tsig
a carbon based life-form
- Joined
- Nov 25, 2005
- Messages
- 39,049
You wouldn't understand the answer.
New guy here: Questions for official hypothesis
- Thread starter Sizzler
- Start date
You wouldn't understand the answer.
eeyore1954
Philosopher
- Joined
- Jun 9, 2006
- Messages
- 6,811
Dave you wrote:
Quote:
I think it basically means if the first floor didn't cause the collapse the second floor impacts the bottom portion but now the height the mass has fallen from is twice as high because it is the second floor above the bottom portion of the building. So the energy in each new floor hitting the bottom is greater than the initial floor because the height it has fallen from increases by one floor each time.
Last edited:
Dave Rogers
Bandaged ice that stampedes inexpensively through
In a realistic collision, one would expect that the upper block and the lower block both suffer some damage. Therefore, even if only the upper block suffers a floor collapse, the top floor of the lower block would be damaged and would collapse more easily in a subsequent collision. The assumption, therefore, that crush-up involves no damage whatsoever to the lower block is biased in favour of the lower block surviving.
This idea of making assumptions biased against the case one is attempting to prove seems lost on many in the truth movement. Bazant's models are a case in point. Some truthers like to point out how the buckle length used by Bazant is too short, and that the actual failed columns show fractures every three floors; what they fail to admit is that this will reduce the energy requirement for failure by about an order of magnitude, while leaving the same amount of energy to drive the process. Therefore, Bazant is taking the scenario where collapse is least favourable, and showing that it is expected anyway. This, incidentally, is why Gregory Urich's calculations don't disprove global collapse; they simply suggest that, in the rather unrealistic scenario Bazant chooses, collapse may not be inevitable.
Also, when Gordon Ross uses the same assumptions as Bazant to try to prove collapse impossible, his methodology is completely wrong; to prove collapse impossible he would need to look at the case in which collapse is most favourable, then disprove it.
Dave
No. I'll explain.
No. It needn't be the floor below the collapsing section. What's important is that the KE of the top section did crush a floor, and this wasn't enough to halt it, so the KE increased before the top section fell one more floor-distance.
The floor just below the collapsing section did not halt the collapse, because some other floor failed in its place. In order to halt the collapse, the falling section must slow down. But this was not happening; you can see in the video that the fall is accelerating even as floors are crushed. The floor's destruction may have been postponed if other, weaker floors, gave way first, but what's important is whether the floor can halt the collapse. This did not happen.
No.
It is not ignored. There is a section named "Generalization of Differential Equation of Progressive Collapse" in Bazant et al. where it is addressed.
You see, we used simplified models earlier. For example, a bowling ball crushing through styrofoam boards. That was fine for its purpose, but it's not a perfect model. Floors in the top section can, of course, be crushed too.
But two points must be emphasized:
1. This does not halt the collapse. The falling mass and its speed are still increasing.
2. The top section can only be crushed up in the beginning of the collapse. Indeed, in the beginning the situation is roughly symmetrical, and floors on either side can collapse. But as the mass of crushed debris builds up, the situation stops being symmetrical, because the crushed debris doesn't just hang there, but is also accelerated by gravity. As the collapse proceeds, the laws of physics dictate - and calculations show - that the forces exerted by the crushed debris on the floors below will exceed forces exerted by the crushed debris on the floors above, by an ever greater amount. (No, this is not a violation of Newton's third law, as I recently explained in another thread. If you have troubles wrapping your mind around it, read my posts in "Questions to Apollo20".)
So although several floors of the top section may be initially crushed, eventually the floors below will be those that fail first. This is the crush-down phase.
Sizzler,
The answer to your question about how parts of the rubble piles reached temperatures of 1000°C is, fire. That is, ordinary combustion of class A combustibles, breaking down hydrocarbon compounds such as cellulose (paper) in an oxygen atmosphere into (primarily) CO2, CO, and H2O, releasing chemical energy as heat in the process.
This is counter-intuitive for most people because when they think of fire they think of flame, and they think that if there is no flame then a fire is extinguished. But a fire is not extinguished until the fuel is exhausted or the heat that sustains the chemical reactions has dissipated away. In the rubble piles, there was plenty of fuel to sustain a slow burning fire for many weeks, and there was almost nowhere for the heat to go. So, even though the combustion was slow because of the limited amount of oxygen diffusing through the rubble, there was no reason for it to stop, and the accumulating heat resulted in high temperatures.
It's the same reason a wood-burning stove, which limits the ventilation of the fire, reaches higher temperatures than an open campfire even though it burns its fuel at a slower rate. It's all about where the heat goes. (And a wood stove is designed to radiate heat to its surroundings; that's what it's for. If you prevented that heat loss by covering it with insulation on the outside, it would get hotter still; an iron wood stove under those conditions would eventually warp or sag to failure, but if you build it out of stuff that won't melt, it's called a kiln.)
Slow-burning oxygen-limited (and heat-trapped) fires reaching high temperatures, similar to the ground zero rubble fires, are seen in underground coal seam fires, some of which have burned for decades. Also cargo hold fires aboard ships -- imagine a longshoreman's smoldering cigarette butt ends up in the center of a 15-meter cube of (say) wooden crates packed with no space between them, ignites a small fire using the little available air nearby, and when that air is depleted a smoldering fire develops. The oxygen is limited but the heat is trapped, and the fire can't be put out by ordinary means. The fire will gradually grow, and eventually the heat will reach a place that will cause something (e.g. a deck or bulkhead) to fail, which will make fresh air available to the super-pre-heated fuel. That ship is in serious jeopardy.
Respectfully,
Myriad
The answer to your question about how parts of the rubble piles reached temperatures of 1000°C is, fire. That is, ordinary combustion of class A combustibles, breaking down hydrocarbon compounds such as cellulose (paper) in an oxygen atmosphere into (primarily) CO2, CO, and H2O, releasing chemical energy as heat in the process.
This is counter-intuitive for most people because when they think of fire they think of flame, and they think that if there is no flame then a fire is extinguished. But a fire is not extinguished until the fuel is exhausted or the heat that sustains the chemical reactions has dissipated away. In the rubble piles, there was plenty of fuel to sustain a slow burning fire for many weeks, and there was almost nowhere for the heat to go. So, even though the combustion was slow because of the limited amount of oxygen diffusing through the rubble, there was no reason for it to stop, and the accumulating heat resulted in high temperatures.
It's the same reason a wood-burning stove, which limits the ventilation of the fire, reaches higher temperatures than an open campfire even though it burns its fuel at a slower rate. It's all about where the heat goes. (And a wood stove is designed to radiate heat to its surroundings; that's what it's for. If you prevented that heat loss by covering it with insulation on the outside, it would get hotter still; an iron wood stove under those conditions would eventually warp or sag to failure, but if you build it out of stuff that won't melt, it's called a kiln.)
Slow-burning oxygen-limited (and heat-trapped) fires reaching high temperatures, similar to the ground zero rubble fires, are seen in underground coal seam fires, some of which have burned for decades. Also cargo hold fires aboard ships -- imagine a longshoreman's smoldering cigarette butt ends up in the center of a 15-meter cube of (say) wooden crates packed with no space between them, ignites a small fire using the little available air nearby, and when that air is depleted a smoldering fire develops. The oxygen is limited but the heat is trapped, and the fire can't be put out by ordinary means. The fire will gradually grow, and eventually the heat will reach a place that will cause something (e.g. a deck or bulkhead) to fail, which will make fresh air available to the super-pre-heated fuel. That ship is in serious jeopardy.
Respectfully,
Myriad
Drudgewire
Critical Doofus
- Joined
- Feb 27, 2006
- Messages
- 9,421
If I didn't know better, I'd swear some day someone will come in here claiming to be "just asking questions" and not really be a twoofer trying to play this retarded game.
Last edited:
Quad4_72
AI-EE-YAH!
- Joined
- Nov 7, 2006
- Messages
- 6,354
I don't mean to quote myself, but sizzler I really would like an answer to those questions. If you would be so kind
rwguinn
Penultimate Amazing
Ditti:If I didn't know better, I'd swear some day someone will come in here claiming to be "just asking questions" and not really be a twoofer trying to play this retarded game.
I want my $1e6, Randi!
If I didn't know better, I'd swear some day someone will come in here claiming to be "just asking questions" and not really be a twoofer trying to play this retarded game.
In this case, I'm not sure if it matters that much. The replies have been very good and have dealt with the questions that an interested layperson might have when they encounter the Truther arguments.
Just because most of it is old news to those of us that have been posting for months, doesn't mean there is no value in repeating it. Also, Sizzler's courteous behaviour has meant that this thread has turned out much better than many of the threads which address the technical side of the collapse.
Drudgewire
Critical Doofus
- Joined
- Feb 27, 2006
- Messages
- 9,421
I do agree with that. I just always find it amusing when the very first thing a "truther" does when they come here is resort to dishonesty.
Sizzler, it's an interesting coincidence that you mentioned this. I thought I was the only one to have ever suggested that particular approach to modeling the towers, and I only mentioned it here in this forum, in two posts, sometime around last May.
Since you are a new guy here, it must be a case of great minds thinking alike, right?
Not that I care one way or the other. I'm always willing to answer questions when I can. Who asked them or why is not my concern.
Respectfully,
Myriad
Last edited:
Stellafane
Village Idiot.
- Joined
- Apr 14, 2006
- Messages
- 8,368
...or maybe they take bets on the over/under for how many pages it takes before the OPer inevitably blows their cover (and cork), commences name-calling, and gets suspended/banned. It's like watching a re-run of Gilligan's Island. You know exactly what's going to happen, but still you watch because it's sort of amusing in a mindless way.
GregoryUrich
Graduate Poster
- Joined
- May 16, 2007
- Messages
- 1,316
You know we are talking about comparing models with models. If you are not willing to constructively engage the issue, why not find something better to do with your time?
GregoryUrich
Graduate Poster
- Joined
- May 16, 2007
- Messages
- 1,316
Dave is correct regarding my calculations and I don't claim to disprove gravity driven global collapse. Nonetheless, my calculations show that Bazant's papers are inconclusive.
FactCheck
Muse
- Joined
- Mar 26, 2007
- Messages
- 619
I have been comming to the conclusion that the leaders of the conspiracy industry are in it for the money (Books, donation, web site hits, tee-shirts, radio listeners ETC...) Politics (people who don't like our present government, both from the left and the right, people pushing candidates like Ron Paul) Religion (People who want a religious government or to push religion on the conspiracy consumers) Some are a combination of two or more. The followers are more complex. I think many of them gew up with X-files and a president who said "The scarest 9 words in the english language are "I'm from the government and I'm here to help" (Something like that) We are being taught to hate and fear it instead of realizing we are it. So when someone tells you the government murdered 3000 people you are more likely to believe it because it you have been brainwashed from birth. Government is always the bad guy in the movies.
The educational system does not teach critical thinking skills. They are told to read books and are not told to question them. Teachers are smart and professors smarter. If David Ray Griffin writes a book that says the towers were blown up then it most likely was in their mind. He is a teacher (Positive Alpha male) talking about the government (Negative group we fear), Our instincts cloud our judgment seamlessly - honed over hundreds of millions of of years to do so.
Its the reptilian brain which have taken over the followers. The pesky part of the brain which causes people to kill for 72 virgins. Or kill to sit on the right hand of the alpha male (God) in the after life.
Anyway, that's my conclusion.
I've watched the collapse several times over and over again in slow motion.
I can see that crush up happens before crush down. It is not just one or two floors. It is several floors.
I may be wrong or my eyes might be playing tricks.
Can anyone one here confirm that the possibility that crush up happened before crush down is real?
Lets assume for a second that I am not wrong.
Wouldn't that mean all of those upper floors are actually much weaker than the top floor of the lower section?
And, becuase the top floor of the lower section didnt collapse, wouldn't bazants number of 8.1 (?!?) be wrong, and NIST calculation of 6 floors falling.
I mean, if crush up happens before crush down, that really does mess the whole thing up.
It means the upper part of the lower section was strong enough to resist collapse of several floors (not all, but several).
It also means that the lower floors of the falling upper section were much weaker than the top floor of the upper section. This strikes me as odd because they are essentually made of the same material.
I understand that progressive collapse could still insue, but it seems to disprove the calculation by bazant and NIST.
I can see that crush up happens before crush down. It is not just one or two floors. It is several floors.
I may be wrong or my eyes might be playing tricks.
Can anyone one here confirm that the possibility that crush up happened before crush down is real?
Lets assume for a second that I am not wrong.
Wouldn't that mean all of those upper floors are actually much weaker than the top floor of the lower section?
And, becuase the top floor of the lower section didnt collapse, wouldn't bazants number of 8.1 (?!?) be wrong, and NIST calculation of 6 floors falling.
I mean, if crush up happens before crush down, that really does mess the whole thing up.
It means the upper part of the lower section was strong enough to resist collapse of several floors (not all, but several).
It also means that the lower floors of the falling upper section were much weaker than the top floor of the upper section. This strikes me as odd because they are essentually made of the same material.
I understand that progressive collapse could still insue, but it seems to disprove the calculation by bazant and NIST.
Last edited:
DGM
Skeptic not Atheist
Don't forget that the mass of those crush floors is still there to do the work of crushing the lower floors. I think what you see is the compaction of the floors damaged by the plane impacts.
DavidJames
Penultimate Amazing
That's pretty darn impressive. You are able to "disprove" the findings of hundreds of scientists and engineers who spent months reviewing the evidence, and you were able to do it in a couple hours (days?) by watching "the collapse several times over and over again in slow motion.
Hundreds of scientists and engineers who put their names and careers out in the public and on the line. People who've completed their education and are active in related careers. All disproved by an anonymous college student with one year of engineering classes.
Well done, my friend, well done.
Last edited:
I don't have one year of engineering class. But I do have one pair of eyes with 27 years of experience.
What Bazant models and what I see are two different things.
NIST states that the upper floor of the lower section had no chance of surviving the initial collapse. But, I think it is fair to say that the video evidence "might" not support this.
I keep thinking about theory and reality.
For example:
If i am not wrong, I think a box of matches has enough energy to make an eight cup pot of coffee.
However, in reality, no one could ever make an eight cup pot of water with just a box of matches and nothing else.
This is why it is hard for me to apply the theory of progressive collapse to WTC collapse.
i fully understand the theory now, and that is thanks to everyone here that has been very kind.
However I don't think it is unfair to use that theory and actually look at the reality.
I am seeing things that do not match.
For example Bazant uses mass shedding of 20% (right?), but in reality I see a lot more than that falling outside of the footprint.
Last edited: