notsoquick
It was not due to the flaming explosion, but due to the aluminum contained within that explosion from both the aluminum cladding of the building and the aircraft parts still moving through the air.
I was simply offering a lucid, logical explanation for why there could be a return ~10 seconds after the Hlava video PROVES the aircraft hit. There may be other, equally logical explanations(radar sweep, radar computer artifact, etc.) for why there was an extended return, but the fact is that by :40 the aircraft had ceased to exist as a unit.
Your cherry picking of the radar time and ignoring of other valid evidence has lead you into error.
Aluminum would give SOME radar return when the aircraft involved could no longer do so. This could have been interpreted by the computer of the radar as a continuation of the return of that aircraft, then, as the aluminum stopped moving and fell out of the cloud that return would end. Perfectly logical unless you are biased to see otherwise. We are talking the difference between SOME radar return and NO radar return, not between SHARP radar return and FUZZY radar return, after all.
Fraud??? Says who??? Your pathetic attempts at trying to prove fraud are seen for what they are. The desperate grasping at straws trying to save your bogus "Explosion before impact" hypothesis. It ain't working, noone but you still sees a firetruck in the back window of the BMW.
Or do you think there is a firetruck following every one of this particular model of BMW all the time so that the red lights are always there???
You are delusional. This degree of delusion is a serious problem that only a professional can help.
No, as adoucette, I and others have shown, there is not. There is only a 10 second difference between when the plane crashed and the last return faded from the radar screen, nothing more.
I still have not heard a logical explanation of how someone in the basement would KNOW when the plane crashed, they couldn't possibly have seen it. So, as far as anyone in the basement COULD know the explosion in the elevator shaft was a RESULT of the impact and a fuel air explosion of the jet fuel of the fireball being contained within that shaft.
As pointed out, the seismic signal coincides exactly with the plane impact in the Hlava video, you have totally failed in your attempt to discredit that video and eyewitnesses in the basement have no way of knowing whether the explosions were before or after impact. Your causal links fail to be logically supported.
Matthew
6:5 And when thou prayest, thou shalt not be as the hypocrites are: for they love to pray standing in the synagogues and in the corners of the streets, that they may be seen of men. Verily I say unto you, They have their reward. (6:5-6)
6:6 But thou, when thou prayest, enter into thy closet, and when thou hast shut thy door, pray to thy Father which is in secret; and thy Father which seeth in secret shall reward thee openly.
Enjoy your reward.
Grumpy
Your post is same-o same-o and you are wrong, as usual, on all accounts.
As to your posting of Scripture, thanks.
However, your intent with the posting of this Scripture and your "Enjoy your reward" remark is quite obvious: You imply I am praying in public.
This I am not doing. I am simply sharing the word of God, which is not praying.
Your thinking is cloudy, as usual.
HE SAVED US
NOT ON THE BASIS OF DEEDS WHICH WE HAVE DONE IN RIGHTEOUSNESS
BUT ACCORDING TO HIS MERCY
BY THE WASHING OF REGENERATION
AND RENEWING BY THE HOLY SPIRIT
newton
27th May 2007 - 07:08 PM
QUOTE (Grumpy+May 27 2007, 03:58 PM)
wcelliott
Yes, I am aware of the differential speed of sound in steel and air, and you are correct about feeling a jolt from below before hearing a sound. CTers take it a step further because the damaging explosions in the basements also preceeded the sounds of impact(though I doubt they could be seperated into discrete noises). Fuel air explosives damaged many floors and blew out elevator doors, concrete block walls, etc, and those in the basements claimed these occured prior to impact(or at least one did). I don't know that they didn't experience the effects of these explosions prior to hearing the airborne noise of impacts, after all, FAE are by definition SUPERSONIC events(as opposed to subsonic conflagrations as seen outside of the buildings).
But this is a case where what the witness experienced is deceiving as to the actual timeline of events. And the lack of any possible VISUAL evidence just makes the situation worse.
Grumpy
FAE(thermobaric) bombs have two detonations, one to release the aerosol, and after a delay to allow greater diffusion, the second detonation ignites the fuel/air mixture.
any contact between spark and fuel before the second detonation will lessen the intensity.
so, if the fuel is already on fire(tell me it wasn't), then there will be no supersonic FAE.
the explosions in the basements were bombs. no FAE. bombs.
pretending that rodriguez, who was there in 1993, and knows exactly what it sounds like, doesn't know what he heard is ludicrous.
sure you'd hear the sound through the steel first. in fact, that's about the only thing you'd hear in the basement, as there is 400, 000 tonnes of dampening material between the impact point, and the basement.
impact go boom. fireball down elevator shaft(freight only) go foosh.
newton
27th May 2007 - 07:11 PM
QUOTE (wcelliott+May 27 2007, 06:08 PM)
What Grumpy said, plus an observation that should be obvious - If 600 tons of explosive were detonated at the site, everyone within 50 miles would've *smelled* it.
Even if it were 1% of that amount, the place would've stunk to high heaven. Explosives have a very distinctive odor. A bomb-sniffing dog would to this day be able to smell the explosives.
i heard all the witnesses say ground zero smelled like a flower garden, so i guess you're right.
QUOTE
.....based on facts presented and the way McVeigh conducted himself, concluded that McVeigh himself likely believed he had been working for a special operations group under government orders and that he would not actually end up being prosecuted for the crime -- that McVeigh understood his mission was to be a patsy, which probably explained why a man in the top 5% of his military peers and considered officer material would do so many seemingly stupid things: the asking for directions and ignoring them to drive by video cameras, the purchase of nitrates, renting a motel room and the Ryder truck under his own name and leaving fingerprints on the related documents, driving away in a car with no plates in a way guaranteed to have him stopped by police, and then having a gun in plain sight guaranteeing any lawman to scrutinize him further... it all sounded a awful lot like the unreasonable stupidity exhibited by the World Trade Center "bombers" -- who were themselves "former" intelligence operatives for CIA and may have also likely been operating on instructions from government handlers -- doing so unaware of the danger and nature of the trap being sprung upon them, or willing to take the fall under orders.
the bomb sniffing dogs were pulled from the towers, and the one that was left died there.
David B. Benson
27th May 2007 - 07:18 PM
QUOTE (wcelliott+May 27 2007, 05:04 PM)
I'm new to the forum, and I didn't go through the prior 219 pages.
On the first page there are links to the previous two threads on this same subject.
Progress is rather slow...
wcelliott
27th May 2007 - 07:28 PM
QUOTE
And all this takes place in a setting in which ABSOLUTELY NO VALID PHYSICAL EVIDENCE OF THE USE OF EXPLOSIVES was found(and, given the history of the towers, it was one of the first things they looked for).
You missed the point completely. Explosives have a *distinctive* odor. When an explosive detonates, you smell *explosives*, not just "something smells bad".
Enough explosives to drop the towers would've resulted in that distinctive EXPLOSIVES smell that people, not just bomb-sniffing dogs, would've smelled miles away.
So how come nobody mentioned the smell of explosives? If it was a CD, then everyone in Manhattan would've smelled it.
wcelliott
27th May 2007 - 07:34 PM
QUOTE
... it all sounded a awful lot like the unreasonable stupidity exhibited by the World Trade Center "bombers" -- who were themselves "former" intelligence operatives for CIA ...
So, you're asserting that Osama bin Laden *is* a CIA stooge?
(Sorry, wrong quote.)
Grumpy
27th May 2007 - 07:56 PM
newton
QUOTE
FAE(thermobaric) bombs have two detonations, one to release the aerosol, and after a delay to allow greater diffusion, the second detonation ignites the fuel/air mixture.
QUOTE (->
| QUOTE |
| FAE(thermobaric) bombs have two detonations, one to release the aerosol, and after a delay to allow greater diffusion, the second detonation ignites the fuel/air mixture. |
so, if the fuel is already on fire(tell me it wasn't),
It wasn't.
The first "detonation" was the planes impact, spreading fuel everywhere at extremely high velocities and pressures, including down the elevator shafts. The conflagration happened a second or so later.
FAE is more likely in confined spaces, especially in a tube with a closed end(like an elevator shaft). Even if the shockwave is not supersonic, when it bounces off the closed end the effective speed of that shockwave doubles, causing detonation. It is probably this which caused the explosion in the basement. Other shock fronts were witnessed travelling up and down the other elevator shafts and damage was observed on multiple floors.
QUOTE
the explosions in the basements were bombs. no FAE. bombs.
Not according to the physical evidence, yes EVIDENCE!!!
QUOTE (->
| QUOTE |
| the explosions in the basements were bombs. no FAE. bombs. |
Not according to the physical evidence, yes EVIDENCE!!!
pretending that rodriguez, who was there in 1993, and knows exactly what it sounds like, doesn't know what he heard is ludicrous.
Pretending that Rodreguez can tell one overpowering explosion from another is ludicrous. FAEs are some of the most powerful explosives and I don't think you could tell the difference between one and an explosives blast, DA.
QUOTE
i heard all the witnesses say ground zero smelled like a flower garden, so i guess you're right.
Actually it smelled like a charnnel house, but not like explosives(the dogs brought in immediately all agreed, no explosives)
Grumpy
David B. Benson
27th May 2007 - 09:43 PM
QUOTE (lozenge124+May 27 2007, 02:34 AM)
... So you cannot just consider events 1-floor at a time. The energy may have been present, but noone[sic] has proposed a mechanism whereby the energy of the upper block is able to be concentrated a floor or 3 below the impact zone with the structure underneath sustaining no damage.
As has been pointed out many times, the paper by Bazant & Verdure treats these matters with complete rigor.
As I recently quoted from NCSTAR1, the tilting means that complete symmetry in the core cannot be assumed. Thus the upper part ( zone A ) together with the crushed part ( zone B ) falls down on the lower part ( zone C ) and progressively crushes it.
David B. Benson
27th May 2007 - 09:57 PM
QUOTE (Oneismany+May 27 2007, 02:47 AM)
I have searched in vain for succinct answers to these questions...
If it is yet unexplained, then how is it a small matter?
(1) Begin by properly learning A level (high school) physics. Continue by reading all the pages in this thread.
(2) It is a small matter it that once ejected, the exterior columns have nothing further to do with the progressive collapse. Since the distribution at Ground Zero is reasonable well understood, it is possible to give a good estimate of the energy consumed in tossing the exterior wall columns into that pattern. This energy consumption slows the progressive collapse and that is the only effect. So the exact mechanism for this energy consumption is of but small interest, although I will be more satisfied once a physically plausible mechanism is elucidated.
David B. Benson
27th May 2007 - 10:12 PM
QUOTE (lozenge124+May 24 2007, 02:37 PM)
There were air shafts in the core connecting every floor with the HVAC on a mechanical floor. So there was a route for the dirty air above to vent down and out the louvers on a mechanical floor.
adoucette
27th May 2007 - 10:15 PM
QUOTE (newton+May 27 2007, 04:45 AM)
there were many hockey pucks flying away from the towers. hockey pucks weighing a hundred tons, even.
Steel weighs ~16,000 lbs per cubic meter.
The perimeter columns were 14" square x 36 ft.
At the upper elevations (near the impacts) they were generally 7/16" thick steel.
3 of these columns were connected by spandrels, which were 52" x 10 ft and at the upper elevations they were also 7/16" steel. There were 3 spandrels per section.
Which works out to ~ .8 of a cubic meter per section
Which works out to a bit less than 7 tons per three column "tree" section.
Arthur
lozenge124
27th May 2007 - 10:57 PM
QUOTE (lozenge124+May 24 2007, 02:37 PM)
there certainly appears to be a lot of debris in the "air"
QUOTE (DBB+)
There were air shafts in the core connecting every floor with the HVAC on a mechanical floor. So there was a route for the dirty air above to vent down and out the louvers on a mechanical floor.
Like I said, that's some pretty substantial "dirt" in the "dirty air".
And that's not a mechanical floor.
adoucette
27th May 2007 - 11:06 PM
Nor is it an explosive.
Arthur
wcelliott
27th May 2007 - 11:08 PM
Could've been one of the floors with the elevator doors blown out, or an open stairwell door.
There's about 20 tons of air in each floor that has to get out of the way somehow.
David B. Benson
27th May 2007 - 11:10 PM
QUOTE (lozenge124+May 27 2007, 10:57 PM)
And that's not a mechanical floor.
Oh? You counted the floors?
Edited to add: About 7% of the total floor area was voids in the core for elevator shafts, utility shafts, air shafts and stairwells. There is definite evidence that some portion of the air escaped this way, all the way to the lobby. That some portion escaped at intermediate stories, with the potential for cracked or broken windows, seems entirely unsurprising...
lozenge124
27th May 2007 - 11:23 PM
QUOTE (lozenge124+)
So you cannot just consider events 1-floor at a time. The energy may have been present, but noone[sic] has proposed a mechanism whereby the energy of the upper block is able to be concentrated a floor or 3 below the impact zone with the structure underneath sustaining no damage.
QUOTE (DBB+)
As has been pointed out many times, the paper by Bazant & Verdure treats these matters with complete rigor.
From Bazant Verdure (www.civil.northwestern.edu/people/bazant/PDFs/Papers/466.pdf)
QUOTE
One-Dimensional Continuum Model for Crushing Front Propagation:
Detailed finite element analysis simulating plasticity and break-ups of all column and beams, and the flight and collisions of broken pieces, would be extremely difficult, as well as unsuited for extracting the basic general trends. Thus it appears reasonable to make four simplifying hypotheses:
(i) The only displacements are vertical and only the mean of vertical displacement over the whole floor needs to be considered.
(ii) Energy is dissipated only at the crushing front (this implies that the blocks in Fig.2 may be treated rigid,i.e., deformations of the blocks away from the crushing front may be neglected).
(iii)The relation of resisting normal force F transmitted by columns of each floor to the relative displacement u between two adjacent floors obeys a known load-displacement diagram (Fig.4,terminating with a specified compaction
ratio (which must be adjusted to take into account lateral shedding of a certain known fraction of rubble outside the tower perimeter).
(iv)The stories are so numerous, and the collapse front traverses so many stories, that a continuum smearing(i.e.,homogenization)gives a sufficiently accurate overall picture.
The mathematical treatment that follows is based on the HYPOTHESIS that "
Energy is dissipated only at the crushing front ". The paper may be mathematically "rigorous", but nowhere in it is the case made or proven that this is a good assumption and that the collapse would proceed in such a manner. It is just stated by decree in order to develop a mathematical model. You are confusing assumption with conclusion.
I agree with metamars here, that a FEA model is probably the only way you can approach this even though it "would be extremely difficult", because the model simplifications that have to be made to make the collapse mathematically treatable are so broad as to make the model meaningless.
From the B&V introduction:
QUOTE (->
| QUOTE |
One-Dimensional Continuum Model for Crushing Front Propagation:
Detailed finite element analysis simulating plasticity and break-ups of all column and beams, and the flight and collisions of broken pieces, would be extremely difficult, as well as unsuited for extracting the basic general trends. Thus it appears reasonable to make four simplifying hypotheses:
(i) The only displacements are vertical and only the mean of vertical displacement over the whole floor needs to be considered.
(ii) Energy is dissipated only at the crushing front (this implies that the blocks in Fig.2 may be treated rigid,i.e., deformations of the blocks away from the crushing front may be neglected).
(iii)The relation of resisting normal force F transmitted by columns of each floor to the relative displacement u between two adjacent floors obeys a known load-displacement diagram (Fig.4,terminating with a specified compaction
ratio (which must be adjusted to take into account lateral shedding of a certain known fraction of rubble outside the tower perimeter).
(iv)The stories are so numerous, and the collapse front traverses so many stories, that a continuum smearing(i.e.,homogenization)gives a sufficiently accurate overall picture. |
The mathematical treatment that follows is based on the HYPOTHESIS that "
Energy is dissipated only at the crushing front ". The paper may be mathematically "rigorous", but nowhere in it is the case made or proven that this is a good assumption and that the collapse would proceed in such a manner. It is just stated by decree in order to develop a mathematical model. You are confusing assumption with conclusion.
I agree with metamars here, that a FEA model is probably the only way you can approach this even though it "would be extremely difficult", because the model simplifications that have to be made to make the collapse mathematically treatable are so broad as to make the model meaningless.
From the B&V introduction:
It is shown that progressive collapse will be triggered if the total (internal) energy loss during the crushing of one story (equal to the energy dissipated by the complete crushing and compaction of one story, minus the loss of gravity potential during the crushing of that story) exceeds the kinetic energy impacted to that story.
We clearly see the same problem here as with Neu-Fonze's "energetics" paper. The concept of "story" is brought into play to model a tower consisting structurally of continuous vertical columns - where the "story" concept does not apply.
David B. Benson
27th May 2007 - 11:43 PM
QUOTE (lozenge124+May 27 2007, 11:23 PM)
The mathematical treatment that follows is based on the HYPOTHESIS that "
Energy is dissipated only at the crushing front ".
The concept of "story" is brought into play to model a tower consisting structurally of continuous vertical columns - where the "story" concept does not apply.
(1) I have offered several times to debate any and all of the B & V assumptions. So far nobody has seriously taken up the challenge.
Anybody who has seen at least one of the videos should seriously doubt that this particular hypothesis is quite a good one. In any case, all that matters in the crush-down equation is that energy consumption is a function of the drop distance, along with the mass, velocity, etc.
(2) The unit of one story is quite convenient and represents some important aspects of the structure, even in the core. At the time Greening wrote his paper, he probably did not know just how easy it was to completely disconnect the trussed floors from the walls and core. For B & V, the concept is irrelevant due to the homogenization assumption. This is very good since the truss disconnections required less than 4% of the energy consumed.
In any case, B & V could have equally well use units of meters, or millimeters, instead of units of stories...
wcelliott
28th May 2007 - 12:03 AM
QUOTE
The concept of "story" is brought into play to model a tower consisting structurally of continuous vertical columns - where the "story" concept does not apply.
Since the majority of the mass of each floor is the floor itself, which is also the ceiling of the next floor down, with supporting members in between the floors, using "floors" seems like the most rigorous way to approach the problem.
As the supporting structure fails, the upper mass accelerates downward at nearly 1g, and collides with the mass of the floor below. It's in this collision that the upper block slows down, the falling 30 floors versus the static floor it's crashing into. It's this collision that generates the huge force that defeats the immediate structure beneath. The forces generated can only be passed along through the structure beneath in so far as their critical strength isn't exceeded, so it isn't surprising that the floors failed in succession, progressively, as seen.
The central core wasn't designed for bending moments, and the floors wouldn't generally be assumed to release on all sides simultaneously (except in the case of a CD), so the core would've snapped from the bending moment. It could've fallen sooner or it could've fallen later than the floors themselves. but they would've fallen together, more or less, as neither were designed to stand without the other.
newton
28th May 2007 - 12:05 AM
i haven't seen any mathematical model that concerns itself with friction(of the loose pieces in the mix), nor the 'cushioning effect'(up down momentum transfers between falling loose debris) of the growing loose debris field between the 'crush up/crush down' forces.
i had hoped the 'avalanche math' guy would have put on his boxing gloves and entered the fray with more vigour, here. that principal of an avalanche is an appropriate analogy.
David B. Benson
28th May 2007 - 12:19 AM
QUOTE (newton+May 28 2007, 12:05 AM)
i haven't seen any mathematical model that concerns itself with friction(of the loose pieces in the mix), nor the 'cushioning effect'(up down momentum transfers between falling loose debris) of the growing loose debris field between the 'crush up/crush down' forces.
I doubt the pieces in the crushing front ( zone B ) were loose. Consider WTC 1, collapsing at close to (1/3)g for the first three seconds. In the first 1.8 seconds already three stories of materials were crushed together, with about half of the next floor down. This provides an approximately 2 meter thick crushing mass which is smashed and re-smashed together as each subsequent floor is impacted. Not to mention all the air resistance from below as the air is forced out of the way of the descent.
This situation has different constraints than an avalanche...
wcelliott
28th May 2007 - 12:22 AM
QUOTE
i haven't seen any mathematical model that concerns itself with friction(of the loose pieces in the mix), nor the 'cushioning effect'(up down momentum transfers between falling loose debris) of the growing loose debris field between the 'crush up/crush down' forces.
I'm curious as to how detailed the model has to be before you acknowledge that it wasn't the Bush administration, but Osama bin Laden who was behind these attacks.
Now you want a mathematical model of the "friction" of the debris?!? What possible contribution could that make to the discussion?
Do we need to produce a finite-element model that tracks every wastepaper basket, every window, every sheet of paper, every speck of grit falling from the sky? Or would even that not be enough?
Will there ever be a point where you go, "OK, it was bin Laden", or are you committed to going to the grave asserting that it must've been Bush, regardless of the complete lack of evidence supporting your view?
Not to mention the fact that bin Laden admitted it already. (Or are you of the belief that bin Laden is a CIA stooge?)
David B. Benson
28th May 2007 - 12:35 AM
QUOTE (wcelliott+May 28 2007, 12:03 AM)
Since the majority of the mass of each floor is the floor itself, which is also the ceiling of the next floor down, with supporting members in between the floors, using "floors" seems like the most rigorous way to approach the problem.
As the supporting structure fails, the upper mass accelerates downward at nearly 1g, ...
The central core wasn't designed for bending moments, and the floors wouldn't generally be assumed to release on all sides simultaneously (except in the case of a CD), so the core would've snapped from the bending moment. ...
(1) Yes, this was Dr. Frank R. Greening's approach. However, the majority of the energy expended was not associated with the actual floors. A careful look at the drop data for the first three minutes of the collapse of WTC 1 shows that the same average rate of energy expenditure occurred before the first collision of two floors as later on. So the Bazant & Verdure assumption of homogenizing the structures, while slightly wrong with regard the momentum, remains the best overall approach to developing a crush-down equation. In any case, it could be solved using the fact that about 4/5 of the mass at the higher elevations was the actual floors and contents. I doubt much would change in the results by doing this.
(2) nearly is subjective. What is clear is that there was enough resistance before the first floors impacted, in WTC 1, at 0.8 seconds, that 0.7g is a good estimate for the first 0.8 seconds, while 0.66g is a good estimate for the first three seconds. Neither figure seems to be 'nearly 1g' to me.
(3) Given that the top block ( zone A ) was tilted, the trusses were certainly not disconnected simultaneously on all sides. For example, the first such disconnections required about 0.4--0.5 seconds in WTC 1. The central core was designed to bend in the wind. The largest such flexure, in the middle portion of the tower, was less than 60 arc-seconds. So your suggestion is interesting.
Edited to add: But the truss seats connecting the trusses to the core were certainly much too weak to transmit any significant torsion to the core. The seats would fail first.
NEU-FONZE
28th May 2007 - 12:38 AM
There is some interesting information on "cushioning effects" in the following paper:
"A Study of Shock Mitigating Materials in a Split Hopkinson Bar Configuration"
By V. I. Bateman et al. Sandia Report SAND96-1437, (1998).
Sorry, I don't have a link to it but you should be able to find it by googling on the info I have provided.
Then, on the collapse itself, I like the problem in Knudsen's book entitled "Elements of Newtonian Mechanics":
A thin homogeneous rod of length L and mass M is at rest on a horizontal, frictionless floor. The rod is given a slight sideways push near the top and begins to move in the gravitational field. The initial velocity of the center of mass is zero.
1. Describe the curve along which the center of mass moves.
2. How does the curve change if there is friction?
NEU-FONZE
28th May 2007 - 01:03 AM
Oh, and by the way,
I used to think there were problems with some posters here on PhysOrgForums, but having tried JREF, well,...... what can I say,..... this site is a breath of fresh air!
There is one word to describe JREF: CONDESCENSION (meaning PATRONIZING)
I appreciate all those who post here in a civil and dignified manner.
Of course, we all have lapses...... But let's stick to science as much as possible.........
newton
28th May 2007 - 02:33 AM
QUOTE (wcelliott+May 28 2007, 12:22 AM)
I'm curious as to how detailed the model has to be before you acknowledge that it wasn't the Bush administration, but Osama bin Laden who was behind these attacks.
Now you want a mathematical model of the "friction" of the debris?!? What possible contribution could that make to the discussion?
Do we need to produce a finite-element model that tracks every wastepaper basket, every window, every sheet of paper, every speck of grit falling from the sky? Or would even that not be enough?
Will there ever be a point where you go, "OK, it was bin Laden", or are you committed to going to the grave asserting that it must've been Bush, regardless of the complete lack of evidence supporting your view?
Not to mention the fact that bin Laden admitted it already. (Or are you of the belief that bin Laden is a CIA stooge?)
gee. you seem pretty convinced it was bin laden, despite the fact that the FBI doesn't have any evidence he was involved.
the real bin laden denied it on middle eastern media channels, and in fact, accused the americans of doing it to themselves. fatty bin laden, the actor, admitted it.
anyway, this is a physics board, and we're not alllowed to talk about the politics, disinformation, the illuminati, zionism, bankers, insider trading, insurance scams, double agents, celebrity doubles, and whatnot.
focus on collapse mechanics, before a teacher sees us, or we'll both be in big trouble.
friction is a real force, and increases with mass.
rub your hand lightly along the wall. now do it with your full body weight behind it.
wcelliott
28th May 2007 - 03:10 AM
QUOTE
anyway, this is a physics board, and we're not allowed to talk about the politics, disinformation
Excuse me, but the "jet fuel can't melt steel" nonsense IS disinformation, and the assertion that it wasn't a terrorist attack is clearly politically motivated, asserting that it was the Bush administration that planned and executed it.
If Clinton was still in-office when it happened, would you be so convinced that it wasn't terrorists that hijacked the planes?
Didn't think so.
My apologies for trying to interject a bit of reality into the discussion.
newton
28th May 2007 - 03:39 AM
QUOTE (wcelliott+May 28 2007, 03:10 AM)
Excuse me, but the "jet fuel can't melt steel" nonsense IS disinformation, and the assertion that it wasn't a terrorist attack is clearly politically motivated, asserting that it was the Bush administration that planned and executed it.
If Clinton was still in-office when it happened, would you be so convinced that it wasn't terrorists that hijacked the planes?
Didn't think so.
My apologies for trying to interject a bit of reality into the discussion.
clinton and bush are both industry's bee hatches, and i see NO difference between them, except that the bush's are much more powerful.
like, bi-partisanism is so far away from my observations of the reality of politics, that not even hubble can see it.
i never even claimed steel wasn't weakened by what heat did exist in the towers, nor that collapse couldn't have initiated from heat.
i claim the fires were not hot enough(and, funnily, NIST's spectral heat distribution, and testing on actual steel reveals the same), and i claim that IF a natural collapse initiated, it would not have looked the way the collapses we see on videos looks.
p.s. thanks, neu fonze, real science is fascinating, no? there was something particularily counter-intuitive for me in those tests, and that was the response of cotton, which i feel is a 'cushiony' thing, and yet is the total opposite!
now, i think, why would my intuition think of it as a 'cushiony' thing? so, it must be the weave of cotton that provides 'give', i guess.
good food for thought.
forthetrees
28th May 2007 - 03:45 AM
DBB wrote:
QUOTE
Not to mention all the air resistance from below as the air is forced out of the way of the descent.
There was no air resistence from below that was of any consequence, as per your explanation of this to me on our go around about it a couple of weeks ago....or, am I missing your point, again?
wcelliott
28th May 2007 - 04:27 AM
QUOTE
i claim the fires were not hot enough(and, funnily, NIST's spectral heat distribution, and testing on actual steel reveals the same), and i claim that IF a natural collapse initiated, it would not have looked the way the collapses we see on videos looks.
I, too, take issue with NIST's assertions regarding the temperature of the fire and how quickly the fuel disappeared. I think perhaps that this isn't their strong suit.
It was clearly a fuel-rich environment, without sufficient oxygen to consume the quantity of jet fuel dumped in the environment. There was a lot of black smoke as a result.
Black smoke is a very good insulator at IR wavelengths. This means that a fire can burn hot at ceiling level, and at carpet level, most of the heat is blocked by the smoke itself. You can have very high thermal gradients in a fuel-rich fire, and that's what I think really happened at the WTC.
The heat generated by the fire would've been severely localized by the ceiling and floor (both concrete, good insulator) and laterally by the smoke (also good insulator). Also the configuration of the floors, being an acre in area, while having only about 10feet in height, would make it extremely difficult for the heat generated in the interior spaces to find its way out of the building. Air could get in through the blown-out windows, but not enough to clear away the smoke, just enough to provide the fuel with oxygen.
As I'd indicated earlier, fuel doesn't burn at one set temperature, as many would have you believe (especially CTs trying to sell their anti-American sentiments), jet fuel can burn hot enough to melt steel, under the right circumstances. This is pretty close to those circumstances. Fuel releases heat, not temperature. Whatever the temperature is when the fuel burns, it makes the environment hotter than it was before. This is how foundries work, they trap the heat while providing a controlled amount of air to burn the fuel.
So in the WTC you had the ideal unintentional foundry, allowing air in at a metered rate, concrete and smoke (and the geometry of the building) providing insulation to trap the heat inside.
I think NIST got that part wrong. I think the fire got a lot hotter than they estimated.
But it didn't *melt* the steel, because it never got the chance, the steel softened and dropped the load as soon as it was no longer strong enough to maintain the structure's integrity (already compromised by the direct impact damage).
I've already addressed (twice) why the floors collapsed progressively as they did, and why "explosive-like sounds" were heard in the basement first, then oscillations felt seconds later. The bellows-like action of the floors collapsing would shoot air down any open duct/stairwell/elevator shaft and shoot debris laterally out the building. Also, if there'd been explosives, especially enough for a CD, then the whole of Manhattan would've reeked of distinctive *explosives" smell, which it didn't. The notion of smuggling explosives into the WTC by the ton and planting it in the structures without getting caught is clearly ludicrous, whoever believes this has been watching too many "Mission:Impossible" movies. Step away from the bong.
So what's left? (Other than your blind hatred of America?)
adoucette
28th May 2007 - 04:38 AM
QUOTE (wcelliott+May 27 2007, 11:27 PM)
I, too, take issue with NIST's assertions regarding the temperature of the fire and how quickly the fuel disappeared. I think perhaps that this isn't their strong suit.
You might be basing this assumption about NISTs Assertions from what Troofers CLAIM NIST said.
They are invariably taking various pieces of NIST data out of context.
NIST thought the fires were VERY HOT.
See NIST NCSTAR 1-5F
For purposes of discussion see Chap 6.3 WTC 1 - Case B.
Arthur
frater plecticus
28th May 2007 - 08:53 AM
QUOTE
So what's left? (Other than your blind hatred of America?)
QUOTE (->
| QUOTE |
| So what's left? (Other than your blind hatred of America?) |
“Why of course the people don’t want war. Why should some poor slob on a farm want to risk his life in a war when the best he can get out of it is to come back to his farm in one piece? Naturally, the common people don’t want war: neither in Russia, nor in England, nor for that matter in Germany. That is understood. But after all it is the leaders of the country who determine the policy, and it is always a simple matter to drag the people along, whether it is a democracy, or a fascist dictatorship, or a parliament, or a communist dictatorship…Voice or no voice, the people can always be brought to the bidding of the leaders. That is easy.
All you have to do is to tell them they are being attacked, and denounce the pacifists for lack of patriotism and exposing the country to danger.”
— Leading Nazi leader, Hermann Goering, at the Nuremberg Trials before he was sentenced to death
wcelliott
28th May 2007 - 09:27 AM
QUOTE
— Leading Nazi leader, Hermann Goering
Oh, gee! What a surprise. You figure that the attacks were plotted by Bush to give him the opportunity to attack Afghanistan and Iraq.
Gee, my eyes are now open for the first time!
Is this as close as you've ever gotten to political insight?
There's a flip-side to this that apparently hasn't occurred to you. Maybe Osama bin Laden actually hates America enough to attack us, and counted on people like you to believe it was the Bush administration that did it.
Maybe this knee-jerk assumption that Bush is behind everything that happens is off-base, and maybe this is exactly what the terrorists are hoping for, that pseudo-intellectuals will always assume that everything's fake, and won't even believe their own eyes, so they (the terrorists) can literally get away with murder.
Osama's counting on you, don't let him down.
But, remember, his family was friends of the Bush family, so if the WTC attacks weren't faked with 600 tons of explosives that nobody smelled, sneaked-in when nobody was looking, put in holes in the structure that nobody noticed or heard them being drilled, to collapse the towers from the points of impact (which would've taken some pretty good guidance systems to make the planes hit at precisely the right floors) then for there to have been a plot, Osama bin Laden must've been working for Bush.
See, if you think about it from the Dr. Evil perspective - Which is harder to plot - recruiting terrorists to hijack four airplanes with box-cutters, or faking the 9/11 attacks?
My money would be on finding 16 Arabs that hate our guts. That seems a lot easier and a lot less risky from an operational perspective.
But that would mean that Osama bin Laden, your hero, is a CIA stooge.
So pass that along to your terrorist-sympathizer friends.
Capracus
28th May 2007 - 11:15 AM
QUOTE (wcelliott+May 28 2007, 09:27 AM)
Oh, gee! What a surprise. You figure that the attacks were plotted by Bush to give him the opportunity to attack Afghanistan and Iraq.
I don't believe that Bush was behind the attacks, but you have to admit that he has politically milked it for all it's worth.
Grumpy
28th May 2007 - 02:50 PM
Capracus
QUOTE
I don't believe that Bush was behind the attacks, but you have to admit that he has politically milked it for all it's worth.
I agree, and if he had stayed in Afghanistan and finished that job he would be seen today as a much better leader and our country would be in much better shape both here and abroad.
By the way, Goering would fit right in to the neo-con wing of the Republican party today, after all, they follow his advice to the T.
Grumpy
einsteen
28th May 2007 - 02:58 PM
Anyone seen this Crockett Grabbe interview ? U of Iowa and Cal Tech
http://video.google.com/videoplay?docid=4445414428897392617A professional "demolitionist"
ps. I'm not going to involve in the reflection discussion
Grumpy
28th May 2007 - 03:15 PM
einsteen
I stopped listening when he said the building hit the ground in six seconds. Why? Because the building took over 18 seconds(by seismic data) to crumble apart, starting from the hole in the south face and proceeding to the east penthouse, then the west penthouse and THEN the north curtain wall fell(in about six seconds). This man(whatever his claimed credentials) knows little or nothing about which he speaks, just someone willing to sell out his professional ethics for his fifteen minutes of fame.
Grumpy
adoucette
28th May 2007 - 03:25 PM
He makes 3 key points.
1) It should have taken much longer than 6 seconds.
==> It did, ~ 14 seconds or more
2) It was COMPLETELY SYMETRICAL
==> It wasn't, as he said, "it probably would not happen all at once" and as we saw, it DIDN'T happen "all at once"
3) The evidence of squibs was "direct evidence"
==> No such "squibs" are seen prior to the "kink" and the falling in or the penthouse.
Later he refers to "the amount of melted steel was MASSIVE" but NO SUCH EVIDENCE of ANY significant quantity of melted steel has EVER been shown.
Here is from an earlier post by this guy:
The evidence from the observations of the collapse itself supports that conclusion, that explosive charges had been laid to collapse the towers. It is known that the steel structures making up buildings can perform badly in a fire without adequate fire retardents, and with hot fires can lose their strength to hold the huge stresses in a building like the World Trade Center. However, if that was the critical problem, the collapse would follow a definitely different path than was observed. Evidence for the structural degradation would likely appear before the final collapse, and the process would accelerate toward catastrophe.
Without explosives, the initial structural degradation upon collapse would not be accomapnied so quickly by the huge dust and massive debris clouds. These dust clouds appeared so quickly because they were created by explosions. For the south tower the plane had only hit the corner of the building and most of the fire quickly flared outside the building upon collision. There was more limited damage from the collision, but that building collapsed first when explosives were ignited. In the case of the north tower, the plane hit higher so that it took longer for the fire to reach the explosives, which upon detonation pulled apart the weakened steel structure above it that had been burning. The dust clouds and destruction covered a much larger area as a result.
Terrorists were likely bringing those explosives in over a period of time, sealing and hiding them at convenient locations that could not be spotted. These probably included sealing them inside concrete and metallic structures, where they would not be detected for a long time. The fact that many thousands members of the public went through the World Trade Center everyday probably made it easy for this to be done. Even though Security had been stepped up since the bombing of the World Trade Center in 1993, undoubtedly very few in that Security imagined the despicable scheme of hate that was being laid.
Having cells of terrorists working to hide these explosives over time is quite consistent with their methodical development of the plans of terror through meticulously studying plane flights and by learning to fly airplanes over time. Their failed effort to destroy the towers in 1993 showed them the importance of having the explosives strategically placed. Their intent all these years was the same as they described in the 1993 attack: to knock down and destroy the twin towers.
Through destructive preparation by laying explosives and planning the evil deeds leading up to September 11, the terrorists finally succeeded in destroying the World Trade Center, leaving us with the massive slaughter of thousands of fellow Americans, bodies tied up in millions of tons of burning rubble, and sad memories of what this country once had. It is incumbent upon all of us to never be fooled by anything like this again.
Typical Troofer nonsense, totally UNSUPPORTED by any evidence.
Arthur
wcelliott
28th May 2007 - 03:31 PM
QUOTE
I agree, and if he had stayed in Afghanistan and finished that job he would be seen today as a much better leader and our country would be in much better shape both here and abroad.
I agree that it's generally unwise to fight two wars at the same time, but that being said...
It's easy to second-guess decisions made years ago, but therein lies the "Fallacy of the False Alternative".
We don't know what the Iraq war *prevented* from happening.
No WMDs? We looked for a while, then stopped looking. We didn't find them, so it's assumed they never existed.
Then again, we looked for Osama bin Laden for a while and didn't find him, either, so are we to assume that *he* doesn't exist?
Since the Iraq war began, Jihadis eager to kill Americans flocked to Iraq. Our troops are pretty good in a firefight, so a lot of Jihadis died taking potshots at our troops. If our troops weren't in Iraq, maybe some of these Jihadis would've attacked other Americans, ones without body armor, training, and automatic weapons. The American-death toll could've been higher if we hadn't gone into Iraq.
And I happen to believe that we are winning that war, or at least that we will win it if we play our cards right. I wonder who that'd upset more, the Jihadis or the Americans who hate Bush more than they love reason.
wcelliott
28th May 2007 - 03:57 PM
QUOTE
Terrorists were likely bringing those explosives in over a period of time, sealing and hiding them at convenient locations that could not be spotted. These probably included sealing them inside concrete and metallic structures, where they would not be detected for a long time. ...
Having cells of terrorists working to hide these explosives over time is quite consistent with their methodical development of the plans of terror through meticulously studying plane flights and by learning to fly airplanes over time. Their failed effort to destroy the towers in 1993 showed them the importance of having the explosives strategically placed.
These people who think it's feasible to smuggle explosives into a building, then drill holes in support structures, without anybody noticing or challenging their authority to do so, are living in a dream world.
The first guy trying to sneak into a company's office space would've been caught by the company's receptionist. Especially if it involved doing anything that could've made noise (like drilling holes in concrete). Complaints would've gone straight to the Building Superintendent, "What are these guys doing in my office space?!?" And this would've had to worked *every* time in order for the overall operation to work - one guy gets caught, once, and the whole building gets searched.
They'd be caught in another failed attempt to bring down the towers, which would've made them look like fools.
And where did they get all this odorless explosives, anyway? Al Queda is in the bathtub-chemistry homemade explosives business. There are no "odorless explosives" that you can make or buy. (I'm not even sure it'd be possible to make an odorless explosive, myself, even with unlimited funds and DuPont/Dow working on it. )
Or, you can just convince them to hijack four airplanes, one mission, each, and get the job done using the tons of jet fuel and tons of aircraft instead of trying to sneak tons of explosives past WTC Security a couple pounds at a time.
The CD notion fails on several fronts, but above all, it'd be a stupid plan from the operational perspective. Too hard to do, too easy to get caught.
And there's no such thing as an odorless explosive, not that I know of, and not that any terrorist group has ever used before or since.
einsteen
28th May 2007 - 04:00 PM
yeah, if you are able to place explosives as a terrorist you don't need the plane at all and you can increase the amount of victims to the highest possible levels.
About those 6 seconds, of course when people talk about those 6 seconds they mean the visible collapse. There is of course a period in which structures are weakened and during that period there is also some movement, but it is still the 6 seconds in which the building fell, in that other period it fell may be some meters, but in mathematical notation, if the function is
x(t), 0<t<14 s
then
a(t):=x''(t)
then
a(t)<<g for 0<t<8 s,
but also
9 m/s^2 <a(t)<g, for 8 s<t<14 s
and that is what matters. The it's 14 - it's 6- it's 14- it's 6 seconds discussion is typical LC/JREF, of course when it falls it falls fast.
Grumpy
28th May 2007 - 04:22 PM
einsteen
When the building STARTED crumbling was at least 10-12 seconds prior to the visible collapse of the north curtain wall. The fire department knew 3 hours before hand the building was likely to collapse due to on the scene reports of the damage to the south face(read the reports, the damage was extensive, the fires spreading). Though NIST has not yet published their report on building 7, the building fell due to known physical processes, no explosives required(and no evidence of it's use found).
Grumpy
einsteen
28th May 2007 - 04:36 PM
Well, I assume NIST then also provide calculations.
I'm just wondering if you take Greening's energy transfer paper and only concentrate on the crush-up (2nd stage of collapse without initial velocity)
then you can reproduce the same stepwise process, assume now that during the collapse of each story an energy factor E_wtc7 is lost, then you can calculate how much this value should be if you fit the data of the drop. Now when you find that value and go back to the time that the situation is completely static then in fact x(t)=constant hence v(t)=0, a(t)=0, there is even no toppling building, no toppling block, no initial speed, nothing, zero.
Now since there was no plane and there is no story to fall there is absolutely nothing to make it plausible that there is some initial momentum and speed. Why did it fall ?
A very weak building (wtc7 was no weak building) could carry a lot of static weight and as long as it is static it remains static even if you put all columns on the barbecue.
wcelliott
28th May 2007 - 05:33 PM
QUOTE
Now since there was no plane and there is no story to fall there is absolutely nothing to make it plausible that there is some initial momentum and speed. Why did it fall ?
OK, I've got a question.
If WTC7 was a CD, why did the terrorists/gov't agents bother with it? Dropping the Twin Towers and attacking the Pentagon are of one scale (major), WTC7 was a footnote compared to those three attacks.
Yet WTC7 had as good or better security, and being a smaller building it would've been harder to sneak explosives in without being noticed. If it didn't fall for natural reasons, why did anybody take the extra risk to drop it with a CD?
shagster
28th May 2007 - 05:53 PM
QUOTE (einsteen+May 28 2007, 04:36 PM)
I'm just wondering if you take Greening's energy transfer paper and only concentrate on the crush-up (2nd stage of collapse without initial velocity)
then you can reproduce the same stepwise process, assume now that during the collapse of each story an energy factor E_wtc7 is lost, then you can calculate how much this value should be if you fit the data of the drop. Now when you find that value and go back to the time that the situation is completely static then in fact x(t)=constant hence v(t)=0, a(t)=0, there is even no toppling building, no toppling block, no initial speed, nothing, zero.
I calculated the collapse duration of WTC7 using a crush-up model, both discrete and continuous using differential equations with the boundary condition being zero velocity at the start. I posted it here a while back. If WTC7 had the same E1 per mass as the towers, the total collapse duration turns out to be 6.6 seconds, very close to what was observed. That's not unusual for a steel frame building. If there had been concrete to absorb some of the energy, the collapse would have taken slightly longer. There isn't anything strange about 6.6 seconds.
How the collapse started is another question. Scheuerman has proposed a different type of failure mechanism compared with the earlier NIST explanation. You might want to check out his paper on the web. There doesn't need to be an initial momentum imparted by an external object for the building to fall. The structure needs to be weakened by fire sufficiently for a story or more to fail. Gravity does the rest. Examples include the partial collapse of the Windsor and the recent collapse of the steel bridge in San Francisco due to fire.
WTC7 wasn't a structurally robust building. The gash on the south side appears to go all the way from the top to the bottom of the building. That's a local progressive collapse all the way down the building similar to Ronan apartment, which is a bad sign in terms of robustness. The failure that started on the east side of the building went from about the 11th or 12th story all the way to the top of the building, another progressive collapse but from bottom to top. There was also a progressive collapse from east to west. All of that shows that the building wasn't robust in spite of whatever the designers may have claimed. The relatively short global collapse duration is also consistent with the structure not being robust. The building overall had a low E1 to mass ratio and it was suspended over an electrical substation with no concrete core. That's not the type of building you would want to use for critical emergency operations.
Daru
28th May 2007 - 06:18 PM
Architects & Engineers for 9/11 Truth!
www.ae911truth.org/
NEU-FONZE
28th May 2007 - 06:31 PM
Shagster:
I also tried my program on WTC 7. I used a mass of 40 floors falling on 7 floors. I assumed the mass of the 40 story block was 40/110 of the mass of one twin tower. Since I used 510,000 tonnes for WTC 1 & 2, this gave 185,455 tonnes for the falling mass which is much heavier than the upper falling mass of either WTC 1 or 2..... For E1 I used 1.8 GJ to allow for strong floors. I have not tried varying E1 yet although this is simple enough to do.
These parameters gave a collapse time of 6.56 seconds. Interestingly, the last part of the collapse slows considerably, rather than accelerates as for WTC 1 & 2 because, for WTC 7, the "hammer" is getting smaller and smaller!
Grumpy
28th May 2007 - 06:33 PM
einsteen
As shagster touched on, the southern face of 7 was cantilevered over an existing substation. Such offset columns CANNOT be as strong or as stable as a vertical column can be. That is one factor.
Another factor was the severe damage done to the south face and south west corner of the building.
Then there was the 12,000 gallons of diesel fuel which not only contributed to the fires, but supplied huge quantities of sulfur compounds at high temps which are well known to erode steel under such conditions.
Then you have progressive collapse of the type the Murrah building suffered after the explosion in Ok City. The original blast scooped out several lower floors and, over time the floors above also crumbled and failed, to the point that most of the face of that building collapsed. In fact, more of the building fell AFTER the original damage from the bomb.
As I have pointed out seismic records indicate a total of 18 seconds for 7's collapse. The east penthouse, a large heavy equipment filled structure, fell into the space where the building below it MUST have already collapsed. When this happened daylight was seen in the top rows of windows, indicating that all that remained WAS the curtain wall, which THEN took 6 seconds to fall. The building seems to have fallen apart piecemeal, not as a crush down, starting with the severely damaged south wall(the cantilevered side), up to the south eastern side(under the east penthouse), the east penthouse, the kink and then the north curtain wall. This is an entirely different process and for entirely different reasons from those that brought down the towers. But, again, there is no physical evidence supporting the use of explosives or thermite(despite any claims from former cold fusion physicists).
Grumpy
NEU-FONZE
28th May 2007 - 06:53 PM
Daru:
I just read part of the A & E for Truth website and found this:
"The interesting fact is that each of these 110-story Twin Towers fell upon itself in about ten seconds at nearly free-fall speed. This violates Newton ’s Law of Conservation of Momentum that would require that as the stationary inertia of each floor is overcome by being hit, the mass (weight) increases and the free-fall speed decreases."
I, and others such as Shagster and David Benson, have looked at this in great detail. Newton's Law of Momentum Conservation is simply that for an isolated (closed) system, the total momentum is conserved. For the WTC collapse we are dealing with inelastic collisions of the type M(n). V1 = M(n+1). V2, where M(n) is the mass of a block of n floors. If you work through the math, with conservation of momentum applied to each impact, you will find that the falling block picks up speed quite nicely and behaves as if the acceleration due to gravity was about 2/3g. This adds but a few seconds to the collapse time, as was observed for both towers. Hence, Newton's Laws were NOT violated and this argument is specious to say the least!
David B. Benson
28th May 2007 - 07:09 PM
QUOTE (NEU-FONZE+May 28 2007, 06:53 PM)
... the A & E for Truth website ...:
"The interesting fact is that each of these 110-story Twin Towers fell upon itself in about ten seconds at nearly free-fall speed. ..."
(1) There is no such thing as free-fall speed. This is the first indication of the inanity of this site.
(2) An acceleration of (2/3)g is far short of nearly free-fall acceleration.
(3) WTC 1 took 18 seconds to completely collapse (except for the temporary spire). This was determined by poster shagster listening to the Health video. I don't consider eighteen seconds to be about ten seconds. So here is another inaccuracy.
(4) Conclusion: A & E for Truth is actually about spreading lies...
frater plecticus
28th May 2007 - 07:13 PM
QUOTE (wcelliott+May 28 2007, 09:27 AM)
Oh, gee! What a surprise. You figure that the attacks were plotted by Bush to give him the opportunity to attack Afghanistan and Iraq.
Gee, my eyes are now open for the first time!
Is this as close as you've ever gotten to political insight?
There's a flip-side to this that apparently hasn't occurred to you. Maybe Osama bin Laden actually hates America enough to attack us, and counted on people like you to believe it was the Bush administration that did it.
Maybe this knee-jerk assumption that Bush is behind everything that happens is off-base, and maybe this is exactly what the terrorists are hoping for, that pseudo-intellectuals will always assume that everything's fake, and won't even believe their own eyes, so they (the terrorists) can literally get away with murder.
Osama's counting on you, don't let him down.
But, remember, his family was friends of the Bush family, so if the WTC attacks weren't faked with 600 tons of explosives that nobody smelled, sneaked-in when nobody was looking, put in holes in the structure that nobody noticed or heard them being drilled, to collapse the towers from the points of impact (which would've taken some pretty good guidance systems to make the planes hit at precisely the right floors) then for there to have been a plot, Osama bin Laden must've been working for Bush.
See, if you think about it from the Dr. Evil perspective - Which is harder to plot - recruiting terrorists to hijack four airplanes with box-cutters, or faking the 9/11 attacks?
My money would be on finding 16 Arabs that hate our guts. That seems a lot easier and a lot less risky from an operational perspective.
But that would mean that Osama bin Laden, your hero, is a CIA stooge.
So pass that along to your terrorist-sympathizer friends.
Firstly I don't figure that Bush 'plotted' the attacks. Your assumption that anyone that doubts the OCT believes that Bush and/or Cheney were somehow directly complicit in the attacks themselves is nothing more than that, an assumption, which In my case specifically, is downright wrong.
I don't waste my time arguing about reflections in windscreens or waiting for the second coming of some non-existent prophet or his camel-selling counterpart, but the absolute and inescapable fact is that the Bush Administration has lied about so many aspects of the attacks themselves, although this in itself is not proof of complicity. As I have said before...
QUOTE
A massive amount of valid evidence exists to show that elements of the official story (itself a conspiracy theory because it is not verifiable), are false. It is not possible, however, to use the newly discovered evidence as the basis for a conclusion about what actually happened and who was responsible. At least not yet. There are many indications, and there is a long trail of evidence suggesting US government complicity, but that is all there is. That much is a theory, but the evidence itself is comprised of facts. That evidence can not be dismissed simply because the theories that are wrapped around them are inconclusive. The proverbial baby cannot be thrown out with the bath water.
Maybe if people like yourself weren't so condescending, with the cocksure arrogance of a schoolboy let loose in the Physics Lab for the first time there would be more educated debate here.
I won't even stoop to your gutter level and answer the charge of "Terrorist sympathizer".
To be quite honest, I couldn't care even if Certain elements of the US security apparatus were complicit in the attacks themselves. It wouldn't exactly be
unprecedented now, would it?
America's War on Terrorism by Michel Chossudovsky
http://sandiego.indymedia.org/media/2006/11/122510.pdf The New Pearl Harbor - Disturbing Questions about the Bush()() Admin. and
9/11 by David Ray Griffin
http://sandiego.indymedia.org/media/2006/10/119637.pdf9/11 Synthetic Terror - Made in the USA by Webster Griffin Tarpley
http://sandiego.indymedia.org/media/2006/10/119638.pdfCrossing The Rubicon: The Decline of American Empire At The End of The Age of Oil by Michael Ruppert
http://sandiego.indymedia.org/en/2007/01/124769.shtmlBody of Secrets: Anatomy of the Ultra-Secret National Security Agency by Bamford -
http://sandiego.indymedia.org/media/2007/02/125027.pdfNATO's Secret Armies - Operation Gladio and Terrorism in Western Europe
2005 by Daniele Ganser
http://sandiego.indymedia.org/media/2006/10/119640.pdfThe Best Democracy Money Can Buy by Greg Palast -
http://sandiego.indymedia.org/media/2007/02/125032.pdf The Iron Triangle - Inside The Secret World Of The Carlyle Group by Dan Briody (2003):
http://newmexico.indymedia.org/uploads/200...rlyle_group.pdf Order Out of Chaos by Paul Joseph Watson
http://sandiego.indymedia.org/media/2006/10/119693.pdf "Cognitive linguistics professor George Lakoff , founder of the progressive think tank the Rockridge Institute, has argued, with respect to the phrase "War on Terror", "Terror is a general state, and it's internal to a person. Terror is not the person we're fighting, the 'terrorist.' The word terror activates your fear, and fear activates the strict father model, which is what conservatives want. The 'war on terror' is not about stopping you from being afraid, it's about making you afraid." He adds "...terrorists are actual people, and relatively small numbers of individuals, considering the size of our country and other countries. It's not a nation-state problem. War is a nation-state problem." Lakoff believes that the frame invoked by the phrase plays a key role in the political changes enacted by President Bush through the implication of the frame."
frater plecticus
28th May 2007 - 07:34 PM
QUOTE (David B. Benson+May 28 2007, 07:09 PM)
(1) There is no such thing as
free-fall speed. This is the first indication of the
inanity of this site.
(2) An acceleration of (2/3)g is far short of
nearly free-fall acceleration.
(3) WTC 1 took
18 seconds to completely collapse (except for the temporary spire). This was determined by poster
shagster listening to the Health video. I don't consider eighteen seconds to be
about ten seconds. So here is another inaccuracy.
(4) Conclusion:
A & E for Truth is actually about spreading
lies...
The time it took for any given object to fall from the top of the twin towers was a *constant.
Therefore if speed is the rate of change of position, the average speed at which an object falls from the top of the tower to the bottom is calculable.
The time t required for an object to fall from a height h (in a vacuum) is given by the formula t = sqrt(2h/g), where g is the acceleration due to gravity. Thus an object falling from the top of one of the towers (taking h = 1306 feet and g = 32.174 ft/sec2) would take 9.01 seconds to hit the ground if we ignore the resistance of the air and a few seconds longer if we take air resistance into account.
*neglecting air resistance and atmospheric conditions
FROM NIST WEBSITE
6. How could the WTC towers collapse in only 11 seconds (WTC 1) and 9 seconds (WTC 2)—speeds that approximate that of a ball dropped from similar height in a vacuum (with no air resistance)?
NIST estimated the elapsed times for the first exterior panels to strike the ground after the collapse initiated in each of the towers to be approximately 11 seconds for WTC 1 and approximately 9 seconds for WTC 2. These elapsed times were based on: (1) precise timing of the initiation of collapse from video evidence, and (2) ground motion (seismic) signals recorded at Palisades, N.Y., that also were precisely time-calibrated for wave transmission times from lower Manhattan (see NCSTAR 1-5A).
As documented in Section 6.14.4 of NIST NCSTAR 1, these collapse times show that:
“… the structure below the level of collapse initiation offered minimal resistance to the falling building mass at and above the impact zone. The potential energy released by the downward movement of the large building mass far exceeded the capacity of the intact structure below to absorb that energy through energy of deformation.
Since the stories below the level of collapse initiation provided little resistance to the tremendous energy released by the falling building mass, the building section above came down essentially in free fall, as seen in videos. As the stories below sequentially failed, the falling mass increased, further increasing the demand on the floors below, which were unable to arrest the moving mass.”
In other words, the momentum (which equals mass times velocity) of the 12 to 28 stories (WTC 1 and WTC 2, respectively) falling on the supporting structure below (which was designed to support only the static weight of the floors above and not any dynamic effects due to the downward momentum) so greatly exceeded the strength capacity of the structure below that it (the structure below) was unable to stop or even to slow the falling mass. The downward momentum felt by each successive lower floor was even larger due to the increasing mass.
From video evidence, significant portions of the cores of both buildings (roughly 60 stories of WTC 1 and 40 stories of WTC 2) are known to have stood 15 to 25 seconds after collapse initiation before they, too, began to collapse. Neither the duration of the seismic records nor video evidence (due to obstruction of view caused by debris clouds) are reliable indicators of the total time it took for each building to collapse completely.
wcelliott
28th May 2007 - 07:42 PM
QUOTE
SEPTEMBERGATE IS COMING.......
Your signature indicates to me that you have a political agenda here that belies your claim of objectivity.
You claim that there are myriad "facts" supporting the CT notion of 9/11.
Produce one.
You've provided links to a lot of politically-motivated innuendo and speculation, none of which makes any real sense, so go ahead, produce your one, best Fact supporting the notion that the WTC wasn't felled by terrorist-hijacked airliners and the subsequent fires/impact damage.
Take your best shot.
frater plecticus
28th May 2007 - 07:54 PM
QUOTE (wcelliott+May 28 2007, 07:42 PM)
Your signature indicates to me that you have a political agenda here that belies your claim of objectivity.
You claim that there are myriad "facts" supporting the CT notion of 9/11.
Produce one.
You've provided links to a lot of politically-motivated innuendo and speculation, none of which makes any real sense, so go ahead, produce your one, best Fact supporting the notion that the WTC wasn't felled by terrorist-hijacked airliners and the subsequent fires/impact damage.
Take your best shot.
Not really. Somebody should be held accountable for 9-11. That's what Septembergate is.
The burden of proof is on you to prove that freedom-hating arabs fueled by a couple of Korans and Allah Akabar's bankrolled by Bin Laden commandeered 4 aircraft outfoxing the defenses of the most technologically advanced country in the world, subsequently crashing into 3 highly symbolic structures, with the loss of around 3000 lives.
The bush administration have lied about most things since 9-11, why should I believe them about 9-11?
The fallacy of appealing to lack of proof of the negative is a logical fallacy of the following form:
"X is true because there is no proof that X is false."
It is asserted that a proposition is true, only because it has not been proven false.
I am not convinced that Bin Laden was responsible for 9--11. Show me proof. It's your claim, not mine. I have no theory about 9-11, I just don't believe the OCT.
wcelliott
28th May 2007 - 07:59 PM
QUOTE
The bush administration have lied about most things since 9-11, why should I believe them about 9-11?
In other words, you can't provide me with one fact supporting your position.
frater plecticus
28th May 2007 - 08:00 PM
QUOTE (wcelliott+May 28 2007, 07:59 PM)
In other words, you can't provide me with one fact supporting your position.
What is my position, exactly?
wcelliott
28th May 2007 - 08:14 PM
QUOTE
What is my position, exactly?
That your cynicism makes you smarter than me.
frater plecticus
28th May 2007 - 08:27 PM
QUOTE (wcelliott+May 28 2007, 08:14 PM)
That your cynicism makes you smarter than me.
We do agree on one thing, however... Free Will
David B. Benson
28th May 2007 - 08:30 PM
This is a
PhysOrgForum thread. Let's stick to sci-tech, exclusively.
frater plecticus
28th May 2007 - 08:31 PM
QUOTE (David B. Benson+May 28 2007, 08:30 PM)
This is a
PhysOrgForum thread. Let's stick to sci-tech, exclusively.
No
wcelliott
28th May 2007 - 08:42 PM
QUOTE
This is a PhysOrgForum thread. Let's stick to sci-tech, exclusively.
Fair enough. I was asking him for sci-tech-type facts supporting the CT/CD position, for further sci-tech-type discussion.
frater plecticus
28th May 2007 - 08:53 PM
What is this? Internet police?
In an off topic general discussion forum too.
Daru
28th May 2007 - 09:32 PM
QUOTE (NEU-FONZE+May 28 2007, 06:53 PM)
...
I, and others such as Shagster and David Benson, have looked at this in great detail. Newton's Law of Momentum Conservation is simply that for an isolated (closed) system, the total momentum is conserved. For the WTC collapse we are dealing with inelastic collisions of the type M(n). V1 = M(n+1). V2, where M(n) is the mass of a block of n floors. If you work through the math, with conservation of momentum applied to each impact, you will find that the falling block picks up speed quite nicely and behaves as if the acceleration due to gravity was about 2/3g. This adds but a few seconds to the collapse time, as was observed for both towers. Hence, Newton's Laws were NOT violated and this argument is specious to say the least!
In my opinion you people are doing it a way to complicated. The "falling block" "picks up speed" and add mass etc... was simply not what happened (in the wtc 1&2 case) ...based on evidence, videos photos ... The "falling block" turned to dust!! The towers turned to dust at a nearly free fall speed!!
But wtc 7 is so obvious CD that I can not understand how people can say that a "fire" did it!
If a fire can destroy massive steelstructure CD style... then there is no use for cd company any more! Just cut 2-3 columns and then set a the building on fire and maybe put some fuel on it... jet fuel would be exelent!.
David B. Benson
28th May 2007 - 09:54 PM
QUOTE (Daru+May 28 2007, 09:32 PM)
The towers turned to dust at a nearly free fall speed!!
(1) There is no such thing as
free fall speed. There is a free fall acceleration, the unimpeded action of the force of gravity.
(2) The acceleration, for the first few seconds, was
WTC 1: (2/3) g
WTC 2: (3.4) g
which is high, but not
nearly free fall.
(3) About 1.6 million tons of materials, not all dust, were hauled from Ground Zero, including WTC 7, to the Fresh Kills landfill. There, thousands of tons of steel was sent for recycling.
And by the way, several who post here accuse NEU-FONZE, shagster and me of making things too simple, not too complicated.
Grumpy
28th May 2007 - 10:00 PM
Daru
QUOTE
In my opinion you people are doing it a way to complicated. The "falling block" "picks up speed" and add mass etc... was simply not what happened...based on evidence, videos photos etc. The "falling block" turned to dust!! The towers turned to dust at a nearly free fall speed!!
No, it did not turn to dust. Very little of the mass of those towers was crushed to dust size, the dust sized particles just occupy a much larger volume than they would as a solid because they are carried in the air. Whenever any building collapses(from cd or earthquake) there is always a large volume of dust, but when the dust settles by far the majority of the building is still there in the rubble.
And once and for all, "free fall speed" is a meaningless phrase!!! Speed is one thing, Free fall ACCELERATION is quite another!!!
Speed= the rate of change of position
acceleration= rate of change of speed
Free fall=acceleration due to gravity(32ft/sec/sec)
QUOTE (->
| QUOTE |
| In my opinion you people are doing it a way to complicated. The "falling block" "picks up speed" and add mass etc... was simply not what happened...based on evidence, videos photos etc. The "falling block" turned to dust!! The towers turned to dust at a nearly free fall speed!! |
No, it did not turn to dust. Very little of the mass of those towers was crushed to dust size, the dust sized particles just occupy a much larger volume than they would as a solid because they are carried in the air. Whenever any building collapses(from cd or earthquake) there is always a large volume of dust, but when the dust settles by far the majority of the building is still there in the rubble.
And once and for all, "free fall speed" is a meaningless phrase!!! Speed is one thing, Free fall ACCELERATION is quite another!!!
Speed= the rate of change of position
acceleration= rate of change of speed
Free fall=acceleration due to gravity(32ft/sec/sec)
But wtc 7 is so obvious CD that I can not understand how people can say that a "fire" did it!
Because it is only "obviously a CD" to those who know nothing about it and cannot think for themselves.
Grumpy
frater plecticus
28th May 2007 - 10:02 PM
QUOTE (David B. Benson+May 28 2007, 09:54 PM)
(1) There is no such thing as
free fall speed. There is a free fall acceleration, the unimpeded action of the force of gravity.
(2) The acceleration, for the first few seconds, was
WTC 1: (2/3) g
WTC 2: (3.4) g
which is high, but not
nearly free fall.
(3) About 1.6 million tons of materials, not all dust, were hauled from Ground Zero, including WTC 7, to the Fresh Kills landfill. There, thousands of tons of steel was sent for recycling.
Where do you get your figures from?
FROM NIST WEBSITE
NIST estimated the elapsed times for the first exterior panels to strike the ground after the collapse initiated in each of the towers to be approximately 11 seconds for WTC 1 and approximately 9 seconds for WTC 2. These elapsed times were based on: (1) precise timing of the initiation of collapse from video evidence, and (2) ground motion (seismic) signals recorded at Palisades, N.Y., that also were precisely time-calibrated for wave transmission times from lower Manhattan (see NCSTAR 1-5A).
AND the math..
The time t required for an object to fall from a height h (in a vacuum) is given by the formula t = sqrt(2h/g), where g is the acceleration due to gravity. Thus an object falling from the top of one of the towers (taking h = 1306 feet and g = 32.174 ft/sec2) would take 9.01 seconds to hit the ground if we ignore the resistance of the air and a few seconds longer if we take air resistance into account.
David B. Benson
28th May 2007 - 10:11 PM
QUOTE (frater plecticus+May 28 2007, 10:02 PM)
Where do you get your figures from?
NEU-FONZE measured the drop of the top of both towers and published this data on earlier incarnations of this thread. Using this data, it was an easy matter to write a computer program to find the best value for the acceleration, a, in the formula
d = (1/2)at^2
by finding that value which minimizes the rms error in the data. To two decimal places one obtains
WTC 1: 0.66 g
WTC 2: 0.75 g
One can go further with the data analysis to show that using a = g gives a terrible fit to the data. Hence, far from free fall near the surface of the earth...
Grumpy
28th May 2007 - 10:11 PM
frater plecticus
QUOTE
NIST estimated the elapsed times for the first exterior panels to strike the ground after the collapse initiated in each of the towers to be approximately 11 seconds for WTC 1 and approximately 9 seconds for WTC 2.
But the period of collapse is calculated from initiation until the LAST part of the building hits the ground, not the first. That should be simple for you to understand.
Grumpy
frater plecticus
28th May 2007 - 10:54 PM
The last part of the building will never hit the ground.
Grumpy
28th May 2007 - 10:59 PM
frater plecticus
QUOTE
The last part of the building will never hit the ground.
nonsense!!!
Grumpy
David B. Benson
28th May 2007 - 11:36 PM
QUOTE (frater plecticus+May 28 2007, 10:54 PM)
The last part of the building will never hit the ground.
The antenna tower, the uppermost part of WTC 1, was found in West Street.
NEU-FONZE
28th May 2007 - 11:52 PM
Frater Plecticus:
I think the confusion arises because NIST is effectively talking about the time for the bottom of the upper block of each tower to hit the ground. In this case we are talking about a drop time from 95/110 x 416 meters for WTC 1 = 359 meters, and 80/110 x 416 = 303 meters for WTC 2.
Now the free fall times may be calculated using t = Sqrt{2h/g}, 8.56 seconds for WTC 1 and 7.86 seconds for WTC 2.
The "11 seconds for WTC 1 and approximately 9 seconds for WTC 2" that you quote are significantly longer than these free fall times, so I have no problem with this.
Grumpy
29th May 2007 - 12:09 AM
David B. Benson
QUOTE
The antenna tower, the uppermost part of WTC 1, was found in West Street.
No, according to frater it is still floating in the air somewhere over ground zero!!!
I think the problem may be a matter of how you measure the collapse. You have measured the initial acceleration by measuring the movement of the top of the building. NIST evidently measured it by when the FIRST panels hit the ground, but the collapse was far from complete at that point as the first panels to hit were freefalling through air while the collapse front was falling slower through the building. Accurate timing of the collapse visibly is not possible due to being obscured by dust, but audio timing gives times of ~12 sec for two, ~14 sec for one, which matches up fairly well with the estimates derived from the first few seconds.
Grumpy
David B. Benson
29th May 2007 - 12:20 AM
QUOTE (Grumpy+May 29 2007, 12:09 AM)
... but audio timing gives times of ... ~14 sec for one, which matches up fairly well with the estimates derived from the first few seconds.
shagster has listened to the Heath video (only audio usable at the end, of course). He states that there is
rumble, rumble, rumble, bang!
with the bang right at 18 seconds. I opine the bang is the west wall of WTC 1 hitting West Street. I would think its falling over would be fairly quiet, so I take the rumble to indicate the upper block ( zone A ) still falling apart right up until the end. I estimate the west wall portion took about 5 seconds to fall over, so crush-down is complete right about 13 seconds, as the crushing mass is what starts the west wall on its way.
This means the estimate from the first 3 seconds is too fast. The collapse acceleration has to become less later on.
The situation for WTC 2 is even more extreme, that is, acceleration way down, but that's for another post another day...
newton
29th May 2007 - 03:23 AM
QUOTE (frater plecticus+May 28 2007, 07:13 PM)
Firstly I don't figure that Bush 'plotted' the attacks. Your assumption that anyone that doubts the OCT believes that Bush and/or Cheney were somehow directly complicit in the attacks themselves is nothing more than that, an assumption, which In my case specifically, is downright wrong.
I don't waste my time arguing about reflections in windscreens or waiting for the second coming of some non-existent prophet or his camel-selling counterpart, but the absolute and inescapable fact is that the Bush Administration has lied about so many aspects of the attacks themselves, although this in itself is not proof of complicity. As I have said before...
Maybe if people like yourself weren't so condescending, with the cocksure arrogance of a schoolboy let loose in the Physics Lab for the first time there would be more educated debate here.
I won't even stoop to your gutter level and answer the charge of "Terrorist sympathizer".
To be quite honest, I couldn't care even if Certain elements of the US security apparatus were complicit in the attacks themselves. It wouldn't exactly be
unprecedented now, would it?
America's War on Terrorism by Michel Chossudovsky
http://sandiego.indymedia.org/media/2006/11/122510.pdf The New Pearl Harbor - Disturbing Questions about the Bush()() Admin. and
9/11 by David Ray Griffin
http://sandiego.indymedia.org/media/2006/10/119637.pdf9/11 Synthetic Terror - Made in the USA by Webster Griffin Tarpley
http://sandiego.indymedia.org/media/2006/10/119638.pdfCrossing The Rubicon: The Decline of American Empire At The End of The Age of Oil by Michael Ruppert
http://sandiego.indymedia.org/en/2007/01/124769.shtmlBody of Secrets: Anatomy of the Ultra-Secret National Security Agency by Bamford -
http://sandiego.indymedia.org/media/2007/02/125027.pdfNATO's Secret Armies - Operation Gladio and Terrorism in Western Europe
2005 by Daniele Ganser
http://sandiego.indymedia.org/media/2006/10/119640.pdfThe Best Democracy Money Can Buy by Greg Palast -
http://sandiego.indymedia.org/media/2007/02/125032.pdf The Iron Triangle - Inside The Secret World Of The Carlyle Group by Dan Briody (2003):
http://newmexico.indymedia.org/uploads/200...rlyle_group.pdf Order Out of Chaos by Paul Joseph Watson
http://sandiego.indymedia.org/media/2006/10/119693.pdf "Cognitive linguistics professor George Lakoff , founder of the progressive think tank the Rockridge Institute, has argued, with respect to the phrase "War on Terror", "Terror is a general state, and it's internal to a person. Terror is not the person we're fighting, the 'terrorist.' The word terror activates your fear, and fear activates the strict father model, which is what conservatives want. The 'war on terror' is not about stopping you from being afraid, it's about making you afraid." He adds "...terrorists are actual people, and relatively small numbers of individuals, considering the size of our country and other countries. It's not a nation-state problem. War is a nation-state problem." Lakoff believes that the frame invoked by the phrase plays a key role in the political changes enacted by President Bush through the implication of the frame."
i missed you.
the frater rocks the world.
newton
29th May 2007 - 03:39 AM
QUOTE (David B. Benson+May 28 2007, 11:36 PM)
The antenna tower, the uppermost part of WTC 1, was found in West Street.
how did it get over there?
why was it not sitting on top of the debris pile?
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