Thanks for all the explanations - I'll ponder further and see if I can get it straight and then think of a graphic to sum it up...
Some Points Regarding a Recent Presentation at ICCF20 on the ‘Lugano Report’ (Rainer Rander)
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Yes thanks, much more consideration needed, but am determined to visualize this ))
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Here is a plot of Planck curves at 1000°C (1273.3 K), and reducing the emissivity by 1/2, then to 1/10th. The total radiance drops while temperature stays constant.
Next is a plot with emissivity set at 1, but with temperature dropping from 1000°C by 1/2 (in K), then 1/10th (in K). Total radiance drops (a lot).
(Not sure why the line colors reversed, annoyingly)
I tried raising temperature and simultaneously dropping the emissivity as above, meanwhile holding total power constant, for another plot. But it was hard. I have a best eyeball guess, if someone wants, but the math needs to be done and it is complicated to get it right.Edit: I managed a pretty close constant radiant power plot (as above), and its not quite what I expected. But it is what it is, so it is image 3, below.
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Indeed the temperature of an object would be hotter being limited to IR output in a limited spectral band portion of the IR band than it would be if it were a blackbody at the same level integrated radiant power.
So you agree perfectly with RB0 !
In fact an object with a limited bandwith emissivity will be really hotter then a Black Body ! This is a real effect and not apperent !
We should note that in the last postings RB0 is just writing about Quantum Mechanics and Physics and DO NOT consider any detector.
So her conclusions are valid for all the detectors ! Even thermocouples.Total radiant power is irrelevant to detecting temperature based on a selected IR window.
Excuse me sir, in your post you say one thing and demonstrate the opposite. By showing that the two curve are almost identical in a limited region you demonstrate that for obtaining a good measure we must consider all the spectrum !
Seems that you say one thing but you think your are saying the opposite !
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I am sure quite a few folks here are still waiting for your derivation...
Ok boys we can start !
Does this help?
Thank you for your contribution but NO, It does NOT help. The Optris window is not part of the reasoning. What we are writing about is physical considerations that motivate what Paradigmoia has found experimentally.
Objects that do have a better emissivity are cooler then object with low or selective emissivity. -
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Paradigmnoia wrote:
Total radiant power is irrelevant to detecting temperature based on a selected IR window.Excuse me sir, in your post you say one thing and demonstrate the opposite. By showing that the two curve are almost identical in a limited region you demonstrate that for obtaining a good measure we must consider all the spectrum !
Seems that you say one thing but you think your are saying the opposite !
Bert, if two curves are almost identical in the same region, but different somewhere else, then the camera cannot tell them apart, because it cannot see somewhere else.
Because the camera is not calculating total power, it does not need to know about the other regions.
Because two (or many more) curves can be nearly identical in the region that the camera can see, the highest possible emissivity value for that part of a curve is always that of a blackbody.
All the camera does is look at what is in the region it can see, and decides what blackbody temperature it corresponds with.
The user decides if a blackbody is not appropriate for what the camera sees in that region. That region is the ONLY region the camera sees in.
The temperature can be calculated without ever knowing the total power output. (What is the total radiant output power of a wall in a house, or a cup of coffee? The Camera does not care.)
The user increases the temperature reported by the camera by changing the camera emissivity function to a lower number.
If the user inputs too low of an emissivity value, where the camera looks, in the same select region, then the camera will claim the temperature is higher than it really is.
If the emissivity input by the user is higher than it really is where the camera looks, in the same select region, then the camera will report too low a temperature, but never lower than a blackbody would be.
The user can ONLY make the emissivity value for the camera lower than a blackbody. -
Quote from rb0
Objects that do have a better emissivity are cooler then object with low or selective emissivity.
I'm glad that we have now found something uncontentious (in fact tautologous) to agree on.
Perhaps, to be precise, you should add "for the same total radiated output power, and given the same geometry". But that was never a matter of contention.
So: I await your further argument with interest.
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Objects that do have a better emissivity are cooler then object with low or selective emissivity.
That should say "Objects that do have a better emissivity are cooler than an object with low or selective emissivity at the same level of total power"
This however does not affect what the Optris camera can see, or how it calculates temperature. The Optris simply measures a select band of IR radiation radiating from an object and compares that to an internal blackbody reference, as seen through that same band.
(I guess THH was quicker. Including same geometry was a good idea)
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The temperature can be calculated without ever knowing the total power output.
For being precise the camera is nit sensitive to temperature but to radiated energy. For making a measurement you must know the ratio of the total emitted power from the body surface and that that would be emitted by a Black Body. So all your reasoning means that total emissivity is an important factor to know during a measure.
Total emissivity and not band emissivity because, as you demonstrated, that for many bodies the energy emitted in a certain band could be identical. -
That should say "Objects that do have a better emissivity are cooler than an object with low or selective emissivity at the same level of total power"
Very good so you agree that a Black Body "Dog Bone" would be much cooler then an Alumina "Dog Bone" at the same level of total power.
That's why Alumina emissivity must be used. To measure the correct temperature.
I'm very glad that you finally agree on this point. -
Below, we have two more plots.
The first shows three segments of equal power, but equal only within the spectral sensitivity range of the Oprtis.
The second are the full curves in which the segments occur.The Optris will view them all as the same, regardless of the total power.
Unfortunately this program only plots black and grey bodies. However, selective emitters can be approximated by grey bodies. (This is where the not so fun integrating occurs)The Optris will view the IR received through its spectral detection sensitivity range window, from each of the large curves below, as the accompanying plotted segments, which all have the same integrated power within that segment, and referenced to the camera blackbody look up tables, will all generate the same blackbody temperature of 1273 K, or 1000°C according to the Optris.
Edit: You might get an idea of how a two-wavelength (or multi wavelength) IR device calculates emissivity and temperature from the second image.
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He did make a blanket statement about ignorance...so I was not too far off the mark in indirectly (peasants) teasing him about it, while also making a point or two about the subject.
One of the more offensive habits of those commenting on fora like this is exaggerating what others have said. Please be careful about that. It is a fact that many comment on these fora who are quite ignorant. Some are at the same time quite intelligent and could, in theory, understand the issues, but don't because they are attached or stuck somewhere. It's common.QuoteSo is Lugano dead now?
Well, limping badly, to be a little closer to the reality. The latest analysis I have seen allows that there might be some XP. That might or might not be correct. What is dead is using Lugano as some sort of proof of "LENR+." Sorry, Peter, that is dead. Not "NiH," which is a baby, with some promise, simply not as well established as PdD, so PdD, in spite of certain difficulties with practical applications, remains an established basis for certain kinds of experiments. Practical applications of PdD are not out of the question, even though palladium is very expensive, because it is a surface effect and it might not take much palladium, and as a catalyst, the palladium is not consumed.Any serious and comprehensive LENR research program will be looking at NiH and PdD and maybe some other materials.
With scientific rigor. It's about time.
A recent private discussion reminded me of something that I never paid sufficient attention to. Pons and Fleischmann used a sophisticated and mathematically complex calorimetry that was a hybrid of isoperibolic calorimetry and adiabatic calorimetery (and not purely either one) and this gave them a claimed precision of +/- 0.1 mW, whereas the more commonly used forms of calorimetry, simpler and allegedly more bulletproof, may have precision in the range of 50 mW.
Why wasn't the FP method used more often? Well, complex calorimetry can be more readily disbelieved, because there are, on the face of it, more opportunities for error. Look at Lugano! Complex calorimetry! I looked at it and decided that no way was I going to spend the time to try to understand it in detail, and without going into detail, "understanding" can be way, way off. I knew that this was risky, but the kicker was the lack of calibration at full input power.
Now, suppose one uses FP calorimetry, which considers not only the standard isoperibolic idea that the temperature of a body with a known heat resistance to a constant temperature bath will vary with the heating power, but combines with the adiabatic concept that if power changes, the rate of change of temperature will vary with the change in power, it is not necessary, as with pure isoperibolic calorimetry, to wait for the temperature to settle. This approach, combined with some other sophistication (such as considering the air pressure), is what allowed the high precision for FP calorimetry.
That could be automated, it's just a Labview setup, given the inputs and the equations to do the math on them. Complicated? Yes. However, if it is then fully calibrated under all operating conditions, it could be transparent. We do not need to know what is under the hood to understand and see that a system makes accurate measurements of power when faced with calibration power and changes in calibration power.
To me, what was revealed was that, in the name of creating experiments that were less easily criticized, precision was sacrificed. It didn't work, because it made the signals closer to noise. Far closer, like 500 times closer, perhaps. LENR, for over two decades, operated with a chip on its shoulder.
Time to shake that off. I've been looking at some NiH work and wondering why the rate of change of temperature is not being used to infer instantaneous power. Well?
If it is calibrated, we should not care how complicated the equations used in the calculations are, as long as they are repeatable and known and reproducible.
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Hmm.. now I'm completly lost ((
I had in mind exactly the scenario illustrated by Grafiker which seems to be logical and could be applied to radio waves with a narrow or broadband receiver.
I guess more study is needed.
You are lost because you did understand it, then Paradigmnoia suffered some kind of brain fault and managed to confuse you and others. He's smart and not terribly attached to being right, so I'm confident he will figure it out, and since I have not read all of this thread yet, maybe he already has.There are two issues being confused here. Temperature determination and Power determination. I highly recommend focusing first on temperature, and as to the measurement of temperature with an Optris camera, Graffiker was quite good. Some Points Regarding a Recent Presentation at ICCF20 on the ‘Lugano Report’ (Rainer Rander)
The graphic explains clearly and simply how using total emissivity (which essentially assumes that black body distribution) instead of band emissivity (where an object is not a gray body, but has preferential emission in a band, and in particular the band that the camera is sensitive to) can create a major error in estimating temperature. Just get that solid, first -- then worry about inferring power, later.
One step at a time.
(Addition: the graphic represents a black body spectrum as level across the spectrum shown. In fact, it is not level, but simply consider the plot as normalized to black-body emission. The graphic still communicates the concept, and more clearly than if it were "correct.")
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will all generate the same blackbody temperature of 1273 K, or 1000°C according to the Optris.
That's why the total emissivity parameter is so important !
However, selective emitters can be approximated by grey bodies.
Thank you Paradigmoia. So if we need to measure Alumina we can treat it as a gray body with the correct emissivity.
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@randombit0, I'm glad you liked my last post, because we are getting warmer, as they say.
But first some dinner.
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Objects that do have a better emissivity are cooler then object with low or selective emissivity.
RB0 is incoherent. Okay, translate "better" as higher. Now what does it mean?There is a missing condition, what is actually being described is missing. This is obviously not it: if I have two objects at the same temperature, and one has higher total emissivity, is this cooler? Of course not, I just defined them as being at the same temperature.
However, if I measure the total emitted power, two objects with the same emitted power, and one has higher emissivity, what is implied?
The object with higher emissivity will be cooler. That must be the intended meaning.
How do we measure total emitted power?
We don't, generally, unless we use calorimetric methods that capture the power or monitor its effect, and that is not what was done at Lugano.
An Optris camera can only measure power in a band to which it is sensitive. So to use the camera to estimate temperature, one must know the emissivity for the band, not total emissivity. Total emissivity is relevant to how the object will radiate power at some temperature, but not to the estimation of temperature.
One step at a time.
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Paradigmnoia wrote:
That's why the total emissivity parameter is so important !
Important for what?QuoteParadigmnoia wrote:
Probably a brain fault if taken literally. The statement is not qualified, i.e., is not a general truth, but only true within some condition or for some purpose.QuoteThank you Paradigmoia. So if we need to measure Alumina we can treat it as a gray body with the correct emissivity.
Not for the purpose of measuring temperature. Once the temperature is known, then the total emissivity can be used to predict radiative cooling.Let's get this straight: to use an Optris camera for determining temperature, band emissivity in the band detected by the camera must be used. To estimate, then, total power radiation, total emissivity must be used, not band emissivity. For that purpose, the alumina is treated as a grey body.
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Anyone want to be the first to tell the emperor that he has no new clothes? Don't look to me, as I am just thankful how easily I got off with my mild transgression against TTH. All I have to do is: "be careful" from now on. That is not easy for me, but to keep the peace....
Thank goodness I am not eating "dinner" somewhere in southern Europe.
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Re selective emitter approximated as grey body:
Yes this must be qualified.
In order to know that a body is selective or grey for power output, one needs to check the full spectrum.But the camera cannot check the full spectrum.
So then we are working with the possibility of grey, selective, or black body within the camera spectral sensitivity range only.
Now we are getting even warmer...Back to dinner...
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Here is a plot of Planck curves at 1000°C (1273.3 K), ....
A little knowledge is a dangerous thing, and a lot of knowledge can confuse the hell out of you.You have gotten entangled in the estimation of power, which is way ahead of the discussion. First, Lugano estimated temperature by using a total emissivity value, when that's a plainly incorrect application of the camera, band emissivity is needed, or an actual calibration, which amounts to the same thing, since it is a band to which the camera is senstive. That must be kept in mind and not complicated by considerations of total power emissivity and total power emitted.
Power emission will vary with total emissivity, and that is what total emissivity is about. It is a measure of the total radiative power of the material compared to black body radiation. It is also a value that varies with temperature. So if one has measured an incorrect temperature, one may also use an incorrect value for total emissivity, but that's getting ahead of the discussion.
First comes estimation of temperature, and then everything else comes after that. And that requires band emissivity of the material, in the operational band of the camera, which is either taken from calibration or from tables designed for the camera.
Calibration would have made all this calculation unnecessary! That is, X power into the dummy reactor, a particular camera reading. If calibration were done in the power region of interest, no need for all the complicated calculations. Just translate the camera reading back to power from the calibration series.
It might be objected that calibrating at 1400 C would be impossible. Indeed. That argument, in fact, is quite against 1400 C being the true temperature, the same reasons that would have made it impossible make it implausible. However, calibration could definitely have been done up to over 900 W. input power, and if the unit actually got hotter, well, at least it would then be shown that it was XP, even if not so accurately determined. As McKubre pointed out, one would then see the trend at 900 W input. That's not fully satisfactory, because emissivity will change with temperature, but definitely better than nothing.
When Rossi showed up to shut the reactor down, presumably he saw the temperature registered by the internal thermocouple. Apparently that has been a closely guarded secret. Why?
