Susanna Gipp <susan.g...@gmail.com> wrote:
> did anybody have the chance to read this? > > http://matslew.wordpress.com/2014/05/12/defkalion-demo-proven-not-to-be-reliable/ > > kinda unbelievable how was cheap the trick they used to fool Gamberale > This trick is so cheap, and so transparent, I doubt it was a trick. My gut feeling is that it was a stupid mistake. It would be mind boggling if a "trick" like that would work on an engineer or scientist. I have heard that the people from NI took one look at the shoddy setup and told Defkalion they were no longer invited to NI Week. I do not know how long it took Gamberale to discover this problem, but . . . While I do not mean to boast here, it would take me 10 minutes to discover the flow rate is wrong by a margin as large as this. The first thing I do when checking flow calorimetry is measure the inlet and outlet temperatures with a hand-held thermocouple, and then I measure the flow rate with a stop watch and a graduated cylinder. (Or a carafe and a weight scale.) This is not rocket science! It is easy. I have done this several times at various labs. As I recall, I found large errors during Patterson's demo, during one of Gene's experiments, at Hydrodynamics, and at two other places I do not recall. That is why I do not trust flow meters. The darn things get clogged up, or they run backwards, as Gamberale described. They are the Achilles' heal of flow calorimetry. You can't trust them until you verify them. You need to keep checking them throughout the experiment. I recall the user manual for one of them specifically said you should test the instrument by collecting water in graduated cylinder. It is just common sense. As I said, when you measure the flow rate manually, the answer is approximate. If the flow meter says 1.16 L/min, and you get somewhere between 0.9 and 1.2 L, you are good to go. You know the thing is working right. Actually, though, with a little practice and several tries, you can get closer than that. You need to do this several times during the course of a test to be sure the flow rate is not fluctuating significantly. Try this at home! You do not even need a flow meter. Turn on the tap and measure the flow of water several times. You will see that the variation is small. Flush the toilet and see if you can measure the difference from the drop in water pressure. When the output is steam, you use a bucket of cold water to sparge the steam. Then you measure the increase in weight and temperature. It amounts to the same thing as measuring a flow of liquid water with a graduated cylinder. If I had been at Defkalion's test and they said "no, you are not allowed to measure the flow rate" I would have told them: "Then I must assume you people are frauds, and I will take the next plane home and tell everyone that." That is more or less what I told Patterson when he refused to let me make my own measurements. He thought about it and changed his mind. Rossi told me I would not be allowed to make measurements so I did not go. I suppose Defkalion uninvited me three times after they realized I meant to actually measure things. I could not make manual measurements of high precision equipment such as SRI's. You can't monkey with that. Fortunately, people like McKubre, Storms and Miles are professionals who use redundant instruments and they check everything to a fare-thee-well. This is described in their papers. Still, if I were to visit them I would check the flow rate if I could. You cannot as easily check the performance of a Seebeck calorimeter. The blue Thermonetics Seebeck calorimeter in Ed's lab belongs to me, so I guess I should believe it. - Jed
