Frank Greening Refuted Easily

[Horatius]

Hey sometimes when the moon is rising, it looks like it's about the size of a bowling ball. Does that mean the moon is about 50 times the size of the sun? Kool....

Why yes, yes it does. Which proves we never landed on the Moon, because how coud they have walked on something 50 times the size of the Sun? The gravity alone would have crushed them.


So, once you refute that, please assume I then turned around and said, "Okay then, how could a full-grown man* walk on something the size of a bowling ball?" It'll just save time.





*And don't give me any guff about how short test pilots are!

 

[Roger_Harris]

Another thing that strikes me is tat Greening does not explicitly tell how he computes the collapse time, if you assume free fall between two floors (not taking into account the merging of mass that looses energy a factor n/[1+n] each time, this gives a time difference of 0 in a valid theoretical model) but the fact that the energy to break a floor takes time. In general energy conservation equations say nothing about the time, it's like a ball that you drop, if you know an amount of energy E is lost then you can calculate the speed after that, that is simply

v -> sqrt(v^2+2(gh-E/m))

but what is the time it takes ? If you assume the force working on it is constant than it is different then only a force that is in fact a kind of delta function (working at one moment in time but infinitely strong, sounds absurd but is valid in physics and even in mathematics), in the last case you lose some energy and the time is in fact the same time as in free fall, and that is what the guy (forgot his name) used in his script and probably Greening in his excel sheet, if you use a more realistic model, maybe a force that goes with F=kx (like a spring) it will influence the collapse time.

Here is the last paragraph of Greening's "simple model" section:

We note in concluding this Section that the values for t_c given above represent the calculated values for the time of collapse of the WTC towers neglecting the energy required to crush or otherwise destroy the support structure of each floor. This energy, which we will call E_1, is considered in detail in Section 4.2. For now it is sufficient to note that the collapse times calculated without allowing for E_1 are already in reasonable agreement with the observed collapse times. This suggests that E_1 is relatively small
compared to the kinetic energy associated with the falling blocks of floors; let us now place this qualitative prediction on a quantitative basis. To do this we must calculate the energies involved in each stage of the WTC collapse and then correct for the resistance offered by each floor. [Italics in original.]

So, in 4.2 Greening estimates the energy used to crush concrete and destroy columns. Then in the final Discussion, Section 6, Greening estimates the resulting contribution to the collapse time. ("This has been done by subtracting an assumed value for the collapse energy, E_1, from the input kinetic energy, T_i, and re-calculating the post-impact velocity...")

 

[Loss Leader]

Yes. Here is a picture of a collapse about 1/3rd over. Yes, it appears that about 1/3rd of a tower's worth of material has been rendered into fine powder and ejected.

Please explain why the way this picture appears to you should be considered by anyone as evidence of anything.

Please show any calculation of the mass of the dust cloud.

Hint: You can't. It's a 2-dimensional picture of a 3D event. You can't even estimate the volume of the cloud. because you can't see all sides of it. Even if you knew it, you can't extimate the density of the cloud because you can't get a sample of it or even view a cross-section of it. And even then the density would not be uniform.

Hint about the hint: If you reach behind you and jam your entire fist up into your colon, you may be able to wrench some numbers out of there.

 

[Roger_Harris]

Yes. Here is a picture of a collapse about 1/3rd over. Yes, it appears that about 1/3rd of a tower's worth of material has been rendered into fine powder and ejected.

Okay, before we get into what that photo "appears" to show, does that first "yes" mean that you are indeed saying that in the animation you posted, it "appears" to you that several floors worth of debris have been ejected and are no longer involved in collapsing the floors immediately below that?

If that's the case, then my prediction was accurate: You've argued yourself into a corner from which you are now forced to make obviously ridiculous claims, which can be refuted by simply looking at the picture. Not that I expect you to take my advice, but perhaps you should stop and consider why that happened before posting again.

 

[einsteen]

There is almost no time lost to breaking structures. On contact, the floors hit accelerate to match the impacting floors almost instantaneously, according to conservation of momentum. The actual fracture is transmitted at the sound speed of the materials, once the lower floor hits its plastic limit.

There is an energy cost, and this is reflected in the kinetic energy of the moving, combined mass after the new floor fails, as a reduction. There is no additional timing correction necessary or missed by Greening.

Thanks R. Yes, I know what you mean, but I was wondering, there are two kinds of supports, if the floor collapses on the other it needs to unrip that floor from the building, but there is also steel between the floors and that needs to be pressed.

ps. the stuff I've written so far does of course only confirms what his model predicts, I want to put it online within some time..RW doesn't believe it I assume

 

[TruthSeeker1234]

no, thats not what [Greening] says, as i have already pointed out to you

Greening :

We now apply this simple model to the WTC collapse. We assume that both
WTC building collapses began with an upper block of nfloors collapsing onto a series of
lower floors as in the “domino effect”. We shall refer to this process as the first stage of
collapse. For this stage, (see equation 1), we have an initial mass nmf falling onto the
floor below and becoming mass (n+1)mf. This new, enlarged, block of floors descends
with velocity v2= {n/(n+1)}v1through a distance hfat which point itstrikes the floor
below and becomes mass (n+2)mf moving at velocity {n/(n+2)}v2, and so on. This
implies a first stage collapse sequence for WTC 1: all floors from 110 to 96 (= 14 floors)
collapse onto floor 95; all these floors collapse onto 94 93 92 and so on to 32 
1; for WTC 2 all floors from 110 to 81 (= 29 floors) follow the same sequential process.
At the end of each of these collapse events we envision a second stage of collapse
involving the destruction of the upper block of the WTC buildings: for WTC 1 the 97th
floor, plus all floors above, collapse onto the pile of rubble topped by floor 96; this is
followed by floor 98 (plus all floors above) collapsing onto floor 97 and so on. The 2nd
stage sequence for WTC 1 ends with floor 110 collapsing on to all lower floors. For
WTC 2 the 2ndstage involves floor 82 collapsing onto floor 81, followed by 83, 84, etc,
collapsing on to the pile of rubble until floor 110 collapses onto all lower floors.

 

[TruthSeeker1234]

Why is it surprising to you that the floors that were most damaged in the impact, and most weaked by the fires, would fail before the relatively undamaged floors just below?

It isn't surprising to me, it's surprising to Greening, evidently. He's the one who says the top block stays intact, not me.

 

[Anti-sophist]

It isn't surprising to me, it's surprising to Greening, evidently. He's the one who says the top block stays intact, not me.

I jump into this thread periodically to remind you that Greening uses that for his MODEL. He doesn't claim that's what actually happened.

You'd think you'd have figured it out by now.

 

[TruthSeeker1234]

I jump into this thread periodically to remind you that Greening uses that for his MODEL. He doesn't claim that's what actually happened.

LOL

 

[Trigood]

Why yes, yes it does. Which proves we never landed on the Moon, because how coud they have walked on something 50 times the size of the Sun? The gravity alone would have crushed them.


So, once you refute that, please assume I then turned around and said, "Okay then, how could a full-grown man* walk on something the size of a bowling ball?" It'll just save time.





*And don't give me any guff about how short test pilots are!

Horatius, I hope they pay you well for your gubmint shillery!!!

Zwounds, you lie. You lie and lie and lie.

I know that all astronauts are put thru the Death-Beam Shrinking Ray and are therefore only 1/16 centimeter tall once they come out. Of course they can walk on a bowling ball. Sheesh....

 

[TruthSeeker1234]

Tell you what guys. I'll rework my position statement.

Greening's model is easily refuted. Greening's model is divorced from reality.

 

[Anti-sophist]

Tell you what guys. I'll rework my position statement.

Greening's model is easily refuted. Greening's model is divorced from reality.

Progress!

All models are divorced from reality. That's why we call them models! When I model the earth has a point mass traveling around the sun as a point mass.. It's a model! It's divorced from reality! It's a complete and utter simplification of reality!

Claiming that models aren't equal to reality isn't a significant claim. Finding how a model is simplified isn't significant.

Significance comes from explaining why the model's predictions would be wrong for reality, not explaining why the model, itself, differs from reality.


You are essentially telling me that I can't calculate the orbit of the earth because my "model" assumes they are point-masses, and the earth is obviously NOT a point! Yes, the earth isn't a point.. but the PREDICTION OF THE ORBIT doesn't suffer, at all, by assuming it is. So to recap, my model is completely divorced from reality, but the predicition it provides is perfectly accurate.

So, again, you need to show that his PREDICTION is adversely effected by the model's simplificaiton. It's uninteresting to explain how the model is just a simplification.

I've explained this every way I know how. I hope you understand.

 

[WildCat]

I've explained this every way I know how. I hope you understand.

He won't understand.

 

[TruthSeeker1234]

I haven't read Greening's paper and so cannot defend it, but you do realize that for a top-powered collapse it matters not at all at what time "the top block is gone."

The mass will still be almost all there. The crushed rubble falling down on the lower floors still constitutes enough mass to ensure continued collapse.

What don't you understand about the reality that breaking up floors does not make all the mass go "poof"?

I am not the one who says it goes poof, Greening is. And by extension, you Jrefs. You say most of the mass stays within the footprint, pushing down, accumulating, pulverizing, and then . . .when its all over . . .it's gone!!

 

[Horatius]

Tell you what guys. I'll rework my position statement.

Greening's model is easily refuted. Greening's model is divorced from reality.

And this could be applied to any model, including your precious Wood's Death Ray O' Doom models. So by your addmission, we're now allowed to completely ignore it, right? Right?

Or would you prefer to admit Anti-sophist has a point, and actually try to move your understanding forward a bit?

 

[TruthSeeker1234]

In reality, most of the mass of the towers was turned into power, and ejected outside the footprint, making it unavailable to push down, which renders Greening's paper moot. This is consistent with the 1" to 2" blanket of dust which covered lower Manhattan.

 

[Horatius]

I am not the one who says it goes poof, Greening is. And by extension, you Jrefs. You say most of the mass stays within the footprint, pushing down, accumulating, pulverizing, and then . . .when its all over . . .it's gone!!



[qimg]http://s18.photobucket.com/albums/b108/janedoe444/ARG/Image129.jpg[/qimg]

When will you admit that the pile of debris in your Mostest Absolutely Favouritist Picture is actually really fracking huge?

Do you realize how big those pieces have to be to be seen on that scale? You're always going on about how big that black building in the foreground is. Those pieces are on almost the same scale as that building!

Get you head out of you a$$ for once in you life, and actually look at it, will you?

 

[TruthSeeker1234]

And this could be applied to any model, including your precious Wood's Death Ray O' Doom models. So by your addmission, we're now allowed to completely ignore it, right? Right?

Or would you prefer to admit Anti-sophist has a point, and actually try to move your understanding forward a bit?

Models attempt to describe reality. They must be simpler than reality, but to be valid must capture some essential aspect of reality. Greening's model requires the mass to accumulate as the "collapse" proceeds. All of the evidence, I repeat, all of it indicates that this is not the case. We observe mass quantities of very dense stuff outside the footprint. When it's over, there is no pile. There is a smoldering crater.

Why don't you guys get to the part where you explain how all of the accumulating mass which stays inside the footprint, suddenly turns into a smoldering crater, as clearly shown in this picture?

 

[Roger_Harris]

In reality, most of the mass of the towers was turned into power...

Freudian slip?

 

[stateofgrace]

In reality, most of the mass of the towers was turned into power, and ejected outside the footprint, making it unavailable to push down, which renders Greening's paper moot. This is consistent with the 1" to 2" blanket of dust which covered lower Manhattan.

Really BS?

So what happened to it all?

Please tell us what happened to all the steel and heavy machinery inside the Towers.

Where did it go?