Cold fusion/Contrary evidence/Dash-Zhang Replication Effort
Original report prepared by Abd 01:14, 1 January 2011 (UTC).
First of all, the original Dash-Zhang results suffer from a common problem. The entire experimental series is not presented. If a series of cells are run, under what seem to be common experimental conditions, or with a single variable, it is of great interest what individual results were found. Cherry-picking the data to show the "best results," which is often done, leaves the data much less subject to interpretation, not to mention criticism. Variability of results in CF experiments is the norm, and so it's useful to try to find accessory indicators of the reaction. Helium is a known one; if there is access to a mass spectrometer, and even with open cells, it's possible to find helium correlations if significant reaction rates are taking place. Loading ratio is of high interest, as well as current density. I've found that cell voltage may be of great interest as well, there are changes in cell voltage that commonly are seen when the reaction starts (these are normally constant-current power supplies).
A great deal of work has been done, and the Dash-Zhang report is not part of the experimental corpus on which major claims are being made; the paper was a conference paper. Perhaps there is, on-line, access to more data. I can always hope!
Secondly, Scott Little of Earthtech ran these tests with the cooperation of Dash and Zhang. The cell is unusual in a number of aspects. The current is high and constant for the experiment, 4 A. The cell is taken to and operated at the boiling point, and the amount of recombiner catalyst is very high (in the Dash/Zhang version, it was 100 grams).
During their visit to our lab, all electrolyte mixes were prepared by Zhang and the cells always contained electrodes provided by Dash and Zhang. This is a generally good practice for what I'd call alpha testing. Before doing a truly independent replication, particularly with cold fusion, which readily fails, an assisted, cooperative replication is generally advisable. I do still have questions, though. "prepared by" doesn't say where the materials came from. In particular, if the heavy water was provided by Earthtech, there could be a variable there; especially for a lab that isn't doing a lot of research with heavy water, older heavy water is more likely to be contaminated with light water, and 1% may be enough to poison the reaction. If Dash and Zhang provided the heavy water, this would not explain differing results. But, as we will see, there were other variations, acknowledged.
There were, in fact, differing results. According to Little, We did observe some apparent excess heat in our testing but not as large as previously reported by Dash and Zhang. However, after much investigation, the evidence points only to mundane causes for the excess heat signals observed in our lab. The results seen were tiny compared to what Dash and Zhang have reported, which are, themselves, not terribly impressive -- though perhaps significant. I can't tell!
Little has stated it correctly. However, note: "observed in our lab." Little's results were smaller than those of Dash and Zhang, and thus more likely to be explainable by a mundane cause. How much smaller, and what was the probable cause?
First of all, examine the input power/output power results, the first cell. There is no sign of excess heat. That's what a "dead cell" should look like. You can see the (small) decline in output heat due to the escape of deuterium from the cell from recombiner failure. This cell had only 1.3 g. of recombiner pellets, and it was run under very different conditions than the Dash-Zhang cells. In the cold fusion field, this is a formula for replication failure, unless Little were to get very lucky. Recipes that work can still be very fragile.
So Little adopted an attempt at exact replication, but it wasn't. He did not use a constant-current power supply; rather he adjusted the voltage to produce what would seem to be the desired current. That's altering a critical process, because changes in voltage produced by changes in current, even brief transients, may have a critical effect on the reaction. I'd want to see the voltage plotted.
The second cell showed a little "excess heat" for part of the run, but if you look at the area under the curves, which represents excess energy, there was no excess energy. Little thought that the excess heat did not have a "ready explanation," but there are lots of possibilities. I notice right away one peculiar thing about the results: energy is obviously being stored or leaked somewhere, because the input energy is quite a bit larger than the output energy. The termination of the run is not shown. What happened when the power was turned off? This will be important in considering what Little later concludes. (Little notices what he calls the "power imbalance." He means energy. This particular sloppiness is common in the field.)
(Later Zhang report, ICCF15, shows negative heat on shutdown in dead runs, thus the integral of heat, i.e., energy, is zero, as would be expected.)
Little eventually abandoned open cell testing after a number of additional failures. They then tried to modify their standard cell to resemble the Dash/Zhang cell more closely. (My comment is that they wasted a lot of time by using their own ideas first. If one is replicating, replicate, or, at least, replicate the operational details, as closely as possible. Indeed, the details of calorimetry here, because they may result in different operating temperatures, may be whacking a critical experimental variable. Higher temperatures are known to be associated with greater excess heat.
They added more recombiner pellets, but it was still only 3 g. instead of the 100 used by Dash and Zhang.
They did four tests of this new configuration, finally being able to get successful calibration runs. None of these cells showed excess heat.
They tried a cell with titanium sulfate, following a suggestion from Dash and Zhang. No excess heat.
Then they tried a sealed DZ cell. Now they saw some excess heat but only a tiny amount. Looking at the plots, there isn't excess heat, there is heat missing. What he must mean by excess heat is that the output power was slightly more than input power. You can't see it in the charts. Anyone who has looked at such charts for active CF cells would see that there is a drastic difference.
To make a long story short, Little attributes the very small amount of excess heat he did find to the "heat of wetting" of the recombiner pellets. It's very reasonable, and seems likely. But he didn't see any excess power. the "heat of wetting" would be recovered as cooling later when the pellets dry, running with wet pellets (which causes them to fail) was a guaranteed source of error. This may be why Dash and Zhang used so much recombiner, to keep it dry.
The conditions did not match those of Dash and Zhang to serve as a decent negative replication. For unknown reasons -- and this is common with CF electrolytic experiments -- the reaction didn't start up. There are host of operational details not disclosed, and something seemingly very innocuous can disrupt excess heat production.
More recent and better-equipped laboratories seem to be trending toward measuring helium as the primary indicator of the reaction, with excess heat then being a confirmation.
Zhang went on to publish Construction, calibration and testing of a decimeter-size heat-flow calorimeter.
I don't have access to that paper. However, there is an abstract of a conference paper presented at ICCF14, presentation number 74, p. 87, by Zhang, Dash, and Zhang, describing results from a CF cell. Their basic work is on the calorimeter, but five Dash-type CF cells were tested. Utterly inadequate reporting to get even a little excited about cell results. Only power results stated, not energy. No input power stated, only current. I have no idea from the abstract if these results are significant.
Here is the ICCF14 paper: . The data provided is sketchy. See, for example, figure 3, the right-hand. Looks impressive, until you notice the scale has been expanded. This shows a small part of the run (30-33 hours) and the Y-axis only shows from 23.4 to 24.3 watts. It might be that an analysis by someone who is familiar with all the symbols, etc., would show something significant here, but I'm far less than impressed. I'm seeing a presentation designed to make the data look good, and that's not useful. However, let's hope that they do something really useful with that calorimeter.
There are some better presentations at . Slide 16 shows excess input power at the beginning and excess output power at the end. Tiny excess heat is shown, not visible in the gross graph. I'd consider this a dead cell. The calorimetry looks accurate.
Now, to be fair, Zhang et al are not trying to prove the reality of cold fusion to anyone. That happened long ago, for those who were paying attention. What they are doing is investigating techniques. However, my opinion, a great deal of work in the field, in this regard, is wasted, because there is little work on controlling a single variable, between experimenters, and the techniques are all over the map. Zhang does, in fact, present some evidence about the effect of pre-electrolysis. That could be useful.
The original topic here is the Earthtech article. Earthtech probably did not reproduce the DZ experiment. He saw nothing like the excess heat they report, it appears. Conclusion: nothing. However, Earthtech's report on heat from wet recombiner is useful. It's got to be discouraging for Earthtech, they have a whole series of experiments they have done where they found nothing where others had reported something. I hope to change that for them.... Or I'll end up in the same position, failing to replicate. This is experimental science, with what can be a deceptively simple experiment. It's not simple! I have reason to hope that I'll succeed, because the protocol has been used by others, but "failure" means, to me, "something left to learn." And, of course, it's always possible that there was nothing to replicate, that an original report was error. The truth will out. If I fail, I'm pretty sure that SPAWAR will get interested, and we will find out why. --Abd 01:14, 1 January 2011 (UTC)
I now have the Zhang article from Thermochemica Acta (2010). Zhang shows results from a single cell, what he calls "trivial results," showing no excess heat. The point was the accuracy of the calorimeter. From the report:
- The input and output energies are 262.38±0.05 and 261.83±0.88 kJ, respectively. Before and after electrolysis, the cell was weighed with Mettler PM1200; the mass loss in this run was 0.022 g. If this loss was caused by poor catalytic recombination, the corresponding energy correction is 0.33±0.03 kJ. The output energy after correction is 262.16±0.90 kJ; the resulting excess energy is −0.22±0.90 kJ, corresponding to (−0.08±0.34)% of the input energy. It means there was no excess heat produced in the electrolytic cell and this calorimeter gave good accuracy (better than 0.1%) at power around 9W running for 8 h.
He states the "calorimetric error" as 0.29%. However, input power (calculated from current and voltage, presumably) and output power from the calorimeter were very close during the stable period from 5-8 hours, within 0.004%. They may simply have been lucky. This is not necessarily a specially accurate calorimeter. Miles and Fleischmann claim, in a paper in the American Chemical Society Low Energy Nuclear Reactions Sourcebook (2008)for an isoperibolic setup, also with a "blank" experiment, "precision and accuracy better than 99.99%" They claim measurement of enthalpy production of electrogenerated oxygen (recombination) accurate to 0.1 mW in experiments with cell input power of 900 to 1000 mW. Perhaps the Zhang calorimeter is able to handle higher input power....
There is no sign of any attempt to measure loading ratio, and the loading time looks inadequate for an electrolytic cell to reach the necessary loading to see excess heat. (This critique would also apply to Earthtech, perhaps.)