It lakes good question to ask, because we speculate on unknown data. It is hard to imagine they have made student mistakes... the transparency question look less "student stupid" than others, but someone handling an IR cam can easily understand the the measurement suffer artifact...
as asked Jed, if we have the IR image and we don't see the visible shape from the photography, then the artifact is at worst limited. we are looking for a 200% error...1500K for 1200K does not even make it if I use T^4 the IR cam have to be fooled by +35% in kelvin to see COP 3.2 (convection may make it more complicated) maybe someone could compute how much the temperature have to be skewed to obtain the same COP as observed, and then explain how it can be so different from blank and active... 2014-10-13 13:12 GMT+02:00 Jack Cole <[email protected]>: > The trouble is, we don't know when that picture was taken and to what > extent the camera affected the color. > > I suspect one of the engineers here could take the temperature data from > the caps vs. the core area and compare the dummy vs. the active run. Since > the caps are not incandescent, perhaps this would be useful to examine. > > Just looking at Delta T/Watt of the caps doesn't seem to be consistent > with what I would expect with the core being 1400C. At the same time, > there is a suggestion of excess heating to me in the shift from 800 to 900W > (just considering the caps). I think someone good at thermodynamics in > solids could figure this out. > > On Sun, Oct 12, 2014 at 11:45 PM, H Veeder <[email protected]> wrote: > >> >> >> On Sun, Oct 12, 2014 at 11:43 PM, David Roberson <[email protected]> >> wrote: >> >>> I refer to the opposite effect in this case Harry. In other words, can >>> the color appear to be too dark in the visual region to our eyes compared >>> to the emission of thermal energy in the IR. >>> >>> Are there surfaces that are very poor emitters of energy in the visual >>> region that behave more like a black body in the infrared region? This is >>> more of a question instead of a statement since it seems like that might be >>> happening in this special case. The light emitted does not have a color >>> that matches what is expected to be seen from a surface of a broad band >>> black body. I wonder if anyone on the list has seen materials with that >>> characteristic. >>> >>> If you consider the behavior of a RF radio transmitter, you will >>> understand the jest of my question. In that case, the amount of power at >>> its transmission frequency, being narrow band and so low in Hertz, would >>> indicate a black body that was at an enormous temperature if the complete >>> spectrum were available as expected. But we know that it does not >>> represent a true black body since it is narrow band. Can anything of a >>> similar nature exist at other frequency ranges such as IR? >>> >>> >> The blackbody would still have a low temperature if the distribution >> peeked at radio wave lengths which are much longer than light waves. See >> how the temperature peek of a blackbody declines as wavelength increases: >> http://voyager.egglescliffe.org.uk/physics/astronomy/blackbody/Image21b.gif >> >> You are struggling to find an explanation which is consistent with the >> claim of excess energy and with the 2nd law of thermodynamics (heat flows >> from a hotter region to a cooler region). Can it be done? You can >> disregard what I am about to say since I am not expert in these matters but >> I think a choice has to be made. Either there is no excess energy or the >> 2nd law has broken down in this system. >> >> Harry >> > >
