At 12:06 PM 12/2/4, Jones Beene wrote: >Horace, you seem to be saying that the condenser was >air-cooled instead of water-cooled. Of course this would >introduce major errors, and it still doesn't address the >issue of tritium.
Actually, there is no mention of a condenser in the Cirillio paper. The standard method of doing boiloff calorimetry is to measure the weight of water boiled off (that disappears) and then multply by the energy required to boil that water (which explicitly *is* the method used by Cirillo.) It appears the plastic cylinder with pyrex lid located above the cell does the condensing. There is apparently no intent to use the condensation heat (i.e. mass flow calorimetry on the secondary coil) as a secondary calorimetric means. Cirillo's method is definitely susceptable to entrained water droplets. I would assume P.J van Noorden (he can clue us in) used an ordinary laboratory condenser. Such condensers are typically made of glass and used in either straight through mode or reflux mode. In straight through mode the steam comes in through one (elevated) end and water comes out the other. In reflux mode the condenser is usually vertical and steam is admitted in at the bottom and water comes out the bottom into an attached flask. Unless you are trying to do dual calorimetry, it doesn't matter how the condenser is cooled, by gas, by water, or by ice. The heat measurment is via the mass of water lost in the reactor. Boiloff calorimeters are typically calibrated using boil-off runs using calibration resistors for heat and cool-off runs to determine the calorimeter constant for ambient losses. P.J van Noorden certianly makes it clear that such calibration runs may be invalid becuase ultrasound or other turbulence creates entraind droplets, and tthe calibration resistor will not cause droplet entrainment like a source of ultrasound does. One solution to this problem is to include an ultrasound device in at least one clibration run to test whatever water drop barrier is used. It would not be possible to calibrate the drop formation rate itself, so some kind of drop barrier would have to be utilized. These principles have ramifications *way* beyond the Cirillo paper. They are fundamental to all boiloff calorimetry. > >Only if it had been water cooled could all the heat be >accounted for, and that is why I assumed it was water cooled >and that the thallium was turning up in the second circuit. > >> This is a very important comment. It means that boiloff >calorimetry can be very suspect without proper controls. > >Yes, proper controls like a second circuit with dual >calorimetry. You need to account for more than just the enthalpy of condensation. > >> A radioactive tracer would be good in labs equipped to >handle them. > >Not unless the possibility of tritium can be eliminated, I have done plenty of tritium counting using liquid scintillation counting. I think it is more difficult to count water borne tritium by other means. Scintillation couters can reliably and automatically discriminate between tritium and say carbon 14. There is almost no penetrating power for 20 keV beta particles, so counting 201 Tl without interference from tritium is easy. Technetium counting and even imaging is readily done using 180 degrees opposed scintillation couters to track positron annihilation photon pairs. I had this procedure done to image my heart. I was signifcantly radioactive for a day. It was a bit scary to turn on my geiger counter and hear it go wild near me. >or >unless your tracer has a far more energetic signature than >tritium. Thallium is just too close IMHO. > >After all, your are doing cold fusion. Cold fusion often >produces tritium. Isn't the cross-connection obvious? BTW >even though tritium "normally" has a significant spread of >energy, can we be sure that tritium produced via CF is not >closer to being mono-energetic? What do you mean significant spread? The peak is fairly confined. BTW, my handbook shows 201 Tl decaying by electron capture (1.36 MeV) with Hg and K shell x-rays of 135.28 keV and 167.40 keV. This stuff should stand out like the sun on a clear day. At 4:14 PM 12/2/4, P.J van Noorden wrote: >Hello >We used 201 Thallium in our nuclear medicine department >to study the perfusion of the heart.The energy emission of radioactive >thallium is about 80 eV. >Now we have a technetium based radiopharmacon which gives a better image >quality.( 140eV) I don't see how 80 keV enters into the picture. Regards, Horace Heffner
