• Quick note - the problem with Youtube videos not embedding on the forum appears to have been fixed, thanks to ZiprHead. If you do still see problems let me know.

9-11 Presentation at NMSR, May 19 2010

The Almond said:
It's beating your head against the wall to try an explain such minutiae, though. Best to use it as a tool to goof off for a few minutes a day.
Click to expand...

As far as I can tell, no one has actually explained this minutiae yet. If it's so logical and so obvious, why don't you just simply show us right now?
 
ergo said:
I'm sorry: are you talking about an "upper structure" or rubble? Please make up your mind.
Click to expand...

That would be both. Do you believe the upper structure instantaneously became rubble? Do you think it was an intact block? How about a combination of structure and rubble as it broke apart as it collapsed through the rest of the building one floor at a time.
 
Mass does not stay the same when an object is broken into many smaller pieces. The disintegration of any structure completely alters the way it functions, the way it moves, the friction it encounters, its ability to do work.

If you disagree, please tell me what laws of physics support this notion.
 
ergo said:
Oh, so it is a block. Thank you.
Click to expand...

"Block" is just a word. "Sub-section" might be more accurate; it's a part of the structure, rather than the whole structure. It's quite popular among truthers to play semantic games by suggesting that a loose classification must imply all the properties implied by a different usage of the same word; this is called the Fallacy of Equivocation. Whatever word is used to describe it, we can know with certainty that an upper part of the structure became disconnected from it and fell on to the remaining lower part of the structure.

ergo said:
A question I asked above is: what is it "falling" through?
Click to expand...

Three-dimensional space. When it encounters solid objects in this space, a collision takes place, and some deformation of materials will result. This will cause damage to both parts of the structure and will separate off many more smaller fragments, each of which is also falling through three-dimensional space and each of which is also capable of colliding with other objects. It very rapidly becomes essentially impossible to calculate in any detail what happens from there on, but energetic analysis makes it abundantly clear that there is sufficient energy released by the system - in fact, many times more than sufficient energy - to fracture the entire structure into relatively very small fragments.

ergo said:
And could you please point out where we see this "falling block" through the collapse progression?
Click to expand...

No, not really. If you are able to view a video of the collapses and can't see that an upper part of the structure is falling on a lower part of the structure, we haven't the most basic common ground to work from. It's as basic as trying to explain why the sky is blue when you insist that it's actually pink.

Dave
 
ergo said:
Oh, then please provide a workable analogy in which a disintegrated structure can crush through an intact structure.
Click to expand...
Here are some analogies in which a disintegrated structure can crush through an intact structure:

 
Dave Rogers said:
"Block" is just a word. "Sub-section" might be more accurate; it's a part of the structure, rather than the whole structure... Whatever word is used to describe it, we can know with certainty that an upper part of the structure became disconnected from it and fell on to the remaining lower part of the structure.
Click to expand...

It's important to use correct, commonly agreed-upon terms in any argument. In this case, to clarify whether we're talking about an intact structure or a layer or more of rubble, because this affects the physics of our argument.

The descriptions being provided here at JREF seem to suggest uncertainty and disagreement.

Three-dimensional space.
Click to expand...

My understanding, from the NIST "findings", is that only about 15% of the columns were severed by the jet impacts. That leaves 85% remaining columns. Whether they are heat-comprised or not, there is "stuff" to crush through. So the word "falling" is a little inaccurate.

It very rapidly becomes essentially impossible to calculate in any detail what happens from there on, but energetic analysis makes it abundantly clear that there is sufficient energy released by the system - in fact, many times more than sufficient energy - to fracture the entire structure into relatively very small fragments.
Click to expand...

No, the analysis provided by Bazant and NIST errs in several ways. And furthermore, if we are now talking about rubble rather than an intact structure, the analysis has just been thrown out the window. No "energetic analysis" has been done showing that rubble can crush through an intact building.

No, not really. If you are able to view a video of the collapses and can't see that an upper part of the structure is falling on a lower part of the structure, we haven't the most basic common ground to work from. It's as basic as trying to explain why the sky is blue when you insist that it's actually pink.
Click to expand...

A simple picture suffices:

site1102_1.jpg
 
pgimeno said:
Here are some analogies in which a disintegrated structure can crush through an intact structure:
Click to expand...

I see an intact upper block crushing through some disabled floors. How is this a correct analogy?
 
ergo said:
Yaaayyy! Was waiting for this.
Click to expand...


Oh, so you deliberately made a false statement expecting to be corrected on it. Interesting.

Please explain how Conservation of Mass applies to rubble crushing through an intact building.
Click to expand...


Conservation of mass applies to everything not involving relativistic speeds or nuclear reactions. Rubble crushing through an intact building does not involve relativistic speeds or nuclear reactions, so conservation of mass applies.

Respectfully,
Myriad
 
Last edited:
ergo said:
It's important to use correct, commonly agreed-upon terms in any argument. In this case, to clarify whether we're talking about an intact structure or a layer or more of rubble, because this affects the physics of our argument.

The descriptions being provided here at JREF seem to suggest uncertainty and disagreement.
Click to expand...

Which, if true, is utterly irrelevant. Bazant models the collapse as a three-part system comprising a substantially intact upper section, an accumulation of rubble, and a substantially intact lower section. This is, of course, a simplification, but is a reasonably valid one.

ergo said:
My understanding, from the NIST "findings", is that only about 15% of the columns were severed by the jet impacts. That leaves 85% remaining columns. Whether they are heat-comprised or not, there is "stuff" to crush through. So the word "falling" is a little inaccurate.
Click to expand...

My understanding is that the collapses took place some time after the jet impacts, and that a progressive failure of the remaining columns occurred as a result of their weakening by heat and of lateral forces that they were not designed to resist. When this progressive failure took place, there was rapid lateral progression resulting in the failure of all vertical elements over a much shorter timescale than was required for the upper section to descend through the length over which the vertical members failed. Therefore, the word "falling" is very accurate, in that the structural support given to the upper portion was, for a significant length of time, negligible.


ergo said:
No, the analysis provided by Bazant and NIST errs in several ways. And furthermore, if we are now talking about rubble rather than an intact structure, the analysis has just been thrown out the window. No "energetic analysis" has been done showing that rubble can crush through an intact building.
Click to expand...

You clearly have failed to understand Bazant's analysis, and conflated it with NIST's analysis. Bazant's work explicitly discusses the role of the intervening layer of rubble in the collapse. Energetic analysis, of course, shows equally well that rubble can crush a substantially intact building as any other form of mass, as it takes no account of the form of the falling mass, only its magnitude.

ergo said:
A simple picture suffices:
Click to expand...

No, in fact, it doesn't. You're suggesting that at no time in the collapse can an upper portion of the structure be seen to be falling, and trying to bolster that suggestion with a single picture of a moment in time of the collapse at which the dust cloud has obscured that part of the structure. That's the pictorial equivalent of quote mining. I'm not going to bother looking for one of the vast number of pictures that shows a subbstantially undamaged upper block falling; if you deny their existence, you'll no doubt continue to do so even when presented with them.

Dave
 
ergo said:
Yes, please explain how.
Click to expand...


That is a meaningless request. It is a law of physics and it applies.
"How" it applies is addressed by the law itself, which is easily looked up.

Respectfully,
Myriad
 
Myriad said:
That is a meaningless request. It is a law of physics and it applies.
"How" it applies is addressed by the law itself, which is easily looked up.
Click to expand...

It is not meaningless to ask someone who is incorrectly applying a law of physics to explain what they mean.
 
Dave Rogers said:
Which, if true, is utterly irrelevant. Bazant models the collapse as a three-part system comprising a substantially intact upper section, an accumulation of rubble, and a substantially intact lower section. This is, of course, a simplification, but is a reasonably valid one.
Click to expand...

So it is the model you are defending here? Thank you.

My understanding is that the collapses took place some time after the jet impacts, and that a progressive failure of the remaining columns occurred as a result of their weakening by heat and of lateral forces that they were not designed to resist. When this progressive failure took place, there was rapid lateral progression resulting in the failure of all vertical elements over a much shorter timescale than was required for the upper section to descend through the length over which the vertical members failed. Therefore, the word "falling" is very accurate, in that the structural support given to the upper portion was, for a significant length of time, negligible.
Click to expand...

"Falling" through the 85% remaining vertical structure. Have it your way.

Energetic analysis, of course, shows equally well that rubble can crush a substantially intact building as any other form of mass, as it takes no account of the form of the falling mass, only its magnitude.
Click to expand...

Please provide a source for this, if not Bazant.

No, in fact, it doesn't. You're suggesting that at no time in the collapse can an upper portion of the structure be seen to be falling, and trying to bolster that suggestion with a single picture of a moment in time of the collapse at which the dust cloud has obscured that part of the structure.
Click to expand...

No, I'm not. It is clear from all the visual evidence that an upper block exists before and as the collapse begins. It is also clear from the visual evidence that this upper block largely crushes up before any crushing down would even be hypothesized.
 
You must log in or register to reply here.

Back
Top Bottom