Robert Horst Verified User
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Posts by Robert Horst

    Looking at the Reed Instruments manual, it talks about "An USB RS232 lead." There is no such thing and the reference to RS232 might be wrong. It looks like it might really a USB connection with the two wires being the D+ and D- of USB 2 or USB 3.


    It looks like they sell an expensive cable to connect to USB. It is not clear if this has any electronics or is just a phono plug to D+ D- cable. You could make one by splicing old USB cable to an old phono plug cable.


    https://www.grainger.com/produ…AfyFdudo:20200127173156:s

    checked the Tx and Rx wires end to end, and nothing happens. There should be a 16 bits-long word but nothing comes out in either single bits or strings and with only two wires (Tx and ground), there is no way to poke the RS232 side into action. It is possible that the level shifter doesn’t like only one signal wire. So today’s diagnostics involves plugging in an RS232 to USB cable and seeing if the laptop can see it working...

    The most common problem with RS232 is needing to switch Tx and Rx. Tx of the sender needs to go to Rx of the receiver. Some cables have Rx and Tx internally swapped, some do not. Murphy's law says you always have the wrong one.


    Other possible problems are the handshake signals. RTS must be asserted, sometimes requiring an extra jumper on the interface even if you are using only a 2-wire cable.

    Why run a 48V power supply at 50.0, i.e. past its rated operating voltage? Might burn it out or be unstable. Why not run it at 48V?

    Many fixed voltage supplies are adjustable over a small range. That lets you set a higher voltage to compensate for voltage drops in the wiring or voltage drops across diodes (when used to OR power from multiple supplies in parallel). There is nothing wrong with taking advantage of the voltage adjustment.

    Here is the full pdf of the Mills '828 Jan 2, 2020 patent application:


    http://www.freepatentsonline.com/20200002828.pdf


    This is a continuation of patent 10,443,139 that was issued in Oct of 2019


    https://patentimages.storage.g…0737b2a2ec/US10443139.pdf


    As with most continuations, it has identical figures and a nearly identical specification. The only important differences are in the claims.


    The '828 application has only a single claim and looks to me like it was filed just before the '139 patent issued to keep this patent family active in the USPTO. They will likely amend it to add more claims later.

    By the way, the USB oscilloscope used in Parkhomov's study only has a 12 MHz bandwidth and to be honest I'm not sure if it's sufficient to record all the peaks produced after the 1200V capacitor quickly discharges when the anode is at 0.5 mm above the surface of the electrolyte. In other words, current spikes shorter than the device's time resolution of 0.1 µs might not be observed.

    ...

    So while that USB oscilloscope seems a nice relatively low-cost tool to have (I've seen it on a local store for about 120 euro), it might not necessarily be the best one.

    Yes, a 12 MHz scope would be very poor in measuring current pulses like those in this experiment. A capacitive discharge pulse like this would have harmonics into the GHz region and a 12 MHz scope could not hope to capture the peaks correctly. Test instruments should sample above the Nyquist rate (twice the frequency of the highest harmonic).


    Also, this type of scope would have large channel-channel skew. It looks like they do not even specify the maximum skew. It is important because power is correct only when averaging simultaneous current and voltage samples. Any skew would give an underestimate of input power because the highest current and lowest voltage would happen nearly simultaneously.


    To correctly measure the power in the pulse, you could use a good digital scope or introduce a circuit to integrate the VI product. Another approach would be to put error bounds on the existing equipment based on input power before the pulse generation (modified by estimates or measurements of losses in generating the pulses).

    Good call -


    But I think in that case 'A' could be the voltage across the resistor, with I = A/Rsens. . Then P = V*A*0.3333 => Rsens = 3. In which case Prsens = (A*0.333)^2 * 3 = A*A/3.


    The equation is then correct, for a 3 ohm current sense resistor

    Yes, you are right that the equation works for a 3 ohm sense resistor. It is easier to see this way:


    If A is the voltage across a 3 ohm resistor, then I=A/3 or A=3I. Substituting, into:

    P= (V*A)*0.3333-(A*A)/3

    you get

    P = VI -3I2

    and the power in the resistor is I2R = I2*3


    But 3 ohms is large for a sense resistor. It will get very hot, even at 1 A (3W). At 2A (12W), you need a high wattage resistor to keep it from burning up. It also adds error to the calculations because the resistance changes when it heats up.


    A typical wirewound resistor has a temperature coefficient of 400 ppm/deg C. If it heats up 100 C, that introduces a 4% error.


    The error and wasted power is reduced if you use a smaller resistance value. DVMs and data acquisition systems can measure small voltages at high accuracy and it would be better to use something like 0.1 or 0.5 ohms.

    The spreadsheet equation for blower power is: (V*A)*0.3333-(A*A)/3


    Sorry, but I seem to be a bit thick today.

    What is everything after (V*A) accomplishing exactly? Is it PWM?

    It looks like he is measuring blower power as the total power from the supply minus the power lost in the current sense resistor.


    Resistor power is I2R, and the (A*A)/3 corresponds to the power through a 1/3 ohm (.3333 ohm) resistor.


    Not sure why V*A is multiplied by .3333 though. Seems like it should be (V*A)-(A*A)/3

    Your graph is interesting.


    IMO, the cause of Delta Tair variations is the noise due to the turbulent rising of the cooling air inside the acrylic box. This air flows over areas of the reactor surface which are at different temperatures, so its vorticity can cause the air to heat not uniformly. The Delta Tsurf is roughly proportional to the Tmax of the reactor body whose heating and cooling trends are substantially delayed by the large mass of the reactor metal. You can see in your first graph that amplitude increases at the power-on and decreases at the power-off following trends very similar to the heating and cooling phases of the reactor.

    You may be right the the cause is related to the turbulent air, but realize that the data points in the spreadsheet are 25 seconds apart. It is hard to imagine a vortex that lasts 25 seconds or longer and makes the average 2 deg C hotter or colder than the previous 25 sec.


    Maybe the problem is the way this spreadsheet was derived from the raw HP data logger measurements. The logger probably sampled much more frequently than once per 25 seconds. I was assuming that each 25 second spreadsheet row is an average of the last 25 seconds, but maybe the spreadsheet just takes one raw measurements from each 25 second period. That may show the large variation we see, while averaging them (integrating over the entire period) would smooth everything out.

    No, I do not think plasma heating or any other heater-related noise could lead to the output temperature variations. If you look at my first graph above (just edited to fix the horizontal scale), the large output temperature variations last for more than 10,000 seconds (> 2.7 hours) after the heater is turned off.

    On a slightly different subject, I have been wondering why there is large variation in the output temperatures while the heater is on, but not when it is off. Here is a graph I produced from the Mizono spreadsheet:

    The temperature varies +- 2 degC while the heater is on, but then less than +- 0.1 degC after it has cooled.


    To look for periodicity in the variation, I took an FFT of the data, here it is plotted in the frequency domain on a log scale, and in the time domain on a linear scale. The input is the delta between measurements, which is like using AC coupling to a scope or putting the signal through a high pass filter.


    There is one peak at .015 Hz (66 seconds), but it is not much higher than the other frequencies. The distribution is pretty flat, like white noise.

    • It seems unlikely to be instrumentation inaccuracies, or they would affect the later measurements with power off.
    • It is not noise coupled from the heater or its power source, or it would drop abruptly when the heater is powered off.
    • I looked at deltaTemp for the input (ambient) air, and it has about the same low variation as the cool part of the experiment. That cannot explain the large heater-on deltas.
    • If the peaks were from excess heat events, it seems like there should be no low peaks. It is hard to imagine excess cool events.

    I am at a loss to think of a cause for the output temperature variations.

    Experiments that use an internal heater have a different equivalent thermal circuit than the one I posted earlier. This circuit would apply to R20 as well as the earlier experiments if they also use an internal plasma heater.

    lenr-forum.com/attachment/9719/

    The diode is here because I assume that when the heater is turned off, it does not contribute to cooling of the mesh. This also uses better values for the heat capacity as suggested by THH and RB. The reactor is 20.3 kg * 500 j/kgC and the mesh is .3 kg * 450 j/kgC.


    For the reactor thermal resistance, I found a reference that says forced air cooling has a convection coefficient, h, between 30 and 600 W/m2C. R = 1/hA. The reactor is 114 mm dia x 600 mm L for an area of about 0.21 m2. That makes Rra = 0.1 to 6.4 degC/W. That is a huge range depending on the blower and surface it is blowing over. I used a value of 1, but it would need to be measured. All thermal resistances are not much better than pure guesses.


    Using the values shown above, here is what the reactor temperature (delta T from ambient) would look like:


    And this shows both the reactor and the mesh temperatures.

    It is hard to draw many conclusions based on the long time constant at the tail of the experiment. The amplitude of the tail is less that 1 degree which is much less than the errors in the rising edge measurements. That means that there might not even be any tail at all. You can't conclude anything from measurements smaller than the noise.


    If your calculation of the heat capacity and thermal resistance of the mesh is correct, you are right that it will not have much effect on the tail. But I am not sure if we can get accurate values for either the heat capacity or the thermal resistance.


    I used "mesh" to mean everything inside the vacuum chamber. There may be other thermal masses, like an internal heater used for later experiments. That would have a big effect on the heat capacity.


    The thermal resistance to the mesh (plus whatever) could be extremely high. Part is in contact with the reactor wall, but part is not. Try heating one end of a screen and see how much heat you detect a few inches away. The thin Ni wire in the screen is a lousy thermal conductor. Also, if there was something else like an unused heater inside, that could be very well insulated by the vacuum.


    My simulation was not intended to try to arrive at any specific numerical results. I posted it more as a technique that could be used by those doing the experiments. They could measure the values of the six parameters fairly easily and come up with a simulation to show what should happen without excess heat, then show what actually happens and analyze the differences.

    Great work Robert

    Four questions if I may be so bold as to ask

    1. Does the SPICE sim give a regression value saying how good the fit is on the heating phase , and on the cooling phase?


    No. SPICE does not do that directly. There are ways of varying parameters or adding comparisons to algorithmicly generated waveforms, but that would take quite a bit of work.

    2. Is it possible to include the thermal inertia of the insulated Perspex walls.. maybe the mass is 11000 g or more? Cw= 1.5


    Yes, more elements could be added easily if enough information could be gleaned from the experiment.

    3. Can the voltage on the vertical axis be made to correspond to energy content in Joules?


    Yes, that could be done. Not sure how much time I have to continue this though.

    4. What is the expected maximum temperature of the Nickel?


    The Nickel should eventually reach the same temperature as the housing if the circuit is generally right. There is a thermal path (Rrm) to heat it from the housing, and no thermal path to cool the mesh (no resistor to ground). But that assumes that the heater stays on long enough. If the mesh heat capacity is large (large Cm) and the vacuum does a good job of insulating the mesh (large Rrm). The time constant to reach equilibrium is very large.

    There is more than one time constant in the Mizono experiment and the interactions between them are not easily solved without simulation tools. The same differential equations for heat flow are the ones used in EE for RC circuits. I have created a simulation based on this and used a SPICE simulation to create the waveforms. This is the circuit, where:

    Cr = Heat capacity of the reactor

    Cm = Heat capacity of the mesh

    Rhr = Thermal resistance from heater to reactor

    Rh = Thermal resistance of the heating element

    Rra = Thermal R from reactor to ambient (fan speed dependent)

    Rrm - Thermal R from reactor to mesh

    Voltage is analogous to temperature.

    The simulations go from 0 - 70 ms, to correspond to 0-70 Ks in the experiment.


    Waveforms below alternate between those from the Mizono spreadsheet and SPICE sim of this circuit. I am using 4 columns from the Mizono spreadsheet - Time, Air In Temp (for ambient), Air Out Temp, and Heater Temp. I used Reactor temp = Air Out Temp. That would not be quite right, but probably just a constant offset. Plots show delta Temp from ambient.



    The reactor temp rises more quickly than it falls because winding the heater around the reactor conducts the heat with thermal resistance that is low compared to convection to ambient air to cool it off later.


    The long tail of the blue simulation is from the extra heat storage in the mesh after the heater is turned off. It takes a long time to make its way out to the reactor and then to ambient, likely because much of the mesh is in the vacuum and has low thermal conductivity to the reactor body.


    I chose values to make the waveforms look as similar as possible. There is no published information on heat capacities and thermal resistances in the experiment. I could get times and max Temperature (Voltage) from the spreadsheet, but had to iterate to find other values to make things fit. Someone else might be able to derive some values based on other published data.


    The simulation does not prove or disprove the existence of excess heat. It just shows that you cannot tell either way based on the shapes of the curves. The long tail might look like heat after death, but the small value is within the noise of other measurements in the same trace.


    With the values shown, the simulations show that you may need to wait a really long time to get accurate calibration constants.


    A great experiment would be to run it once with He, then run the same reactor with D keeping other parameters the same. Then differences could easily be subtracted out to show any net excess.

    I think you are using "input" to mean different things. Jed says Mizono measures input to the heater and you are talking about input to the power supply powering the heater. Your posts would be clearer if you used "heater input" or "power supply input" depending on what you are referring to.


    When power is measured to the heater, it will be very precise, whether done with an expensive power meter or just measuring V and I and multiplying. Measuring power to a resistive heater driven by DC is about as easy as it gets.

    The fan is much quieter than the axial fan I previously tried, and really doesn't seem to be blowing as hard as the axial fan.

    Blowers generally deliver air at higher pressure but lower velocity than axial fans.


    When testing, if you restrict the output flow to increase backpressure, there will be some point where the blower delivers more air (CFM) than the axial fan.

    Just as with the other Mizono-type experiments, much could be learned in the Zhang experiment from showing graphs while cycling the input power on and off at some interval longer than the thermal time constant.

    • Is the output delay for excess heat the same same as the delay with just heater power observed in the control?
    • Are there spikes in the excess or is it a constant delay from when heater power is applied?
    • Do excess heat spikes appear only with input power applied or also when it is off?
    • How long, if at all, is there heat after death?
    • Does the baseline with heater power off rise or fall gradually over time or remain the same?

    Heat is heat. If the system is sufficiently exothermic to overcome losses, and sufficient heat is returned to the reactor from the cooling system (if there is one), the reactor will run without further electrical heater input.

    But IR radiated from the heater to the mesh is not the same as the heat generated by the reaction and conducted through the mesh. If the mesh temperature is all that is important, then any version with high COP should self-sustain. But I get the impression that will not happen with this reactor, meaning the IR radiation is the key to making it work.


    If we get data with heater power on and off, that would help understand whether or not IR from the heater is important. If IR is important, that gives an avenue to understand the experiment more. What frequency gives best performance? Is the frequency/wavelength related to the size of the microvoids, cracks or grain boundaries in the Pd or Ni?