencil. Unfortunately it conducts less electricity than desired, partially also due longer length (31 mm) and shorter diameter (~2 mm) and likely higher amount of clays than the previous ones used. This graphite core will be the anode (+). The cathode (-) will be a steel screw of unknown composition, but I suspect rich in Cr and V. It's been already used for previous tests and has a partial carbon residue coverage that is difficult to remove.

The water solution has also been already used. It initially was grocery store-grade distilled water. It now contains previously formed carbon particles (possibly also in the form of nanotubes and onions) and has a noticeable (albeit not deep) yellow tinge from probably iron ions dissolved in it on purpose from another test.

An objective of this test is observing if the coloration and the particles will go away after performing arc discharges. A possible reason for this would be carbon monoxide (CO) production and metal-carbonyl production (e.g. Fe(CO)₅). These are hazardous, highly toxic compounds. According to Sano et al, a large percentage of the carbon vaporized during carbon arc discharges under water is lost as CO gas. In the presence of metals this would lead to carbonyl formation.

For safety reasons I normally perform the experiments with a large 70W, 500mm fan pulling air away from me. However, this might not be considered a sufficient precaution measure against chemical hazards.

Observations

The HB graphite core held well and felt it had the right electrical resistance (not measured) for the setup. It could be that the shorter diameter helped concentrating current onto a smaller area.

Following a round of testing I can confirm that the yellow tinge almost completely disappeared. The carbon particles deposited on the bottom of the jar at the end of the experiment overall increased.

Possible hypotheses for this:

• Nascent, very absorbant carbon particles (onions) removed these impurities from the water.
• Metal carbonyl formation and evaporation due to the relatively high temperature of the water. Iron pentacarbonyl evaporates at 103°C (Wikipedia), which is only exceeded in the areas immediately surrounding the electric arc. Other metal carbonyls can evaporate at lower temperatures.
• …something else?

For the record, yesterday after some testing with two strong Nd magnets from an old Hard Disk Drive I verified that the particles appear overall to exhibit weak ferromagnetism (= are attracted to the magnet) through the walls of the glass jar, so carbonyl formation didn't make the metal(s) dissolved evaporate away (or at least not to a large extent). Magnetism is not strong enough to allow separation of just the ferromagnetic particles, so I cannot be sure yet if absorption has really occurred in the porous carbon 'onion' particles (and other porous carbon particles) possibly produced.

I'm wondering if the report attached below, which was presented at the NASA Breakthrough Propulsion Physics Workshop of 1997, is related in some way to the Ohsawa carbon arc discharge experiments and similar experiments with graphite, both in atmosphere and under water like those I also performed on a smaller scale.

Here instead of using arc discharges they heated a small graphite rod with 10 second-long bursts of 500 amperes direct current until the rod reached white hot temperatures. Apparently doing so, even factoring the combustion of carbon, would result in anomalous heating with the output/input energy ratio between 1.5-2.0. I don't know if there has ever been any follow-up to this experiment. Recent contact info for the author doesn't appear to be available.

Source: https://ntrs.nasa.gov/search.jsp?R=19990023204

Ahlfors

I was already aware that he's still worked for MSE-TA until at least the early 2000's. He's also coauthored at least one paper with Dennis Bushnell and written a couple reports for NASA Langley you've already linked. I meant that there's doesn't seem to be direct recent contact information, and he seems to have disappeared from the Internet after year 2005 or so.

I guess the fact that the previously referred experiment never got mentioned again (not even in the 'Breakthrough' sections of the other reports by the same author, from a very quick read I previously had) likely means that it never really worked, but it would have been nice to read a final word on it with modern equipment.