Magnesium is another possibility as a heat source.  I don't know offhand if there were any significant amounts of magnesium in the 767.  Perhaps there was some in the wheel hubs or other components.  Magnesium burns fiercely and water actually makes it burn hotter.

Foxx leaves out VERY SELECTIVE pieces from that NIST report.

I suggest you read the ACTUAL report.

Arthur

if you look(and zoom in) to the to the right of the h-beam in the foreground, you will see a row of horizontal beams which were sheared off close to the column they are attached to. there are four stories cut on the left side(the top four visible, floors four to seven), and one story one the right(the third floor).
they are cut at nearly the exact same distance from the column. there is simply NO WAY for this to happen naturally. those beams were purposely cut.

these bomb boys had a frickin' field day with the complex.

James X asks a simple question, why are you not able to answer it? The computer models you speak of would be of great help if they exist. Please enlighten us all CS, Arthur, it shouldn't be this hard to convince us of the truths you speak of.

I guess your hand waving covered this from your eyes...



http://www.geocities.com/debunking911//computermodel.jpg







Silverstein's insurers claim the collapse of the south tower, Two WTC, rendered the north tower, One WTC, unsalvageable even before it collapsed. If they prevail, Silverstein would receive only $3.5 billion (ENR 10/7 p. 11). Click here to view one WTC collapse sequence (SECOND DOWN North tower lasted longer due to impact site. (Graphics courtesy of Weidlinger Associates Inc.))

The insurers commissioned their own engineering study, written by Exponent Failure Analysis Associates Inc., Los Angeles. Also released, the report disagrees with the Weidlinger findings, but mostly on points relating to the insurance battle. Engineers from Wiss, Janney, Elstner and Associates Inc., Northbrook, Ill., also working for the insurers, would not comment on their work.

In the Silverstein study, engineers put forth similar but not exact failure scenarios for both towers: The planes and flying debris hobbled the buildings at the zones of impact. Intact columns, their fireproofing knocked off by flying debris, ultimately lost strength and failed in the fuel-triggered fire.

Though hit by the second plane later than One WTC, Two WTC fell first, "primarily" because the plane struck it off-center and at an angle and caused damage that compromised the southeast corner of the core. "This confirms an earlier theory," says Levy. Click here to view two WTC collapse sequence (FIRST DOWN Plane took out corner of core, which hastened collapse. (Graphics courtesy of Weidlinger Associates Inc.)).


At each tower, exterior wall and core columns, connected by a steel "hat truss" at the building's top, initially redistributed loads away from the damaged areas to remaining columns. In Two WTC, the hat truss eventually could not deal with the situation of the corner columns gone, says Levy.

The team determined that the initial hits destroyed 33 of 59 perimeter columns in the north face of One WTC and 29 of 59 perimeter columns in the south face of Two WTC. Computer analysis showed that the impact of the planes also destroyed or disabled some 20 of 47 columns in the center of the core of One WTC and some five of 47 columns in the southeast corner of the core of Two WTC.

The Silverstein findings are based on analysis of original structural drawings, thousands of photos and dozens of videos. The team used computer modeling, including a program called FLEX developed by Weidlinger for the Dept. of Defense, and fire evaluation techniques to simulate the condition of each tower at critical times, creating impact and collapse sequences.

http://construction.com/NewsCenter/Headlin...R/20021104d.asp



Abstract: Mechanical simulation and parameter discussion for the collapse of WTC (World Trade Center) after aeroplane impact are presented in this paper with the dynamic FEA software of LS-DYNA. The simulation results are very close to the real situation, which means that such type of special damage process can be recurred on the computer with proper parameter and numerical model. The results show that the direct reason for the collapse is the softening of steel under fire and the chain reaction damage of floors under the impact load of upper floors. If improve the fire resistance and the ductility of the structure, the collapse may can be avoided.

1. Introduction

The two towers of world trade center in New York were impact by two aeroplanes on Sep. 11 of 2001. The two towers were collapsed completely and more than 3 thousand people died in this affair. This affair obtained everyone¡¯s focus and many explanations are put forward for the reason of this collapse, including fire damage, heaped load, second-damage and so on. Because the collapse of the towers is very complex and it is difficult to recur by test, most explanations are based on qualitative analysis. However, the computer technology applied us a chance to simulate the collapse in the computer, so that the reason for the collapse can be discussed, as well as the methods can be raised to avoid this disaster.

2. Numerical model

This simulation is based on the dynamic FEA software of LS-DYNA, which is developed by the Software Company of Livemore.

The WTC is topical tube-in-tube structure system, whose outer tube is dense-columns-deep-beams system. The width of the column is 476.25mm while the space between columns is just 558.8mm. The thickness of beams is 1219.2mm. In order to simplify the numerical model and decrease the degree of freedom, the outer dense-columns-deep-beams tube system and inner steel truss tube system are approached with shell elements. The thickness of shell elements is established with equivalent section method. Such approximate tube has the same stiffness of global bending and axial deformation as the real structure, while the local bending stiffness of structure elements is not consisted with the real condition. Since the primary deformation of tube-in-tube structure system is global bending and axial compression deformation, this approximate method should be feasible.

The material of inner and outer tube is set to be steel in the numerical model, with the constitutive relationship of Material 3, Plastic Kinematic model in LS-DYNA. The density of steel is 7800Kg/m3. The Yang¡¯s modulus is 200GPa. The Poisson ratio is 0.27. The yield strength is set to be 310MPa, according to Steel A440 in U.S. The hardening modulus is set to be 2GPa, 1% of initial modulus. As the fracture of steel is considered in this analysis, the failure plastic deformation is discussed as parameters, whose value is set as 0.5%, 1% and 5% respectively

The material of floor is set to be RC material, with the constitutive relationship of Material 3, Plastic Kinematic model, too. The density is 2500Kg/m3. The Yang¡¯s modulus is 30GPa. The Poisson ration is 0.2. The yield strength is 30MPa. The hardening modulus is 0. All the fracture plastic deformation is set to be the maximum compression strain of concrete, whose value is 0.38%.

Because of the weak fire resistance capacity of steel, the high temperature caused by the burning of aeroplane oil will soften the steel. So the material of steel under fire is needed to be setup, whose other parameter is the same to normal steel except that the Yang¡¯s modulus and strength is set as 1/20 of normal ones, to approach the performance of steel at 700¡æ.

As the collapse analysis is very complex, the Single Face Erosion contact module of LS-DYNA is used in this case. This contact model can search the contact face automatically to establish the contact relationship, and those complex border conditions such as penetration, erosion can be considered, too. The friction factor of material is set to be 0.25.

Since the LS-DYNA is explicit dynamic software, when applying the gravity load, the structure will vibrate for a short time. It is not consisted with the real conditions. So the whole computation should be divided into two stages. In the first stage, the towers have not been impacted. The gravity load is applied to the model and relatively large damp ratio is applied to the towers, whose value is 10%. Computing the model until the vertical vibration disappeared. Then, the second computation stage starts. In the second stage, some elements in the tower are ¡°killed¡± to approach the hole of airplane impact, and the material property of some survival elements is modified to simulate the fire influence, too.

4 Conclusions

The following conclusions are obtained from the simulation.

1) The reasons for the entire collapse of the towers are the structure elements¡¯ soften of fire and impact of the upper layers¡¯ collapse. From the numerical results, the towers does not collapse immediately after the impact. The north tower can go on standing. Likely, the south one dose not collapse, too, though there are some large deformations in it, which are caused by the asymmetric damage. This is consisted with the real situations.

2) Improving the structure fire resistance ability or control the fire influence area will avoid or delay the structure collapse, efficiently. We simulate the fire influence by adjusting the material property of elements. From the numerical results, even though the structure has been damaged seriously by the impact, if the influence area is smaller than 20%~25% of the survival section in the tower, the collapse still can be avoided. When more than 30~50% of the survival section near the impact zone fails, the collapse will start.

3) When the towers go into the collapse stage, the reason for the chain failure of un-impact layers is the impulse of upper collapsing floors. The impact force of upper floors is much larger than the heap load. And because there are a lot of bump and eject on the contact surface of collapsing floors and lower floors, the fragment of structure falls consecutively so that there is no chance to form a lot of heap load. So the heap load is not the critical reason for the collapse.

4) Improving the ductility of structure elements is an efficient way to avoid the chain collapse happens. In the simulation above, if the fracture plastic strain of steel structure is 0.5%, the chain collapse will take place entirely. However, if the fracture strain is improved to 1%, the impact energy of upper floors will be absorbed by the lower structures and the chain collapse will be stopped at about 100m under the airplane impact zone. When the fracture strain is improved to 5%, only part of the structure near the airplane impacting zone will be damaged, and no chain collapse will take place. Hence, if the structure has enough ductility to absorb the energy of upper floors¡¯ collapse, the chain damage will be controlled. Even though consider the influence of heap load, the towers still have much larger chance to escape from the entire collapse.

http://www.luxinzheng.net/publications/english_WTC.htm

That's TWO computer models done outside NIST (Plus the NIST final report which says there was one done by NIST [first image above]) which say it CAN happen. Wheres yours saying it can't?

Large font for the hand waving impaired.

There are other flammable in the aircraft, such as hydraulic fluid and pressurized oxygen containers.  Someone would have to look at a whole list of what's inside a 767.  It's a unique event to have a jumbo jet inside an office building.

Magnesium alloys can melt around 550C or lower depending on the alloying.  Something like melted magnesium wheels in the building in the presence of oxygen can burn fiercely.  If you had a situation like oxygen leaking from canisters and molten aluminum or magnesium alloy, that could produce a very hot fire.  Most of the plane probably ended up in the northeast corner of the south tower.  Only one landing gear assembly came out of the building, so the others must have still been inside.

James X asks a simple question, why are you not able to answer it? The computer models you speak of would be of great help if they exist. Please enlighten us all CS, Arthur, it shouldn't be this hard to convince us of the truths you speak of.

<br>Luckily for us, they explained it all in the NIST report.

Arthur

<br>No, they didn't.

Not to mention this comes from a lying CT site. But then what CT site isn't.

The chemical oxygen generators (1 per seat are also EXOTHERMIC)

The nose gear went through, leaving TWO landing gear assemblies (8 wheels & hubs) inside.

Arthur

Not to mention Rove's Shill has posted these issues and they were dealt with, but he's still posting them, though now he KNOWS they are lies.

Like the First bullet of the first slide.

"Actual fire tests with models didn't collapse."

They were models OF THE FLOOR TRUSSES. The Trusses were AS BUILT, i.e. they had the INSULATION INTACT. The term COLLAPSE is inappropriately used as a single truss can't actually "collapse". The TEST was done to see the impact of heating on the truss in order to calibrate the fire model. While they didn't FAIL, they DID sag almost 6 feet in the middle!


Arthur

<br>Don't have a heart attack, buddy.

Not to mention Rove's Shill has posted these issues and they were dealt with, but he's still posting them, though now he KNOWS they are lies.

Like the First bullet of the first slide.

"Actual fire tests with models didn't collapse."

They were models OF THE FLOOR TRUSSES. The Trusses were AS BUILT, i.e. they had the INSULATION INTACT. The term COLLAPSE is inappropriately used as a single truss can't actually "collapse". The TEST was done to see the impact of heating on the truss in order to calibrate the fire model. While they didn't FAIL, they DID sag almost 6 feet in the middle!


Arthur

Arty, is this one of your infamous half truths/ half lies? I will check when I have more time however I recall several test without insulation.

Let's pretend the ArsoNIST's do explain everything. (I know they don't, but just for the sake of this discussion.) Could you put it into brief, simple language that even a MORON could understand? Or is your foilhat fantasy really that fu<king mystical, Arty?

...

What's causing that huge explosion, Arty?

Nist Appendixj page 6 line 4

Tests were done on bare steel and insulation of two thicknesses.

Gordon.

When the towers were built the steel and concrete were hoisted up, much of it over 1,000 feet.

It took ENERGY to hoist the material up against the force of gravity.

In doing so the material gained potential energy.

As an EXAMPLE, say you took a 20lb piece of concrete and you placed it upon a car next to the WTC.

Assuming you did this carefully you wouldn't even scratch the paint.

Now take an identical piece of concrete and ride the elevator up to the observation deck. This is analogus to the concrete being poured on a top floor. In this case the elevator has imparted POTENTIAL energy to the piece of concrete.

Now walk over to the side of the WTC and drop the concrete onto the car parked below.

It will do a LOT more than scratch the paint.

It will TOTAL the CAR.

Why do you think that something as MASSIVE as the top of the WTC falling onto the fixed LOWER portion WOULD NOT look like an EXPLOSION.

An EXPLOSION is the sudden release of stored energy.

The collapse of the WTC was the sudden release of stored energy.

Simple enough?

Arthur

THOUGHT EXPERIMENT

Imagine a solid block of granite as tall as the World Trade Center.

Now cut off the top 1/3 of that granite block, and embed enough steel columns into the underside of the block to redundantly support the weight of this block.

Gently put the block back on top of the stump, making sure to embed the columns into deep cavities which have been conveniently cut into the stump. Set with concrete.

In terms of our experiment, imagine that a 1 story height of steel columns remains exposed between stump and top block.

Now, heat up a few columns on one side of the composite block. Keep applying heat until you see downward movement in the top block.

Now stand back.

What happens next?

.
Hi all!

One question for the 'Controlled Demolition' CTers:

Why would the 'Controlled Demolition' perpetrators FIRST demolish the tower which was hit SECOND....shouldn't anyone trying to avoid suspicion first demolish the tower that was hit FIRST?

RC.
.

Thanks, Art, that's better than nothing I guess but I don't see a 'collapse' accounting for this kind of explosion

especially considering it happened twice in one day to two buildings that were compromised in different ways. Maybe if it only happened to one building (and even then only if it were much more compromised), then maybe I could believe it. But TWO of them?

Oh, wait... three of them... (I know, I know, WTC 7 was a normal, implosion-style CD, different story)

But thanks, anyway.

Part of the core.

This image seems to show a small part of the core. What happened to the rest.

Why do we see perimiter walls towering over this little stump?

Thanks, Art, that's better than nothing I guess but I don't see a 'collapse' accounting for this kind of explosion



especially considering it happened twice in one day to two buildings that were compromised in different ways. Maybe if it only happened to one building (and even then only if it were much more compromised), then maybe I could believe it. But TWO of them?

Oh, wait... three of them... (I know, I know, WTC 7 was a normal, implosion-style CD, different story)

But thanks, anyway.

Jamies reverse explosion. It goes off on top then the cloud gets bigger as it goes down...

Jamie bomb...

<br>Hi CS. Now, CS, I'm going to use a term which I do NOT want you to apply to CTers, no matter how much 'that way' they may appear to be. OK? Promise?

Now some time back when researching rockets/missiles/ballistics (the latter also including small arms/bullets/projectiles etc), I witnessed some police forensic surgeon's experiments on the effects on 'cadavers' of DUM DUM rounds (bullets with hollow points which 'enter clean' but 'exit messy' because they 'spread' and 'entrain' much pressure-waves and material by the time they exit...which is why the 'head' of the cadaver soon EXPLODES and sprays brain, bone and blood everywhere.

I think that if a little bullet can have THAT 'explosive' an effect, think of what MILLIONS of pounds of hat truss and upper BOX structure and floors can do as it ALL ACCELERATES into the lower parts of the towers. Cheers!

PS: Remember, CS....please do NOT use the legitimate term 'DUM DUM' bullet for your own entertainment at the expense of any innocent CTer! OK? Promise?

RC.
.

This image seems to show a small part of the core. What happened to the rest.

Why do we see perimiter walls towering over this little stump?

<br>Hi Zoktober! Since you're online too, would you like to have a go at answering my question (above)? Cheers!

PS: hereward? reasonwhy? Mel? Rove's? gordon? James? Cosmo? newton? Temp? Foxx? metamars? Andrew?....anyone? from the alleged-CD 'side'?

RC.
.

.
Does any Controlled Demolition theorist have an answer to my earlier question regarding the ORDER of "demolition"...that is, Why did the tower impacted SECOND get allegedly 'demolished' FIRST if they didn't want to arouse suspicion?

RC.
.

.
Does any Controlled Demolition theorist have an answer to my earlier question regarding the ORDER of "demolition"...that is, Why did the tower impacted SECOND get allegedly 'demolished' FIRST if they didn't want to arouse suspicion?

RC.
.

I promise, I'm just afraid they'll think you just threated to shoot them with dum, dum bullets.

HEHE!

In both photos we have one row of interior box columns. The inner wall of the outer tube. This image is taken from inside the core.



The row of box columns here are closely mated on the right side to a featureless gray mass. What could that be?



None of the columns we see had thermite at the base, and ................. why doesn't the top image have the gray mass next to it??

*Crickets*

The answer would be speculative and a giant waste of time.

This image seems to show a small part of the core. What happened to the rest.

Why do we see perimiter walls towering over this little stump?

Why???

Because of a thing called angular momentum.

The south tower's cap was leaning well beyond the plane of the south face.

From the pre-collapse perspective of the watchers; it could rotate, right off.

What would you do, with a compromised, decapitated building; full of demolition devices, still standing, in the middle of lower Manhattan?

How would you explain, a subsequent collapse with out a source of accelerated mass?

They had to compress the time frame, in the algorithm, to avoid that.

There was a lot on the line, including someones insurance money.

Just for the record, I'm addressing the issue in your post, not you.

Until you get back on your meds, it's going to be like that, at least from me.

Cause the mass of the tower fell slightly the other way???

Actually I have no idea.

Chaos theory and all.

I'm curious though, why do you think someone should be able to explain every feature you see?

Arthur

Cause the mass of the tower fell slightly the other way???

Actually I have no idea.

Chaos theory and all.

I'm curious though, why do you think someone should be able to explain every feature you see?

Arthur

<br>Hi Zoktober!

The CTer scenarios say that the controlled demo mob cunningly set/shaped charges to go off so that it would look like a gravity collapse after impact/fire danage was enough.

If that were so, wouldn't the FIRST tower have sustained enough 'cover' damage to allow CD FIRST.....again, so as not to arouse the GUARANTEED suspicion if they first 'blew' the tower that was hit SECOND?

In that case, what was happening to the tops wouldn't BE 'relevant', now would it? I mean, if CD was the cause, it wouldn't have to BE the TOPS collapsing that did the 'deed', but the alleged CHARGES which made them LOCALLY COLLAPSE. You will recall that it was YOU CTers that said the LOCAL collapse couldn't happen, let alone the global collapse.

So according to y'all, it WAS CD, and so it couldn't have depended on which TOP was doing what. See?

RC.
.

One more thing, that loader is dwarfed by what's left of the core. That "Little stump" has got to be about 6 or 7 stories above gound given that the debris is also a few stories above ground.

It all about finding the best explanation for the observed evidence. The CD hypothesis is an explanation which fits these observed phenomena well. (ie. cutting charges were used).

RC proposes that the columns snapped due to leverage on the lowest exposed parts of the columns. That's a different explanation.

If the evidence had been forensically analysed for explosive residue in an open and accountable way we could put this controversy to rest - the evidence would have been in the steel.

If there was a forensic examination of the steel then it was done in secret. Neither NIST nor FEMA were given such a task. It would be their field anyway would it?

You would need demolition experts for that job.

(: hereward

It looks to me as if the load is smack in the middle of the core. There's vertical columns sticking up all around it.

And they all seem to have been very neatly sliced don't they?

I don't think tha we "CT'ers" have said that a partial local collapse was out of the question.

Not at all. This would have been a likely scenario. Once a partial local collapse occured, it would be much harder to stage the global collapse.

(: hereward

RC, this is for you, baby!!!  Long live objective observation!!!