QUOTE (NEU-FONZE+Oct 1 2007, 11:15 AM)
This is why Riera's formula, as modified by Kar: Fmax ~ 1.5 WV^2/gL, works. (W is the total weight of the aircraft, L is its length and V its velocity just before impact).
When and where was Riera's formula published?
When and where was Kar's modification published?
What do you get for the two tower impacts using this formula?
When and where was Riera's formula published?
When and where was Kar's modification published?
What do you get for the two tower impacts using this formula?
DBB:
Riera's paper was published in Nuclear Engineering and Design Volume 8, pp 415 - 426, 1968.
Kar's paper was in Journal of the Structural Division of the ASCE Volume 105, pp 2243 - 2260, 1979.
I get about 230 MN using rough numbers for the aircraft size, weight and speed.
Riera's paper was published in Nuclear Engineering and Design Volume 8, pp 415 - 426, 1968.
Kar's paper was in Journal of the Structural Division of the ASCE Volume 105, pp 2243 - 2260, 1979.
I get about 230 MN using rough numbers for the aircraft size, weight and speed.
QUOTE (NEU-FONZE+Oct 1 2007, 12:08 PM)
Kar's paper was in Journal of the Structural Division of the ASCE Volume 105, pp 2243 - 2260, 1979.
I get about 230 MN using rough numbers for the aircraft size, weight and speed.
That journal is now called the ASCE Journal of Engineering Mechanics. So one might have hoped that the NIST research engineers might have known about it.
So:
NIST: 75 MN (250 m/s) --- Sep 2005
NEU-FONZE: 230 MN (?? m/s)
P. Mendus et al.: 320 MN (140 m/s) --- 2003
Y. Omika et al.: 380 MN (250 m/s) --- 2005
I suppose the NIST report does not say how they obtained their low-ball estimate?
Edited to add: This does not mean their estimate is wrong, but I don't have the time to explain my reasoning just now.
I get about 230 MN using rough numbers for the aircraft size, weight and speed.
That journal is now called the ASCE Journal of Engineering Mechanics. So one might have hoped that the NIST research engineers might have known about it.
So:
NIST: 75 MN (250 m/s) --- Sep 2005
NEU-FONZE: 230 MN (?? m/s)
P. Mendus et al.: 320 MN (140 m/s) --- 2003
Y. Omika et al.: 380 MN (250 m/s) --- 2005
I suppose the NIST report does not say how they obtained their low-ball estimate?Edited to add: This does not mean their estimate is wrong, but I don't have the time to explain my reasoning just now.
QUOTE
Please note that this formula is INDEPENDENT OF THE TARGET!
Therefore, we know for a fact that the formula is wrong.
The towers were open and relatively soft structures, so they didn't put up much resistance at the point of impact. The deceleration would've been distributed over a larger distance than if the structure were concrete&steel.
From Physics 101, we know that the force needed to stop an object decreases as the distance over which that object decelerates increases. That's why stunt men fall on thick airbags rather than thin mattresses.
V^2 = 2*a*s
where:
V is the velocity
a is the acceleration (deceleration in this case)
s is the distance over which the object is decelerated by V.
If this "expert" says that the building ("target") type is irrelevant, he doesn't understand first-semester physics.
So why do *you* think he's smart?
QUOTE (NEU-FONZE+Oct 2 2007, 06:15 AM)
Trippy:
Sorry to tell you this, but one of the world's leading authorities on aircraft impacts, J. D. Riera, had this to say about the influence of the target on aircraft impacts:
"Several case studies indicate that the impact force is not significantly affected by the yielding of the target. Clearly, the effect is more pronounced for military fighter planes than for large commercial aircraft, in which case deformations do not affect the results whatsoever."
This is why Riera's formula, as modified by Kar: Fmax ~ 1.5 WV^2/gL, works. (W is the total weight of the aircraft, L is its length and V its velocity just before impact).
Please note that this formula is INDEPENDENT OF THE TARGET!
And yet you make no justification for this (outrageous) claim.
Are you saying that a Boeing 767 crashing into a wall of sponge will decelerate at the same rate as an identical Boeing 767 crashing into a wall of steel, or a wall of Osmium?
I find that difficult to believe, and what I understand of ballistics suggests you're wrong.
Sorry to tell you this, but one of the world's leading authorities on aircraft impacts, J. D. Riera, had this to say about the influence of the target on aircraft impacts:
"Several case studies indicate that the impact force is not significantly affected by the yielding of the target. Clearly, the effect is more pronounced for military fighter planes than for large commercial aircraft, in which case deformations do not affect the results whatsoever."
This is why Riera's formula, as modified by Kar: Fmax ~ 1.5 WV^2/gL, works. (W is the total weight of the aircraft, L is its length and V its velocity just before impact).
Please note that this formula is INDEPENDENT OF THE TARGET!
And yet you make no justification for this (outrageous) claim.
Are you saying that a Boeing 767 crashing into a wall of sponge will decelerate at the same rate as an identical Boeing 767 crashing into a wall of steel, or a wall of Osmium?
I find that difficult to believe, and what I understand of ballistics suggests you're wrong.
Arthur
WCELLIOTT
Because Riera's formula agrees with more detailed calculations!
That's why people use it!
We are talking about buildings, not sponges, by the way.
I guess no one here has heard of MINORSKY'S method of evaluating energy absorbtion in collisions. It is somewhat similar to Riera's approach and is used to estimate the effects of ship collisions and works well too.....
So WCE, why do you believe NIST's number is correct when all other published numbers are many times higher?
You should try reading Timoshenko's book on the Strength of Materials - perhaps even Mr HI IQ still has somethings to learn about materials!
You claim : "The towers were... relatively soft structures"
Really?
Another guy who thinks WTC 1 & 2 were sponges!
DBB:
I used 250 m/s in my calculation.
Because Riera's formula agrees with more detailed calculations!
That's why people use it!
We are talking about buildings, not sponges, by the way.
I guess no one here has heard of MINORSKY'S method of evaluating energy absorbtion in collisions. It is somewhat similar to Riera's approach and is used to estimate the effects of ship collisions and works well too.....
So WCE, why do you believe NIST's number is correct when all other published numbers are many times higher?
You should try reading Timoshenko's book on the Strength of Materials - perhaps even Mr HI IQ still has somethings to learn about materials!
You claim : "The towers were... relatively soft structures"
Really?
Another guy who thinks WTC 1 & 2 were sponges!
DBB:
I used 250 m/s in my calculation.
QUOTE
"The towers were... relatively soft structures"
Really?
Really?
Really. They didn't completely stop either aircraft.
What part of "V^2 = 2*a*s" do you feel is wrong?
QUOTE (NEU-FONZE+Oct 1 2007, 10:37 AM)
In NCSTAR 1-5D we read:
"Based on the airplane acceleration time history ... the peak force was determined to be 75 MN."
NCSTAR1--5D: Reaction of Ceiling Tile Systems to Shocks.
Could you give me a page number? The Table of Contents is not informative...
"Based on the airplane acceleration time history ... the peak force was determined to be 75 MN."
NCSTAR1--5D: Reaction of Ceiling Tile Systems to Shocks.
Could you give me a page number? The Table of Contents is not informative...
Well, genius, let's use V^2 = 2as
Let's assume the aircraft penetrated the perimeter wall and was stopped by the time it reached the middle of the tower.
Acceleration, a = (250)^2 / (2 x 32) = 976 m/s^2 or about 100 g's
Now use F=Ma
F = 124,000 x 976 = 121 MN
Not bad!
But in reality the outer wall of WTC 2 offered very little resistance to the aircraft. (See Wierzbicki's paper, where he estimates only 4 % of the impact KE was consumed by the aircraft penetrating the exterior wall).
So we should use a stopping distance closer to say 20 meters, which makes a even higher!
So, anyway you cut it, 75 MN is too low and cannot be correct!
Q.E.D.
Let's assume the aircraft penetrated the perimeter wall and was stopped by the time it reached the middle of the tower.
Acceleration, a = (250)^2 / (2 x 32) = 976 m/s^2 or about 100 g's
Now use F=Ma
F = 124,000 x 976 = 121 MN
Not bad!
But in reality the outer wall of WTC 2 offered very little resistance to the aircraft. (See Wierzbicki's paper, where he estimates only 4 % of the impact KE was consumed by the aircraft penetrating the exterior wall).
So we should use a stopping distance closer to say 20 meters, which makes a even higher!
So, anyway you cut it, 75 MN is too low and cannot be correct!
Q.E.D.
QUOTE (NEU-FONZE+Oct 2 2007, 08:06 AM)
WCELLIOTT
Because Riera's formula agrees with more detailed calculations!
That's why people use it!
We are talking about buildings, not sponges, by the way.
I guess no one here has heard of MINORSKY'S method of evaluating energy absorbtion in collisions. It is somewhat similar to Riera's approach and is used to estimate the effects of ship collisions and works well too.....
So WCE, why do you believe NIST's number is correct when all other published numbers are many times higher?
You should try reading Timoshenko's book on the Strength of Materials - perhaps even Mr HI IQ still has somethings to learn about materials!
You claim : "The towers were... relatively soft structures"
Really?
Another guy who thinks WTC 1 & 2 were sponges!
DBB:
I used 250 m/s in my calculation.
Oh look, there's a surprise.
NEU-FONZE taking quotes out of context and twisting them to fit his own agenda.
Who would have seen that one coming.
The fact that buildings aren't made out of sponges is irrelevant.
[Your] claim: "The rate of decceleration of an impacting object is independent of the physical properties of the object being impacted"
Prediction of [your] claim: "A plane impacting a wall made of sponge decelerates at the same rate as a plane impacting a wall of steel"
I am asking you to back up your claim by proving, or disproving the prediction.
No where did I say that the Twin Towers were made of sponge.
The fact that NASA used Aerogel to capture GCRs and Solar wind particles/inter stellar medium samples in their err... I think it was Genesis mission (or was that the one that used different materials?) suggests that your wrong.
So either stop waving your arms and crying into your cup of tea, or actually copy and paste the justifications of the assumptions that were made.
Because Riera's formula agrees with more detailed calculations!
That's why people use it!
We are talking about buildings, not sponges, by the way.
I guess no one here has heard of MINORSKY'S method of evaluating energy absorbtion in collisions. It is somewhat similar to Riera's approach and is used to estimate the effects of ship collisions and works well too.....
So WCE, why do you believe NIST's number is correct when all other published numbers are many times higher?
You should try reading Timoshenko's book on the Strength of Materials - perhaps even Mr HI IQ still has somethings to learn about materials!
You claim : "The towers were... relatively soft structures"
Really?
Another guy who thinks WTC 1 & 2 were sponges!
DBB:
I used 250 m/s in my calculation.
Oh look, there's a surprise.
NEU-FONZE taking quotes out of context and twisting them to fit his own agenda.
Who would have seen that one coming.
The fact that buildings aren't made out of sponges is irrelevant.
[Your] claim: "The rate of decceleration of an impacting object is independent of the physical properties of the object being impacted"
Prediction of [your] claim: "A plane impacting a wall made of sponge decelerates at the same rate as a plane impacting a wall of steel"
I am asking you to back up your claim by proving, or disproving the prediction.
No where did I say that the Twin Towers were made of sponge.
The fact that NASA used Aerogel to capture GCRs and Solar wind particles/inter stellar medium samples in their err... I think it was Genesis mission (or was that the one that used different materials?) suggests that your wrong.
So either stop waving your arms and crying into your cup of tea, or actually copy and paste the justifications of the assumptions that were made.
QUOTE (David B. Benson+Oct 1 2007, 04:34 PM)
NCSTAR1--5D: Reaction of Ceiling Tile Systems to Shocks.
Could you give me a page number? The Table of Contents is not informative...
David, see Chap 2.
The NIST document clearly states that this number was used PRIOR to the FEA model being developed and was used simply to get a handle on how the ceiling tiles performed.
As they stated, they made a number of simplifiing assumptions such as the weight of the plane, the speed of the plane that were based on PRELIMINARY data as well as how long the plane decelerated etc etc
For the COLLAPSE model though, the ACTUAL forces were derived FROM the model impacts.
Once again, a Neu tempest in a teapot.
Sheesh
Neu is now battling strawmen but you notice during all this time he doesn't say what his issues are with the simplifing assumptions used in 5-D, nor where he disagrees with the formulas they used.
Arthur
Could you give me a page number? The Table of Contents is not informative...
David, see Chap 2.
The NIST document clearly states that this number was used PRIOR to the FEA model being developed and was used simply to get a handle on how the ceiling tiles performed.
As they stated, they made a number of simplifiing assumptions such as the weight of the plane, the speed of the plane that were based on PRELIMINARY data as well as how long the plane decelerated etc etc
For the COLLAPSE model though, the ACTUAL forces were derived FROM the model impacts.
Once again, a Neu tempest in a teapot.
Sheesh
Neu is now battling strawmen but you notice during all this time he doesn't say what his issues are with the simplifing assumptions used in 5-D, nor where he disagrees with the formulas they used.
Arthur
QUOTE
So we should use a stopping distance closer to say 20 meters, which makes a even higher!
Is that consistent with your prior assertion that "this formula is INDEPENDENT OF THE TARGET! "?
And who said the aircraft stopped in 20 meters? I saw parts of it flying out the other side of the building, after traversing 208 feet. (Hint: longer deceleration distances will reduce the average decelerating forces.)
Maybe instead of reading books/papers with dubious conclusions, you should go back and re-read the first few chapters of your college physics book, so you can spot the BS before embarassing yourself here with this sort of nonsense.
"....where as the Phantom II almost literally evaporated on contact" (with the wall).
You mean it didn't punch a clean hole right through it, and 5 move, had they been there, BEFORE evaporating into nothingness? Gee... good "official" science suggests that should've happened.
Planes not designed to penetrate, penetrating (multiple) barriers designed not to be penetrated.
Oh, I forgot, only "wing nuts" raise such dilemmas.
Long live the wing nuts!
You mean it didn't punch a clean hole right through it, and 5 move, had they been there, BEFORE evaporating into nothingness? Gee... good "official" science suggests that should've happened.
Planes not designed to penetrate, penetrating (multiple) barriers designed not to be penetrated.
Oh, I forgot, only "wing nuts" raise such dilemmas.
Long live the wing nuts!
QUOTE (adoucette+Oct 1 2007, 01:46 PM)
The NIST document clearly states that this number was used PRIOR to the FEA model being developed and was used simply to get a handle on how the ceiling tiles performed.
Starting on page 43 (77 ordinal).
Wherein they clearly state their assumption that the center of mass of the aircraft traveled 60 meters.
But none of it matters, because the shake table employed could not even handle that and the accelerations had to be reduced for the survival of the shake table.
Oh well. We knew the ceiling system would come down anyway. It is only a question of how far away from the impact zone it would fail. I guess they could determine that...
Starting on page 43 (77 ordinal).
Wherein they clearly state their assumption that the center of mass of the aircraft traveled 60 meters.
But none of it matters, because the shake table employed could not even handle that and the accelerations had to be reduced for the survival of the shake table.
Oh well. We knew the ceiling system would come down anyway. It is only a question of how far away from the impact zone it would fail. I guess they could determine that...
QUOTE (NEU-FONZE+Oct 2 2007, 06:15 AM)
This is why Riera's formula, as modified by Kar: Fmax ~ 1.5 WV^2/gL, works. (W is the total weight of the aircraft, L is its length and V its velocity just before impact).
L is the length of what? The air craft?
And g is what? Normally this would be the acceleration due to Gravity.
Which would mean that this formula represents the equation for a vertically falling aircraft, but wait... The aircraft that hit the twin towers were (to a very good approximation) travelling horizontally...
L is the length of what? The air craft?
And g is what? Normally this would be the acceleration due to Gravity.
Which would mean that this formula represents the equation for a vertically falling aircraft, but wait... The aircraft that hit the twin towers were (to a very good approximation) travelling horizontally...
Well, it was sure fun to watch the NIST R&R team (Rescue and Recovery) in action!
First off Trippy, better take a closer look at that formula. W = Mg in case you forgot! And L = the length of the aircraft....
Wcelliott: What, no comment on my excellent use of YOUR formula to show that 75 MN is too small.
DBB: Glad to see you found NIST's litany of errors starting at page 43 of NCSTAR 1-5D.
I think someone should tell NIST to stop hiring those summer students.....
But sorry, got to go!
So fellow NISTIANS here at PhysOrg:
Have a good evening bashing those nasty twoofers.....
And always remember:
IN NIST WE TRUST
First off Trippy, better take a closer look at that formula. W = Mg in case you forgot! And L = the length of the aircraft....
Wcelliott: What, no comment on my excellent use of YOUR formula to show that 75 MN is too small.
DBB: Glad to see you found NIST's litany of errors starting at page 43 of NCSTAR 1-5D.
I think someone should tell NIST to stop hiring those summer students.....
But sorry, got to go!
So fellow NISTIANS here at PhysOrg:
Have a good evening bashing those nasty twoofers.....
And always remember:
IN NIST WE TRUST
QUOTE
Wcelliott: What, no comment on my excellent use of YOUR formula
**MY** formula?!?
NeuF - Are you saying you've NEVER seen the formula I posted?
It's in most first-semester physics books.
Where'd you go to school?
It was fairly easy to locate
DOE-STD-3014-96; DOE Standard Accident Analysis For Aircraft Crash into Hazardous Facilities
a .pdf file wherein beginning about page 72 there are lots of formulas to be used to estimate damage and penetration by an aircraft. J.D. Reira's paper is listed as a reference, but I did not notice his formula in the welter of ones to be used.
Notice this is a 1996 document...
DOE-STD-3014-96; DOE Standard Accident Analysis For Aircraft Crash into Hazardous Facilities
a .pdf file wherein beginning about page 72 there are lots of formulas to be used to estimate damage and penetration by an aircraft. J.D. Reira's paper is listed as a reference, but I did not notice his formula in the welter of ones to be used.
Notice this is a 1996 document...
QUOTE (NEU-FONZE+Oct 2 2007, 09:31 AM)
Well, it was sure fun to watch the NIST R&R team (Rescue and Recovery) in action!
First off Trippy, better take a closer look at that formula. W = Mg in case you forgot! And L = the length of the aircraft....
Wcelliott: What, no comment on my excellent use of YOUR formula to show that 75 MN is too small.
DBB: Glad to see you found NIST's litany of errors starting at page 43 of NCSTAR 1-5D.
I think someone should tell NIST to stop hiring those summer students.....
But sorry, got to go!
So fellow NISTIANS here at PhysOrg:
Have a good evening bashing those nasty twoofers.....
And always remember:
IN NIST WE TRUST
Apparently NEU-FONZE (et al) has forgotten, that because the building is providing the resistive force to the impacting airplane, that ultimately, what limits the decceleration of the airplane is the ability of the structural members to resist shear stresses.
Did you stop to think that maybe that's how they derived the figure of 75 MN?
Perhaps the structural members were incapable of withstanding shear stresses greater then that.
First off Trippy, better take a closer look at that formula. W = Mg in case you forgot! And L = the length of the aircraft....
Wcelliott: What, no comment on my excellent use of YOUR formula to show that 75 MN is too small.
DBB: Glad to see you found NIST's litany of errors starting at page 43 of NCSTAR 1-5D.
I think someone should tell NIST to stop hiring those summer students.....
But sorry, got to go!
So fellow NISTIANS here at PhysOrg:
Have a good evening bashing those nasty twoofers.....
And always remember:
IN NIST WE TRUST
Apparently NEU-FONZE (et al) has forgotten, that because the building is providing the resistive force to the impacting airplane, that ultimately, what limits the decceleration of the airplane is the ability of the structural members to resist shear stresses.
Did you stop to think that maybe that's how they derived the figure of 75 MN?
Perhaps the structural members were incapable of withstanding shear stresses greater then that.
QUOTE (Trippy+Oct 1 2007, 03:13 PM)
Did you stop to think that maybe that's how they derived the figure of 75 MN?
Perhaps the structural members were incapable of withstanding shear stresses greater then that.
If you read the relevant section of NCSTAR1--5D, you will see that that was not their method.
Possibly not, but at the time the ceiling system tests were being devised (early 2003), they did not know.
(Now let's see... Just who was it that was saying something about solving the problem within a timeline and a budget...
)
Perhaps the structural members were incapable of withstanding shear stresses greater then that.
If you read the relevant section of NCSTAR1--5D, you will see that that was not their method.
Possibly not, but at the time the ceiling system tests were being devised (early 2003), they did not know.
(Now let's see... Just who was it that was saying something about solving the problem within a timeline and a budget...
)
Again, this is a NEU driven tempest in a teapot.
He is attacking a SIMPLIFIED analysis that used PRELIMINARY data and ROUGH ESTIMATES to come up with an estimate of peak loading to see if the SUSPENDED CIELINGS could handle those loads.
Its a MINOR aspect of the NIST report.
The ACTUAL Impact analysis is detailed in NIST NCSTAR 1-2 Chapter 9 IMPACT ANALYSIS. (The one Neu ignores)
The key differences is the graph in 1-2 of the impact loads on WTC 2 (fig 9-28) show that in the first ~0.07 seconds only approx 10% of the plane's momentum has been lost to the structure but then the wings/engines hit and by 0.2 seconds, the time it took the entire plane to enter the building, only 30% of the plane's momentum remained, by 0.3 seconds 90% was accounted for.
Contrast this with the PRELIMINARY estimates used in 1-5D of 0.6 seconds and you will see that the plane's peak loads were considerably higher than the Ceiling tile shake testers estimated.
Which, of course had LITTLE impact on the study since their conclusion, that the ceiling tiles would have failed, is REINFORCED by the later study.
Arthur
He is attacking a SIMPLIFIED analysis that used PRELIMINARY data and ROUGH ESTIMATES to come up with an estimate of peak loading to see if the SUSPENDED CIELINGS could handle those loads.
Its a MINOR aspect of the NIST report.
The ACTUAL Impact analysis is detailed in NIST NCSTAR 1-2 Chapter 9 IMPACT ANALYSIS. (The one Neu ignores)
The key differences is the graph in 1-2 of the impact loads on WTC 2 (fig 9-28) show that in the first ~0.07 seconds only approx 10% of the plane's momentum has been lost to the structure but then the wings/engines hit and by 0.2 seconds, the time it took the entire plane to enter the building, only 30% of the plane's momentum remained, by 0.3 seconds 90% was accounted for.
Contrast this with the PRELIMINARY estimates used in 1-5D of 0.6 seconds and you will see that the plane's peak loads were considerably higher than the Ceiling tile shake testers estimated.
Which, of course had LITTLE impact on the study since their conclusion, that the ceiling tiles would have failed, is REINFORCED by the later study.
Arthur
QUOTE (adoucette+Oct 1 2007, 03:33 PM)
Its a MINOR aspect of the NIST report.
Exceedingly minor. Because the shake tables could not even handle their (under)estimate. But even that didn't matter, because they could still shake down the ceiling tile. All that was needed for the later fire analysis is how far away from the impact zone would the tiles fail. And that, it seems, they could and did estimate (once the aircraft impact FEA did its thing).
Exceedingly minor. Because the shake tables could not even handle their (under)estimate. But even that didn't matter, because they could still shake down the ceiling tile. All that was needed for the later fire analysis is how far away from the impact zone would the tiles fail. And that, it seems, they could and did estimate (once the aircraft impact FEA did its thing).
QUOTE (zoktoberfest+Oct 1 2007, 05:00 PM)
"....where as the Phantom II almost literally evaporated on contact" (with the wall).
You mean it didn't punch a clean hole right through it, and 5 move, had they been there, BEFORE evaporating into nothingness? Gee... good "official" science suggests that should've happened.
Planes not designed to penetrate, penetrating (multiple) barriers designed not to be penetrated.
Oh, I forgot, only "wing nuts" raise such dilemmas.
Long live the wing nuts!
You expected that a much smaller jet (60,000 lbs) going 475 mph would punch a clean hole through a hardened concrete barrier that was over 3 meters thick sitting on 'frictionless bearings' and thus could move?
Nope.
Arthur
You mean it didn't punch a clean hole right through it, and 5 move, had they been there, BEFORE evaporating into nothingness? Gee... good "official" science suggests that should've happened.
Planes not designed to penetrate, penetrating (multiple) barriers designed not to be penetrated.
Oh, I forgot, only "wing nuts" raise such dilemmas.
Long live the wing nuts!
You expected that a much smaller jet (60,000 lbs) going 475 mph would punch a clean hole through a hardened concrete barrier that was over 3 meters thick sitting on 'frictionless bearings' and thus could move?
Nope.
Arthur
QUOTE
"....where as the Phantom II almost literally evaporated on contact" (with the wall).
You mean it didn't punch a clean hole right through it, and
You mean it didn't punch a clean hole right through it, and
You're forgetting (if you ever knew) Conservation of Momentum.
When a quarter-million pounds of aircraft going 500mph hits a concrete wall, its momentum gets transferred to the debris field its collision generates. That debris now has the same momentum (velocity*mass), headed in the same direction. More mass means less velocity, but the same net momentum, which the subsequent walls it encounters has to deal with.
It's only after the debris scatters around/away from the initial velocity vector that the net debris field loses enough focus to lose its penetration capacity.
There are no mysteries, only the physics you don't know.
QUOTE (David B. Benson+Oct 2 2007, 10:21 AM)
If you read the relevant section of NCSTAR1--5D, you will see that that was not their method.
Possibly not, but at the time the ceiling system tests were being devised (early 2003), they did not know.
(Now let's see... Just who was it that was saying something about solving the problem within a timeline and a budget... )
I haven't read the NIST reporst - don't even know where to find them.
Hence my generally not referencing to them, or debating them.
Possibly not, but at the time the ceiling system tests were being devised (early 2003), they did not know.
(Now let's see... Just who was it that was saying something about solving the problem within a timeline and a budget...
) I haven't read the NIST reporst - don't even know where to find them.
Hence my generally not referencing to them, or debating them.
Final reports section is linked towards the upper right of
NIST and the World Trade Center
The sections are fairly long, so downloading first is recommended.
Enjoy!
NIST and the World Trade Center
The sections are fairly long, so downloading first is recommended.
Enjoy!
QUOTE
Hence my generally not referencing to them, or debating them.
Before the flames begin, I haven't bothered reading them, either. I'm not here to defend NIST's work (although I think it's probably 99% right), but 100% of the troothers arguments are wrong.
And it usually doesn't take particularly sophisticated physics to debunk them.
It's simple physics, guys. You've been expending TONS of effort trying to promote this BS, and you could've understood the flaws in all these arguments by taking a first-semester physics class (and paying attention).
Yeesh!
QUOTE (atmosphere+Sep 28 2007, 09:45 AM)
I'm familiar with that information .
Jowenko is probably the only independent experienced demolition expert that commented on WTC 7 . I believe opinions of independent demolition experts are the most relevant when we want to find out if the WTC 7 collapse was a controlled demolition, agree?
"when FEMA reports says something you can not start claiming something else as a Demolition company in the US, because then your out of business pretty soon. "
Jowenko says. He also works with American Demolition company's ,so he can know what he is talking about .
For those who didn't see to complete video of Jowenkos comments :
He explains how the job could be done the same day, and more. He's still convinced today WTC 7 was a CD ,after analyzing all the available facts .
Just type Jowenko in you tube's search engine and you will find the videos. I'm interested in your comments on that video's
atomosphere, one small point here needs to be addressed (my emphasis bolded).
http://video.google.com/videoplay?docid=-8...earch&plindex=1
If you watch closely, you see that when he was told the building was on fire all day, he then shook his head in amazement--and thus confirmed his realization that indeed it was a controlled demolition THAT COULD NOT HAVE BEEN DONE THAT DAY BY ANY STRETCH OF THE IMAGINATION.
Jowenko is an expert at CD, while ordinary people are not. Yet anyone can see that WTC7 looks just like a controlled demolition.
It does because it was, and this is confirmed by CD expert Danny Jowenko...and this is exactly why NIST has had such a hard time getting "a handle on it" (to quote Sunder).
adoucette: You said Barry Jennings was not lying, just confused.
However, the confusion is yours.
Jennings was Deputy Director, Emergency Services Department, New York City Housing Authority, and his "confusion" was altogether something different:
http://mujca.com/jennings.htm
Jennings and Hess then proceeded to the stairs, and made it to level 6, when there was an explosion, and the stairwell collapsed from under their feet, Mr. Jennings was actually hanging, and had to climb back up. They made it back up to level 8, where Barry Jennings had a view of the twin towers, both buildings were still standing. This is an important detail, as many debunkers have used Mr. Jennings statements out of context to claim the damage came to WTC 7 from the towers collapsing, not the case according, to Mr. Jennings.
The interview has been cut off where they say how they made it to the lobby, but when they did make it down, Mr. Jennings found it destroyed and littered with dead bodies. He said it looked like, "King Kong had came through it and stepped on it, so destroyed, I didn't know where I was. So destroyed that they had to take me out through a hole in the wall, that I believe the fire department made to get me out." Shortly after he made it out, he was seen on several news channels telling his story.
His testimony is here, along with other pertinent information on this:
http://www.911blogger.com/node/11678#comment
Jennings speaks of multiple explosions, dead bodies in the lobby, and confirmed this all happened BEFORE EITHER TOWER FELL.
When you listen to him, he is not "confused" at all, but does want to know why WTC7 came down.
That makes two of us "twoofers".
PS Dylan Avery wanted to keep this information secret until "Loose Change: Final Cut" came out because it is in the film.
Jowenko is probably the only independent experienced demolition expert that commented on WTC 7 . I believe opinions of independent demolition experts are the most relevant when we want to find out if the WTC 7 collapse was a controlled demolition, agree?
"when FEMA reports says something you can not start claiming something else as a Demolition company in the US, because then your out of business pretty soon. "
Jowenko says. He also works with American Demolition company's ,so he can know what he is talking about .
For those who didn't see to complete video of Jowenkos comments :
He explains how the job could be done the same day, and more. He's still convinced today WTC 7 was a CD ,after analyzing all the available facts .
Just type Jowenko in you tube's search engine and you will find the videos. I'm interested in your comments on that video's
atomosphere, one small point here needs to be addressed (my emphasis bolded).
http://video.google.com/videoplay?docid=-8...earch&plindex=1
If you watch closely, you see that when he was told the building was on fire all day, he then shook his head in amazement--and thus confirmed his realization that indeed it was a controlled demolition THAT COULD NOT HAVE BEEN DONE THAT DAY BY ANY STRETCH OF THE IMAGINATION.
Jowenko is an expert at CD, while ordinary people are not. Yet anyone can see that WTC7 looks just like a controlled demolition.
It does because it was, and this is confirmed by CD expert Danny Jowenko...and this is exactly why NIST has had such a hard time getting "a handle on it" (to quote Sunder).
adoucette: You said Barry Jennings was not lying, just confused.
However, the confusion is yours.
Jennings was Deputy Director, Emergency Services Department, New York City Housing Authority, and his "confusion" was altogether something different:
http://mujca.com/jennings.htm
Jennings and Hess then proceeded to the stairs, and made it to level 6, when there was an explosion, and the stairwell collapsed from under their feet, Mr. Jennings was actually hanging, and had to climb back up. They made it back up to level 8, where Barry Jennings had a view of the twin towers, both buildings were still standing. This is an important detail, as many debunkers have used Mr. Jennings statements out of context to claim the damage came to WTC 7 from the towers collapsing, not the case according, to Mr. Jennings.
The interview has been cut off where they say how they made it to the lobby, but when they did make it down, Mr. Jennings found it destroyed and littered with dead bodies. He said it looked like, "King Kong had came through it and stepped on it, so destroyed, I didn't know where I was. So destroyed that they had to take me out through a hole in the wall, that I believe the fire department made to get me out." Shortly after he made it out, he was seen on several news channels telling his story.
His testimony is here, along with other pertinent information on this:
http://www.911blogger.com/node/11678#comment
Jennings speaks of multiple explosions, dead bodies in the lobby, and confirmed this all happened BEFORE EITHER TOWER FELL.
When you listen to him, he is not "confused" at all, but does want to know why WTC7 came down.
That makes two of us "twoofers".
PS Dylan Avery wanted to keep this information secret until "Loose Change: Final Cut" came out because it is in the film.
Well its REAL SIMPLE Quickie.
Simply post a link to someone who can CORROBORATE Jennings story.
Simply show a PICTURE that shows the damage to WTC 7 lobby but no WTC 1 debris in the street.
Without CORROBORATION you have NOTHING.
Oh, and I think it is much more likely that Dylan Avery wanted to keep it a 'secret' so he could MAKE MORE MONEY off the dead of 9/11 and, of course, people with weak minds, like yourself.
Arthur
Simply post a link to someone who can CORROBORATE Jennings story.
Simply show a PICTURE that shows the damage to WTC 7 lobby but no WTC 1 debris in the street.
Without CORROBORATION you have NOTHING.
Oh, and I think it is much more likely that Dylan Avery wanted to keep it a 'secret' so he could MAKE MORE MONEY off the dead of 9/11 and, of course, people with weak minds, like yourself.
Arthur
I had seen that F-4 test before, and it was easy to find again. This shows it from about a dozen different angles. F-4 test videostream
The purpose of the test was to determine the impact force, versus time, due to the impact, of a complete F-4 Phantom — including both engines — onto a massive, essentially rigid reinforced concrete target (3.66 meters thick). Previous tests used F-4 engines at similar speeds. The test was not intended to demonstrate the performance (survivability) of any particular type of concrete structure to aircraft impact. The impact occurred at the nominal velocity of 215 meters per second (about 480 mph). The mass of the jet fuel was simulated by water; the effects of fire following such a collision was not a part of the test. The test established that the major impact force was from the engines. The test was performed by Sandia National Laboratories under terms of a contract with the Muto Institute of Structural Mechanics, Inc., of Tokyo.
The purpose of the test was to determine the impact force, versus time, due to the impact, of a complete F-4 Phantom — including both engines — onto a massive, essentially rigid reinforced concrete target (3.66 meters thick). Previous tests used F-4 engines at similar speeds. The test was not intended to demonstrate the performance (survivability) of any particular type of concrete structure to aircraft impact. The impact occurred at the nominal velocity of 215 meters per second (about 480 mph). The mass of the jet fuel was simulated by water; the effects of fire following such a collision was not a part of the test. The test established that the major impact force was from the engines. The test was performed by Sandia National Laboratories under terms of a contract with the Muto Institute of Structural Mechanics, Inc., of Tokyo.
In Professor Astaneh's latest WTC investigation he concludes that the unique design of the towers left them vulnerable to the attacks on 9/11.
The above statement contradicts the earlier claim by engineers that the towers could survive an accidental impact by a large jet aircraft. Could it be possible that OBL(for CTs insert CIA) was aware of these vulnerabilities and specifically chose the WTC towers for these reasons? Maybe the engineers made the claims to discourage would be attackers from targeting their inherently weak structures.
QUOTE
At a special presentation Tuesday, professor Astaneh will unveil new animated simulations showing what would have happened to the World Trade Center if it had been built using traditional code approved methods. Another simulation will shows what would have happened to the world trade center even if it had been hit by a much smaller planes. The result he says would have been the same.
http://abclocal.go.com/kgo/story?section=local&id=5646058The above statement contradicts the earlier claim by engineers that the towers could survive an accidental impact by a large jet aircraft. Could it be possible that OBL(for CTs insert CIA) was aware of these vulnerabilities and specifically chose the WTC towers for these reasons? Maybe the engineers made the claims to discourage would be attackers from targeting their inherently weak structures.
QUOTE
Maybe the engineers made the claims to discourage would be attackers from targeting their inherently weak structures.
The story as I understand it was that the WTC had been designed and was already well through the approval process when someone asked what would happen if an aircraft on-approach to land at the airport accidentally hit one of the towers, as they were adjacent to the normal landing approaches. One of the engineers/architects did a quick calculation of what he thought would happen, and answered the question the following day, saying that the towers' design would withstand an aircraft impact. His notes were never published, his analysis was never reviewed.
One guy doing back-of-the-envelope calculations addressing an objection raised at the eleventh-hour, and all subsequent CDiots misrepresent that as Absolute Truth - that the Towers were DESIGNED to survive an aircraft impact!!!
They weren't *designed* to withstand an aircraft impact, they were designed to be tall and profitable and not collapse on their own. The aircraft-impact issue was an afterthought. The one-man-day analysis was wrong in so far as it assumed that the aircraft would be flying at landing speed and not fully-laden with fuel. Also, you'd have to think that the guy doing the analysis wasn't about to say anything different, as he was trying to get the deal signed on the existing design.
But the "troothers" aren't interested in the Real Truth, they'll misrepresent anything they can think of to try to sell their notion that "Bush = Evil" and that, they feel, is such an important message that it justifies any lies they tell along the way to getting that point made.
QUOTE
"....where as the Phantom II almost literally evaporated on contact (with the wall)."
zoktoberfest
"You mean it didn't punch a clean hole right through it, and"
You're forgetting (if you ever knew) Conservation of Momentum.
When a quarter-million pounds of aircraft going 500mph hits a concrete wall, its momentum gets transferred to the debris field its collision generates. That debris now has the same momentum (velocity*mass), headed in the same direction. More mass means less velocity, but the same net momentum, which the subsequent walls it encounters has to deal with.
It's only after the debris scatters around/away from the initial velocity vector that the net debris field loses enough focus to lose its penetration capacity.
There are no mysteries, only the physics you don't know."
--Are you gonna' dress up as scientist for Halloween and scare the kiddies?
--The phantom II vector was exactly perpendicular, relative to the plane of the crash barrier. Only in that configuration can a projectile deliver its' maximum force to a hardened barrier. And yet, relatively slight damage was done. Conclusion: regular aircraft are not good bunker busters
--The vector of the craft that hit the Pentagon was 45 degrees off the perpendicular along the horizontal axis. Entering on that diagonal increases the thickness of the barrier by a factor of the square root of 2, or 1.414...
You would expect a more elliptically shaped hole, since the force would have been greater on the right side, respective to the line of entry, where the majority of the mass was. When a soft lead bullet hits a hard surface at 45 degrees, it slides as much as it penetrates. So, a slide factor to the left should have elongated that side also. Hence a flattened ellipse not a circle, should have resulted if....
--Secondly, because the barriers alternately open into courtyards, dispersion of debris would have occurred as it exited the confinement of the solid wall, through the aperture of the exit hole. I don't understand how it could have stayed so solidified. The length of the impact bore compared to its bore diameter is very short. Not unlike a sawed off shot gun, which has no chocking action, and therefore no shot grouping what so ever. Why would crushed, irregular, non unified debris, under pressure behave any differently? Why weren't huge amounts of back pressure, and heat released in the open court yard? The entrance of the second hole should have been much wider, less defined, and the entire area around it, ravaged, by heat and dispersed debris. If so much mass, under so much pressure was trying to fit through such a relatively small hole, so quickly, why didn't much of it dissipate sideways and blow a huge hole in the wall instead?
--[Pentagon impact craft]
F=MA
M= 250,000(lb.), A= Dv/Dt, assume t = (1 sec.)*, A= 500(MPH) / (1) = 500(MPH)
*Note; 1 sec. is a generously short duration for a deceleration through 6 levels
>unit conversion factor (.0455) to reference force in pounds<
F = 250,000 x 500 x (.0455) = 5,687,500lb.
--[Phantom II ]
M=60,000lb., A= Dv/Dt, t = (.2sec)*, 475MPH / (0.2) = 2375
*Note; plane came to a dead stop, 0.2sec. represents the almost instantaneous crush of the fuselage. arthur, see below
F = 60,000 x 2375 x (.0455) = 6,483,750lb.
--The barriers experienced proportionate levels of mass but the results were absolutely disproportionate. Even without factoring in the 45 degree vector angle. The pentagon craft did more with less, while the F-4 did less with more
" You expected that a much smaller jet (60,000 lbs) going 475 mph would punch a clean hole through a hardened concrete barrier that was over 3 meters thick sitting on 'frictionless bearings' and thus could move?"
--Of course not. I was, however, expecting a little more proportionality. A bigger plane, more damage, a smaller plane less damage. Not, all damage, and no damage. The official account has set the standard of what should be expected when an airliner hits a hardened target off the charts. Therefore, relative to that new standard, and applied retroactively, one would have expected to see more damage in the test crash.
--OBTW, here is the F-4 crash video. I can't perceive any movement of the crash barrier. What would be the point of allowing movement, will the containment wall of a nuclear reactor move away on frictionless bearings?
http://www.sandia.gov/videos2005/F4-crash.asx
"....where as the Phantom II almost literally evaporated on contact (with the wall)."
zoktoberfest
"You mean it didn't punch a clean hole right through it, and"
You're forgetting (if you ever knew) Conservation of Momentum.
When a quarter-million pounds of aircraft going 500mph hits a concrete wall, its momentum gets transferred to the debris field its collision generates. That debris now has the same momentum (velocity*mass), headed in the same direction. More mass means less velocity, but the same net momentum, which the subsequent walls it encounters has to deal with.
It's only after the debris scatters around/away from the initial velocity vector that the net debris field loses enough focus to lose its penetration capacity.
There are no mysteries, only the physics you don't know."
--Are you gonna' dress up as scientist for Halloween and scare the kiddies?
--The phantom II vector was exactly perpendicular, relative to the plane of the crash barrier. Only in that configuration can a projectile deliver its' maximum force to a hardened barrier. And yet, relatively slight damage was done. Conclusion: regular aircraft are not good bunker busters
--The vector of the craft that hit the Pentagon was 45 degrees off the perpendicular along the horizontal axis. Entering on that diagonal increases the thickness of the barrier by a factor of the square root of 2, or 1.414...
You would expect a more elliptically shaped hole, since the force would have been greater on the right side, respective to the line of entry, where the majority of the mass was. When a soft lead bullet hits a hard surface at 45 degrees, it slides as much as it penetrates. So, a slide factor to the left should have elongated that side also. Hence a flattened ellipse not a circle, should have resulted if....
--Secondly, because the barriers alternately open into courtyards, dispersion of debris would have occurred as it exited the confinement of the solid wall, through the aperture of the exit hole. I don't understand how it could have stayed so solidified. The length of the impact bore compared to its bore diameter is very short. Not unlike a sawed off shot gun, which has no chocking action, and therefore no shot grouping what so ever. Why would crushed, irregular, non unified debris, under pressure behave any differently? Why weren't huge amounts of back pressure, and heat released in the open court yard? The entrance of the second hole should have been much wider, less defined, and the entire area around it, ravaged, by heat and dispersed debris. If so much mass, under so much pressure was trying to fit through such a relatively small hole, so quickly, why didn't much of it dissipate sideways and blow a huge hole in the wall instead?
--[Pentagon impact craft]
F=MA
M= 250,000(lb.), A= Dv/Dt, assume t = (1 sec.)*, A= 500(MPH) / (1) = 500(MPH)
*Note; 1 sec. is a generously short duration for a deceleration through 6 levels
>unit conversion factor (.0455) to reference force in pounds<
F = 250,000 x 500 x (.0455) = 5,687,500lb.
--[Phantom II ]
M=60,000lb., A= Dv/Dt, t = (.2sec)*, 475MPH / (0.2) = 2375
*Note; plane came to a dead stop, 0.2sec. represents the almost instantaneous crush of the fuselage. arthur, see below
F = 60,000 x 2375 x (.0455) = 6,483,750lb.
--The barriers experienced proportionate levels of mass but the results were absolutely disproportionate. Even without factoring in the 45 degree vector angle. The pentagon craft did more with less, while the F-4 did less with more
" You expected that a much smaller jet (60,000 lbs) going 475 mph would punch a clean hole through a hardened concrete barrier that was over 3 meters thick sitting on 'frictionless bearings' and thus could move?"
--Of course not. I was, however, expecting a little more proportionality. A bigger plane, more damage, a smaller plane less damage. Not, all damage, and no damage. The official account has set the standard of what should be expected when an airliner hits a hardened target off the charts. Therefore, relative to that new standard, and applied retroactively, one would have expected to see more damage in the test crash.
--OBTW, here is the F-4 crash video. I can't perceive any movement of the crash barrier. What would be the point of allowing movement, will the containment wall of a nuclear reactor move away on frictionless bearings?
http://www.sandia.gov/videos2005/F4-crash.asx
Using 1 second for the 757 is SILLY.
Some few HARDENED parts exited, but MOST did not. The parts that exited clearly DIDN'T decelerate that much within the building.
Note that in the WTC, like the Pentagon SOME parts exited the building, but 70% of the kinetic energy was released in 0.2 seconds.
That Shotgun analogy is likewise to SILLY to comment on.
How can you say the F4 did NO damage?
It turned the plane into itty bitty pieces, it DID move that 25 times more massive concrete block and it did damage the block (just not punch a hole in it).
In contrast the 757 turned itself into itty bitty pieces AND punched a hole through a SUBSTANTIALLY weaker wall.
Once it breached the EXTERNAL wall, the internal walls were relatively minor.
Arthur
PS take this to the Pentagon thread.
Some few HARDENED parts exited, but MOST did not. The parts that exited clearly DIDN'T decelerate that much within the building.
Note that in the WTC, like the Pentagon SOME parts exited the building, but 70% of the kinetic energy was released in 0.2 seconds.
That Shotgun analogy is likewise to SILLY to comment on.
How can you say the F4 did NO damage?
It turned the plane into itty bitty pieces, it DID move that 25 times more massive concrete block and it did damage the block (just not punch a hole in it).
In contrast the 757 turned itself into itty bitty pieces AND punched a hole through a SUBSTANTIALLY weaker wall.
Once it breached the EXTERNAL wall, the internal walls were relatively minor.
Arthur
PS take this to the Pentagon thread.
Damage to the wall in the Sandia f-4 test was... 6 cm.
QUOTE (Daru+Oct 2 2007, 09:10 AM)
Damage to the wall in the Sandia f-4 test was... 6 cm.
Not surprising.
Arthur
Not surprising.
Arthur
Um...no. Thats true.
Rule nr. 1 in plane crash physics: A plane can not "enter" a massive steelstructure.
The airliner does not behave as a rigid body in the crash with the
containment. It behaves as a series of smaller longitudinal slices of
aircraft. The containment wall deals very effectively with each slice
of airliner in turn. That's why the wall handles a heavier
longer airliner just as effectively as a lighter shorter airliner
That is why something is wrong with the video of 2. plane impact:
Yes, yes...I know some people will get very angry...but it can not be ignored. The impact videos show things that can not happen in real world.
Rule nr. 1 in plane crash physics: A plane can not "enter" a massive steelstructure.
The airliner does not behave as a rigid body in the crash with the
containment. It behaves as a series of smaller longitudinal slices of
aircraft. The containment wall deals very effectively with each slice
of airliner in turn. That's why the wall handles a heavier
longer airliner just as effectively as a lighter shorter airliner
That is why something is wrong with the video of 2. plane impact:
Yes, yes...I know some people will get very angry...but it can not be ignored. The impact videos show things that can not happen in real world.
QUOTE (Daru+Oct 2 2007, 08:28 AM)
Rule nr. 1 in plane crash physics: A plane can not "enter" a massive steelstructure[sic].
The impact videos show things that can not happen in real world.
Wrong. Go back a page or two and read the DoD document I provided a link to.
Can not? 
The impact videos show things that can not happen in real world.
Wrong. Go back a page or two and read the DoD document I provided a link to.
Can not?
So Daru, is Purdue's model is wrong as well?
Arthur
Arthur
QUOTE
So Daru, is Purdue's model is wrong as well?
If I understand Daru's point, I believe he's saying that everyone in NYC watching it happen in real-time was likewise "in on it", as he's claiming that something other than an aircraft hit the towers.
What color is the sky in your world, Daru?
Resistive force:
Using B & V's normalized crush-down equation (22), the resistive force F(Z) depends open the normalized drop Z. The normalized drop begins at some Z0 between 0 and 1 and proceeds towards 1 as the collapse progresses.
Up until now I have taken F(Z) to be a constant for the first three seconds of the collapse of WTC 1. This is reasonable since all the impacted floors in this time interval were ordinary office floors while the speed was still too slow for much concrete comminution or for moving the air out of the tower to have much effect. However, we now want to consider the slow collapse of the tower before NIST's t0, the buckling of three walls. For this another functional form is required. (We continue to use the crush-down equation even for this period, since it will offer a good approximation to the assumed kinematics.)
Several have suggested that in this initial period that the slow collapse ought to be, in some sense, exponential in that some damage leads, faster and faster, to more damage. Here I suggest (for comments) that the exponential character is in the equation for the resistive force F(Z) while solutions to equation (22) then provide the drop, speed and acceleration as time progresses.
F(Z) then is a sum of two resistances, the exponentially decreasing portion and a final constant resistance once the collapse is sufficiently past NIST's t0. Let the constant resistive force be K and the variable resistive force be (V exp(-x)) where x = (Z-Y)/U where Y and U are constants. Then
F(Z) = K + V exp(-(Z-Y)/U)
where Y lies between 0 and Z0 (being quite close to Z0) and U is the characteristic drop of the variable part, thought to be rather small.
From equation (22), there is no motion when F(Z) = Z. The value of Y is then chosen so that
Y = F(Y) = V + K
and we see that only two of K, V, Y are independent. Furthermore, for the value of Z corresponding to t0+1.8 seconds, call it W, we expect the variable part of the resistive force to be vanishing small. This implies that
W-Y >> U,
say W-Y = 5U. Then as W is obtained from measurements, U is a dependent parameter. So it is only necessary to estimate, say, K and Y, as V and U are then constrained as above.
===
Is this a kinetically sound approach? I have little qualms about using the crush-down equation for these small drops since the pulling-in of exterior walls and the resulting small tilt of the top block amounts to a form of crushing and the crush-down equation appears kinetically sound. I have less confidence in the resistive force equation proposed and since this must be a matter of using first principles correctly, I am open now to comments before proceeding further.
Using B & V's normalized crush-down equation (22), the resistive force F(Z) depends open the normalized drop Z. The normalized drop begins at some Z0 between 0 and 1 and proceeds towards 1 as the collapse progresses.
Up until now I have taken F(Z) to be a constant for the first three seconds of the collapse of WTC 1. This is reasonable since all the impacted floors in this time interval were ordinary office floors while the speed was still too slow for much concrete comminution or for moving the air out of the tower to have much effect. However, we now want to consider the slow collapse of the tower before NIST's t0, the buckling of three walls. For this another functional form is required. (We continue to use the crush-down equation even for this period, since it will offer a good approximation to the assumed kinematics.)
Several have suggested that in this initial period that the slow collapse ought to be, in some sense, exponential in that some damage leads, faster and faster, to more damage. Here I suggest (for comments) that the exponential character is in the equation for the resistive force F(Z) while solutions to equation (22) then provide the drop, speed and acceleration as time progresses.
F(Z) then is a sum of two resistances, the exponentially decreasing portion and a final constant resistance once the collapse is sufficiently past NIST's t0. Let the constant resistive force be K and the variable resistive force be (V exp(-x)) where x = (Z-Y)/U where Y and U are constants. Then
F(Z) = K + V exp(-(Z-Y)/U)
where Y lies between 0 and Z0 (being quite close to Z0) and U is the characteristic drop of the variable part, thought to be rather small.
From equation (22), there is no motion when F(Z) = Z. The value of Y is then chosen so that
Y = F(Y) = V + K
and we see that only two of K, V, Y are independent. Furthermore, for the value of Z corresponding to t0+1.8 seconds, call it W, we expect the variable part of the resistive force to be vanishing small. This implies that
W-Y >> U,
say W-Y = 5U. Then as W is obtained from measurements, U is a dependent parameter. So it is only necessary to estimate, say, K and Y, as V and U are then constrained as above.
===
Is this a kinetically sound approach? I have little qualms about using the crush-down equation for these small drops since the pulling-in of exterior walls and the resulting small tilt of the top block amounts to a form of crushing and the crush-down equation appears kinetically sound. I have less confidence in the resistive force equation proposed and since this must be a matter of using first principles correctly, I am open now to comments before proceeding further.
Daru/Zoktoberfest.
Neither the pentagon, nor the twin towers are 'hardened react walls".
Zoktoberfest:
At least one point about reality that you're ignoring.
You seem to be under the delusion that the first three rings of the pentagon are seperate areas. They're not. For the three outer rings floors 3,4, and 5 are seperated by walls, but floors 1 and 2 are not.
Daru:
Kinetic energy is what gives a projectile it's penetrative power, double the speed, quadruple the kinetic energy. The rest of your argument after that is bunk.
Neither the pentagon, nor the twin towers are 'hardened react walls".
Zoktoberfest:
At least one point about reality that you're ignoring.
You seem to be under the delusion that the first three rings of the pentagon are seperate areas. They're not. For the three outer rings floors 3,4, and 5 are seperated by walls, but floors 1 and 2 are not.
Daru:
Kinetic energy is what gives a projectile it's penetrative power, double the speed, quadruple the kinetic energy. The rest of your argument after that is bunk.
DBB:
That's an interesting formalism... I just wonder why you would have a DECREASING exponential term for the initial (slow) part of the collapse.
That's an interesting formalism... I just wonder why you would have a DECREASING exponential term for the initial (slow) part of the collapse.
QUOTE (NEU-FONZE+Oct 2 2007, 11:37 AM)
That's an interesting formalism... I just wonder why you would have a DECREASING exponential term for the initial (slow) part of the collapse.
Because the resistive force has to start large enough to overcome the force of gravity, I.e., at the uncrushed elevation Y, and eventually decay to merely K = E1/h.
Edited to add: That does not mean I have a kinetically correct formalism.
Another addendum: Another possible equation for F(Z) is of the form
F(Z) = Y - V exp(x)
where x is some function of Z which for Z = Y is minus infinity and then grows so that eventually only F(Z) = K is left. Haven't really thought this one through yet...
Because the resistive force has to start large enough to overcome the force of gravity, I.e., at the uncrushed elevation Y, and eventually decay to merely K = E1/h.
Edited to add: That does not mean I have a kinetically correct formalism.
Another addendum: Another possible equation for F(Z) is of the form
F(Z) = Y - V exp(x)
where x is some function of Z which for Z = Y is minus infinity and then grows so that eventually only F(Z) = K is left. Haven't really thought this one through yet...
QUOTE
since all the impacted floors in this time interval were ordinary office floors while the speed was still too slow for much concrete comminution
I'm not sure that the comminution was due only to impact/collisions during the collapse.
Each floor was one large, thin wafer of concrete poured into a corrugated metal pan. The pan was supported at the edges by fixtures/brackets to various different structural columns. All of those columns originally (prior impact) were equally loaded, more or less, and compressed uniformly (more or less). As columns fail, though, they would unload and uncompress. I'm thinking this would lead to differential warpage of the floor, and concrete doesn't go from flat to warped without breaking. I'm thinking that if a structural member failed under load, the shock would likewise be transferred to the concrete, which would tend to fracture and accelerate it at high-g's.
I'd expect there to be significant comminution of the concrete floors as an integral part of the collapse mechanism, starting before the collapse was visible from outside the towers.
QUOTE (wcelliott+Sep 26 2007, 05:59 AM)
The strength of steel is a function of TEMPERATURE, not HEAT.
Higher temperature fires will make steel weaker than lower temperature fires that burn longer.
Buy a clue.
I have to read 15 pages but here a reply already from an old post and since I don't know much about material science and never read the NIST (only snippets and some summaries) I'm maybe talking nonsense but I was wondering if steel has a kind of heat hysteresis effect ? (like iron has when an external magnetic field disappears) I mean steel weakens if it heats up, but I would say it get its strength back when it cools down, when steel was constructed it was very hot and weak at that time.
Higher temperature fires will make steel weaker than lower temperature fires that burn longer.
Buy a clue.
I have to read 15 pages but here a reply already from an old post and since I don't know much about material science and never read the NIST (only snippets and some summaries) I'm maybe talking nonsense but I was wondering if steel has a kind of heat hysteresis effect ? (like iron has when an external magnetic field disappears) I mean steel weakens if it heats up, but I would say it get its strength back when it cools down, when steel was constructed it was very hot and weak at that time.
IIRC, steel (and Iron) loose mechanical strength as crystals form.
IIRC, this is the whole purpose of quenching steel - quenching it cools it so quickly that crystals can not form, where as allowing it to cool naturally allows larger crystals to form.
IIRC, this is the whole purpose of quenching steel - quenching it cools it so quickly that crystals can not form, where as allowing it to cool naturally allows larger crystals to form.
QUOTE (wcelliott+Oct 2 2007, 01:02 PM)
I'd expect there to be significant comminution of the concrete floors as an integral part of the collapse mechanism, starting before the collapse was visible from outside the towers.
Depends upon what significant means to you. I think your analysis is quite good and proper, helping to explain some more of the E1 = 348 megajoules consumed per story. But my sense is that this process would leave rather substantial pieces. (Even with this most useful addition, there is still an embarrassingly large portion of E1 still inadequately accounted for.)
After the collapse picks up some speed the concrete comminution becomes quite substantive, consuming a substantial portion of the available energy. See the Bazant/Le/Greening/Benson paper for details.
Depends upon what significant means to you. I think your analysis is quite good and proper, helping to explain some more of the E1 = 348 megajoules consumed per story. But my sense is that this process would leave rather substantial pieces. (Even with this most useful addition, there is still an embarrassingly large portion of E1 still inadequately accounted for.)
After the collapse picks up some speed the concrete comminution becomes quite substantive, consuming a substantial portion of the available energy. See the Bazant/Le/Greening/Benson paper for details.
QUOTE (wcelliott+Oct 2 2007, 12:47 PM)
If I understand Daru's point, I believe he's saying that everyone in NYC watching it happen in real-time was likewise "in on it", as he's claiming that something other than an aircraft hit the towers.
What color is the sky in your world, Daru?
Daru is one of those CT'ers with the more EXTREME view that there were no planes involved in the WTC or the Pentagon.
Arthur
QUOTE
Depends upon what significant means to you.
Fair enough. I wasn't thinking it'd be a large percentage in any case, but I think it's a contributor to the overall collapse process. Like when a steel truss heats up the point where the steel gets soft, it starts sagging and stops acting like a truss and more like a heavy chain. When a solid slab of concrete gets fragmented into chunks, it no longer acts like a solid slab but allows the floor to flex and sag (piecewise-approximate, at least). This would add to the pulling-in of the walls that's normally attributed solely to the trusses cooling off.
As for steel, it's made strong at the foundry, it's cooled/quenched under controlled conditions. When it's heated in a building fire and cools, it isn't heated/cooled under controlled conditions, so you can expect it to be weaker than it would've been in the state it was when it left the foundry. It does get stronger as it cools back down, so the heating process allows it to sag while expanding from thermal effects, but as it cools it shrinks and strengthens simultaneously. It ends up acting like a linear actuator, pulling inwards with increasing force as it cools. (Which is pretty much what NIST said, BTW.)
And if the concrete floor it was supporting has turned itself into chunks from the differential warping, then instead of it acting as a single slab helping to hold up the sagging trusses, it's weight of the floor chunks adds to the pulling-in force, like a fat guy in a hammock.
[removed, offtopic]
QUOTE (adoucette+Oct 2 2007, 08:54 AM)
So Daru, is Purdue's model is wrong as well?
Arthur
Purdue's simulation on the Pentagon was wrong -- they neglected to add the engines.
Now those are large things to forget.
Arthur
Purdue's simulation on the Pentagon was wrong -- they neglected to add the engines.
Now those are large things to forget.
We are talking about the WTC1 model, not the early visualization work they did on the Pentagon.
I take it from that last rambling garbage post, where you clearly avoided addressing the ISSUE, simply means that you have NO CORROBORATION for Jennings story nor can you find one PICTURE that shows the damage to WTC 7 lobby but no WTC 1 debris in the street.
Get back to us when you have SOMETHING.
Arthur
I take it from that last rambling garbage post, where you clearly avoided addressing the ISSUE, simply means that you have NO CORROBORATION for Jennings story nor can you find one PICTURE that shows the damage to WTC 7 lobby but no WTC 1 debris in the street.
Get back to us when you have SOMETHING.
Arthur
QUOTE
Gee, what can such coincidences possibly mean?
The likeliest thing it would mean is that the intelligence community pieced together separate clues indicating that something along those lines was being plotted by Al Qaeda, and so they did the responsible thing, putting together a preparedness plan to test to see if the plotted attack(s) could affect the stability of the government agencies and/or determine what they could do better if, in the future, such an attack were to occur.
Timing isn't as coincidental as you might expect. Intel gets clues that something big's happening, pieces together a scenario, presents it to the White House, the President orders his cabinet to make suggestions as to what to do about it, they go off and come back with a dozen or so ideas, most of which aren't worth spit, and the least-controversial of those would be to conduct a "readiness exercise", which they put into effect ASAP.
Simultaneously, the terrorists were carrying-out the preparations, meetings, test-flights, etc., that they went through before boarding the planes.
Both tend to take about the same amount of time, give or take. For the government, it was moving as quickly as it could, for the terrorists, they were working at a slow, deliberate pace to reduce the chance of their actions drawing attention to themselves.
It's exactly what you'd expect, if you had any idea how things really work in the real world.
QUOTE (adoucette+Oct 2 2007, 08:36 PM)
We are talking about the WTC1 model, not the early visualization work they did on the Pentagon.
Arthur
I knew that but just couldn't resist. Those engines were way too large to "forget".
And it did remind me of the "fairy tale" aspect of the OCT.
And...it is the same school.
But back to the other, is Jennings lying? He sure is not confused (like you).
Corroboration? How about this newspaper article from Sept. 11, 2001, about Jennings together with his companion, Michael Hess, who was at the time one of New York’s chief lawyers and longtime friend of Mayor Rudolph Giuliani:
http://archives.record-eagle.com/2001/sep/11scene.htm
After the initial blast, Housing Authority worker Barry Jennings, 46, reported to a command center on the 23rd floor of 7 World Trade Center. He was with Michael Hess, the city's corporation counsel, when they felt and heard another explosion. First calling for help, they scrambled downstairs to the lobby, or what was left of it. "I looked around, the lobby was gone. It looked like hell," Jennings said.
So let's have a new Congressional investigation question them both.
Let's question Indira Singh about WTC7 and who they were going to bring WTC7 down.
Let's question Robin Hordon, retired Boston Air Traffic Controller, about the change in terrorist protocol that occurred that day.
Let an investigation look into the many testimonies of explosions that day that never made it into the 9/11 Commission Report.
And why did the 9/11 Commission not even mention WTC7?
There is such a thing as "a preponderance of evidence" as in the many witnesses who learned they were going to bring down WTC7 before they did it.
You are not more learned than Danny Jowenko when it comes to CD's, Arthur, and what would be wrong with a real criminal investigation into 9/11?
Like I said, your modus operandi is to not answer hard questions.
Arthur
I knew that but just couldn't resist. Those engines were way too large to "forget".
And it did remind me of the "fairy tale" aspect of the OCT.
And...it is the same school.
But back to the other, is Jennings lying? He sure is not confused (like you).
Corroboration? How about this newspaper article from Sept. 11, 2001, about Jennings together with his companion, Michael Hess, who was at the time one of New York’s chief lawyers and longtime friend of Mayor Rudolph Giuliani:
http://archives.record-eagle.com/2001/sep/11scene.htm
After the initial blast, Housing Authority worker Barry Jennings, 46, reported to a command center on the 23rd floor of 7 World Trade Center. He was with Michael Hess, the city's corporation counsel, when they felt and heard another explosion. First calling for help, they scrambled downstairs to the lobby, or what was left of it. "I looked around, the lobby was gone. It looked like hell," Jennings said.
So let's have a new Congressional investigation question them both.
Let's question Indira Singh about WTC7 and who they were going to bring WTC7 down.
Let's question Robin Hordon, retired Boston Air Traffic Controller, about the change in terrorist protocol that occurred that day.
Let an investigation look into the many testimonies of explosions that day that never made it into the 9/11 Commission Report.
And why did the 9/11 Commission not even mention WTC7?
There is such a thing as "a preponderance of evidence" as in the many witnesses who learned they were going to bring down WTC7 before they did it.
You are not more learned than Danny Jowenko when it comes to CD's, Arthur, and what would be wrong with a real criminal investigation into 9/11?
Like I said, your modus operandi is to not answer hard questions.
QUOTE (wcelliott+Oct 2 2007, 08:57 PM)
The likeliest thing it would mean is that the intelligence community pieced together separate clues indicating that something along those lines was being plotted by Al Qaeda, and so they did the responsible thing, putting together a preparedness plan to test to see if the plotted attack(s) could affect the stability of the government agencies and/or determine what they could do better if, in the future, such an attack were to occur.
Timing isn't as coincidental as you might expect. Intel gets clues that something big's happening, pieces together a scenario, presents it to the White House, the President orders his cabinet to make suggestions as to what to do about it, they go off and come back with a dozen or so ideas, most of which aren't worth spit, and the least-controversial of those would be to conduct a "readiness exercise", which they put into effect ASAP.
Simultaneously, the terrorists were carrying-out the preparations, meetings, test-flights, etc., that they went through before boarding the planes.
Both tend to take about the same amount of time, give or take. For the government, it was moving as quickly as it could, for the terrorists, they were working at a slow, deliberate pace to reduce the chance of their actions drawing attention to themselves.
It's exactly what you'd expect, if you had any idea how things really work in the real world.
Such utter and complete rubbish.
My degree is in statistics, and the likelihood of these terror drills being done for the same scenario on the same day at the same time for not one but two attacks, 9/11/01 and 7/7/05, pegs the meter to "no way, Jose".
One pegs the meter into "extremely suspicious".
Pure unadulterated garbage, so please keep your nonsense to yourself.
QUOTE (Not So Quick+)
Corroboration? How about this newspaper article from Sept. 11, 2001
Ah, but Quick, that's not Corroboration.
Why?
Because it says NOTHING about WHAT caused and/or WHEN the damage to the Lobby occurred.
So, again, PRODUCE some CORROBORATION that the WTC 7 lobby was damaged beyond recognition ("I looked around, the lobby was gone. It looked like hell," ) BEFORE WTC 1 fell.
So, until you do, get used to DISAPPOINTMENT, pal.
Arthur
Ah, but Quick, that's not Corroboration.
Why?
Because it says NOTHING about WHAT caused and/or WHEN the damage to the Lobby occurred.
So, again, PRODUCE some CORROBORATION that the WTC 7 lobby was damaged beyond recognition ("I looked around, the lobby was gone. It looked like hell," ) BEFORE WTC 1 fell.
So, until you do, get used to DISAPPOINTMENT, pal.
Arthur
Boys, don't bother posting a reply and expect me to answer. You OCTs become way too boring way too soon. You are not serious about 9/11 truth, so I feel I am wasting time on you now. A person can only take so much from BS artists.
But you do need a lot more truth barbs stuck into your thick heads...
Adios
But you do need a lot more truth barbs stuck into your thick heads...
Adios
QUOTE
My degree is in statistics, and
Say no more. You don't have a clue about how ANYTHING works.
Two processes that take about the same amount of time, triggered by the same event, are probably going to occur simultaneously, or close to it.
My degrees are in Electrical Engineering, and I've worked in the aerospace industry most of my career. Most of the customers are from the government, various different agencies, so over the course of my career I've had the opportunity to get to know people from all of the various government agencies that you've only fanasized about or seen in the movies. I know how they work, and how they think.
You're living in a fantasy. All of it. This 9/11 conspiracy bs is just all in your head.
QUOTE (adoucette+Oct 2 2007, 09:46 PM)
QUOTE (Not So Quick+)
Corroboration? How about this newspaper article from Sept. 11, 2001
Ah, but Quick, that's not Corroboration.
Why?
Because it says NOTHING about WHAT caused and/or WHEN the damage to the Lobby occurred.
So, again, PRODUCE some CORROBORATION that the WTC 7 lobby was damaged beyond recognition ("I looked around, the lobby was gone. It looked like hell," ) BEFORE WTC 1 fell.
So, until you do, get used to DISAPPOINTMENT, pal.
Arthur
I knew that was not corroboration, Arthur. The point I am making is, if I had 20 million dollars to investigate, I am sure I would find out what caused it...[hint--hint...we need a new, real investigation]...
The time is not an issue, however, as they definitely say it was before the towers fell.
These are serious claims coming from people of some reputation.
Also, you never do get around to Jowenko, do you?
I had to answer you this last one (see my prior post).
BTW, I am not disappointed at all, pal. I feel real good.
The truth will do that for you.
Adios
Say no more. You don't have a clue about how ANYTHING works.
Two processes that take about the same amount of time, triggered by the same event, are probably going to occur simultaneously, or close to it.
My degrees are in Electrical Engineering, and I've worked in the aerospace industry most of my career. Most of the customers are from the government, various different agencies, so over the course of my career I've had the opportunity to get to know people from all of the various government agencies that you've only fanasized about or seen in the movies. I know how they work, and how they think.
You're living in a fantasy. All of it. This 9/11 conspiracy bs is just all in your head.
We too seem to have criss-crossed, so one more for you, Carter.
For someone as educated as you purport to be, you don't sound like it.
Like I wrote, keep your mickey mouse BS to yourself cause I ain't buying it.
At least Arthur is a good shill. I can't say the same for you.
Adios
I ain't buying that you have a degree in anything, you sound like you're still in high school.
You definitely haven't got a clue how any aspect of the real world works.
I ain't buying that you have a degree in anything, you sound like you're still in high school.
You definitely haven't got a clue how any aspect of the real world works.
So Danny Jowenko, a professional demolitionist, is wrong when he said WTC7 is a CD?
And, once again, catastophic mechanical failures do not sound like explosions
But your speakers do.
Think this one through. You're supposedly some sort of "sound guy", right?
A speaker has a rigid diaphragm and a coil that drives it back and forth.
The better the speaker, the more rigid and bigger the diaphragm, and the more power available to drive that diaphragm back and forth.
You were the one who said your expensive speakers had better fidelity than headphones do, remember? Better at reproducing the sounds of explosions?
Do they run on C-4?
Or do they use electricity to shove that diaphragm?
So, HIGH FIDELITY "EXPLOSION" SOUNDS can come from RIGID DIAPHRAGMS being shoved suddenly by means OTHER THAN EXPLOSIVES.
Look at how those floors of the WTC Towers were made. LARGE FLAT DIAPHRAGMS supported around the middle and around the outside. Those core columns were failing under-load.
What, Mr. Sound Guy, would YOU expect that to sound like? Impulse-shocks delivered to large flat diaphragms? Those floors were like MEGA-WOOFERS being driven with MEGAWATTs of power.
Of course they sounded like explosions. Your speakers don't need explosives to make BANG! noises, and neither did the WTC towers.
But your speakers do.
Think this one through. You're supposedly some sort of "sound guy", right?
A speaker has a rigid diaphragm and a coil that drives it back and forth.
The better the speaker, the more rigid and bigger the diaphragm, and the more power available to drive that diaphragm back and forth.
You were the one who said your expensive speakers had better fidelity than headphones do, remember? Better at reproducing the sounds of explosions?
Do they run on C-4?
Or do they use electricity to shove that diaphragm?
So, HIGH FIDELITY "EXPLOSION" SOUNDS can come from RIGID DIAPHRAGMS being shoved suddenly by means OTHER THAN EXPLOSIVES.
Look at how those floors of the WTC Towers were made. LARGE FLAT DIAPHRAGMS supported around the middle and around the outside. Those core columns were failing under-load.
What, Mr. Sound Guy, would YOU expect that to sound like? Impulse-shocks delivered to large flat diaphragms? Those floors were like MEGA-WOOFERS being driven with MEGAWATTs of power.
Of course they sounded like explosions. Your speakers don't need explosives to make BANG! noises, and neither did the WTC towers.
So Danny Jowenko, a professional demolitionist, is wrong when he said WTC7 is a CD?
Yes, and you're an idiot for believing him (if that's actually what he really said).
But back to the other, is Jennings lying? He sure is not confused (like you).
Corroboration? How about this newspaper article from Sept. 11, 2001, about Jennings together with his companion, Michael Hess, who was at the time one of New York’s chief lawyers and longtime friend of Mayor Rudolph Giuliani:
http://archives.record-eagle.com/2001/sep/11scene.htm
After the initial blast, Housing Authority worker Barry Jennings, 46, reported to a command center on the 23rd floor of 7 World Trade Center. He was with Michael Hess, the city's corporation counsel, when they felt and heard another explosion. First calling for help, they scrambled downstairs to the lobby, or what was left of it. "I looked around, the lobby was gone. It looked like hell," Jennings said.
Craig, why don't we hear about any conformation of Berry Jenning's story from Michael Hess?
I would agree that we'd have been better-off with someone other than Rumsfeld in that post, but in fairness, it needs to be noted that every government official in high office has more than one "hat" to wear at any given time, and politics is part of the job. Probably shouldn't be, but realistically, it is and probably always will be in a democracy.
Part of politics is public image, and photo-ops are central to creating/maintaining that public image.
In a perfect world, people in office would do their primary responsibilities first and foremost, and nobody would be posing for pictures or visiting classrooms talking to school children when the country is under attack, but since terrorists don't post their attack schedules for public review, there will inevitably be times when the guy who should be barking orders into a phone is off doing something else, and as adults in a democracy, we should recognize that fact.
As Churchill put it, “The best argument against democracy is a five minute conversation with the average voter.” Until voters start acting like adults, we'll be getting the democracy that we deserve, not the democracy that we want. If we were more interested in news programs that focussed on important issues than we were about the stains on Monica Lewinsky's dress, then news organizations would've spent more resources discussing serious issues and less on tabloid stories.
The main problem is obvious and in-evidence right here in this thread - How many dumbass arguments would've been settled had the CDiots bothered to take physics in high school? How much of what we discuss here is simply remedial physics? There are people here who'd have Bush hanged if they had a chance based solely on their own inadequate grasp of how gravity works.
It's easy to say that it's the government's problem, but Jefferson said that a well-informed populace was essential for a democracy to function, and the populace has dropped that ball a long time ago.
OK, would anybody care to discuss the acoustic characteristics of floors connected to failing structural members and their similarities to megawoofers simulating explosive sounds?
I keep trying to get support/feedback on that topic, but I only get Al Kawasaki's "bunk" response. I think there's some valid physics there that hasn't been discussed.
Ah, but Quick, that's not Corroboration.
Why?
Because it says NOTHING about WHAT caused and/or WHEN the damage to the Lobby occurred.
So, again, PRODUCE some CORROBORATION that the WTC 7 lobby was damaged beyond recognition ("I looked around, the lobby was gone. It looked like hell," ) BEFORE WTC 1 fell.
So, until you do, get used to DISAPPOINTMENT, pal.
Arthur
I knew that was not corroboration, Arthur. The point I am making is, if I had 20 million dollars to investigate, I am sure I would find out what caused it...[hint--hint...we need a new, real investigation]...
The time is not an issue, however, as they definitely say it was before the towers fell.
These are serious claims coming from people of some reputation.
Also, you never do get around to Jowenko, do you?
I had to answer you this last one (see my prior post).
BTW, I am not disappointed at all, pal. I feel real good.
The truth will do that for you.
Adios
QUOTE (quicknthedead+Oct 3 2007, 12:54 AM)
Boys, don't bother posting a reply and expect me to answer. You OCTs become way too boring way too soon. You are not serious about 9/11 truth, so I feel I am wasting time on you now. A person can only take so much from BS artists.
But you do need a lot more truth barbs stuck into your thick heads...
Adios
What a COP OUT.
You can't provide the evidence so you make up a BS cover story about being bored.
AMF
But we BOTH know you'll be back.
But only when you think this latest round of your BS has been forgotten.
Arthur
But you do need a lot more truth barbs stuck into your thick heads...
Adios
What a COP OUT.
You can't provide the evidence so you make up a BS cover story about being bored.
AMF
But we BOTH know you'll be back.
But only when you think this latest round of your BS has been forgotten.
Arthur
WC, I would just add that I bet exercises like that with NORAD and SAC are going on quite often, we just don't hear about them.
QUOTE (Alan (ex elevator man)+Oct 3 2007, 05:08 AM)
WC, I would just add that I bet exercises like that with NORAD and SAC are going on quite often, we just don't hear about them.
Too bad they don't do much good.
Too bad they don't do much good.
QUOTE (wcelliott+Oct 2 2007, 09:57 PM)
Say no more. You don't have a clue about how ANYTHING works.
Two processes that take about the same amount of time, triggered by the same event, are probably going to occur simultaneously, or close to it.
My degrees are in Electrical Engineering, and I've worked in the aerospace industry most of my career. Most of the customers are from the government, various different agencies, so over the course of my career I've had the opportunity to get to know people from all of the various government agencies that you've only fanasized about or seen in the movies. I know how they work, and how they think.
You're living in a fantasy. All of it. This 9/11 conspiracy bs is just all in your head.
We too seem to have criss-crossed, so one more for you, Carter.
For someone as educated as you purport to be, you don't sound like it.
Like I wrote, keep your mickey mouse BS to yourself cause I ain't buying it.
At least Arthur is a good shill. I can't say the same for you.
Adios
QUOTE (quicknthedead+Oct 3 2007, 01:05 AM)
Also, you never do get around to Jowenko, do you?
QUOTE (OneWhiteEye+Oct 2 2007, 11:11 PM)
Too bad they don't do much good.
I dunno 'bout that. I've never heard of a Russian Mig sneaking into our airspace, have you?
I know you haven't forgotten the whole reason for our air defense. It sure wasn't to pick a needle out of a haystack of civilian planes already in our airspace. Again, look how long it took them to find Payne Stewart's plane.
I dunno 'bout that. I've never heard of a Russian Mig sneaking into our airspace, have you?
I know you haven't forgotten the whole reason for our air defense. It sure wasn't to pick a needle out of a haystack of civilian planes already in our airspace. Again, look how long it took them to find Payne Stewart's plane.
QUOTE (OneWhiteEye+Oct 3 2007, 01:11 AM)
Too bad they don't do much good.
They weren't designed to stop US civilian aircraft.
Which even now, given the density of traffic, would be an almost hopeless task.
Which is why we are focused not on a NORAD solution but on keeping terrorists out of the cockpit.
Arthur
They weren't designed to stop US civilian aircraft.
Which even now, given the density of traffic, would be an almost hopeless task.
Which is why we are focused not on a NORAD solution but on keeping terrorists out of the cockpit.
Arthur
Arthur, one is saying they went into WTC 7 with explosives after it was damaged and the fire was roaring... and the other is saying the explosives were already there and going off before the towers fell. They never read the memos so they'd at least be on the same page. haha
A few questions, and then I promise I'll drop the politics.
Is it reasonable to have expected the multi-trillion dollar defense establishment of the time to have been able to have made wing contact with at least one of the hijacked planes? Do you think that the administration's claim that they could not have possibly anticipated this type of attack is an adequate explanation for what they acknowledge was a poor response?
If hopeless, why were fighters enagaged in such exercises, apparently to the detriment of their ability to respond to a real threat of a similar nature? Isn't this evidence that the defense and intelligence agencies had not only assumed a posture of responsiblity and planning for such attacks, but they had some realistic expectation of success in that endeavor?
Is it reasonable to have expected the multi-trillion dollar defense establishment of the time to have been able to have made wing contact with at least one of the hijacked planes? Do you think that the administration's claim that they could not have possibly anticipated this type of attack is an adequate explanation for what they acknowledge was a poor response?
If hopeless, why were fighters enagaged in such exercises, apparently to the detriment of their ability to respond to a real threat of a similar nature? Isn't this evidence that the defense and intelligence agencies had not only assumed a posture of responsiblity and planning for such attacks, but they had some realistic expectation of success in that endeavor?
To put it mildly, molten lead is not a rational explanation for either the metal fire or the radiant molten cascade, Arthur.
I've done some soldering in my time!
And, once again, catastophic mechanical failures do not sound like explosions.
I've done some soldering in my time!
And, once again, catastophic mechanical failures do not sound like explosions.
QUOTE
cause I ain't buying it.
I ain't buying that you have a degree in anything, you sound like you're still in high school.
You definitely haven't got a clue how any aspect of the real world works.
QUOTE (adoucette+Oct 2 2007, 10:08 PM)
What a COP OUT.
You can't provide the evidence so you make up a BS cover story about being bored.
AMF
But we BOTH know you'll be back.
But only when you think this latest round of your BS has been forgotten.
Arthur
At least I have real people telling what they saw and experienced, not a bunch of computer simulations and disallowing of testimonies of those who want to come forward.
It is your BS that is the pile, Arthur.
Besides, what about Jowenko?
Cat got your tongue again, huh?
And one more: Is Jennings a liar then?
Since you are quiet on this, we can only surmise your approval of Barry Jennings to give his testimony under oath...correct?
And a real investigation would get more, wouldn't it, Arthur?
So long, Mr. NO-Answer. Conversing with you is like talking to a wall.
Once again, you have become all too quickly both boring and a waste of time.
So cry like a baby, Mr. NO-Answer.
If copping out means getting out of your stupid circular reasoning that goes nowhere, then I am long gone.
And, Lord willing, I come and go as I please.
Til the next time.
Adios
You can't provide the evidence so you make up a BS cover story about being bored.
AMF
But we BOTH know you'll be back.
But only when you think this latest round of your BS has been forgotten.
Arthur
At least I have real people telling what they saw and experienced, not a bunch of computer simulations and disallowing of testimonies of those who want to come forward.
It is your BS that is the pile, Arthur.
Besides, what about Jowenko?
Cat got your tongue again, huh?
And one more: Is Jennings a liar then?
Since you are quiet on this, we can only surmise your approval of Barry Jennings to give his testimony under oath...correct?
And a real investigation would get more, wouldn't it, Arthur?
So long, Mr. NO-Answer. Conversing with you is like talking to a wall.
Once again, you have become all too quickly both boring and a waste of time.
So cry like a baby, Mr. NO-Answer.
If copping out means getting out of your stupid circular reasoning that goes nowhere, then I am long gone.
And, Lord willing, I come and go as I please.
Til the next time.
Adios
QUOTE (wcelliott+Oct 2 2007, 10:33 PM)
I ain't buying that you have a degree in anything, you sound like you're still in high school.
You definitely haven't got a clue how any aspect of the real world works.
So Danny Jowenko, a professional demolitionist, is wrong when he said WTC7 is a CD?
QUOTE
And, once again, catastophic mechanical failures do not sound like explosions
But your speakers do.
Think this one through. You're supposedly some sort of "sound guy", right?
A speaker has a rigid diaphragm and a coil that drives it back and forth.
The better the speaker, the more rigid and bigger the diaphragm, and the more power available to drive that diaphragm back and forth.
You were the one who said your expensive speakers had better fidelity than headphones do, remember? Better at reproducing the sounds of explosions?
Do they run on C-4?
Or do they use electricity to shove that diaphragm?
So, HIGH FIDELITY "EXPLOSION" SOUNDS can come from RIGID DIAPHRAGMS being shoved suddenly by means OTHER THAN EXPLOSIVES.
Look at how those floors of the WTC Towers were made. LARGE FLAT DIAPHRAGMS supported around the middle and around the outside. Those core columns were failing under-load.
What, Mr. Sound Guy, would YOU expect that to sound like? Impulse-shocks delivered to large flat diaphragms? Those floors were like MEGA-WOOFERS being driven with MEGAWATTs of power.
Of course they sounded like explosions. Your speakers don't need explosives to make BANG! noises, and neither did the WTC towers.
QUOTE (->
| QUOTE |
And, once again, catastophic mechanical failures do not sound like explosions |
But your speakers do.
Think this one through. You're supposedly some sort of "sound guy", right?
A speaker has a rigid diaphragm and a coil that drives it back and forth.
The better the speaker, the more rigid and bigger the diaphragm, and the more power available to drive that diaphragm back and forth.
You were the one who said your expensive speakers had better fidelity than headphones do, remember? Better at reproducing the sounds of explosions?
Do they run on C-4?
Or do they use electricity to shove that diaphragm?
So, HIGH FIDELITY "EXPLOSION" SOUNDS can come from RIGID DIAPHRAGMS being shoved suddenly by means OTHER THAN EXPLOSIVES.
Look at how those floors of the WTC Towers were made. LARGE FLAT DIAPHRAGMS supported around the middle and around the outside. Those core columns were failing under-load.
What, Mr. Sound Guy, would YOU expect that to sound like? Impulse-shocks delivered to large flat diaphragms? Those floors were like MEGA-WOOFERS being driven with MEGAWATTs of power.
Of course they sounded like explosions. Your speakers don't need explosives to make BANG! noises, and neither did the WTC towers.
So Danny Jowenko, a professional demolitionist, is wrong when he said WTC7 is a CD?
Yes, and you're an idiot for believing him (if that's actually what he really said).
QUOTE (quicknthedead+Oct 3 2007, 04:27 AM)
But back to the other, is Jennings lying? He sure is not confused (like you).
Corroboration? How about this newspaper article from Sept. 11, 2001, about Jennings together with his companion, Michael Hess, who was at the time one of New York’s chief lawyers and longtime friend of Mayor Rudolph Giuliani:
http://archives.record-eagle.com/2001/sep/11scene.htm
After the initial blast, Housing Authority worker Barry Jennings, 46, reported to a command center on the 23rd floor of 7 World Trade Center. He was with Michael Hess, the city's corporation counsel, when they felt and heard another explosion. First calling for help, they scrambled downstairs to the lobby, or what was left of it. "I looked around, the lobby was gone. It looked like hell," Jennings said.
Craig, why don't we hear about any conformation of Berry Jenning's story from Michael Hess?
QUOTE (quicknthedead+Oct 3 2007, 04:27 PM)
Corroboration? How about this newspaper article from Sept. 11, 2001, about Jennings together with his companion, Michael Hess, who was at the time one of New York’s chief lawyers and longtime friend of Mayor Rudolph Giuliani:
http://archives.record-eagle.com/2001/sep/11scene.htm
After the initial blast, Housing Authority worker Barry Jennings, 46, reported to a command center on the 23rd floor of 7 World Trade Center. He was with Michael Hess, the city's corporation counsel, when they felt and heard another explosion. First calling for help, they scrambled downstairs to the lobby, or what was left of it. "I looked around, the lobby was gone. It looked like hell," Jennings said.
Here's an idea.
Why don't you go back a page or two and have a look at a link that I provided.
The link has a bunch of interviews in it, including interviews with some of the fire officers that were actually in the WTC7 lobby when it was trashed.
Including the Officer that was responsible for setting up the OEM command center in the lobby of WTC7. He even goes into the reasons for using the lobby instead of whichever floor the OEM command center was based on. IIRC at that point they were concerned about the possibility that the towers might come down - there were bodies, body parts, and bits of building falling down by that point, and the WTC plaza was strewn with aircraft debris as well.
(here's the links, just incase you have trouble finding them)
http://wtc7lies.googlepages.com/accountsofwtc7damage
http://graphics8.nytimes.com/packages/pdf/...HIC/9110045.PDF
http://archives.record-eagle.com/2001/sep/11scene.htm
After the initial blast, Housing Authority worker Barry Jennings, 46, reported to a command center on the 23rd floor of 7 World Trade Center. He was with Michael Hess, the city's corporation counsel, when they felt and heard another explosion. First calling for help, they scrambled downstairs to the lobby, or what was left of it. "I looked around, the lobby was gone. It looked like hell," Jennings said.
Here's an idea.
Why don't you go back a page or two and have a look at a link that I provided.
The link has a bunch of interviews in it, including interviews with some of the fire officers that were actually in the WTC7 lobby when it was trashed.
Including the Officer that was responsible for setting up the OEM command center in the lobby of WTC7. He even goes into the reasons for using the lobby instead of whichever floor the OEM command center was based on. IIRC at that point they were concerned about the possibility that the towers might come down - there were bodies, body parts, and bits of building falling down by that point, and the WTC plaza was strewn with aircraft debris as well.
(here's the links, just incase you have trouble finding them)
http://wtc7lies.googlepages.com/accountsofwtc7damage
http://graphics8.nytimes.com/packages/pdf/...HIC/9110045.PDF
QUOTE (OneWhiteEye+Oct 3 2007, 01:31 AM)
A few questions, and then I promise I'll drop the politics.
Is it reasonable to have expected the multi-trillion dollar defense establishment of the time to have been able to have made wing contact with at least one of the hijacked planes? Do you think that the administration's claim that they could not have possibly anticipated this type of attack is an adequate explanation for what they acknowledge was a poor response?
If hopeless, why were fighters enagaged in such exercises, apparently to the detriment of their ability to respond to a real threat of a similar nature? Isn't this evidence that the defense and intelligence agencies had not only assumed a posture of responsiblity and planning for such attacks, but they had some realistic expectation of success in that endeavor?
No, its not reasonable.
And the amount of money we spend on Submarines, Missiles, Carriers, the Army, The Marines, the Navy etc has NOTHING to do with how much we spend on Coastal Air Defense. The fact is the reduction of aircraft in this mission and their relaxed "ready time" was due to a reduction of a percieved threat "the peace dividend" that came from the end of the cold war.
Was it possible?
NOT at all for the first plane and had everything gone PERFECTLY it would have just BARELY been possible for the second plane.
The third plane they had time to find but didn't have the planes in the right area (middle seaboard) to do it with.
The fourth plane they would have likely met inbound to the capitol had it not crashed.
Its standard practice for the FAA to request FOLLOWING assistance from NORAD which at the time would provide a plane, IF PRIORITY and TIME permitted.
Their ONLY role was to trail the aircraft at a safe distance to see where it goes.
The exercise was ALWAYS dependent on the FAA controlling the intercept and thus on a plane with a cooperating pilot with a working TRANSPONDER.
No possibility of SUCCESS for the first three jets in that there was no authority, at that time, to shoot down a civilian jet.
Arthur
Is it reasonable to have expected the multi-trillion dollar defense establishment of the time to have been able to have made wing contact with at least one of the hijacked planes? Do you think that the administration's claim that they could not have possibly anticipated this type of attack is an adequate explanation for what they acknowledge was a poor response?
If hopeless, why were fighters enagaged in such exercises, apparently to the detriment of their ability to respond to a real threat of a similar nature? Isn't this evidence that the defense and intelligence agencies had not only assumed a posture of responsiblity and planning for such attacks, but they had some realistic expectation of success in that endeavor?
No, its not reasonable.
And the amount of money we spend on Submarines, Missiles, Carriers, the Army, The Marines, the Navy etc has NOTHING to do with how much we spend on Coastal Air Defense. The fact is the reduction of aircraft in this mission and their relaxed "ready time" was due to a reduction of a percieved threat "the peace dividend" that came from the end of the cold war.
Was it possible?
NOT at all for the first plane and had everything gone PERFECTLY it would have just BARELY been possible for the second plane.
The third plane they had time to find but didn't have the planes in the right area (middle seaboard) to do it with.
The fourth plane they would have likely met inbound to the capitol had it not crashed.
Its standard practice for the FAA to request FOLLOWING assistance from NORAD which at the time would provide a plane, IF PRIORITY and TIME permitted.
Their ONLY role was to trail the aircraft at a safe distance to see where it goes.
The exercise was ALWAYS dependent on the FAA controlling the intercept and thus on a plane with a cooperating pilot with a working TRANSPONDER.
No possibility of SUCCESS for the first three jets in that there was no authority, at that time, to shoot down a civilian jet.
Arthur
QUOTE (NEU-FONZE+Oct 2 2007, 11:37 AM)
I just wonder why you would have a DECREASING exponential term for the initial (slow) part of the collapse.
Upon further reflection, this decreasing exponential is wrong here.
Before t) the tower's drop is largely elastic: compression and bowing, tilting of the antenna tower. Once the elastic limit is reached the behavior suddenly shifts to being inelastic, for which the resistive force is taken as K = E1/h.
So possibly F(Z) has to be treated as two constants; one for before t0 and K = E1/h afterward. (While this might suffice, I am most uncertain whether this is correct for the time before t0.)
Upon further reflection, this decreasing exponential is wrong here.
Before t) the tower's drop is largely elastic: compression and bowing, tilting of the antenna tower. Once the elastic limit is reached the behavior suddenly shifts to being inelastic, for which the resistive force is taken as K = E1/h.
So possibly F(Z) has to be treated as two constants; one for before t0 and K = E1/h afterward. (While this might suffice, I am most uncertain whether this is correct for the time before t0.)
QUOTE (adoucette+Oct 3 2007, 12:23 PM)
No, its not reasonable.
And the amount of money we spend on Submarines, Missiles, Carriers, the Army, The Marines, the Navy etc has NOTHING to do with how much we spend on Coastal Air Defense. The fact is the reduction of aircraft in this mission and their relaxed "ready time" was due to a reduction of a percieved threat "the peace dividend" that came from the end of the cold war.
Was it possible?
NOT at all for the first plane and had everything gone PERFECTLY it would have just BARELY been possible for the second plane.
The third plane they had time to find but didn't have the planes in the right area (middle seaboard) to do it with.
The fourth plane they would have likely met inbound to the capitol had it not crashed.
Its standard practice for the FAA to request FOLLOWING assistance from NORAD which at the time would provide a plane, IF PRIORITY and TIME permitted.
Their ONLY role was to trail the aircraft at a safe distance to see where it goes.
The exercise was ALWAYS dependent on the FAA controlling the intercept and thus on a plane with a cooperating pilot with a working TRANSPONDER.
No possibility of SUCCESS for the first three jets in that there was no authority, at that time, to shoot down a civilian jet.
Arthur
Everything you said makes a great deal of sense. If it isn't reasonable or possible for our air defenses to respond to the threat, I can accept that. As a taxpayer, then, I would prefer that the defense (against some threats) establishment not spend untold billions on equipment, personnel and drills that are merely exercises in futility. Such as the exercises going on that day.
I guess the US is quite lucky that a Mig pilot had never taken off from Cuba, spoofed a transponder, then turned it off when crossing our border four minutes later and proceeded from there to be an uncooperative pilot. Thirty years ago.
I know how ignorant that sounds. But wait...
Alan said he thought maybe domestic air defense drills were happening a lot more than we knew. My comment was that it DIDN'T work well in the 911 scenario. Apparently you agree with me because it's your position that there's little that can be done even now to counter such a threat. Alan asserted that the air defense was designed for the cold war and it worked pretty well for that, but it wasn't designed for what happened on 911.
Alan, if our defense department was geared toward threats like those posed by wooden sailing ships armed with cannons, would it be acceptable if we only had an excellent defense against such attack? At what point and after how much time do we expect that our defense, costing trillions for in-service resources, would rise to contemporary challenges?
Bojinka was uncovered about 8 years before 911, as I recall. Rappers had album covers depicting planes hitting the towers, a fricking TV show had a plot about this very thing! How long ago was Running Man written? How many intelligence reports warned of this?
There are anti-aircraft batteries in DC. I guess they were waiting for a rainy day or perhaps an errant Cessna to use them. No authority for shoot-down? Why the hell not? Does it make any sense to have batteries that can't be used without a lengthy approval procedure (obviously of the order of two hours)? Kinda reminds me of the Iraqi WMD that didn't get used as the country was overrun... except that we actually had such defenses.
I don't advocate shooting down a passenger jet without just cause. But I do believe that just cause scenarios do exist and contingencies should have been in place long ago. If they were, they weren't followed. Heads should roll. If they weren't, planners weren't even keeping up with the public conciousness, let alone intelligence reports and, again, heads should roll. No heads rolled.
If I tried to give my clients the type of lame excuses for inadequate peformance that were given me as a taxpayer, my head would roll.
Again, sorry for the OT.
And the amount of money we spend on Submarines, Missiles, Carriers, the Army, The Marines, the Navy etc has NOTHING to do with how much we spend on Coastal Air Defense. The fact is the reduction of aircraft in this mission and their relaxed "ready time" was due to a reduction of a percieved threat "the peace dividend" that came from the end of the cold war.
Was it possible?
NOT at all for the first plane and had everything gone PERFECTLY it would have just BARELY been possible for the second plane.
The third plane they had time to find but didn't have the planes in the right area (middle seaboard) to do it with.
The fourth plane they would have likely met inbound to the capitol had it not crashed.
Its standard practice for the FAA to request FOLLOWING assistance from NORAD which at the time would provide a plane, IF PRIORITY and TIME permitted.
Their ONLY role was to trail the aircraft at a safe distance to see where it goes.
The exercise was ALWAYS dependent on the FAA controlling the intercept and thus on a plane with a cooperating pilot with a working TRANSPONDER.
No possibility of SUCCESS for the first three jets in that there was no authority, at that time, to shoot down a civilian jet.
Arthur
Everything you said makes a great deal of sense. If it isn't reasonable or possible for our air defenses to respond to the threat, I can accept that. As a taxpayer, then, I would prefer that the defense (against some threats) establishment not spend untold billions on equipment, personnel and drills that are merely exercises in futility. Such as the exercises going on that day.
I guess the US is quite lucky that a Mig pilot had never taken off from Cuba, spoofed a transponder, then turned it off when crossing our border four minutes later and proceeded from there to be an uncooperative pilot. Thirty years ago.
I know how ignorant that sounds. But wait...
Alan said he thought maybe domestic air defense drills were happening a lot more than we knew. My comment was that it DIDN'T work well in the 911 scenario. Apparently you agree with me because it's your position that there's little that can be done even now to counter such a threat. Alan asserted that the air defense was designed for the cold war and it worked pretty well for that, but it wasn't designed for what happened on 911.
Alan, if our defense department was geared toward threats like those posed by wooden sailing ships armed with cannons, would it be acceptable if we only had an excellent defense against such attack? At what point and after how much time do we expect that our defense, costing trillions for in-service resources, would rise to contemporary challenges?
Bojinka was uncovered about 8 years before 911, as I recall. Rappers had album covers depicting planes hitting the towers, a fricking TV show had a plot about this very thing! How long ago was Running Man written? How many intelligence reports warned of this?
There are anti-aircraft batteries in DC. I guess they were waiting for a rainy day or perhaps an errant Cessna to use them. No authority for shoot-down? Why the hell not? Does it make any sense to have batteries that can't be used without a lengthy approval procedure (obviously of the order of two hours)? Kinda reminds me of the Iraqi WMD that didn't get used as the country was overrun... except that we actually had such defenses.
I don't advocate shooting down a passenger jet without just cause. But I do believe that just cause scenarios do exist and contingencies should have been in place long ago. If they were, they weren't followed. Heads should roll. If they weren't, planners weren't even keeping up with the public conciousness, let alone intelligence reports and, again, heads should roll. No heads rolled.
If I tried to give my clients the type of lame excuses for inadequate peformance that were given me as a taxpayer, my head would roll.
Again, sorry for the OT.
[QUOTE=OneWhiteEye,Oct 3 2007, 11:16 AM] Alan, if our defense department was geared toward threats like those posed by wooden sailing ships armed with cannons, would it be acceptable if we only had an excellent defense against such attack? At what point and after how much time do we expect that our defense, costing trillions for in-service resources, would rise to contemporary challenges?
---
---
There are anti-aircraft batteries in DC. I guess they were waiting for a rainy day or perhaps an errant Cessna to use them. No authority for shoot-down? Why the hell not? Does it make any sense to have batteries that can't be used without a lengthy approval procedure (obviously of the order of two hours)? Kinda reminds me of the Iraqi WMD that didn't get used as the country was overrun... except that we actually had such defenses.
"Alan, if our defense department..."
Keyword: if
Again, our air defense was for INCOMING military threats.
Making up some b/s about wooden ships doesn't change that fact. The best response to 9/11 is to keep hijackers OUT of civilian planes, not do an overhaul of our defense against FOREIGN military threats.
----
----
Care to guess what the chain-of-command is for those shootdown orders?
Authority comes from the president, directly to the Sec. of Defense, who then commands the military to respond. Guess where our dumbazz Sec. of Defense was during 9/11. A photo-op, carrying one-fourth of a stretcher at the Pentagon, instead of doing HIS JOB coordinating a response. He was muchly admired by the military personell on hand for 'putting himself in danger' to help with rescues. *gag*
The very FIRST step to mitigating mistakes that day should have been to FIRE Rumsfeld.
---
---
There are anti-aircraft batteries in DC. I guess they were waiting for a rainy day or perhaps an errant Cessna to use them. No authority for shoot-down? Why the hell not? Does it make any sense to have batteries that can't be used without a lengthy approval procedure (obviously of the order of two hours)? Kinda reminds me of the Iraqi WMD that didn't get used as the country was overrun... except that we actually had such defenses.
"Alan, if our defense department..."
Keyword: if
Again, our air defense was for INCOMING military threats.
Making up some b/s about wooden ships doesn't change that fact. The best response to 9/11 is to keep hijackers OUT of civilian planes, not do an overhaul of our defense against FOREIGN military threats.
----
----
Care to guess what the chain-of-command is for those shootdown orders?
Authority comes from the president, directly to the Sec. of Defense, who then commands the military to respond. Guess where our dumbazz Sec. of Defense was during 9/11. A photo-op, carrying one-fourth of a stretcher at the Pentagon, instead of doing HIS JOB coordinating a response. He was muchly admired by the military personell on hand for 'putting himself in danger' to help with rescues. *gag*
The very FIRST step to mitigating mistakes that day should have been to FIRE Rumsfeld.
QUOTE
Guess where our dumbazz Sec. of Defense was during 9/11. A photo-op, carrying one-fourth of a stretcher at the Pentagon, instead of doing HIS JOB coordinating a response.
I would agree that we'd have been better-off with someone other than Rumsfeld in that post, but in fairness, it needs to be noted that every government official in high office has more than one "hat" to wear at any given time, and politics is part of the job. Probably shouldn't be, but realistically, it is and probably always will be in a democracy.
Part of politics is public image, and photo-ops are central to creating/maintaining that public image.
In a perfect world, people in office would do their primary responsibilities first and foremost, and nobody would be posing for pictures or visiting classrooms talking to school children when the country is under attack, but since terrorists don't post their attack schedules for public review, there will inevitably be times when the guy who should be barking orders into a phone is off doing something else, and as adults in a democracy, we should recognize that fact.
As Churchill put it, “The best argument against democracy is a five minute conversation with the average voter.” Until voters start acting like adults, we'll be getting the democracy that we deserve, not the democracy that we want. If we were more interested in news programs that focussed on important issues than we were about the stains on Monica Lewinsky's dress, then news organizations would've spent more resources discussing serious issues and less on tabloid stories.
The main problem is obvious and in-evidence right here in this thread - How many dumbass arguments would've been settled had the CDiots bothered to take physics in high school? How much of what we discuss here is simply remedial physics? There are people here who'd have Bush hanged if they had a chance based solely on their own inadequate grasp of how gravity works.
It's easy to say that it's the government's problem, but Jefferson said that a well-informed populace was essential for a democracy to function, and the populace has dropped that ball a long time ago.
QUOTE (wcelliott+Oct 3 2007, 12:46 PM)
How many dumbass arguments would've been settled had the CDiots bothered to take physics in high school? How much of what we discuss here is simply remedial physics?
Indeed.
And given the moderator's restriction in the very first post of this thread, could we stick to the physics?
Indeed.
And given the moderator's restriction in the very first post of this thread, could we stick to the physics?
QUOTE
could we stick to the physics?
OK, would anybody care to discuss the acoustic characteristics of floors connected to failing structural members and their similarities to megawoofers simulating explosive sounds?
I keep trying to get support/feedback on that topic, but I only get Al Kawasaki's "bunk" response. I think there's some valid physics there that hasn't been discussed.
What was the mass of the floor pans and concrete, does anybody have an estimate on this?
QUOTE (carterelliott+Oct 3 2007, 02:37 PM)
... their similarities to megawoofers simulating explosive sounds?
First of all, due to the tilt of the top block, the floors were impacted in one location before others. Let us restrict ourselves to WTC 1. In that tower, the south edge of each floor was impacted first. The crushing proceeded from south to north, rapidly.
The air had to be quickly expelled. Supposing a speed of 25 m/s, there is only 0.146 seconds to remove all the air. Assuming the air in the core went down the core, the longest distance for particles of air and dust to travel is from just outside the core on the widest side of the office area, 18.3 meters. Assuming the entire 0.146 seconds is available to do this, the average speed is 124 m/s. Since the test pint is accelerated, I suppose the exit speed is twice that, about 250 m/s.
I would expect that to be noisy, but don't know details just at the moment...
First of all, due to the tilt of the top block, the floors were impacted in one location before others. Let us restrict ourselves to WTC 1. In that tower, the south edge of each floor was impacted first. The crushing proceeded from south to north, rapidly.
The air had to be quickly expelled. Supposing a speed of 25 m/s, there is only 0.146 seconds to remove all the air. Assuming the air in the core went down the core, the longest distance for particles of air and dust to travel is from just outside the core on the widest side of the office area, 18.3 meters. Assuming the entire 0.146 seconds is available to do this, the average speed is 124 m/s. Since the test pint is accelerated, I suppose the exit speed is twice that, about 250 m/s.
I would expect that to be noisy, but don't know details just at the moment...
QUOTE (Trippy+Oct 3 2007, 02:46 PM)
What was the mass of the floor pans and concrete, does anybody have an estimate on this?
The floor pans were only 20 gauge, so essentially their mass is negligible. The lightweight concrete and the dimensions of the floor are found in an appendix to Greening's Energy Transfer paper, hosted
here.
Why do you ask?
The floor pans were only 20 gauge, so essentially their mass is negligible. The lightweight concrete and the dimensions of the floor are found in an appendix to Greening's Energy Transfer paper, hosted
here.
Why do you ask?
DBB/Trippy:
This may also help:
To calculate the mass of concrete on each WTC floor proceed as follows:
Core floor area = 862 m2
Out-of-core (Office space) floor areas:
2 long one-way slabs = 1,225 m2
2 short one-way slabs = 486 m2
4 two-way slabs = 1,137 m2
Total out-of-core area = 2848 m2
The floors in the core areas were made of normal weight concrete, density 1760 kg/m3
The floors in the office areas were made of lightweight concrete, density 1500 kg/m3
Volume of 5-inch normal weight concrete per floor = 109.5 m3
Weight of normal weight concrete per floor = 193 tonnes
Volume of 4-inch thick lightweight concrete per floor = 289.4 m3
Weight of lightweight concrete per floor = 434 tonnes
Total weight of concrete on one floor of a WTC tower = 627 tonnes
This may also help:
To calculate the mass of concrete on each WTC floor proceed as follows:
Core floor area = 862 m2
Out-of-core (Office space) floor areas:
2 long one-way slabs = 1,225 m2
2 short one-way slabs = 486 m2
4 two-way slabs = 1,137 m2
Total out-of-core area = 2848 m2
The floors in the core areas were made of normal weight concrete, density 1760 kg/m3
The floors in the office areas were made of lightweight concrete, density 1500 kg/m3
Volume of 5-inch normal weight concrete per floor = 109.5 m3
Weight of normal weight concrete per floor = 193 tonnes
Volume of 4-inch thick lightweight concrete per floor = 289.4 m3
Weight of lightweight concrete per floor = 434 tonnes
Total weight of concrete on one floor of a WTC tower = 627 tonnes
I was just thinking about the audio properties of floors, treating them as a diaphragm. Mass and rigidity are important.
QUOTE (Trippy+Oct 3 2007, 03:31 PM)
... treating them as a diaphragm. ...
I don't see it, myself. The impact of the crushing block upon the next floor down is more like the sound of two hands clapping. See my post two or three back.
I don't see it, myself. The impact of the crushing block upon the next floor down is more like the sound of two hands clapping. See my post two or three back.
NIST POLITICIZATION
I'd file this under the "Completely unsurprising if true, but I'd like to see verification" category.
From George Washington's Blog
A NIST employee recently made the following statements regarding NIST's politicization and corruption:
Communication dated October 1, 2007:
"NBS/NIST had become fully hijacked from the scientific into the political realm well before he became involved. That hijacking happened in the mid-90's, and has only grown stronger to the present. Prior to that time, the Director of NBS/NIST was appointed via the political process (Presidential nomination, Congressional confirmation), but with the firm understanding in the scientific community that the job was essentially a non-political one, as the leader of the government's premiere scientific research institution. Directors were carefully selected from a field of well-known senior scientists with management skills, typically from within the NBS staff, after gaining much credibility in their fields. Once appointed, Directors tended to stay on for several years, through different administrations in an essentially career mode, usually until they retired. That all changed under the Clinton administration.
I saw it happen. After retirement from the Army, in 1983 I joined then-NBS as a scientist on the staff. After 3 years, I decided to move on (engineering on the Star Wars project). Becoming sick of that charade in 1989, I succumbed to my former boss' entreaties and returned to now-NIST in a supervisory scientist position at the top civil service grade. I retired from there in 2001, and worked as a part-time contractor for them until last year. So I've had a chance to observe some of the higher-level NIST goings-on up close and personal for some time, and was personally involved in some of its politicization.
I don't know whether the NBS Director, Dr. John Lyons, was forced into retirement by the Clinton administration; I just remember the abruptness of the change after only 3 years on his job. He was replaced by a relatively unknown and also quite young scientist from DARPA. What I remember about her is her lack of credibility in representing NIST in scientific circles, her choice of senior staff with little regard for their scientific standing, and her keen emphasis on political sensitivities. She departed after a long four years, and the Director's office (and hence the whole Institute) has been in turmoil ever since. Four of her six successors to the present time have been "Acting", meaning in a practical sense that they may well not have had the personal credibility and scientific standing to survive the scrutiny of the confirmation process.
About the time of this major reduction in stature of the Director's office, some other major shifts took place at NIST, the echoes of which may have direct relevance to [9/11 truth]. Prior to that time, we were focused on scientific research and standards development that tended to be independent of what other government agencies were doing. All of a sudden, the senior levels of NIST were flooded with what I perhaps over-harshly termed "political commisars", whose job was principally to deal with what may be called "the political sensitivities" of our work and also making sure it supported big industry.
That support became an overtly-stated major mission for us. We lost a major share of our direct research funding, and from then on have been largely dependent upon receiving funds from other government agencies (the majority from Depts of Defense and Energy) for research and standards-making to support their own work. This "other agency" work amounted to about 40% of our total budget in my last several years there. In essence, we lost our scientific independence, and became little more than "hired guns".
When I first heard of [9/11 truth] and how the NIST "scientists" involved in 911 seemed to act in very un-scientific ways, it was not at all surprising to me. By 2001, everyone in NIST leadership had been trained to pay close heed to political pressures. There was no chance that NIST people "investigating" the 911 situation could have been acting in the true spirit of scientific independence, nor could they have operated at all without careful consideration of political impact. Everything that came from the hired guns was by then routinely filtered through the front office, and assessed for political implications before release.
Sorry this blurb became overly long, but I did want to make sure that an "insider's view" got onto the record."
Email dated October 2, 2007:
"A little more general insight into what I referred to as the NIST politicization, some of which may be of interest to you. In addition to the NIST "front office" looking closely over our shoulders, we had three major external oversight groups keeping close track of our little part of NIST, which admittedly dealt at times with some sensitive issues regarding technological security.
One was NSA (no surprises there!), another was the HQ staff of the Department of Commerce, which scrutinized our work very closely and frequently wouldn't permit us to release papers or give talks without changes to conform to their way of looking at things. A third was a bit of a surprise to some -- the Office of Management and Budget (OMB) had a policy person specifically delegated to provide oversight on our work. Just as a reminder, the OMB is an arm of the Executive Office of the President.
One more tidbit - a gentleman named William A Jeffrey served as NIST Director from July 2005 until last month. Interestingly, Dr. Jeffrey's previous assignment was in the EOP's Office of Science and Technology Policy! Talk about high-level oversight!! So one can be certain that on so hot a topic as yours, Dr. Jeffrey (and his previous political handlers in the WH - if they still were "previous") would be very personally involved at every step.
I don't know what more I can add that might be relevant, as I have been once-removed from NIST for the past 6 years as a contractor via Booz-Allen Hamilton. However, I do have some good NIST friends who are rather highly placed, so if you have any other questions re NIST, I might be able to ferret out an answer. Would be worth a shot anyway."
(emphasis mine)
I'd file this under the "Completely unsurprising if true, but I'd like to see verification" category.
From George Washington's Blog
QUOTE
A NIST employee recently made the following statements regarding NIST's politicization and corruption:
Communication dated October 1, 2007:
"NBS/NIST had become fully hijacked from the scientific into the political realm well before he became involved. That hijacking happened in the mid-90's, and has only grown stronger to the present. Prior to that time, the Director of NBS/NIST was appointed via the political process (Presidential nomination, Congressional confirmation), but with the firm understanding in the scientific community that the job was essentially a non-political one, as the leader of the government's premiere scientific research institution. Directors were carefully selected from a field of well-known senior scientists with management skills, typically from within the NBS staff, after gaining much credibility in their fields. Once appointed, Directors tended to stay on for several years, through different administrations in an essentially career mode, usually until they retired. That all changed under the Clinton administration.
I saw it happen. After retirement from the Army, in 1983 I joined then-NBS as a scientist on the staff. After 3 years, I decided to move on (engineering on the Star Wars project). Becoming sick of that charade in 1989, I succumbed to my former boss' entreaties and returned to now-NIST in a supervisory scientist position at the top civil service grade. I retired from there in 2001, and worked as a part-time contractor for them until last year. So I've had a chance to observe some of the higher-level NIST goings-on up close and personal for some time, and was personally involved in some of its politicization.
I don't know whether the NBS Director, Dr. John Lyons, was forced into retirement by the Clinton administration; I just remember the abruptness of the change after only 3 years on his job. He was replaced by a relatively unknown and also quite young scientist from DARPA. What I remember about her is her lack of credibility in representing NIST in scientific circles, her choice of senior staff with little regard for their scientific standing, and her keen emphasis on political sensitivities. She departed after a long four years, and the Director's office (and hence the whole Institute) has been in turmoil ever since. Four of her six successors to the present time have been "Acting", meaning in a practical sense that they may well not have had the personal credibility and scientific standing to survive the scrutiny of the confirmation process.
About the time of this major reduction in stature of the Director's office, some other major shifts took place at NIST, the echoes of which may have direct relevance to [9/11 truth]. Prior to that time, we were focused on scientific research and standards development that tended to be independent of what other government agencies were doing. All of a sudden, the senior levels of NIST were flooded with what I perhaps over-harshly termed "political commisars", whose job was principally to deal with what may be called "the political sensitivities" of our work and also making sure it supported big industry.
That support became an overtly-stated major mission for us. We lost a major share of our direct research funding, and from then on have been largely dependent upon receiving funds from other government agencies (the majority from Depts of Defense and Energy) for research and standards-making to support their own work. This "other agency" work amounted to about 40% of our total budget in my last several years there. In essence, we lost our scientific independence, and became little more than "hired guns".
When I first heard of [9/11 truth] and how the NIST "scientists" involved in 911 seemed to act in very un-scientific ways, it was not at all surprising to me. By 2001, everyone in NIST leadership had been trained to pay close heed to political pressures. There was no chance that NIST people "investigating" the 911 situation could have been acting in the true spirit of scientific independence, nor could they have operated at all without careful consideration of political impact. Everything that came from the hired guns was by then routinely filtered through the front office, and assessed for political implications before release.
Sorry this blurb became overly long, but I did want to make sure that an "insider's view" got onto the record."
Email dated October 2, 2007:
"A little more general insight into what I referred to as the NIST politicization, some of which may be of interest to you. In addition to the NIST "front office" looking closely over our shoulders, we had three major external oversight groups keeping close track of our little part of NIST, which admittedly dealt at times with some sensitive issues regarding technological security.
One was NSA (no surprises there!), another was the HQ staff of the Department of Commerce, which scrutinized our work very closely and frequently wouldn't permit us to release papers or give talks without changes to conform to their way of looking at things. A third was a bit of a surprise to some -- the Office of Management and Budget (OMB) had a policy person specifically delegated to provide oversight on our work. Just as a reminder, the OMB is an arm of the Executive Office of the President.
One more tidbit - a gentleman named William A Jeffrey served as NIST Director from July 2005 until last month. Interestingly, Dr. Jeffrey's previous assignment was in the EOP's Office of Science and Technology Policy! Talk about high-level oversight!! So one can be certain that on so hot a topic as yours, Dr. Jeffrey (and his previous political handlers in the WH - if they still were "previous") would be very personally involved at every step.
I don't know what more I can add that might be relevant, as I have been once-removed from NIST for the past 6 years as a contractor via Booz-Allen Hamilton. However, I do have some good NIST friends who are rather highly placed, so if you have any other questions re NIST, I might be able to ferret out an answer. Would be worth a shot anyway."
(emphasis mine)
QUOTE (metamars+Oct 3 2007, 03:37 PM)
I'd file this under the "Completely unsurprising if true, but I'd like to see verification" category.
Yes.
But most unlikely to affect the Building Safety Group which wrote the NCSTAR1 report.
Yes.
But most unlikely to affect the Building Safety Group which wrote the NCSTAR1 report.
QUOTE (David B. Benson+Oct 4 2007, 10:35 AM)
I don't see it, myself. The impact of the crushing block upon the next floor down is more like the sound of two hands clapping. See my post two or three back.
Yes, I saw that post, and I think I've said very similar things in the past, however, the collapse of the floors onto the ones below it wasn't neccessarily symetric, and there are other sources of energy for driving the floors as diagrams, for example the unloading of the central columns.
Yes, I saw that post, and I think I've said very similar things in the past, however, the collapse of the floors onto the ones below it wasn't neccessarily symetric, and there are other sources of energy for driving the floors as diagrams, for example the unloading of the central columns.
QUOTE (Trippy+Oct 3 2007, 03:54 PM)
... wasn't neccessarily[sic] symetric[sic],
and there are other sources of energy for driving the floors as diagrams, for example the unloading of the central columns.
Most certainly was not symmetric, as I said. The tilt.
Yes, this could happen below the crushing front, but I'm having a bit of difficulty getting the sound out the windows until the blasts of air blow out the windows. At that point the air is escaping rather rapidly...
and there are other sources of energy for driving the floors as diagrams, for example the unloading of the central columns.
Most certainly was not symmetric, as I said. The tilt.
Yes, this could happen below the crushing front, but I'm having a bit of difficulty getting the sound out the windows until the blasts of air blow out the windows. At that point the air is escaping rather rapidly...
QUOTE (David B. Benson+Oct 3 2007, 10:53 PM)
Yes.
But most unlikely to affect the Building Safety Group which wrote the NCSTAR1 report.
Why is that?
But most unlikely to affect the Building Safety Group which wrote the NCSTAR1 report.
Why is that?
QUOTE (David B. Benson+Oct 4 2007, 10:58 AM)
Most certainly was not symmetric, as I said. The tilt.
Yes, this could happen below the crushing front, but I'm having a bit of difficulty getting the sound out the windows until the blasts of air blow out the windows. At that point the air is escaping rather rapidly...
Well, the pressure between the floors builds up rather rapidly (c 0.1 seconds) so those would be some nice strong pressure waves, but also the core. Is there any reason why sound could not excape through the core, and would not the core act like an organ pipe (by very very very very rough analogy)?
Yes, this could happen below the crushing front, but I'm having a bit of difficulty getting the sound out the windows until the blasts of air blow out the windows. At that point the air is escaping rather rapidly...
Well, the pressure between the floors builds up rather rapidly (c 0.1 seconds) so those would be some nice strong pressure waves, but also the core. Is there any reason why sound could not excape through the core, and would not the core act like an organ pipe (by very very very very rough analogy)?
QUOTE (metamars+Oct 3 2007, 03:59 PM)
Why is that?
Since the reply had very little to do with sci-tech, I sent a PM.
Since the reply had very little to do with sci-tech, I sent a PM.
QUOTE (Trippy+Oct 3 2007, 04:04 PM)
Well, the pressure between the floors builds up rather rapidly (c 0.1 seconds) so those would be some nice strong pressure waves...
Is there any reason why sound could not excape[sic] through the core, and would not the core act like an organ pipe (by very very very very rough analogy)?
Yup. And due to the tilt (assuming it was maintained), in WTC 1 three to four floors were simultaneously in various stages of being crushed. I don't know enough acoustics to be able to say anything about the sound produced.
None at all! At least WTC 2 had all the lobby glass blown out. (I don't know about WTC 1.) As an organ pipe the fundamental frequency would be low infrasound, not audible. The overtones might be. I seem to recall that some witnesses heard a low moaning sound. If correct, this could well help explain it.
Is there any reason why sound could not excape[sic] through the core, and would not the core act like an organ pipe (by very very very very rough analogy)?
Yup. And due to the tilt (assuming it was maintained), in WTC 1 three to four floors were simultaneously in various stages of being crushed. I don't know enough acoustics to be able to say anything about the sound produced.
None at all! At least WTC 2 had all the lobby glass blown out. (I don't know about WTC 1.) As an organ pipe the fundamental frequency would be low infrasound, not audible. The overtones might be. I seem to recall that some witnesses heard a low moaning sound. If correct, this could well help explain it.
Metamars:
Thanks for that very interesting post. Having worked for a government-run nuclear research group in Canada, I can say the same thing happened to us. Nuclear energy is a VERY touchy issue and by the time I left in 2000 we had to be politically correct in everything we did. The main thrust of our work shifted towards producing documents to placate the regulators, not to do good science. Consensus was the order of the day; if you didn't toe the line, you got no funding - it was as simple as that!
Thanks for that very interesting post. Having worked for a government-run nuclear research group in Canada, I can say the same thing happened to us. Nuclear energy is a VERY touchy issue and by the time I left in 2000 we had to be politically correct in everything we did. The main thrust of our work shifted towards producing documents to placate the regulators, not to do good science. Consensus was the order of the day; if you didn't toe the line, you got no funding - it was as simple as that!
QUOTE (Al Khwarizmi - step-by-step+Oct 3 2007, 01:33 AM)
To put it mildly, molten lead is not a rational explanation for either the metal fire or the radiant molten cascade, Arthur.
I've done some soldering in my time!
And, once again, catastophic mechanical failures do not sound like explosions.
Not for the metal fire, but that's most likely part of the plane that is lodged in that corner.
I've done some soldering in my time as well, but so what?
Still a LOT of molten lead with debris from the fire certainly seems like a fairly plausible explanation for what is observed.
Much more so than THERMITE.
Arthur
I've done some soldering in my time!
And, once again, catastophic mechanical failures do not sound like explosions.
Not for the metal fire, but that's most likely part of the plane that is lodged in that corner.
I've done some soldering in my time as well, but so what?
Still a LOT of molten lead with debris from the fire certainly seems like a fairly plausible explanation for what is observed.
Much more so than THERMITE.
Arthur
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