• Similarly, models for LENR/Cold-fusion are not possible with the low resolution data we have from current calorimeters. We have to push the metrology part in order to get sufficient data with low enough uncertainty before we sincerely get into modeling. Bruce_H may be ahead of the curve in his thought experiments on modeling, and who knows? Maybe he may find something that turns out to be useful in the future.

    With the very low thermal mass of the systems Russ and I were using meaningful calorimetry wasn't practical, so we depended on 2 factors, relative thermometry between matched systems (working fuel/non-working fuel) and particle emissions- this last being the one we considered to be the main thing. I know that the latter is not really possible using your systems because of the metal containment, but we were using sub 1mm thick alumina.

    On the topic of using 'non-working fuel' in control systems, a particular piece of Russ George wisdom was "there is no better control than a failed experiment."

  • All I can propose our measurements of LENR's are all 'relative to controls' but the relevant equations describing nuclear fusions surely must be governed by Einstein's theory of relativity - whether it's fission of uranium, hot fusion (as in the Sun) or cold fusion (as in LENR).

  • I think that some people are failing to appreciate that the model analysis I recently posted is qualitative, rather than quantitative. It identifies the existence and nature of broad behaviour regimes within the model by tracking the nature of steady-state solutions to the governing equations.

    My analysis so far has centred on the interplay of linear cooling, and internal, temperature-activated, heating in a thermal mass. The steady states in the system occur where the heating and cooling just balance and, in the model I have been considering so far, there are either 2 of these steady states, or none at all, depending on the amount of external heating being forced into the system. I showed a diagram before and I will repost it now so that I can make a particular point.

    Once again, the 2 upper panels show how equilibria (aka "steady states") are identified for different values of external heating. On the left there is no external heat being applied and on the right external heat is being driven into the system. The effect of external heating can be imagined as a vertical upwards shift in the heating curve. ... And now here is the point I want to make about the qualitative nature of this analysis. Oce can see from the figure that there are 2 steady states at each value of external heating and that the location of these steady points changes dependent on external heating. But the existence of the 2 steady states does not depend on the exact details of the heating and cooling curves. You can imagine the cooling curve being steeper or less steep -- or even being not quite straight. Likewise you can image the heating curve being a bit more wiggly than shown, or rising faster or more slowly with temperature than shown. You can imagine all sorts of small perturbations to the picture as shown and yet the topological properties that lead to the existence of the 2 steady states and the way they react to changes in external heating would remain.

    So I am not too disturbed when I hear that particular empirical results aren't very precise, or are old, or what have you. The basic nature of a temperature-dependent internal heat source in a thermal mass

    determines quite a bit about the nature of its broad behaviour regimes (e.g., stability, thresholds, hysteresis). I think that such qualitative modelling is a valuable aid to thinking in a robust way (rather than in a way that requires precise knowledge of parameter values) about how these systems work and how to proceed with research.

    Finally, I note that convection and radiative cooling in particular could alter the topology of the cooling curve to such an extent that the number of steady-states and how they coalesce or change stability might be affected. I am working on this. It would be useful to see a plot of input power vs steady-state temperature that goes above 200C if Daniel_G has it.

  • Bruce__H

    your expectations seem to be very close with some charts we have seen about Rossi.

    What you could say on that ?

  • your expectations seem to be very close with some charts we have seen about Rossi.

    What you could say on that ?

    I have not proposed any mechanism for the internal heating. My analysis is good for any source of internal heating that increases as temperature increases. LENR heating, as described by a number of investigators fits the bill but so does almost any any chemical exothermic reaction.

    For what it is worth, I think that Rossi is an obvious fraud.

  • Bruce_H, I am hoping to publish a paper for ICCF24 with this data. I am waiting to hear if they accept our work.

    OK. To be clear, I was hoping to see the input power vs temperature plot only for the calibration case. I wasn't asking you to reveal such data for the active mesh.

    I am really just interested to know whether the calibration plot is only gently curved between 200C and 500C, or whether is really very strongly curved.

  • The general convention -widely but not entirely honoured- is that you do not use ICCF meetings to present old news.

    The ICCF committee ask that results not have been presented before verbatim. The general convention at all scientific meetings is that you do not arrive and give the same talk you have given elsewhere or submit a paper that you have published previously. But it is not purdah. One is free to talk about results beforehand as long as the presentation on the day is original.

    I have asked Daniel_G if a commercial oven he is using acts in a more or less linear way across its temperature range. No LENR in sight. If this constitutes his "news" then it is going to be one boring talk!

  • I have been thinking about the consequences of adding radiative cooling to the minimal reactor model that I had considered previously which consisted of a lumped thermal mass with LENR heating and conductive cooling. The question is to what extent will adding the radiative cooling alter some of the qualitative behaviours that I had previously deduced should be present (i.e., thresholds, hysteresis, and thermal escape to meltdown). The answer I arrive at is that, in many cases, radiative cooling makes little qualitative difference.

    Here is my reasoning. I will begin with a reminder of the situation that exists when cooling is via conduction only -- before radiative cooling is introduced. Conductive cooling is linear with temperature as shown in the 2 top panels in the figure below (blue lines). Internal (LENR-style) heat generation is assumed to depend on temperature in a nonlinear manner, as shown by the red lines in the 2 top panels (the difference between the 2 top panels is that on the right, in addition to LENR heat, a external heat is applied which has the effect of shifting the red curve vertically upwards). Heating just balances cooling where the red and blue lines cross, and this identifies equilibrium points of the system, You can see that the equilibria move around as the level of external heating changes. For any particular value of external heating, the lower-temperature equilibrium point is stable but the higher-temperature one is unstable. As external heating increases the stable and unstable equilibria move towards each other and, at a threshold value of external heating (called a bifurcation point) the equilibria annihilate each other to create a region where no steady-state solutions are possible and the system simply increases in temperature to meltdown. The bottom panel shows this process.

    I have added one element to the diagram above that wasn't in it in previous posts. This is the red trajectory in the bottom panel. The trajectory illustrates the concept of hysteresis. If you start with a moderate level of external heating, the system sits near its equilibrium (marked "1"). Slowly Increasing the level of external heating causes the system to track along the branch of stable equilibria until a threshold is reached at the bifurcation point. At this time the system's equilibria disappear and consequently it increases in temperature (marked "2"). Once the temperature increases sufficiently, even suddenly shutting down external heating will fail to stop further the temperature increase (marked "3"). This is hysteresis. Hysteresis occurs when identical settings of a control parameter yield different behaviours. Here, the same value of external heating that previously produced a stable equilibrium now produces temperature runaway.

    Now to add radiative cooling. Radiative cooling should transfer heat at a rate more or less proportional to T**4 where T is degrees K . This means that the blue cooling line in the diagram above should really be curved upwards. How curved depends on experimental conditions. But I now point out something I mentioned before. The existence of multiple equilibria that annihilate at a threshold to yield hysteresis is a robust finding. Robust in the sense that things would play out the same way if either the heating or cooling curves weren't exactly as portrayed in the figure above. For many such alterations, you would still see the same qualitative behaviours as previously described. No real difference. Adding radiative cooling appears to be one of these alterations. I show what this might look like in the diagram below where the bottom panel illustrating qualitative behaviours (existence of a threshold, hysteresis etc.) is actually taken from the first figure above because the qualitative behaviours have not changed. In the top 2 panels you see why this is ... the heating and cooling lines still cross in 2 places (equilibria) and the crossings still disappear at a threshold value of external heating (pictorially given by the point where the red and blue lines stop crossing as the red line moves vertically upwards).

    So ... thus far, adding radiative cooling does not change the characteristic behaviours that a reactor with (LENR-like) temperature-dependent internal heating should show. One might argue that the qualitative behaviours should change if radiative cooling is really strong. After all, radiative cooking scales as T**4 and so is a profoundly increasing effect as temperature rises. This view can, in some cases, be correct. If radiatively assisted cooling overwhelms heating then the red and blue lines in the top panels will cross only once at low temperatures and so the entire system will only show a single stable equilibrium no matter what value of external heating you use (consistent with Daniel_G's results so far). There will be no threshold and no hysteresis. But so far, the Mizuno system is advertised as having an exponential dependence of LENR heating on reactor temperature. And an exponential rises even faster that T**4. So the high-temperature, unstable equilibria shown in the upper panels of the figure really should be there. The robustness of the results I derived earlier therefore still holds.

    This isn't the end of things. I haven't yet considered cooling by mass transport (convection) and there are other scenarios where qualitative behaviours might still change. I will take those on in future posts.

  • It's good to see some serious thought given to developing this model. I do find the graphs a bit unclear, for a simple reason. In a typical graph we expect the dependent (output) variable to be in the vertical axis, and from my technical background I have an instinctive tendency to interpret visual data from that perspective.

    So I would prefer that the graph with the T^4 radiative cooling to have reactor temperature on the vertical axis, giving the thermal Q of the system as the slope of the curve, or dT/dP. If I understand Bruce's examples correctly, the red trace curving upward does show decreasing dT/dP. The vertical axis is labeled as dQ/dt in the first two graphs, which may be the equivalent of input power P.

  • Radiative cooling becomes the main one above 700°. So his expectations are closely linked with the kind of reactor we are talking about.

    Yes, in the R20 case the conduction plays now in the case of Glowstick experiments only the radiative cooling was involved, i think.

  • Way back in this thread there should be images I posted of a series of incandescent lamps being turned on in W steps, including switching two lamps at once using various wattage lamps (50, 100, 150, for example), for a wide range of input steps in my enhanced Mizuno-based mass airflow calorimeter. This by remotely independently switching 4 different lamps inside during a non stop, no messing with the calorimeter operation, (add 50 W, settle, etc.). It may be informative.

    *If I find it I’ll link it HERE.

    In general, the object just reaches whatever temperature it needs to be in order to reach steady state, surface area and airflow the most critical dimensions as to final surface temperature required at whatever emissivity it is. Poor emissivity just results in a higher surface temperature so that convection transfer can compensate, but at the same total wattage.(If poor emissivity reduces the radiant power by 30W compared to a blackbody version then the surface temperature increases until convection can carry the 30W away. This happens instantly, since very few materials can strongly change total radiant emissivity very much at a given temperature.

    But really it is just a geometry problem of solving or designing how hot the surface of a heating body might be in a given power range. Surface area is the strongest control of heat transfer, since that’s where the rubber hits the road. Perhaps a heat memory metal origami fin structure that works like a heat governor could optimize the heat transfer to the ideal rate for any temperature over a large range.

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