Chemistry/Physics Behind the Attacks

Actually, no it's not - not to me at least. But what I have always been open to is the possibility that 9/11 was ALLOWED to happen. Because I don't believe there is enough evidence to rule that out. And I personally believe that the information gaps and the anomalies in the official record (which include the mishandling of evidence, the misinterpretation of evidence, the disappearance of evidence and the changing of evidence) beg the logical mind to NOT dismiss that possibility.

So...I guess it's a matter of hysteresis in how we view the same set of data.

Even if explosives were proven, the Bin Laden family owns the largest Islamic construction firm in the world.
Osama himself is highly qualified in construction and god knows how far his connections go. Don't ever think they are 'simple cave dwellers' as put forward by the likes of letsroll911, which is in fact a highly racist and inaccurate view. They are just as capable and willing as anyone else and have huge amounts of resources in assets and money.
Their plot may have been more complex then we are allowed to believe, maybe there were explosives and they planted them. You could understand why the Government would not want people to know, the fact the planes got hijacked and flown in was a big enough cockup, let alone if there had been a long term infiltration of the buildings themselves.

And that's just Bin Laden, let alone any other foreign organisations.

Fine, in case Al-cia-duh had actually somehow managed to rig the buildings themselves, then why not investigate fully and come to this conclusion? Wouldn't it be even more scary if "the terrists" were not only able to hijack planes with box-cutters or plastic knifes and proceed to fly them across half the US unhindered for hours, but also set up controlled demolitions with just public access to those buildings?

Honestly, if you want to suggest that visitors to a building could set this up, then my suggestion would be to re-enter the sphere of rationality.

[edit on 4-3-2006 by Lumos]

Typical, Lumos. Typical bizarroid behavior and attitude of an obsessed theorist.

Fine, let's draw the line here...

____________________________________

If you don't agree with Lumos's theory - you're an idiot or not in touch with reality.

Cool! We've got the delineation. Like it did one stinking bit of good toward finding the facts. for being consistently close-minded.

Originally posted by Lumos
Fine, in case Al-cia-duh had actually somehow managed to rig the buildings themselves, then why not investigate fully and come to this conclusion? Wouldn't it be even more scary if "the terrists" were not only able to hijack planes with box-cutters or plastic knifes and proceed to fly them across half the US unhindered for hours, but also set up controlled demolitions with just public access to those buildings?

From a military/defense point of view admitting weakness if one of the dumbest things you can do. Not only that, all the information we get from the media/Internet is also available to our enemies just as easily. Did that cross your mind? Probably not, as it doesn't seem to cross many people's minds at all, all they think about is me, me, me, me, me and have some sort of delusion that they are the centre of the universe and that setting their mind at rest is the most important thing in the world....
I can see the Government now, "Oh lets divulge all our secrets so poor little Lumos doesn't feel left out". Pathetic
The whole point of Government is elected bodies who can be trusted to run everything, unfortunately it's not that simple in practise - so do something about it by getting involved, voting, etc. Don't expect human civilisation to go back in time or everyone to spill the beans to satisfy your curiosity.
Saying all of that though, one would hope that by now tighter measures would be in place and no security would be jeopordised by giving all the details, but who knows? A cover-up does not always automatically mean the worst possible scenario, the fact that is wishful thinking to you is tragically sad. There are varying degrees of 'bad', a cover up for financial reasons, or some sort of national pride, military, etc are all negative reasons but not as terrible as what you hope for.

They also didn't fly them for hours and hours like you seem to be trying to imply, nor do I imagine you have any experience in flying or any knowledge no matter how vague of air traffic control procedures. Why do you think there are so many near misses every day? Do you think it's all controlled by computer? Do you have any friends who are air traffic controllers to speak to about it?

Honestly, if you want to suggest that visitors to a building could set this up, then my suggestion would be to re-enter the sphere of rationality.
[edit on 4-3-2006 by Lumos]

Do you think? Or are you like Mr Bush?

Originally posted by Lumos
were not only able to hijack planes with box-cutters or plastic knifes and proceed to fly them across half the US unhindered for hours

There are plenty of weapons available designed for the purpose of evading detection by metal detectors.

For instance:

Why a non-metallic knife? A GPR Knife in a stitched Kydex tm sheath is lightweight and can be carried very comfortably. In a neck sheath, it can be tucked away under uniform shirt or jacket and forgotten until needed. Granger Knives' GPR Knives are now
carried by some Federal Agents for use in covert operations where a steel knife would be exposed by a metal detector. GPR Knives appeal to undercover police officers for the same reason. The GPR Knife is intended for use as a secondary or covert means of self defense. It is not intended to be a utility knife. They excel at cutting seat belts and the enemies of society and America. The GPR Knife possesses strength and edge-holding abilities far beyond "plastic knives" like zytel tm or G-10.

www.grangerknives.com...

And stanley knives/box cutters are pretty nasty too:

I teach Technical Theatre and Set Construction. I always tell my
students that the Stanley Knife is the most dangerous tool in the
shop. The danger of the tool is inversely porportonial to the
amount of noise it makes. I have seen a few horrific injuries with
a table saw or a radial arm, but I have seen more injuries with a
stanley knife than any other tool.

Count me among the injuries. Once, in my late teens I was cutting open
boxes and accidently cut open my hand and wrist... about 15 stitches.
Hit a vein just right and blood exploded out of my arm. Almost
completely severed a tendon. I was actually pretty lucky. That wrist
is still a little more fragile than the other. Yeah, those things will
hurt you ;-)

Joe Barta
www.diyprojects.info...

The main thing is the element of surprise, no-one would have expected what was gong to happen no matter how well trained you are. When someone starts slashing throats a piece of glass will do, a stanley knife cuts through flesh and makes one bleed exceptionally well. Have you ever seen it?

The hijacker's were in first class so they only had a few people to contend with, the door that protects the pilots also works well locking hijackers in and passengers/flight crew out.
Once you kill one person the rest usually become pretty docile, so then it's just a matter of control or elimination. People are unlikely to come up from economy to see what the disturbance is because it's not human nature as people want it to be someone elses's problem, besides the doorway would make it easy to pick people off as they come through. People are funny too in that one could say if they rushed it they would get some through, problem is not many people want to volunteer being in the front

People can become exceptionally good at tasks when the adrenaline is going, especially with nothing to lose. Look at car thieves who suddenly become amazing drivers.
With flying, I remember my first lesson where the Instructor did nothing and I had to do it all. My usual one was away and I would always chicken out and be a bit bumpy with the landings and such, but the girl I had just sat there and said I had to do it all. With the adrenaline going from not wanting to crash for an hour and doing touch and gos, I suddenly became an ace pilot managing constant take-offs, flying and landings the whole lesson unaided. Usually I was lucky if I could taxi in a straight line before then. I improved after that, but that's irrelevant.

[edit on 4-3-2006 by AgentSmith]

Greetings Fellow Believers,

Bringing down a building isn't hard if you know the harmonics of the structure you want to bring down.

In "Tesla: Man Out of Time," by Margaret Cheney, Tesla created a device that, when placed on the steel girders of a building, would create a harmonic frequency that would cause a building to shake and eventually be brought down in pieces. This device was roughly palm sized and had a wind-up key on it.

Now tell me...how complicated would it be to place this type of device on either or both towers?

Originally posted by Valhall
If you don't agree with Lumos's theory - you're an idiot or not in touch with reality.

Fancy slander, Miss moderator?

All I said was that the scenario of AQ rigging the building with only the access a visitor would have is outside the sphere of rationality. Quite a difference to what you said, isn't it?

I suggest you help yourself to a warn.


And besides: What's with your pledge that you would investigate the strange time-lapse a few weeks ago involving me and Agent Smith? No, you don't have to answer this time either - I think I have a fairly accurate understanding already.

[edit on 4-3-2006 by Lumos]

I couldn't find anything out. So I had nothing to report. All I could do was ask the question...I couldn't make the answer up.

Originally posted by Lumos
All I said was that the scenario of AQ rigging the building with only the access a visitor would have is outside the sphere of rationality. Quite a difference to what you said, isn't it?

Like I said, how do you know what levels they had infiltrated? No matter who put in any explosives, if that was done, they would have to pose as normal building contractors. Al-Qaeda members may have been working there for years.

And besides: What's with your pledge that you would investigate the strange time-lapse a few weeks ago involving me and Agent Smith? No, you don't have to answer this time either - I think I have a fairly accurate understanding already.

wtf are you on about?

[edit on 4-3-2006 by AgentSmith]

Originally posted by craig732

Originally posted by Griff
i2.tinypic.com...
my drawing will be on the left and the NIST drawing is on the right.

Four of the core columns on your drawing are in different spots than the ones in the NIST drawing. Which one is correct?

[edit on 4-3-2006 by craig732]

Would it be possible to take a break from the arguing and name calling so that Griff could answer my question? Thanks.

Originally posted by Valhall
What if some one actually was able to get to the data from NIST; model the buildings; and show they couldn't have collapsed the way they did without explosive help? At that point, that's where you're at - there had to be explosive help. You can't just jump from there to

AND BUSH DID IT!

right? This is the type of illogical and flawed non-thinking that tends to turn people away from theories. You just can't make illogical jumps like that. You have to keep plodding forward and looking for the evidence, the facts.

well, i would say that bush saying he saw the first plane hit the tower on television a smoking gun argument against his ignorance(or conversely, FOR his GENERAL ignorance. 'if i only had a brain' is his theme song).

and, then, while holding the happy goat upside down, and learning of the second plane hitting the tower, he continues to stare into space like a deer in the headlights.

the secret super heavy duty most nasty bodyguards and intelligence network in the known world let him sit there, instead of whisking him to safety.

i liked watching michael moore's F911 just to see bush sitting in that classroom. he looks like he's on a bad hit of prozac.

Originally posted by Jack of Scythes
Greetings Fellow Believers,

Bringing down a building isn't hard if you know the harmonics of the structure you want to bring down.

In "Tesla: Man Out of Time," by Margaret Cheney, Tesla created a device that, when placed on the steel girders of a building, would create a harmonic frequency that would cause a building to shake and eventually be brought down in pieces. This device was roughly palm sized and had a wind-up key on it.

Now tell me...how complicated would it be to place this type of device on either or both towers?

resonance is perhaps the most powerful thing in the universe, imho. i have thought of this, too. in fact, when watching the rapid decent of the 'spire', which was some 40 to 60 stories high a piece of the core that remained standing briefly after the second tower collapsed, it appears to turn into dust and blow away.

it's behaviour is also bizaare, because there is no crushing weight falling on it to knock it down, and it begins tipping to one side, and then suddenly falling straight down, at near freefall acceleration. once again, there was a loss of angular momentum.
i think the really weird part is the dust that hangs in the air in place of the steel. it really looks like it just evaporated as it was falling. could be a too poor frame rate, i guess, but in light of the overall collapse, i don't doubt that multiple types of devices were used, and unknown top secret weapons are certainly a REAL possibility.

Hi folks. My first post here.
I’ve been reading the discussions on these boards for some six weeks, but have till now found myself with little actual substance to contribute to the discussion at hand. As an outsider to conspiracy theories I at the moment prefer just observing what others have to say on the topics at hand and do my own educational research in the meantime, hoping that some time in the future I might have some of my own constructed opinions to present here.

End digression.

Returning to the topic at hand: I remember some five weeks ago, when I was reading up on the 9/11 events stumbling upon (yes, I believe that is the word to use) a lil’ article written by Zdenek P. Bazant and Yong Zhou titled: «Why Did the World Trade Center Collapse?—Simple Analysis». In this article (written just two days after the attacks) the authors set out with no more information then you guys have now (and sadly, no less either) to offer a simple, intuitive and yet scientifically backed explanation of the nature of collapse of the aforementioned high-rise buildings. I don’t know how many of you have read it (haven’t done any search on the forum, sorry) but I found it very illuminating at the time, indeed. The only other comparable “scientific” approach I have had the privilege of reading was the oftenly cited (on these boards) BYU professor’s one. Those who have read the both are undoubtedly aware that they tell different stories entirely. My personal preference is not of importance here, but for the record let it be stated that I lean more towards the former rather than the latter. Where am I going with all this, you may be wondering? A certain distinguished member by the moniker Vallhal has initiated an effort to elucidate the reasons why the South Tower has collapsed in the way it had (apparently, many people find the collapse unintuitive). I think someone here asked why didn’t the upper part of the tower fall to the side like a tree, pivoting about the center of the critical floor? (I'm not certain of his nick, so it’s best if I don’t mention it at all – but it doesn’t matter anyway) In this article I mentioned, there is a very convincing attempt to do just that which you people have set out to do (albeit in pure theory only). I’ll post just the relevant paragraph and provide the link to the rest of the article (I first read the article from 911research I think, with some really funny (by the virtue of a complete lack of understanding) comments embedded with the text in a miserable attempt to refute the articles claims. Since those comments may prove distracting or annoying to some people I link the unedited pdf version instead)

Article link: www-math.mit.edu...
(relevant section can be found under Appendix II. Why Didn’t the Upper Part Pivot About Its Base)

Could the combined plastic shear resistance Fp of the columns of one floor (Fig. 3f) sustain this horizontal reaction? For plastic shear, there would be yield hinges on top and bottom of each resisting column; Fig. 3e (again, aiming only at an optimistic upper bound on resistance, we neglect fracture). The moment equilibrium condition for the column as a free body shows that each column can at most sustain the shear force F1 = 2Mp/h1 where h1 2:5 m = effective height of column, and Mp 0:3 MN m = estimated yield bending moment of one column, if cold. Assuming that the resisting columns are only those at the sides of the framed tube normal to the axis of rotation, which number about 130, we get Fp 130F1 31 MN. So, the maximum horizontal reaction to pivoting would cause the overload ratio

Fmax/Fp~10

if the resisting columns were cold. Since they are hot, the horizontal reaction to pivoting would exceed the shear capacity of the heated floor still much more (and far more if fracture were considered).
Since F is proportional to sin 2θ, its value becomes equal to the plastic limit when sin 2θ = 1/10.3. From this we further conclude that the reaction at the base of the upper part of South Tower must have begun shearing the columns plastically already at the inclination

Angle~2,8°

The pivoting of the upper part must have started by an asymmetric failure of the columns on one side of building, but already at this very small angle the dynamic horizontal reaction at the base of the upper part must have reduced the vertical load capacity of the remaining columns of the critical floor (even if those were not heated). That must have started the downward motion of the top part of the South Tower, and afterwards its motion must have become predominantly vertical. Hence, a vertical impact of the upper part onto the lower part must have been the dominant mechanism.
Finally note that the horizontal reaction Fmax is proportional to the weight of the pivoting part. Therefore, if a pivoting motion about the center of some lower floor were considered, Fmax would be still larger.

The reason why the upper part had it's rotation slowed (to a virtual stop eventually) was because the majority of it's rotational energy was spent on shearing, buckling and fracturing of the trusses and collumns along it's way down. And it's a really interesting result that the collapse started at such a low angle of only 2,8 degrees.
Upon having read the whole article I had, upon some reflection, come to the conclusion that the towers couldn't have collapsed in any other manner than the one they had. Fascinating isn't it? That's what I thought first as well. But think about it. (after you have read the whole of the article) It actually does make sense.

For those who have used the arguments that the buildings have collapsed with a suspicously high velocity, the article has to say this:

It has been suggested that the inelastic deformation of columns might have ‘cushioned’ the initial descent of the upper part, making it almost static. However, this is impossible because, for gravity loading, a softening of the load-deflection diagram (Fig. 5) always causes instability and precludes static deformation (Bazant and Cedolin 1991, Chpt. 10 and 13). The downward acceleration of the upper part is ü = N[P10 - P1(u)]/m where N = number of columns and, necessarily, P10 = mg/N. This represents a differential equation for u as a function of time t, and its integration shows that the time that the upper part takes to fall through the height of one story is, for cold columns, only about 6% longer than the duration of a free fall from that height, which is 0.87 s. For hot columns, the difference is of course much less than 6%. So there is hardly any ‘cushioning’.

Hope this helps further the discussion.
Cheers.

[edit on 5-3-2006 by Max Demian]

So what exactly was wrong with 9/11 RS's points on the article?

The paper repeatedly claims to make the most optimistic assumptions about building survival with no discussion of what that means. It contains nonsensical engineering claims such as:
[... if the] majority of columns of a single floor to lose their load carrying capacity, the whole tower was doomed.

There are two major fallacies in this assertion:

* It implies that the columns were capable of supporting only twice the gravity loads they were bearing above the impact zone. This ignores the fact that the upper floors, lacking standing-room-only crowds, were not carrying their design live loads, and it implies that reserve strength ratios (the extra strength designed into a structure beyond what is required to resist anticipated loads) are two-to-one instead of the five-to-one typical in engineered steel structures.
* It implies that a failure of the columns to support the gravity loads above the impact zones would automatically lead to total collapse, despite the absence of a single example of a local collapse event leading to total collapse in any steel-framed building.

Source.

I don't think many people here are big fans of the idea of a mass of 13 floors crushing 97 floors without loss of speed, especially when most of mass is being ejected radially and the mass of those floors are totally lost pretty quickly. No loss of speed, and symmetrical all the way down. And to this point it has never been shown that the fires were sufficient to cause a single floor's collapse, let alone for a floor to collapse so uniformly within such a small frame of time.

think too, that the 'hinges' created by tilting the upper mass were at every connection that held together the 'cap'. these 'plastic hinges' would be the first things to fail, and hence should have caused a sideways cascade.
the remaining completely intact frame below was progressively more massive and stronger, and BZ's equations do not reflect this.
i find it suspicious that their paper came out only TWO DAYS after the event.

Originally posted by billybob
the remaining completely intact frame below was progressively more massive and stronger, and BZ's equations do not reflect this.

Something to keep in mind:

You can dress up math to come to any conclusion by picking and choosing your variables.

When you come up with an equation and solve it, you're creating an intellectual world of sorts that exists separately from the real world. Your goal is to make this world as close to our actual world as possible. When you leave out variables or generally don't take things into account properly, you're not going to get an accurate solution to the real-world problem. But you can make math fit most any conclusion this way. You can say the same for a lot of science, too.

We could settle this whole matter in one swoop if we only had the construction drawings and an expert physicist. Then we could take the weights of a building, the weights of each floor, determine the energy behind the caps falling resisted initially by weakened steel, and then perfectly strong steel, determine the impulse of each floor thereby with the floor plans and the properties of the steel, concrete, etc., taken into account, and then it'd be pretty much done with. The whole thing. Either there will be enough energy in the system, or there will not be. All we need are the construction drawings and a physicist.

So why are the construction drawings freaking locked up with NIST?

[edit on 6-3-2006 by bsbray11]

Originally posted by bsbray11
I don't think many people here are big fans of the idea of a mass of 13 floors crushing 97 floors without loss of speed, especially when most of mass is being ejected radially and the mass of those floors are totally lost pretty quickly.

What does "many people here" prove exactly?

I wasn't aware that science was dictated by democracy, or what people feel about things.

There are plenty of engineers who think that 13-20 floors would be more than enough to bring down the towers.

If your going to discard their opinion, then I guess we can safely discard the opinions of "many people here" as well.

(This partly addresses what bsbray11 commented)
I'm not a structural engineer, so I really wouldn’t know much about these safety carrying load guidelines. But as far as my intuition goes, those guidelines might have remained exactly that what they are: guidelines. Who can beyond reasonable doubt claim that the WTCs were actually designed with such carry load reserve ratios in mind? And if they were, how much has the actual implementation adhered to it anyway. The very reason that the construction drawings are denied to the official investigation warrants extreme suspicion in that very direction. That the buildings were actually rated to survive the impact of such aircraft, and have collapsed not the less, does even more so.

I’m still finding it hard (not being a structural engineer and all) to imagine why someone would go all his way to assure that the WTC load bearing columns can hold five times the weight they normally carry which would amount to 2,500 000 tons(!) (at the ground floor) assuming that the buildings weighed 500,000t each. Unless they were planning to make the buildings 2km tall, I really don’t believe they would go to that much trouble, and even more importantly spend all that money for some hard to envisage scenario. (Was someone to land a million tons on the top!? – this is of course just a figurative example, as the top floors would most assuredly collapse under such load regardless of how strong the base is).

Just think, if every floor is to carry as much as N times the weight above it, then because of the virtue of the WTCs having a 110 floors the base columns would have over a hundred times the surface (or over ten times the cross section dimensions) of the columns at the top floors. This is all imaginable, but for me as a lay person a bit weird. (the columns would look like some Ziggurats then) I’d wager that the columns at the base couldn’t handle even twice the weight they carry, but that still doesn’t make them weak, coz the safety margin is still in the range of several hundreds of thousands of tons. It’s more likely as one proceeds the way up the building that the safety margins more closely approach that of three or five the normal load. (since it’s much cheaper to assure, and more important for stability) But the bottom line is that I really don’t know anything how these things are done in reality (though I can guess), so I better shut up now.

Even though the article makes a lot of assumptions (which is understandable, since it was written only two days after the incidents) the core logic seems (at least to me) to be sound, since the values they reach are of orders of magnitudes higher then one could expect of the buildings to normally bear. The most obfuscated part of the article is the one regarding the percentage of kinetic energy lost in the initial collapse of the single floor section, which consequently results in the progressive collapse of the entire structure, as shown by the article. They claim a value of 12%, using the data they had at their disposal. The only problem with this is that they haven’t made that part of the calculation transparent, i.e. they haven’t provided the values they used. It shouldn’t be to much trouble retracing their steps and going back from the result to the yield moments they used, and seeing whether that makes sense or not.

As for the optimistic assumptions they used, here’s what they have to say:

The main purpose of the present analysis is to prove that the whole tower must have collapsed if the fire destroyed the load capacity of the majority of columns of a single floor. This purpose justifies the optimistic simplifying assumptions regarding survival made at the outset, which include unlimited plastic ductility (i.e., absence of fracture), uniform distribution of impact forces among the columns, disregard of various complicating details (e.g., the possibility that the failures of floor-column connections and of core columns preceded the column and tube failure, or that the upper tube got wedged inside the lower tube), etc. If the tower is found to fail under these very optimistic assumptions, it will certainly be found to fail when all the detailed mechanisms are analyzed, especially since there are order-of-magnitude differences between the dynamic loads and the structural resistance.

So the optimism wasn't directed at making their equations work, but at making the building most likely to survive. Hope this has helped to clarify some things. And yes I agree, it takes a very competent physicist to explain all this and I really hope someone does this - eventually.
Cheers

Originally posted by craig732

Four of the core columns on your drawing are in different spots than the ones in the NIST drawing. Which one is correct?

[edit on 4-3-2006 by craig732]

I don't know which ones are correct. I took the core column layout from the NIST figure 2-12 "Core column layout in WTC towers". There are columns in different places than what they show in the floor framing plan drawing, so which one is correct, I have no idea. Again, why the misleading drawings? What is true and what is false info?