Friday, May 08, 2009

A Response to Harrit, Jones, From Dr Greening

Copied from here, reproduced without permission in the interests of science:

I just sent this e-mail to the authors of the "Active Thermite" paper:

The "Active Thermite" debate, (if there ever was one!), has now sadly reached a state of stasis and stalemate. It basically boils down to this: do you believe Harrit and Jones or not. Or stated another way: Are the red/gray chips definitive evidence that "energetic" nanothermitic agents were pre-planted in the WTC or are these chips explainable in some other, less conspiratorial, way?

To begin to answer this question we need to consider just how unusual, (or not!) these red/gray chips really are. Harrit et al. believe that the red/gray chips are indeed very remarkable - so much so that these authors insist that these chips simply could not be found in dust produced by a "natural" collapse of the Twin Towers. Harrit et al. make this claim mainly because of two characteristics of the chips:

(i) Their alleged engineered "nano-scale" structure

(ii) Their alleged "highly energetic" pyrotechnic properties

With regard to the first of these points it is quite evident that Harrit et al. have based their characterization of the WTC red/gray chips almost entirely by copying the work of scientists at Texas Tech University and the Lawrence Livermore National Labs who have made and patented nano-structured energy-dense materials for use as detonators and pyrotechnic agents. (See the papers and reports of authors such as M. L. Pantoya, T. M. Tillotson, R. L. Simpson, B. J. Clapsaddle and A. E. Gash, as well as Chapter 7 of the book "Energetic Materials" by U. Teipel) It is therefore very significant that these nano-technology materials scientists consistently and repeatedly make use of scanning electron microscopy, X-ray analysis, and DSC to characterize their samples - precisely the techniques used by Harrit et al to characterize their red/gray chips. But in spite of this obvious attempt to convince the scientific community that the WTC red/gray chips are indeed the high-tech creations of dedicated "nano-engineers" toiling away in some clandestine weapons laboratory, these chips are in reality quite low-tech and decidedly micro, as opposed to nano, in scale and structure.

With regard to point (ii) above, Harrit asserts that the chips are fragments of an "energetic material". This claim is mostly based on DSC measurements, but we need to consider: is it supported by experimental evidence? The Harrit paper reports the energy content of the red chips to be in the range 1.5 - 7.5 kJ/g. This is in fact not very "energetic" at all when you consider that common organic materials such as simple hydrocarbons or oxygenated hydrocarbons contain far more energy per gram than the red chips. Thus gasoline releases about 48 kJ/g, and stearic acid, found in plant and animal fats, releases about 40 kJ/g upon combustion. Since carbon, in some as yet unknown chemical state, is also found in the red chips, it is certain that some of the energy content of the red chips is accounted for by this non-thermitic ingredient. In fact, if the chips contained a mere 10 % of graphitic carbon it would account for more than half of their energy content!

Nevertheless, on page 28 of their paper, Harrit et al. offer another reason to believe that the red chips are a highly energetic thermitic material:

". the DSC tests demonstrate the release of high enthalpy, actually exceeding that of pure thermite. Furthermore, the energy is released over a short period of time, shown by the narrowness of the peak in Figure 29."

This statement, also repeated in the Abstract to the paper, is simply not correct and shows a complete lack of understanding of DSC by the authors of the paper. Why do I say this? Well, Figure 29 is the DSC trace of a red chip heated from 20 deg C to 700 deg C at 10 deg C/ min and shows an exothermic peak extending from approximately 420 - 470 deg C. Now, as someone who has run many DSC analyses on a wide variety of materials, I know that the height and width of a DSC peak depends on many factors such as the sample-holder, the furnace atmosphere, the sample packing density, etc, but most of all, DSC peak widths depend on the heating rate. Given that the DSC trace of Harrit et al. was acquired at 10 deg C/min and has a FWHM ~ 25 deg C, one can be certain that a different peak width would have been obtained if a different heating rate had been used. Thus DSC peak widths are not indicative of reaction rates. This is amply illustrated by many of the DSC traces and the discussion given in Chapter 5 of the well-known chemistry textbook "Thermal Analysis" by W. Wendlandt.

Finally, I should add that DSC is most effectively used to study reaction rates if it is carried out in isothermal mode using the Avrami-Erofeev equations to analyse the data. This experimental approach allows a rate constant and an activation energy to be calculated for the reaction responsible for an exothermic peak. I am surprised that a Chemistry Professor at a well-respected University appears to be unaware of this simple fact ....

Yes indeed Prof. Harrit, you had the temerity to tell me to take my time and not waste yours, when perhaps I should be telling you to take your time, but not waste mine!

The thread over there is pretty interesting to read. You can see quite clearly that only Greening (Dr G) speaks with confidence and authority; the Truther posters are mostly "Well, what about this, and what about that?" I don't want to knock them, because I get the sense that Metamars, in particular, is making an honest attempt to discuss the issues but clearly doesn't know the science (and let me add that I don't know it either; I can only judge by the way the discussion flows).

I am a bit surprised to learn that Steven Jones swears in his emails; it just seems out of character for someone who is generally soft-spoken and genial.

Note also this key point:

I've already done a calculation, (see my post from a few days ago), of how much heat energy a layer of nano-thermite (such as the one allegedly found by Jones et al) could generate. And, by the way, you have not commented on this calculation as you said you would. Nevertheless, my conclusion was that Jones' chips would do no more than slightly warm a WTC column!

Faced with this, what did Jones claim?

So when I bounced my calculations and conclusions off Jones et al, all he could come up with was the suggestion that there were probably other explosives used in the WTC and the nanothermite chips were maybe just fuses!

Thus, after all the fuss about high-tech nano-thermites, we are back to good-old "bombs in the buildings" as the answer to how the buildings were destroyed.

No kidding; after all that fuss, Jones is claiming that sooper-nano-thermite was just a fuse!

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