Chemistry/Physics Behind the Attacks

Originally posted by Valhall
The problem is, Howard, that this...

(see image above, H.R.

isn't pulling anything inward. Just prior to complete failure, the northwest portion of the building is in tension, which makes it very difficult to naturally make it collapse.

The east side of the building was buckling inward as is apparent from this photo (and despite bsbray’s continued denial of the obvious).



Now let’s think about this for a second. If the east face was buckling inward, those columns were no longer supporting their loads.

The south face was extensively damaged by the impact, so its ability to support its loads was reduced.

If, as you say, the loads on columns on the northwest portion of the building were in tension (or reduced) then where did all those loads go?

Keep in mind that the exterior columns were tied to the interior columns at the hat truss at the top of the building. Thus those loads were being redistributed to the interior core columns.


Now we don’t know the extent of the damage to the interior core caused by the impacts, but anyone who denies that there was any damage at all is being extremely disingenuous.

In addition, under the above scenario, there would be rotational forces put on the core columns as well. Since the core of the building was not built to resist lateral forces, there would be little resistance in the core structure to racking movement of the columns.

Originally posted by Valhall
Now, I can see the northwest portion of the building failing in tension, which would result in partial collapse of floors below the failure point (but on the southeast side of the building due to the center of gravity of the top portion now displaced through an offset vector) and the top going on over, but I'm not intuitively seeing this type of displacement causing the type of total collapse that ensued. That doesn't mean I'm not missing something, that's just to say it is extremely counter-intuitive. In fact, it's painfully counter-intuitive.

Once again, remember that all of the structural elements, the exterior walls and the core, were tied together at the top via the hat truss.

Thus once the exterior walls reached a point of complete failure due to buckling, then the loads would have to be carried by the core, which given the damage sustained by the impact, it would not have been able to support.

Originally posted by billybob
when you have weight pushing down on something, ANYTHING, it effectively increases the mass of that object. the columns which were intact would be harder to move sideways because of the added mass.

Wrong.

The columns were pinned above and below the damage zone. The stiffness of a column is based on Young’s modulus. For steel, this stiffness factor is not affected by the strain on the column. In other words, the load has no effect on the stiffness.

Originally posted by billybob
when they begin to reach the CRITICAL point, elasticity becomes RELAVENT. until that moment in time, the perimeter columns have effectively increased their mass, and are harder to push sideways, as their strength is mostly uncompromised

You have no idea what you are talking about.

In any case, you have missed my point entirely and that is that as the internal floors failed, the effective length of the columns increased. This drastically lowered the critical buckling load of the columns. In other words, the existing weight of the building was enough to cause the columns to buckle.

Originally posted by billybob
as testified by the LACK OF MOLTEN ALUMINUM RUNNING DOWN THE SIDES.

like this?



In any case, the temperature of the exterior columns is irrelevant. They buckled because they were no longer receiving lateral support from the floors.

Originally posted by billybob
NIST would have us believe that the critical point was reached simultaneously across the whole perimeter and core for BOTH towers.

Not quite instantaneous, but fast enough that it look to be instantaneous. That is the definition of a runaway failure.

Originally posted by billybob
BS say all of us. it was BOMBS, as evidenced by the SOUND OF BOMBS(911eyewitness video),

Not proven

and the upward ejections of debris,

immaterial

and the ultrafine dust

Immaterial

and vapourised metal, and molten steel 'running' for weeks in the rubble pile.

The result of prolonged heating iin the subgrade fires.

not to mention the UNPRECEDENTED media COMPLETELY IGNORING tower seven,

Proves what? That you are paranoid?

There is no proof that the columns were bowing at all. It could very well be refracted light from the heat.

NIST fails to consider an alternative explanation for the bowed appearance of columns in its selected photographs of the Twin Towers: light refraction caused by the layer of hot air adjacent to the Towers. Such atmospheric conditions would refract light in a way that is consistent with apparent distortion of the columns seen in the photographs.

molten aluminum is silver, howard. thanks for the picture of the thermite reaction turning steel instantly into the molten state.

HA!

I'm glad you posted that image howard.

That is clearly NOT molten aluminum.

IN FACT.........it is evidence of a thermite reaction perhaps accidentally set off early from the impact of the plane.

Here is a video of that exact same picture with a closeup for you to observe......

rare footage of tower


Clearly that is NOT the aluminum panels melting since it is continuous and from one spot.

But it sure looks suspiciously a lot like
THIS!

It is probably aluminum from the aircraft.

The reason that it is flowing from one spot is that the floor in that corner has started to drop.

BTW, has anyone ever considered what happened to all of the oxygen generators that were on the planes?


BTW, a thermite reaction is quite white. That is not.


[edit on 20-2-2006 by HowardRoark]

Originally posted by HowardRoark
It is probably aluminum from the aircraft.

Oh ok. So then I guess we have established that the temperatures were NOT hot enough to melt the aluminum panels and therefore the "buckling" of the columns that NIST cites is likely heat refraction.

Regardless though.....that is NOT aluminum in that video. We already went over this. Aluminum melts at too low of a temperature to be that color. In fact it looks like this:

BTW, has anyone ever considered what happened to all of the oxygen generators that were on the planes?

Military drones don't have oxygen generators.

BTW, a thermite reaction is quite white. That is not.

Watch the thermite reaction video I posted. It looks EXACTLY like that what we see in the wtc video.

I can see quite a bit of orange and yellow in this thermite reaction too.


[edit on 20-2-2006 by Jack Tripper]

While aluminum can be molten without it glowing red, that does not mean that it doesnt glow red when it's hot enough.

www.metaullics.com...







Good try though.

white, eh?

as howard would have us believe that all molten metal is glowing, so would he have us believe that there is only one type of thermite reaction. maybe you should have your wisdom MOLAR checked, howard.

leftbehind, that aluminum has nowhere to go to escape the heat. as SOON as it gets hot enough to run, it runs. there is NO silver aluminum running in any picture i've ever seen of the towers. do you have one?

[edit on 20-2-2006 by billybob]

Originally posted by Jack Tripper

Originally posted by HowardRoark
It is probably aluminum from the aircraft.

Oh ok. So then I guess we have established that the temperatures were NOT hot enough to melt the aluminum panels and therefore the "buckling" of the columns that NIST cites is likely heat refraction.

No we have NOT established that. Nice try though.

Heat refraction? Sheesh, your understanding of light and optics is positively prehistoric.

Not only do you completely fail to acknowledge the effect of compressed perspectives in the taxi thread, but now your claim that the buckling of the exterior columns is due to heat refraction is so totally wrong that it is ludicrous.

Dude, people are laughing at you.

Originally posted by Jack Tripper

Originally posted by HowardRoark
BTW, has anyone ever considered what happened to all of the oxygen generators that were on the planes?

Military drones don't have oxygen generators.

Is that your latest theory? That it was a military drone?

Let’s have a show of hands (or posts) from those out there that agree with this.


Anyone?

exactly billybob. once it melted it would have to run.

Plus the aluminum in that picture is CHERRY.


It is clearly not orange.


See color/temperature chart on previous page.

While the actual thermite reaction is inititally white it's by-product is molten iron which is more orangish and what we can see in the wtc video.


Besides.....you guys are ingoring the fact that the aluminum panels were clearly NOT melting!

How could that possibly be if the fires were hot enough to melt structural steel!!?

Originally posted by HowardRoark

Heat refraction? Sheesh, your understanding of light and optics is positively prehistoric.

Pssh. You can't prove it either way. It is a plausible explanation and I did not make it up.

A key part in NIST's theory of the collapse initiation is that the perimeter columns on one of the faces of each Tower bowed inward, pulled by sagging trusses. The Report contends that the columns on the south face of the North Tower bowed inward in the moments before its collapse and that the columns on the east face of the South Tower bowed inward some time before its collapse. As evidence for the supposed bowed columns NIST cites photographs. The Report includes one annotated photograph allegedly showing bowing in the North Tower, but no such photographs of allegedly bowing of columns in the South Tower. There are two photographs of alleged South Tower column bowing in an earlier slide presentation.

NIST fails to consider an alternative explanation for the bowed appearance of columns in its selected photographs of the Twin Towers: light refraction caused by the layer of hot air adjacent to the Towers. Such atmospheric conditions would refract light in a way that is consistent with apparent distortion of the columns seen in the photographs

source

Dude, people are laughing at you.

Dude, YOU and your bloated out pseudoskepticism are not "people". But it's apparent to me that more "people" in this thread have been laughing at you.

Is that your latest theory? That it was a military drone?

MY theory? Where the heck have you been? It is widely believed within the movement that all 3 planes were unmanned/retrofitted with ATG missles and flown to their targets by remote control with military precision. Why do you think the Northwoods document is so significant? They talked about swapping out a commercial airliner with a military drone painted like one to fake it's destruction by Cuba as a pretext for war. And this was way back in 1964! Why would you think it's so absurd? You obviously haven't been paying attention.

And you are ignoring the fact that no one has claimed that he collapse was the result of molten steel. In fact, as I have shown in this post, it wasn’t necessary for the exterior columns to heat up at all.

All that was necessary was for the fireproofing to have been knocked off the steel trusses by the force of the impact. Actually that isn’t even all that necessary, based on the pictures of the trusses that were taken in the 90’s. Those pictures show that the fireproofing was woefully inadequate. Now I don’t know what specific floor those pictures were taken on, it really doesn’t matter. Given the obvious friability of the material and the known issues with adhesion, it is clear that the quality of the fireproofing in the towers was sub-par as a whole.

Without fireproofing to protected it, the thin steel chords and diagonals of the trusses would have quickly heated up to the point of failure.

Without the floors to provide lateral stiffness, the external walls would have buckled.

Jack, interesting info on heat affecting the appearance of the columns.

Originally posted by HowardRoark
The east side of the building was buckling inward as is apparent from this photo (and despite bsbray’s continued denial of the obvious).

So what do you have to back that up?

POSTING PICTURES OF BENT ALUMINUM COVERINGS DOES NOT = STEEL SUPPORT COLUMNS WERE BOWING INWARDS.

Remember, the aluminum facades could go OUTWARDS -- and DID!

Also realize that aluminum MELTS above 600 degrees Celsius. When it's approaching that temperature, it won't stand firm!





The whole NIST case rests on little pictures like this, which, as you can see above, are greatly exaggerated by the way they're presented.

If I were a credible scientist, or even pretending to be, I would not in a million years baselessly assert that the above must indicate that the steel support columns were bowing inwards. That would be among the LAST things I would consider, after all the other numbers of things that could have affected those thin little covers of aluminum over the columns, exposed to heat and the jet impact. The steel columns would be the last things to go.

When we see images of the actual steel columns bending inwards, then we can believe that there were truss problems, which would have led to a local collapse at best (and even then, only after a signifcant portion of perimeter column failures).

Originally posted by HowardRoark
Not only do you completely fail to acknowledge the effect of compressed perspectives in the taxi thread, but now your claim that the buckling of the exterior columns is due to heat refraction is so totally wrong that it is ludicrous.

Dude, people are laughing at you.

Well maybe now you two finally have something in common. But I wasn't laughing at him.

All that was necessary was for the fireproofing to have been knocked off the steel trusses by the force of the impact.

And sufficient fires. There's no evidence to suggest those existed.

Though, you have had a good run trying to make it sound like flashovers can be sustained for long periods of time, and ignoring the fact that the WTC fires roamed and did not stay in any one place the whole time.



[edit on 20-2-2006 by bsbray11]

If the temperatures reached was hot enough to compromise the integrity of the steel at all then it would be hot enough to melt aluminum which has a much lower melting point obviously.

Originally posted by Jack Tripper

Originally posted by HowardRoark

Heat refraction? Sheesh, your understanding of light and optics is positively prehistoric.

Pssh. You can't prove it either way. It is a plausible explanation and I did not make it up.

Heat refraction in air is also known as a mirage.

When light waves pass over hot surfaces the heat gradient gradually alters the air's index of refraction, causing the light wavefronts to bend away from the the hot surface. When those refracted rays strike our eyes, we "dot them back" to form a virtual image. The image appears as a reflection of the object, giving the impression of a wet surface.

Now if you are claiming that the refraction is like a giant convex lens, then your theory that the buckling is really a heat refraction requires that there be a perfectly shaped bubble of hot air over the damage zone of the building. The hot air would have to be a consistent temperature throughout and furthermore, the hot air would not be allowed to rise at all, since it is apparent from the photos that the columns lines bend back into line above the damage zone.

Sorry, “heat refraction” doesn’t cut it.




[edit on 20-2-2006 by HowardRoark]

It was merely a possible explanation to be considered but none of the stuff you claim about "perfect temperature bubbles" is mentioned in your source.

Sounds like more bloated out Howardesqe pontification if you ask me.

POSTING PICTURES OF BENT ALUMINUM COVERINGS DOES NOT = STEEL SUPPORT COLUMNS WERE BOWING INWARDS.

The NIST report is CLEARLY what doesn't cut it.

Okay, I ran the numbers (rudimentary 2D analysis, I will do a 3D analysis later on) on the moment effect of the southeast corner's degradation as captured in this photo.

The angle (in 2D) is 21 degrees. As shown here...



I have assumed the failure floor at the 83rd.
I have assumed the mass distribution for WTC2 as 2/3 for the bottom half and 1/3 for the top half. I think this is both reasonable and conservative (for my calculations).
I have used two figures for the total mass for WTC2 (300,000,000 kg and 500,000,000 kg) because Lyte Trizzle a.k.a. whoever they are now has a problem with the 500,000,000 kg figure.

12 ft/floor (3.66 m/floor)
324 ft from 83rd floor to top (98.76 m)
length of tower side 207 ft (63.09 m)
length of diagonal 292.74 ft (89.23 m)
c.g. offset from center of tower and along diagonal for 21 degree tilt 116.11 ft (35.39 m)
vertical drop of c.g. 6.56 m (approximately 2 floors)
minimum moment due to offset of c.g. 1,737,361,370 kg-m
maximum moment due to offset of c.g. 2,895,602,283 kg-m
min tensile load on northwest corner to create equilibrium 38,942,142 kg
max tensile load on northwest corner to creat equilibrium 64,903,572 kg

This constitutes a 40% "unloading" of the compressive stress that had been acting on the northwest side of the building prior to the southeast corner giving. So in order for the top portion of the building to "right" itself, it not only has to catch up on a 2 floor collapse, it has to do so under a 40% less compressive load than before the s.e. corner collapsed.

That's the part that's not connecting with me.

Originally posted by Valhall


This constitutes a 40% "unloading" of the compressive stress that had been acting on the northwest side of the building prior to the southeast corner giving. So in order for the top portion of the building to "right" itself, it not only has to catch up on a 2 floor collapse, it has to do so under a 40% less compressive load than before the s.e. corner collapsed.

That's the part that's not connecting with me.

Question on this Valhall,

If the "core" gave way would the "unloading" happen? Would the moment or pivot then become the SE corner? adding compression rather than removing it.