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Szamboti's Missing Jolt paper

You don't need any initial freefall state. You just need the downward velocity to stay above zero.
You seem to misunderstand...(I have a fairly functional ROOSD model to play with locally)...I'm specifically asking about the Bazant model(s)...which do of course have an initial freefall drop included...

If the upper block was dropped by 0.01mm, with everything else in the Bazantian model being left alone, would it arrest ?

How about 1mm ?

How about 1cm ?

How about 1m ?

What is Xmin such that progression is not arrested ?
 
...There is an implicit assumption in the above, that the work/damage to the structure that slows the fall is all occurring in the top of the lower section. But that actually doesn't matter; if the damage were to the bottom of the upper section during the first story of descent, that would have exactly the same effect in terms of rendering a solid collision between "intact" floors (let alone an impact that transfers enough momentum to arrest the collapse) impossible....
...plus it is all in the impact and fire damaged areas where the "initiation" mechanism has just happened so lot of damage has already occurred. We are not talking about pristine so far undamaged office spaces.
 
...I'm specifically asking about the Bazant model(s)...which do of course have an initial freefall drop included...
I understood - which goes to why I have been very explicit about the distinction Bazantian model v real happenings.

One or the other. Trying to mix the two gets confusing and almost certainly wrong.
 
You seem to misunderstand...(I have a fairly functional ROOSD model to play with locally)...I'm specifically asking about the Bazant model(s)...which do of course have an initial freefall drop included...

If the upper block was dropped by 0.01mm, with everything else in the Bazantian model being left alone, would it arrest ?

How about 1mm ?

How about 1cm ?

How about 1m ?

What is Xmin such that progression is not arrested ?


Sorry for the misunderstanding.

The answer is, about 1.2 centimeters.

This is from Bazant's equation 1, solving for h after setting 3.0 as the maximum Pdyn/P that the lower structure can withstand, and using his estimates for the parameters C and m.

Respectfully,
Myriad
 
I understood - which goes to why I have been very explicit about the distinction Bazantian model v real happenings.

One or the other. Trying to mix the two gets confusing and almost certainly wrong.

I'm not mixing, simply curious about the limiting case in terms of drop height.

I suggest 1mm drop will arrest.

1m ? Don't know.

12ft is a long way...

Curious about how much headroom the Bazant model has...
 
You seem to misunderstand...(I have a fairly functional ROOSD model to play with locally)...I'm specifically asking about the Bazant model(s)...which do of course have an initial freefall drop included...

If the upper block was dropped by 0.01mm, with everything else in the Bazantian model being left alone, would it arrest ?

How about 1mm ?

How about 1cm ?

How about 1m ?

What is Xmin such that progression is not arrested ?

Given Bazant's assumptions, which are valid for this question, your answer is here:

picture.php


Let's see you find it.

tk
 
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Sorry for the misunderstanding.

The answer is, about 1.2 centimeters.

This is from Bazant's equation 1, solving for h after setting 3.0 as the maximum Pdyn/P that the lower structure can withstand, and using his estimates for the parameters C and m.

Respectfully,
Myriad
Hmm. Thanks. I'll have a cross-check.
 
Sorry for the misunderstanding.

The answer is, about 1.2 centimeters.

This is from Bazant's equation 1, solving for h after setting 3.0 as the maximum Pdyn/P that the lower structure can withstand, and using his estimates for the parameters C and m.

Respectfully,
Myriad
Interesting.

And I nearly embarrassed myself. I was tempted to say "so that means........" AND send myself directly into mixing Bazant with real events.

Despite my recent preaching not to do that.

...this "brain only half engaged mode" is dangerous. :o :o
10:25 Sunday - a mild spring morning and I have lawns to mow.

I may post some of my conjecturing as to what really happened - could be good for a laugh if nothing more.
 
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ROFL.

Just can't help yourself, can you.

Don't cwy tfk ;)

LoL. THIS is the best that you can do...??

I've contended that your main failure is a lack of understanding of mechanics.
You deny this.

You ask a specific question.
I give you the data that contains your answer, given that someone understands some rudimentary mechanics.

I didn't think that you could interpret the graphs.

Thanks for proving me right.

Soooo....

I'm not crying.

Laughing.
 
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Wrong.

I did.

I've seen several other mechanical & structural engineers, (as well as several mathematicians & scientists) who have read BLGB, understand its approach, its assumptions, its simplifications & its conclusions, and agree with it.

I've also seen lots of truthers like you two, who don't seem to possess a clue how to interpret the meaning or the math in the papers, yet claim that it must be wrong.

… somehow.

… in some unstateable fashion.



I do.

I'm not really convinced that either of you understand the boundaries of the concept.

Either of you care to write down your understanding of what it really means.



Something to do with "being correct", perhaps...



Care to state where BLBG makes this claim? (Without excising a comment from its context, of course.)

Care to explain why, if BLBG states that his model "matches all observations" (as you assert), he explicitly states the following:



Still think that Bazant thinks that his model "matches all observations"?



Nope.

Checking Bazant's claims (& math) requires an understanding of structural mechanics, in order to first understand which variables are important to his analysis, and which variables are irrelevant.

The structural mechanics & the math are the pieces of the puzzle that you, and femr, lack.

AFTER you understand which variables are significant, THEN you can go to videos or engineering references to verify that you're using appropriate values for that subset of variables.

The flip side of this coin is that there are 10,000 variables that are totally irrelevant to his methods & his math.

These irrelevancies seem to be the specific variables (& observations) that you truthers are hung up on.

Tom, try reading the part near the end when he says his model matches all observables. Not my words. His.

You are still going to hang onto crush down, then crush up? Tom, you seem to be running on 100% ego. Your posts and those of Beachnut seem to go hand-in-hand.
 
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Tom, try reading the part near the end when he says his model matches all observables. Not my words. His.
I guess you are referring to this passage from the conclusions:

Several of the parameters of the present mathematical model have a large range of uncertainty. However, the solution exhibits small sensitivity to some of them, and the values of others can be fixed on the basis of observations or physical analysis. One and the same mathematical model, with one and the same set of parameters, is shown to be capable of matching all of the observations, including: (1) the video records of the first few seconds of motion of both towers; (2) the seismic records for both towers; (3) the mass and size distributions of the comminuted particles of concrete; (4) the energy requirement for the comminution that occurred; (5) the wide spread of the fine dust around the tower; (6) the loud booms heard during collapse; (7) the fast expansion of dust clouds during collapse; and (8) the dust content of the cloud implied by its size. At the same time, the alternative allegations of some kinds of controlled demolition are shown to be totally out of range of the present mathematical model, even if the full range of parameter uncertainties is considered.

If so, you are showing that you can't interpret it correctly. The «including» part is important, as it gives context to what they mean with «all» there, something that you are neglecting to consider when you say that «he says his model matches all observables». Also you might probably want to attack point 1 on the video record. Before you do so, let me explain to you that for us who have read the paper and understood even it even partially, it's crystal clear that they are referring to the speed of fall as registered in the video record, which is what is analyzed in the paper.

But still, I might be wrong and you may be referring to some part of the paper that I have forgotten about. You're invited to clarify it.
 
The «including» part is important, as it gives context to what they mean with «all» there, something that you are neglecting to consider when you say that «he says his model matches all observables».

Do you think those that are listed are vaid and match the model ? (be careful)
 
That's quite a broad group there Oystein. :)
True, but I could even include myself and I'd still know if ergo was to the north or south of that group :D

It's an artefact of M_T's own approach to WTC Collapse and which parties are Right OR Wrong. There is no grey area; no distinction between "big picture" and details in M_T's approach. Only his way which is "right" and all the rest which are wrong. Fully wrong. Totally wrong. Not even right on the big picture wrong in a bit of detail. Ergo gets sort of conditional benefit of the doubt because he runs takes an occasional step or two against the tide
...
Yep, that's my impression: Sort of "the enemy of my enemy is my friend". Just wanted to know from M_T if my impression is correct.
 
...
You ask a specific question.
I give you the data that contains your answer, given that someone understands some rudimentary mechanics.

I didn't think that you could interpret the graphs.
...

Uhm, tfk? femr2 asked for a value, expressed in meters.
Your graphs do not contain any "data". No numbers.
So they do not contain the answer femr2 was seeking.

Just saying...
 
Do you think those [observables] that are listed are vaid and match the model ? (be careful)
By "vaid" I guess you mean valid instead of, say, void. If not, please clarify.

I would discard 2 and 6.

Leaving those apart, I think that the rest match the output of the model to a sufficient accuracy.

How the model adapts to the observables is what is subject to the «spheric cow» type of question. There are arguments in both senses. I haven't yet seen any reasonable argument discarding the validity of the model when applied to the specific observables mentioned. But I have seen reasonable arguments in the opposite sense, i.e. that despite the oversimplification, some invariants hold both in the model and in the real world, making the model valid within these limits.
 
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By "vaid" I guess you mean valid instead of, say, void. If not, please clarify.
Valid.

I would discard 2 and 6.
(1) the video records of the first few seconds of motion of both towers;

Detectable motion began ~9.5s in advance of release, and was a ROOSD type initiation, not, as we all know, the limiting case type virtual 1D column-on-column type used ofr the limiting case energetics calcs in the Bazant model. Suggesting that the behaviour of the limiting case matches the actual first few seconds post-release is a pretty thin suggestion, imo. There are a number of comparisons over on the911forum iir.

(2) the seismic records for both towers;

Nah.

(3) the mass and size distributions of the comminuted particles of concrete;

Pretty thin.

(4) the energy requirement for the comminution that occurred;

Occured most upon impact with t'ground...

(5) the wide spread of the fine dust around the tower;

Pretty thin.

(6) the loud booms heard during collapse;

Nope. Grasping.

(7) the fast expansion of dust clouds during collapse;

Pretty thin. During ?

(8) the dust content of the cloud implied by its size.

Pretty thin.


When I say "pretty thin" I'm saying that the Bazant model itself doesn't really have a lot to say about that item. The relationship is not because the model is "correct", simply that it's an energetics based model, and the authors have attempted to stick a round peg in a square hole.

My own spreadsheet contained model (derived from a simple 1D CoM model a-la Greening and co) could be said to "match" the same kind of "observables".

Leaving those apart, I think that the rest match the output of the model to a sufficient accuracy.
Hmm. I think the level of "match" is based upon no intention of real accuracy. For example, the model outputs near "supersonic" booms because of the error in the progression method. In reality, the rate at which floors impacted each other (in part or whatever) was a fairly constant 28m/s.

How the model adapts to the observables is what is subject to the «spheric cow» type of question.
Agreed.

Given the specified initial state, there was enough energy for propogation to ground. More than that is where the "applicability" thread comes back into play, and the over-reaching of some of the authors becomes increasingly clear.

There are arguments in both senses. I haven't yet seen any reasonable argument discarding the validity of the model when applied to the specific observables mentioned.
I'll perhaps go into detail on each in turn.

But I have seen reasonable arguments in the opposite sense, i.e. that despite the oversimplification, some invariants hold both in the model and in the real world, making the model valid within these limits.
Examples ?
 

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