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</o:shapelayout></xml><![endif]--></head><body lang=EN-CA link=blue vlink=purple><div class=WordSection1><p class=MsoPlainText>Dear Andrew<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText><span lang=EN-US>></span>The temperature will be at an equilibrium when the heat from the gas flame equals the heat lost by the metal by radiation conduction and convection, <o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>Agree.<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>>...as it is in the flame we can assume the conduction and convection have little effect. <o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText><span style='color:black'>Wow. Well, I need to think about that one. From the things I have calculated I estimate the convection to be a large fraction even for things that are not very hot so I might need to go back to the spreadsheet to look at something this hot. 14% comes to mind for some reason, for radiation. I guess you could also say that the colour is a measure of the gas temperature <i>if the material is radiating poorly</i>. The more efficiently it radiates, the larger will be the difference between the gas temp and the material doing the radiating, no? It is effectively a heat sink.<o:p></o:p></span></p><p class=MsoPlainText><span style='color:black'><o:p> </o:p></span></p><p class=MsoPlainText><span style='color:black'>My point (sort of) is that yes it is radiating but not very efficiently in the IR band, which makes it so loud in the visible. As the emissivity does not change much with temperature (in spite of many opinions to the contrary) a shiny silver part will not emit well in the infrared so the temp keeps going up.<o:p></o:p></span></p><p class=MsoPlainText><span style='color:black'> <o:p></o:p></span></p><p class=MsoPlainText>>The only conclusion I can see from this is that at equilibrium a poor emitter will become hotter than a good emitter.<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText><span style='color:black'>Exactly. And the worse, the closer it will get to the gas temp. Yes?<o:p></o:p></span></p><p class=MsoPlainText><span style='color:black'><o:p> </o:p></span></p><p class=MsoPlainText><span style='color:black'>Regards<o:p></o:p></span></p><p class=MsoPlainText><span style='color:black'>Crispin<o:p></o:p></span></p><p class=MsoPlainText><span style='color:black'><o:p> </o:p></span></p><p class=MsoPlainText><span style='color:black'><o:p> </o:p></span></p><p class=MsoPlainText><span style='color:black'><o:p> </o:p></span></p></div></body></html>