XPost: sci.physics, alt.solar.thermal   
   From: amdx@knology.net   
      
   Snips   
      
      
   > If ignition occurs, there will be another latency as heat is transferred   
   > from the containment vessel into the heater tube - but I think that   
   > situation would exist for any affordable strategy.   
   >   
   > The change in resistance looks like it'll be small, and I guessed that   
   > an op-amp circuit might be useful to produce a larger temperature swing.   
   > A temperature range of 25-537°C would probably be a sensible design   
   > target. (I'm /aware/ of op-amps, but I've never designed a circuit that   
   > actually /used/ one of the little buggers.)   
   > > A linear output would be "nice to have", but isn't essential - I don't   
   > think a table look-up/interpolation is likely to overburden even the   
   > little Arduino.   
   >   
   > -----   
   >   
   > For my first go at this problem, I plan to start at a very low H2   
   > pressure and increase it incrementally. At each pressure setting I'll   
   > start at a low temperature setting and increase the temperature   
   > incrementally to some safe limit (probably 250°C)   
   > The entire exercise is to discover whether a self-sustaining reaction   
   > can be initiated and, if so, the minimum (pressure,temperature) values.   
   >   
      
     Hey Morris, is there a reason you don't want to stick a thermocouple in   
   the tube for your temp measurements as others have suggested? It would   
   sure simplify this section, and, you could get lots of design help on   
   sci.electronics.design to raise the thermocouple output voltage nearer   
   5v at 537*C.   
     Also I suspect you have thought that if the temp sustains itself or   
   starts to run away, your Ardiuno will sense this and start limiting   
   hydrogen input and/or pump more water.   
                                 Mikek   
      
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