Fusione fredda Renzo Mondaini—trascrizione

  • That may be because of magnetic fields from the current flow through the plasma disturbing the Hall Sensor in your clamp-meter. See it it disturbs a compass-needle. Or if you don't have one, magnetise an ordinary sewing needle and suspend it by the balance point from a piece of thread.


    Here is a 10x sped-up gif animation of an old compass used in a similar test. There seems to be a response, but the movement is so small that it's difficult to tell for sure which is the real cause. I didn't notice it until I accelerated the video.


  • For the sake of reporting it: among the tests made today, one included putting an SBM-20 Geiger tube (unshielded) directly in front of the jar and connected to the Geiger counter's high-voltage terminals using 30–40 cm wires (also unshielded), in order to see if the intense RF emissions from the plasma reaction had any immediate effect on the measured radiation level like it apparently did with the multimeter probe cables.


    I couldn't notice any immediate sharp spike from this test, but it was relatively short. The average radiation level is normally relatively high in my location.


  • Then (00:58), I tried placing the multimeter-clampmeter without cables close to the jar, and I got disturbances in the order of hundreds of millivolts.

    Why did you place the clamp meter (and his electronic circuitry) so close to the jar?

    The current value can be measured also locating the ammeter far from the jar because the current is the same in a wire.

    Did you tried to use an old moving coil DC ammeter, range of amperes with a shield enclosure and a robust passive low pass filter in series to the line that feeds the jar?

  • Why did you place the clamp meter (and his electronic circuitry) so close to the jar?

    The current value can be measured also locating the ammeter far from the jar because the current is the same in a wire.

    It was a test aimed to verify the effect of the RF emissions on the instrument when it's operating as a voltmeter, since I have been using it earlier on (at 40–100 cm distance) to measure the voltage of the 12V battery powering the DC boost converter used for the plasma reaction. It's this unit: https://www.amazon.com/Meterk-…Non-contact/dp/B0721MKXBC


    It appears that its electronic circuitry on its own is only somewhat sensitive to the emissions, but the disturbances increase significantly when probes are also added (even if not connected to anything). I guess the unshielded cables must be working as antennas.


    Did you tried to use an old moving coil DC ammeter, range of amperes with a shield enclosure and a robust passive low pass filter in series to the line that feeds the jar?

    I also have an analog multimeter but I don't think it can measure currents in the order of amperes (or current at all; I would need to find it and check out). I could still try to use it to measure the input 12V battery voltage like I did so far, but more than average values I was interested knowing if the spikes were real, and the instrument might be too slow for them, if such voltage spikes are indeed produced.

  • Quote

    I was interested knowing if the spikes were real, and the instrument might be too slow for them, if such voltage spikes are indeed produced.

    Spikes seen using a high impedance meters with long wires do not imply real high power.

  • It appears that its electronic circuitry on its own is only somewhat sensitive to the emissions

    All measurement tools must be shieled and should run on battery. Do not use a common ground e.g. use a thick shielded wire to a cenertal heating steel tube . Even better sink a copper plate in you garden connected with a long thick shielded wire.

    Experiments with no clean setup are just fun!

  • Wyttenbach


    There is no need to use coaxial wire for an earth connection. it is 'by definition' the earth. I agree about the usefulness of a dedicated earth with a thick wire though- in the lab I have copper plate around 30x30 cms buried in the main drain connected by a 3mm diameter copper wire to the labjack data systems..

  • A multimeter is not enough, I think to an old DC ammeter moving coil type closed inside a shielded enclosure.

    Unfortunately I do not have DC ammeters like the one depicted in the attached photo.


    Spikes seen using a high impedance meters with long wires do not imply real high power.

    I was more interested from a personal and equipment safety point of view. E.g. am I damaging the 12V battery-source on the long term? Could I be causing actual issues to other power supplies? Could I safely touch the battery terminals without getting shocked? And so on.


    The battery is not getting recharged with these apparent voltage spikes, that's for sure.


    All measurement tools must be shielded and should run on battery. Do not use a common ground e.g. use a thick shielded wire to a central heating steel tube . Even better sink a copper plate in you garden connected with a long thick shielded wire.

    Experiments with no clean setup are just fun!

    I have a radiator a few meters away from the 'setup', but I do not have thick shielded cables that I could readily use. All the multimeters which are seemingly showing issues or large oscillations when the plasma reaction produces significant RF noise are battery-powered, but not shielded. The Geiger counter (currently 5V USB-powered) never showed anything except when I once tried to run a fan in front of it (I guess the GM tube was electrostatically attracting radioactive dust/radon progeny from the environment).


    I am also using a USB-powered RF receiver. This one seems to work as intended.

    I get larger disturbances to nearby appliances if I use a 12V computer power supply (instead of a 12V battery).

  • All the multimeters which are seemingly showing issues or large oscillations when the plasma reaction produces significant RF noise are battery-powered, but not shielded.

    I did recommed to wrap the counter into a Swiss chocolate ALU foil (These are thinner than commercial ones!) You potentially will have a loss in beta electrons but not much for gamma. Also Xrays up from10 keV should go through in a somwhat reduced rate.

  • Wyttenbach

    In most of the occasions when I recently used it (except for yesterday's quick test), I enclosed the Geiger counter inside a <1mm-thick polypropylene plastic enclosure. Since I started doing this, air current-induced variations disappeared, for the most part.

  • @ can

    I understood you are using a HV device to feed the jar (I suppose a DC-DC converter) starting from 12VDC of the battery.


    I think that the current it feeds to the load is not constant but fast intemittent with very large value variation so your DC-DC converter will produce current spikes also on its input.

    Under certain limits the battery can supply large current peaks if they are not too fast, the battery acts like low pass source toward fast AC variation.

    When you used a computer DC power supply instead of the battery, under fast load current variation, being it again an inverter, it propagates these large variation to the grid, producing many disturbances to all other equipment connected.

    I fear that your set-up produces remarkable disturbances conducted but also radiated.

  • truth

    Yes, the complete toolchain is something like this:


    [12V DC input] => [DC–DC boost converter] => [Electrodes/jar]


    The 12V DC input source may be either a 7Ah 12V VRLA battery or a 12V power supply that can provide 35A at this voltage. The DC–DC boost converter is basically this one.


    I tried measuring current into the boost converter with the clamp meter, and it gave very wildly varying values (several amperes) when the plasma reaction was operating as intended, but it's not clear how reliable this measurement would have been under such high RF emission conditions.


    These disturbances are powerful enough to affect also the telephone line/DSL connection (the DSL modem- router and telephone line are in a completely different room). When using the computer power supply I get disconnections and unrecoverable errors within a few seconds of operating the reaction under high-RF conditions, while this takes some effort with battery power.


    This is not really a "problem", in that (if it wasn't clear already) so far I have been deliberately trying to look for operating conditions which caused the most RF emissions.



    Wyttenbach

    Yes, that's what I was referring about. The same Geiger counter appears to be completely insensitive to EM noise, so metal shielding does not seem necessary, except for reducing the background gamma level.

  • I've been able to get the direct waveform signal from my USB RF receiver during the plasma reaction, at a sample rate of 2 MHz while it was tuned to a 35 MHz frequency. Then, I converted it to an audio .wav file and opened it in an audio editing program (Audacity).



    Many of the peaks were separated by as low as 2 samples (1 µs), the minimum that could be measured. Definitely much is going on and the 2 MHz sampling rate is far from sufficient.



    No particular features stand out and the overall character of the signal over larger sections appears to be close to 1/f noise.



    To extract the waveform I used a method similar to the one described here, but adapted for the Python programming language, and using AM demodulation:


    http://www.aaronscher.com/wire…DR_AM_spectrum_demod.html



    EDIT: for mostly entertainment purposes, I have attached to the post the audio file resampled to a rate of 48000 Hz. The noise that can be heard is loosely similar to the one that was acoustically emitted by the plasma reaction.


    From this mostly audio frequencies-only file it appears there is a relatively strong 100 Hz tone (it can also be heard), which is probably from 50 Hz AC. I'm not entirely sure why it would appear during the plasma reaction, though. Only strong RF noise would be captured at the gain setting used, and the no-plasma sections are almost completely silent.


  • I made another cathodic plasma test with slight amounts of sodium hydrogen carbonate (NaHCO3). It seems to work just as well as the potassium alkali electrolytes tried so far for local RF emission, but the cathode does not erode or shine to the same extent. With the other potassium electrolytes it is easy to reach conditions where the cathode will produce rather bright flashes.


    There appears to be (at least with my power supply) a maximum concentration over which it does not seem to be useful to increase electrolyte concentration. That is about 2 ml of 6 wt.% NaHCO3 solution in about 31 ml water (+1.25ml acetone). By increasing it further, the reaction becomes acoustically noisier and "choppier" without a corresponding increase in RF emission.


    Below is a gif animation of the differences between 1..3 ml 6% NaHCO3 added to the solution (click for full-screen) in the maximum RF emission recorded with my USB receiver in the 24–150 MHz range. Most of the differences were between 1 ml and 2 ml addition. The yellow line shows background RF emission.


    (EDIT: note that since this is a rather strong 1/f-type RF signal as seen in the previous post, the general shape and location of the peaks here—which appear mostly unchanged between the runs even though I cleared the results every time—is probably mostly determined by the position of the jar relatively to the antenna used and its frequency response)



    So far, for apparent effectiveness I would rate the electrolytes used in this order:


    NaHCO3 < KOH < K2CO3


    I have a slight suspicion that what apparently makes K2CO3 better than KOH is not the carbon atom per se, but the carbonate anion (CO32-). If this is the case, potassium sulfate (K2SO4) might work equally as well from the sulfate anion (SO42-). It might however also just be that since it evolves CO2 in the plasma process, it helps forming a gas layer around the cathode (though, NaHCO3 did not seem to be particularly exceptional in this regard).

  • For the record, I did eventually try potassium sulfate (K2SO4)—made by reacting together potassium carbonate and epsom salts (MgSO4.7H2O) in suitable amounts (details here and here)—but it did not seem to help. While the reaction could occasionally produce the same bright flashes as with potassium carbonate, adding it in larger amounts appeared to produce feebler results and a "choppier" reaction with decreased RF emissions (again, mainly of the 1/f type). This seemed due to combustible decomposition products, possibly SO2 from the vague "burnt match" smell (no acetone was added in several tests). Therefore, the best choices tested so far still seem KOH and K2CO3, with the latter being safer to use and apparently performing slightly better.


    A less obvious contributor to the partial success with these tests is the plastic tube(s) surrounding the cathode. Not only it improves local water heating (making a water vapor layer form more efficiently around the cathode wire) but it also has a current limiting effect which increases effective voltage (due to my HV converter not being able to provide a very large current at higher voltages), and higher voltages seem to improve the reaction.


    The last one I used was an ordinary clear plastic cap of ~15 mm internal diameter (at the opening) and with a 2 mm side hole on the bottom. Electrolyte flow was restricted enough that sometimes a plasma would occur in the cavitation voids formed there with larger currents (but RF emissions were low compared to the actual reaction at the cathode, when it began). This could be an interesting effect to take advantage of in a more optimized design, but it probably needs higher voltages and better materials.