From: DROEGE@fnald.fnal.gov
Subject: Status #7 Cell 4A3
Reply-To: DROEGE@fnald.fnal.gov
Organization: Sci.physics.fusion/Mail Gateway
Date: Wed, 6 Jan 1993 20:07:25 GMT

Status #7 Cell 4A3

We are presently running a Takahashi style Pons and Fleischmann "cold fusion" 
experiment.  Cell 4A3 contains a 1 cm by 1 cm by 1mm Pd cathode.  The cathode 
was squeezed down to 1 mm thickness from a 3mm thick coin bar in a high 
pressure hydraulic press.  Fill is 30 cc of .47 M D2O.  Cell is running with a 
Pt dummy electrode at a 300 microampere bias current positioned off to one 
side of the anode grid.  The Pt anode is wound around the cathode like the 
grid in a 6AS7 vacuum tube.  (I might as well say positioned like the tongue 
in a Plesiosarus for all most of you would know.)  A glass tube down the 
center of the cell supports the teflon anode/cathode structure at its end.  
The tube contains two solid state thermometers.  One where the tube is 
surrounded by the liquid measures the cell temperature.  A second is located 
above where the tube is surrounded by gas in the vicinity of the catalyst.  
The glass tube between the two thermometers is stuffed with foam to reduce 
coupling.  The catalyst is Engelhard Palladium Catalyst D, which is Palladium 
based.  The catalyst is formed as small cylinders which are 0.1" in diameter 
by 0.1" long.  The catalyst is located in eight sodium glass tubes which are 
supported in the top of the cell by teflon spacers.  The glass tubes are 
mounted vertically with the bottoms slightly closed to keep the cylinders in 
place.  This allows condensate to drip out the bottoms of the tubes.  About 15 
of the catalyst cylinders are in each of eight tubes.  The cell is sealed with 
"O" rings external to the cell volume and any excess gas is removed to an 
atmospheric pressure motor driven syringe.  The cell was assembled in an Argon 
filled glove bag after an appropriate cleaning ritual.  The cell is operated 
in a null balance calorimeter of my design with a one sigma calibration for 
this run of 0.035 watts.  (We will repeat this summary from time to time for 
new readers.) 

We are presently operating at 800 ma which results in a cell voltage of 4.5 
volts.  Present calorimeter balance is at 7.300 watts.  Peak to peak changes 
over the last several hundred hours are consistent with the 0.035 mw one sigma 
calibration.  But there is an offset from the December calibration with only 
probable cause due to high temperature TED creep.  Remember to get the 
temperature range we are operating with the shell servo off and floating.  A 
curious observation is that we are more sensitive to the outside air 
temperature than to the room temperature.  So while the room temperature is 
relatively constant, the calorimeter "sees" the outside through the dewar, 1 
1/2" of foam, a (now) floating aluminum radiation shield, 1 1/2" foam, 10' of 
air, and an R19 house wall or R30 roof.  

After about 350 hours of charging, we have accumulated enough (presumed 
oxygen) gas to indicate that the cathode has absorbed D2 gas to an apparent 
3.0 to 1 D/Pd. 

At this point, I guess I favor the "Trickle Down" gas theory.  While running 
at one ampere there was a gas run away where the catalyst could not keep up.  
Backing down the cell current to 0.8 ampere gives stable operation, but there 
are still gas bumps.  Looks like previously we were running right on the edge 
of what the catalyst could convert.  The gas volume is observed to bump up 
slowly 5 cc or so over 15 minutes.  Then it decays back to the baseline.  This 
is accompanied by a cooling of the catalyst.  They are mirror images of each 
other - gas goes up/catalyst goes down.  

This still does not explain why there is so much gas in the syringe.  3/1 is a 
lot but for comfort I have the Moore thesis where he found 2.3/1.

For the first week or so the cell voltage had been slowly rising.  Now it is 
quite stable so there is every indication that we will be able to run here for 
a long time.  
                            
Tom Droege