On Mon Feb 9 David said [snip] Since the original product was very close to becoming unstable, with the increase in gain the latest experiment most likely resulted in a situation where the positive feedback gain exceeded unity. This is just another way of saying that a negative resistance region is now present. Of course, once the input power pushes the temperature into that region the device will self sustain all the way to thermal destruction. This increase in temperature can be extremely rapid since it is of an exponential nature. [/snip]
Agreed, even with power off but did not Rossi always have to carefully manage the coolant flow - This appears to be a workhorse that relies heavily on the load to choke it back as opposed to removing drive, that is to say once self sustain is present only additional loading can balance it and the drive is effectively out of the picture. Fran From: David Roberson [mailto:[email protected]] Sent: Monday, February 09, 2015 8:47 PM To: [email protected] Subject: EXTERNAL: [Vo]:Explosion May Be Out of Control LENR I just read the latest facebook entry by the MFMP group and suspect that they witnessed an explosion due to a thermal runaway event. The latest Parkhomov experiment appears to indicate the same out of control system problem. We know that the earlier Parkhomov device was stable but appeared to be on the verge of entering a negative resistance type of operation. The slope of power input versus temperature for that original system was very close to zero but slightly positive according to the data he reported. Although I would like to have a much more extensive collection of points defining power input versus temperature, I am having to assume that the curve connecting the three given points is relatively smooth. This is not too much of a stretch since the entire temperature range over which the points are taken is very limited. When Parkhomov increased the insulation surrounding his device for the recent testing, he effectively increased the positive feedback gain by a large amount. With the insulation the amount of input power required to obtain the same temperature readings was substantially reduced. It seems reasonable to assume that the core generates the same amount of heat power when subjected to the same temperature. If this is true then the ratio of internally generated power to input power must become larger at any temperature where internal heat is being generated. Since the original product was very close to becoming unstable, with the increase in gain the latest experiment most likely resulted in a situation where the positive feedback gain exceeded unity. This is just another way of saying that a negative resistance region is now present. Of course, once the input power pushes the temperature into that region the device will self sustain all the way to thermal destruction. This increase in temperature can be extremely rapid since it is of an exponential nature. With this thought under consideration I strongly suspect that the MFMP team observed the same sequence of events. Until they increased the drive level to the threshold of destruction everything would have appeared fairly normal. The main difference I would expect is for the temperature to rise faster than expected had a dummy system been driven in a like manner. Unfortunately, it might be a fine line between a stable input drive power and the initiation of run away. My take on the debris following the explosion is that there is evidence of an extreme heating event having taken place. The spheres of molten metal along with the other indications is pretty strong evidence. I do not believe that the time frame during which the heat is emitted is necessarily very long in duration. An exponential release can occur very quickly and the heat is confined by the structure as the damage is being done. To prevent this from occurring too often, I would recommend that the amount of fuel be reduced significantly for the earlier testing. A curve can then be constructed under stable conditions which will act as a guide to indicate how much fuel can be inserted before the thermal run away condition can begin. Perhaps the fact that MFMP guys and Parkhomov did such a good job of sealing in the hydrogen under a large amount of pressure is the root cause of the issue. There remains many unanswered questions, but the important fact is that we may now be witnessing an excellent example of LENR. Dave
