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6th December 2015, 02:46 AM | #441 |
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I am not trying to be difficult here, but - where the heck do you see "rapidly occurring expulsion of building material" at 7:30 in this video??
https://www.youtube.com/watch?v=38Vsv0eve_U&t=448 As DGM pointed out, the building obviously was already collapsing before 7:30 (the visible descent of the east penthouse begins at 7:24), so I wouldn't even be surprised to see building material being pushed out, given that a descending roof decreases building volume and MUST push out massive amounts of air[*]. But I can't see any such expulsions in that video? Can you make screenshots and draw arrows so O know where to look? [*] Little fun fact: The area between col 76-78 and the east wall was roughly 1000 m2. By the time the collapse started to progress to the western core (5.5 seconds after EPH collapse started), the cave-in of the eastern roof had gone down at least 1/4 of the building's height on average (wasn't even), that's almost 50 meters. So the enclosed building volume had decreased by almost 50,000 cubic meters, most of which was air. The air that must have been expelled by 7:30 in notconvinced's video weighed roughly 50 tons. (Density of air is 1.2 kg/m3) |
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6th December 2015, 03:14 AM | #442 |
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6th December 2015, 03:28 AM | #443 |
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Nice to see you don't subscribe to the oft-mentioned notion that the observed fall required simultaneous removal of all vertical support.
And it reduces the number of charges required. Ballpark: 8 storeys, 25 columns, 5 charges per storey-section - a mere 1,000 explosive charges, detonated almost simultaneously. What a dreadful load of nonsense. (cue - "But nanothermite can be tailored to be both quiet and explosive") eta: My mistake. It would likely be 2 charges per flange, top and bottom, plus a kicker charge. 9 per column section, so more like 1,800 charges in total. The amount of detcord alone is mind-boggling. |
6th December 2015, 03:59 AM | #444 |
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6th December 2015, 04:53 AM | #445 |
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6th December 2015, 08:18 AM | #446 |
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6th December 2015, 08:20 AM | #447 |
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6th December 2015, 08:24 AM | #448 |
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6th December 2015, 08:27 AM | #449 |
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Which is why I said "ballpark". You quibbling about round numbers?
Really? At that low level where the columns are massive? They'll just flip out of the way? Maybe, but see below: Sounds very loud when they're exploding almost simultaneously, even if you're dead right about the numbers. |
6th December 2015, 08:28 AM | #450 |
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6th December 2015, 08:36 AM | #451 |
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Because of the recovery of the bodies, the NYPD, did not see any visual evidence of any explosive charges.
Explosives leave visual evidence of having been used even thermite cutters leave a distinctive visual pattern if you had tested one you would recognize it instantly. |
6th December 2015, 09:25 AM | #452 |
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6th December 2015, 10:02 AM | #453 |
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6th December 2015, 10:29 AM | #454 |
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 ] https://www.youtube.com/watch?v=p22OkclAU3o  https://www.youtube.com/watch?v=KB-6Sp7mKlQ  https://www.youtube.com/watch?v=4wfpRO9bTfo I do not observe any comparison to what happened to WTC7. While the upper section of WTC7 descends and is crushed out of view below, you can clearly see that it remained far more intact than your proffered video examples of comparable instability.  The measured 2.5 seconds (8 stories) of free fall was obtained from the perimeter movement. While I agree that a lower core failure occurred first, it would have not been impossible for those perimeter facades to drop at free fall acceleration and with such corner to corner synchronization if they were still meeting structural resistance from below. Hence, there could not have been any perimeter structural resistance for at least 8 lower floor stories of WTC7. My point being; if the perimeter was dropping at free fall acceleration, it could not have been “pulled” at free fall against residual vertical structural resistance unless there was an additional pulling force greater than the force of gravity and strong enough to negate the remaining structural resistance in the perimeter. And no, I do not believe there was some unseen additional force crushing WTC7 from above.  Your example above of how this could be manifested is truly pathetic.  I would like to hear your logical engineering explanation that provides for the existence of a force other than gravity, which could have pulled WTC7 down at an acceleration greater than that induced by gravity. |
6th December 2015, 10:42 AM | #455 |
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6th December 2015, 11:04 AM | #456 |
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6th December 2015, 11:19 AM | #457 |
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6th December 2015, 11:21 AM | #458 |
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6th December 2015, 11:24 AM | #459 |
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6th December 2015, 11:44 AM | #460 |
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6th December 2015, 11:51 AM | #461 |
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6th December 2015, 11:55 AM | #462 |
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6th December 2015, 12:01 PM | #463 |
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Yes. Leverage by PARTS or subsystems WITHIN a system that is falling as a whole. IIRC an anonymous person did make a very crude graphic for Chris Mohr's video series.
Is it time to dust off those posts on "Introduction To Free Body Physics"? ...AGAIN??? It would sort the sheep from the goats in terms of who can apply physics from basic principles. |
6th December 2015, 12:06 PM | #464 |
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6th December 2015, 12:07 PM | #465 |
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Simple structural dynamics - the internal structure frame collapses first. The internal frame is still attached to the exterior structural frame (shell). The internal frame induces a downward force on the exterior structural frame, helping the exterior to appear to accelerate greater than gravity.
You have to look at the building as a complete system. The sum of the both the internal frame and the exterior structural frame is less than gravity acceleration. Got it? Simple, right? |
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6th December 2015, 12:10 PM | #466 |
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I'm not getting into a peeing contest with you on this (you were involved in the threads and discussions about this). It's just your way of avoiding the neon elephant in the room, that being ~400 high explosives going off that no one noticed and were not picked up by any recording device.
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6th December 2015, 12:19 PM | #467 |
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If you don't know much about the clean up operation, isn't it down to you to get information from people involved in the clean up ?
Yes, you do know they didn't save steel from wtc7, as to why is another thing you will need to ask. Funny how you know explosives were used and you haven't spoken to anybody. |
6th December 2015, 12:19 PM | #468 |
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6th December 2015, 12:21 PM | #469 | |||
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Let's listen to the video that was presented as proof of explosive discharges. The audio is working, you can hear talking and everything.
I don't hear anything. |
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6th December 2015, 02:26 PM | #470 |
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While I quite understand the principle of leverage, I fail to see how leverage could be produced that would exert a downward uniform force capable of accelerating the whole descent of WTC7 building beyond that induced by gravity.
 As you can plainly see, WTC7, over the free fall part of its descent, is not subjected to any external leverage. Once in free fall it would take a major glaringly obvious upper explosion (become a downward aimed rocket) to make its descent acceleration faster than g. |
6th December 2015, 02:52 PM | #471 |
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"Remember that the goal of conspiracy rhetoric is to bog down the discussion, not to make progress toward a solution" Jay Windley "How many leaves on the seventh branch of the fourth tree?" is meaningless when you are in the wrong forest: ozeco41 |
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6th December 2015, 02:57 PM | #472 |
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Your appeal to uninformative photographs notwithstanding, any measurement plotted on a graph is a measurement of a point on WTC7, not of the "whole descent" (if such a concept had any useful meaning in this context). Rotation of the building is rather an obvious form of leverage; if the centre of mass is accelerating at 1G and the building is also rotating, it's inevitable that some part of it will be accelerating at greater than, and some other part at less than, 1G.
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6th December 2015, 03:02 PM | #473 |
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You'll note that I didn't actually comment on whether such a thing had been reliably measured. Some measurements, including those of Chandler's that you recently referred to, show brief interludes of >g acceleration, whether due to actual signal or to noise, and there is a perfectly reasonable mechanism to produce >g accelerations at specific points on the façade; why do you choose to take issue with either of these things except out of knee-jerk denialism?
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6th December 2015, 03:25 PM | #474 |
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Thermodynamics hates conspiracy theorists. (Foster Zygote) The business of Progressives is to go on making mistakes. The business of the Conservatives is to prevent the mistakes from being corrected. (Gilbert Keith Chesterton) |
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6th December 2015, 03:27 PM | #475 |
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It would be internal, not external leverage. As clearly evidenced by the photo's you provided the core collapsed first, pulling floors down with it - floors that were attached to the perimeter columns which in turn pulled them down, twisting the structure at the same time (it was not at all symmetrical).
All of this of course happens well after collapse initiation so by the time the G and over-G accelerations occur it has nothing to do with whatever initiated the collapse. |
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6th December 2015, 03:50 PM | #476 |
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6th December 2015, 03:55 PM | #477 |
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"Remember that the goal of conspiracy rhetoric is to bog down the discussion, not to make progress toward a solution" Jay Windley "How many leaves on the seventh branch of the fourth tree?" is meaningless when you are in the wrong forest: ozeco41 |
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6th December 2015, 03:55 PM | #478 |
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6th December 2015, 03:57 PM | #479 |
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"Remember that the goal of conspiracy rhetoric is to bog down the discussion, not to make progress toward a solution" Jay Windley "How many leaves on the seventh branch of the fourth tree?" is meaningless when you are in the wrong forest: ozeco41 |
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6th December 2015, 04:54 PM | #480 |
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