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Post by papageno on May 17, 2007 15:20:06 GMT -4
I have been discussing on an Italian blog about the structural steel samples analyzed by the NIST engineers in their work about WTC1 and WTC2 collapse.
The conspiracist claims that the fact that no analyzed sample had been expose to temperatures above 600 degrees proves that there were no high temperatures in the impact zone. (Despite the fact that the NIST explicitly states that the results of the analysis cannot be generalized.)
My counterargument is that the selection of the samples to be analyzed introduced a bias that excludes most likely structural elements that were exposed to high temperatures. My reasoning is this: One of the selection criteria was that the element could be identified, by using paint, stampings or other marks, so that its position before the collapse could be determined. It seems unlikely that any markings can survive exposure to high temperature for a significant time, especially if the element is directly involved in the collapse initiation. Therefore it is unlikely that an element exposed to high temperatures would have been selected for the analysis.
Unfortunately I could not find anything in the NIST reports that supports explicitly my reasoning (although it is stated that the analyzed samples might not be representative of the whole spectrum of temperatures).
So, the question is if my reasoning is reasonable, or if I missed something. (It is of course no surprise that the conspiracist could not refute my argument, so I have to ask somebody who knows more than me.)
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Post by VALIS on May 18, 2007 20:06:53 GMT -4
It makes sense to me, at least. I haven't followed very closely the whole debate here, but my understanding is that the purpose of analyzing these samples was to validate the numerical model (which makes a lot of sense to the engineer that I am). If the original location of the samples can't be known, they are pretty much useless for this.
Out of the top of my head I can see just one way they could be used. It's if the temperature they reached was outside what the analysis predicted in any location. That is, a sample on which the location is not know would be useful if it reached a temperature way higher (outside the uncertainties which I guess would be considerable) than the model predicts anywhere at any time. Somehow I doubt that dismissal of high temperature samples is the exact concern of the "inside job" believers.
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Post by papageno on May 19, 2007 4:48:10 GMT -4
It was pointed out to me that it is possible that markings survived on an element exposed to high temperatures. Due to the relatively low thermal conductivity of the steel and the fact that the temperature was not uniform, it is possible that only one part of a structural element reached high temperature while the part with the markings remained relatively cool. Indeed, the analysis of the steel samples were carried out on several locations on a single element.
Anyway, samples exposed to high temperatures were not a necessary condition to validate the simulations.
Conspiracy theorists would cling to anything just to make the "official version" look bad. Just look at how they clung to Silverstein's "pull it".
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Post by turbonium on May 20, 2007 4:18:54 GMT -4
Anyway, samples exposed to high temperatures were not a necessary condition to validate the simulations. Then, could you please explain just what was necessary to validate the simulations?
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Post by papageno on May 20, 2007 5:42:11 GMT -4
Anyway, samples exposed to high temperatures were not a necessary condition to validate the simulations. Then, could you please explain just what was necessary to validate the simulations? Jay has explained this to you at length and in detail on the BAUT forum: www.bautforum.com/showthread.php?t=35175 . If you did not accept his explanations, there is no reason to believe you would accept mine.
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Post by turbonium on May 20, 2007 6:17:22 GMT -4
Then, could you please explain just what was necessary to validate the simulations? Jay has explained this to you at length and in detail on the BAUT forum: www.bautforum.com/showthread.php?t=35175 . If you did not accept his explanations, there is no reason to believe you would accept mine. Why not? Are they 100% identical?
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Post by gwiz on May 20, 2007 6:46:43 GMT -4
Anyway, samples exposed to high temperatures were not a necessary condition to validate the simulations. Then, could you please explain just what was necessary to validate the simulations? To give an example that happens to lie within my speciality: Aerodynamicists use computer programs to predict airflow effects, such as the distribution of pressure over an aircraft wing. To validate the computer methods, wind-tunnel models instrumented with pressure sensors are used. For reasons of space, only a limited number of sensors can be fitted to a model. If the program predicts accurate pressures at the points where the model sensors are located, then you presume that it is also predicting pressures with similar accuracy elsewhere on the model. You do not have to locate the sensors at the points where the pressures are maximum or minimum. The same principle applies to any computer model: if it fits all the available experimental data then you assume that it also fits reality at points where experimental data is not available.
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lenbrazil
Saturn
Now there's a man with an open mind - you can feel the breeze from here!
Posts: 1,045
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Post by lenbrazil on May 20, 2007 17:37:08 GMT -4
IIRC they didn't collect many or any truss samples due to the inability to identify their “as built locations”. Also NIST only theorized that fires hot enough to weaken the trusses occurred on part of one side each (out of four) of each tower and on only 2 or 3 out of 116 floors. 4 x 116 = 464, 3 < 1% of 464. Thus they would have been looking for less than 1% of the trusses and an even smaller percentage of the total steel and an even smaller percentage of the total debris. Given that they only wanted samples whose location could be determined the analogy of a “needle in a haystack” seems quite apt, I imagine the thin hollow trusses whose total diameters were less than the wall thickness of typical columns would have been quite mangled by the collapses.
Now if NIST were part of a cover-up why didn’t they just lie an say they had tested samples an found that they had reached temps hot enough to weaken steel?
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Post by nomuse on May 20, 2007 18:33:52 GMT -4
I believe I heard a different reason for the particular selection made.
Although I am in no way a mettalurgist, the understanding I gathered from some forgotten source is that the crystalline changes they are tracking to determine the highest temperature reached on a particular sample do not plot (aka, the structure of the steel changes irrevocably) beyond certain temperatures. It is an equivalent problem to, say, trying to use radioisotope dating on a sample that is too old, or too recent. My understanding is there is a certain domain of temperatures in which certain distinctive and well-known changes occur in steel, and that was the range the samples were selected for.
By the by, the existence of selection criteria means, explicitly, that various trained people had to look at a wide variety of available steel and make determinations on it's suitability for further testing. So in no way does existence of a criterion magically prevent "smoking gun" steel members from being seen by those with the training and equipment to understand what they were seeing. The existence of the criterion does not require or imply that investigators saw several pieces of steel that were heated beyond the highest specific temperature sampled, but neither does it prevent these pieces from existing.
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Post by gillianren on May 20, 2007 21:19:34 GMT -4
Now if NIST were part of a cover-up why didn’t they just lie an say they had tested samples an found that they had reached temps hot enough to weaken steel? Don't be silly; that's not half byzantine enough.
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Post by turbonium on May 26, 2007 4:50:05 GMT -4
IIRC they didn't collect many or any truss samples due to the inability to identify their “as built locations”. Also NIST only theorized that fires hot enough to weaken the trusses occurred on part of one side each (out of four) of each tower and on only 2 or 3 out of 116 floors. 4 x 116 = 464, 3 < 1% of 464. Thus they would have been looking for less than 1% of the trusses and an even smaller percentage of the total steel and an even smaller percentage of the total debris. Given that they only wanted samples whose location could be determined the analogy of a “needle in a haystack” seems quite apt, I imagine the thin hollow trusses whose total diameters were less than the wall thickness of typical columns would have been quite mangled by the collapses. From the above, it's apparent that you either forgot, or have never read, the relevant section of the NIST report which describes the criteria for steel examination and recovery. Nor did you look at the inventory lists, because you would have seen that ~25 items of truss material was recovered - partial or entire trusses. Among other things, the criteria included specifically searching for, and recovering, any steel components which had been exposed to fire (and/or impact damage). They didn't try to identify where the steel came from first, look for stampings, etc. and exclude it simply because they couldn't identify it among the unsorted debris at Fresh Kills, etc. Even unidentified samples were catalogued. Look at the report. Now if NIST were part of a cover-up why didn’t they just lie an say they had tested samples an found that they had reached temps hot enough to weaken steel? Straw man. It presupposes that NIST would have lied about the steel temperatures if they were involved in any way whatsoever- directly or indirectly, in whole or in part - in a cover-up. It excludes the possibility of valid scientific investigation, or the release / publication of any valid scientific data, from NIST, if it contradicts, or doesn't support, their working hypothesis and conclusions, in support of the official collapse theory. Their floor models - ideally - would not have been reported at all, or would have been falsified, because the tests did not support their theory and conclusions. But they simply reported the tests, then dismissed them as entirely irrelevant to their investigation. No steel examined or collected was exposed to temperatures high enough to weaken to failure (> 600 C). That was also put in the report, then they simply moved on to computer simulations to support their theory of critically high steel temperatures initiating the collapses. Input data - even with an admission it was spiked - was never included in the reports, nor released to the public at all. If you don't get my point yet, it's this.... There is no need to falsify scientific data - to wit, make a bold-faced lie - when it's possible to twist, manipulate, and/or suppress that data, in order to meet your pre-determined conclusions. It's valid data (at least regarding the physical (steel) analysis), based on valid physical evidence, so there is no risk of being caught in a lie that could ruin your career, and maybe your whole life. But - despite being the strongest physical evidence, with valid analysis, resulting in valid data - it played no part in their conclusions.Just like the floor model tests. They based everything on extreme, least accurate case models in their computer simulations, and didn't release the spiked input data. Because that was the only way they could get the results they needed to justify their pre-determined conclusions. And not have to lie about the results of their steel analysis. Physical evidence and physical tests contradict your theory? No worries - computer simulations can make those pigs fly!! (just don't show 'em the tweaked input data)
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Post by papageno on May 26, 2007 7:58:26 GMT -4
But - despite being the strongest physical evidence, with valid analysis, resulting in valid data - it played no part in their conclusions.From NIST's main report, section 6.4.3: These results were for a very small fraction of the steel in the impact and fire zones. Nonetheless, these analyses indicated some zones within WTC 1 where the computer simulations should not, and did not, predict highly elevated steel temperatures.
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Post by twinstead on May 26, 2007 13:06:10 GMT -4
I remember the thread on baut with Jay.
Turbonium you did not win that debate. The most you could ever hope for would be to declare it a draw, although IMHO you would be wrong.
Why are you rehashing it here?
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Post by turbonium on May 27, 2007 1:01:00 GMT -4
But - despite being the strongest physical evidence, with valid analysis, resulting in valid data - it played no part in their conclusions.From NIST's main report, section 6.4.3: These results were for a very small fraction of the steel in the impact and fire zones. Nonetheless, these analyses indicated some zones within WTC 1 where the computer simulations should not, and did not, predict highly elevated steel temperatures.That's exactly what I said - it played no part in their conclusions. They didn't - and couldn't - create models which showed elevated temperatures for the steel they collected and analyzed. But the rest of the steel in the fire-affected areas was fair game for modeling at high temperatures. This allowed them to reach a conclusion that was entirely contradicted by the physical evidence they had collected. Nobody knows, nor will we ever know, what temperatures were reached by the rest of the steel in those areas. But if any steel was found and not affected by fire, NIST made sure it wasn't collected. I made this point earlier, but it bears repeating - NIST did not seek out steel specifically from the fire and/or impact damaged floors. They sought out steel as specified below...... - Exterior column trees and interior core columns from WTC 1 and WTC 2 that were exposed to fire and/or impacted by the aircraft.
- Exterior column trees and interior core columns from WTC 1 and WTC 2 that were above the impact zone.
- Badly burnt pieces from WTC 7.
- Connections from WTC 1, 2, and 7, such as seat connections, single shear plates, and column splices.
- Bolts from WTC 1, 2, and 7 that were exposed to fire, fractured, and/or that appeared undamaged.
- Floor trusses, including stiffeners, seats, and other components.
- Any piece that, in the engineer's professional opinion, might be useful for evaluation. When there was any doubt about a particular piece, the piece was kept while more information was gathered. A conservative approach was taken to avoid having important pieces processed in salvage yard operations. The first two criteria, again.... - Exterior column trees and interior core columns from WTC 1 and WTC 2 that were exposed to fire and/or impacted by the aircraft.
- Exterior column trees and interior core columns from WTC 1 and WTC 2 that were above the impact zone.So, NIST sought out any of the steel above the impact zone. But within the impact zone, they only sought out steel that was affected by fire and/or impact damage. They specifically excluded any steel from the fire / impact floors - unless it had fire exposure / impact damage!! Why didn't NIST seek out any and all steel from the fire / impact floors - as they did for the unaffected floors above?? NIST excluded unaffected steel from the most critical areas, while they included all the steel from the far less critical areas, just above it. These ridiculous qualifications allowed NIST to arrive at the exact conclusions that they had always hoped for, right from the start, They didn't have to worry about ever being proven wrong, later on. Totally dishonest, unethical, prejudicial, and deceptive scientific practices. If NIST truly wanted to investigate the cause(s) of collapse, they would have tried - first and foremost - to reconstruct the critical floors. They would have sought out and collected any and all steel from those very floors - regardless of condition. This is such a basic idea. Even a child would understand why this should be done. And yet, some adults apparently cannot grasp the concept.
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Post by turbonium on May 27, 2007 1:14:07 GMT -4
I remember the thread on baut with Jay. Turbonium you did not win that debate. The most you could ever hope for would be to declare it a draw, although IMHO you would be wrong. Your opinion has been duly noted. I wasn't aware that my only hope was a draw. Thanks for filling me in.. Why are you rehashing it here? Because what NIST did was a complete travesty, and I consider it well worth bringing up once again. Whether you consider it irrelevant, a closed issue, or otherwise disagree with my view.
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