The great thermate debate

[Gevurah]

(11-13-2010 11:53 PM)JFK Wrote:  And some say that you can not use therm*te as an explosive.

More like an area effect incendiary. Thermite has to be packed and contained for it to burn evenly and cut or weld. If it is not, the air in between the particles heats up and expands as the reaction proceeds, and scatters the burning particles everywhere. The blast is more of an airburst of superheated air (which is bad enough).

Nasty stuff, but fun.

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(11-15-2010 04:58 PM)JazzRoc Wrote:  It's YOUR point which fails because THERMITE product at 2,500 deg C DESTROYS "heat shields" no matter how much air they contain.

It should be noted that the Space Shuttle's heat shields reach between 1600 and 1700 degrees Centigrade upon re-entry, far lower than the temperature of a thermite reaction. There are some materials which will retain stability at those temperatures (like some aerospace-grade carbon-carbon composites, a few exotic aluminum alloys, and a few ceramics) but they are expensive - too expensive to build entire buildings out of at this time. Thus, I think there is merit to your statement.

Quote:Had it been thermite product, I REPEAT, it would have gone STRAIGHT DOWN. The very fact that ANYTHING contained it PROVED the molten metal wasn't thermite-produced iron. Had it been, it would have been WHITE HOT - NOT YELLOW.

Materials, when molten, emit light of characteristic wavelengths in the visible spectrum. Has anyone tried comparing the colors of the molten metal seen in footage with known tables of emission spectra? I do not recall seeing anyone's results if this has been done, though this seems like an obvious analytic technique. Granted, cameras act by sampling light, so there would be a degree of error...

[JazzRoc]

(02-18-2011 05:50 PM)rsol Wrote:  all a heat sink requires is a place to collect heat and a place to dissapate it. that was also fulfilled. most furnaces are generally contained within its insulators without a mesh of metal heatpiping out. dont forget all that metal is interconnected to other metal. large big lumps of it.

Steel isn't a "heatpipe" for heat. Its thermal conductivity and thermal mass are relatively low. With an inch or so of insulating foam the architects expected the steel to withstand the effects of fire without softening for long enough to evacuate the building.

This, of course, HAPPENED - except where the kerosine/air explosion had stripped that foam away. And THAT was where the steel failed.

The towers were NOT "blocks of steel". Their construction was possibly the lightest possible "mesh" of foam-coated steel hollow columns, with floors of 4" aerated concrete over steel tube trusses.

In THIS picture you can really see this.



The ONLY progress this debate makes is in engineering understanding - yours.

That fact, and the immensity of scale of this particular topic, are the only parts of it that keep me interested.

[rsol]

"With an inch or so of insulating foam the architects expected the steel to withstand the effects of fire without softening for long enough to evacuate the building."

They expected it to hold. not just hold on long enough. you assume their design ethic but its not the case. "confident of multiple impacts" was the phrase.

"The towers were NOT "blocks of steel". Their construction was possibly the lightest possible "mesh" of foam-coated steel hollow columns, with floors of 4" aerated concrete over steel tube trusses."

its actually a mesh made of blocks of steel. and interconnections dont just melt/soften when they encounter heat if they have cold steel to disapate to. you cant argue away from that.c yes the trusses were light. thats because they were just holding up whatever was on that floor. they didnt have significant weight compared to the central columns. once again you are abstracting from a small detail and throwing it over the entire scene.

[Doc Quack]

"the great thermate bait"

[Alisha]

Lightweight concrete can be helpful through a thorough use of aluminium alloy and a mix of metal that hardens it a bit. that could be really helpful in gaining the strength and desired weight.

[JazzRoc]

(03-15-2011 07:55 PM)Alisha Wrote:  Lightweight concrete can be helpful through a thorough use of aluminium alloy and a mix of metal that hardens it a bit. that could be really helpful in gaining the strength and desired weight.

Lightweight concrete "helpful"? How?

"Aluminum alloy" is the main constituent of the 767, and seen pouring out of the building - due to its low melt point temperature of around 600+ C.

Aluminum alloys have a DIFFERENT COEFFICIENT OF EXPANSION from concrete. Heating or freezing such a mixture of materials would shatter it.

Aluminum is also REACTIVE to concrete and moisture together, going into solution as an ALUMINATE compound.

Apart from those points....

[JazzRoc]

(02-25-2011 11:50 AM)rsol Wrote:  its actually a mesh made of blocks of steel

There are NO "blocks of steel" anywhere in the structure. You've seen the picture. What are you trying to "unthink"?

Quote:Interconnections don't just melt/soften when they encounter heat if they have cold steel to dissipate to. You can't argue away from that.

Watch me.
They weren't just flash-heated. They were soaked in heat in what was effectively a muffle furnace: the combustion products (fire) warmed the whole of the local environment up until the interior was orange. That's around 1100 deg C.

Quote:Yes the trusses were light. That's because they were just holding up whatever was on that floor. They didn't have significant weight compared to the central columns.

The significant factor wasn't the weight but the location. When the floors got above about 700 deg C their concrete began to explode its water of crystallization. Without the compressive bracing of the concrete the supporting steel sheet pans began to sag into a catenary shape. The leverage of this change in angle to the fixings BROKE THEM.

The floors tied back and restrained the vertical columns from buckling. Once they were gone there was less restraint. Use your eyes.

Quote:Once again you are abstracting from a small detail and throwing it over the entire scene.

NO. Once again you are taking me on from a weak position.

Don't stop. I enjoy such exchanges.

[JazzRoc]

(05-25-2011 08:41 AM)vivian Wrote:  Perhaps you are drawing away from the more salient point that thermite iron at 2,500 deg C will NOT be contained by lightweight concrete.

Not intentionally.
Everyone else may be, but they're the ones trying to believe the impossible. As long as their dissonance is held at arm's length it appears endurable.
Such dissonance isn't possible to endure from a science-based point of view, and the conclusion MUST be drawn that the liquid metal seen flowing out of the tower could NEVER be thermite iron.

The thermite evidence is left with no visual proof.
The forensic traces of iron microspherules could easily have been produced from the energy produced by dropping half a million tons of steelwork through a tenth of a mile, an energy which could have melted 5,200 tons of iron. The forensic traces of sulfur compounds could have been produced the same way from the gypsum wall-boarding in the tower. And NO traces of Al3O4 - alumina dust, the OTHER thermite reaction by-product - were ever discovered.

No visual and no forensic... Just like a spaghetti monster, isn't it?

[Amerikagulag]

Wow, what started out as a good thread turned into a pissing contest.
Well, we can all agree on one thing though......it WASN'T ARABS!
At least I hope we can agree on that.

[JFK]

(06-02-2011 05:04 AM)Amerikagulag Wrote:  Wow, what started out as a good thread turned into a pissing contest.

Yep... That is one reason why I now post here so infrequently.

Unfortunately Jazzroc ( and others ) have that effect on threads.

[Amerikagulag]

"...Unfortunately Jazzroc ( and others ) have that effect on threads...."


Well thanks for the heads -up dude. I'll definitely keep it in mind. This is a great site with plenty of 'stuff'. I'm new here and don't know my way around too well yet.

Definitely keep my eyes open.

Thanks again

[rsol]

when did the exterior walls hold this building up? have the central columns disappeared again?

[JFK]

(06-04-2011 11:59 AM)rsol Wrote:  when did the exterior walls hold this building up? have the central columns disappeared again?

Don't quote me, but I do remember reading that the ratio was something like 60/40 in relation to the core/exterior columns supporting the weight of the towers...

I'll have to go through my archives at home to find the actual cite.

[JazzRoc]

(06-04-2011 04:35 PM)JFK Wrote:  

(06-04-2011 11:59 AM)rsol Wrote:  when did the exterior walls hold this building up? have the central columns disappeared again?

Don't quote me, but I do remember reading that the ratio was something like 60/40 in relation to the core/exterior columns supporting the weight of the towers... I'll have to go through my archives at home to find the actual cite.

It's around 60/40 (from memory).
Once the tower side had dropped a foot or two, of course, ALL bets were off, and POINT LOADS TOOK PLACE, one after the next, in a sequence of destruction. This is completely out of engineering calculation range. Engineers use the phrase "uniformly-distributed load" in their calculations for a reason.
Some of the internal columns within the heat-soak area of the fire above the impact area, according to NIST, were relieved of their loads by being allowed to CREEP as their temperature rose above 400 deg C. This would have INCREASED the loading on the external columns.
It's in the report.

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(06-02-2011 05:04 AM)Amerikagulag Wrote:  Wow, what started out as a good thread turned into a pissing contest.

It STARTED as such a contest, with pseudo-engineering as the piss.

Quote:Well, we can all agree on one thing though......it WASN'T ARABS!
At least I hope we can agree on that.

I don't believe we can.

If you cannot prove that the towers didn't fall naturally then your dislike of the Bush cabal is all you can cling to. For what it's worth, I'm with you on that.
I left my country (UK) because I wanted nothing to do with its coat-tail clinging, and wished to feel clean of its filthy politics.

[Negentropic]

The last word on 'nanothermite':
http://www.veteranstoday.com/2011/08/27/...st-acquit/


Nanothermite: If It Doesn’t Fit, You Must Acquit!
T. Mark Hightower (with Jim Fetzer)

http://www.veteranstoday.com/2011/08/27/...st-acquit/