How WTC 7 was pulled down

[Furcifer]

Blech... guy's just trying to see how many different ways he can rearrange thermodynamic terms. I betcha he couldn't actually set up a proper, applicable equation if he had a gun to his head.

Yes this is what he's doing. He seems to be trying to incorporate the little hints we give him into his "patchwork" attempt at a thermodynamic analysis. He's conflating the second law and conservation of energy and then equating them.
I don't think there's anything inherently wrong with what he's doing. It's just that there's absolutely no room for error. If he fails to account for the smallest amount of energy his analysis is useless. Doing this on a closed system would be almost impossible, on an open system like WTC7 the probability of success approaches zero.

As an example, if you were tasked with determining if the dynamite that blew up the mine went off on accident, or was deliberately set off in an act of vandalism, you could calculate the change in entropy.

If you could somehow pick up all the pieces and put them back together again and determine the amount of energy required to spread them over the scene you could theoretically determine if someone lit the fuse. The extra energy of the lit match would violate the second law and you could say for certain it was deliberate.

But the energy of the lit match is so small in comparison, if you missed a single piece evidence, the smallest rock moved 4 feet from the blast area instead of 3 feet your analysis would be flawed.

In an open system, all it takes is the slightest breeze to blow the unstable dynamite off the shelf and cause the accident. Miss that and again your analysis is flawed.

In the WTC there are litterally trillions of pieces you would have to put back together painstakingly to analyze the entropy of the system. Many of them we hidden from view, I have no idea how you would determine if a ream of paper was from the 9th floor or the 29th floor.

It's such a mind boggling proposition. I don't think this poster even realizes how ridiculous it is. It's like a child looking up into the night sky and saying with authority they are going to count all the stars in the heavens. So cute!

 

[Miragememories]

"Yes this is what he's doing. He seems to be trying to incorporate the little hints we give him into his "patchwork" attempt at a thermodynamic analysis. He's conflating the second law and conservation of energy and then equating them.
I don't think there's anything inherently wrong with what he's doing. It's just that there's absolutely no room for error. If he fails to account for the smallest amount of energy his analysis is useless. Doing this on a closed system would be almost impossible, on an open system like WTC7 the probability of success approaches zero."

How do you determine such success vs failure?

"As an example, if you were tasked with determining if the dynamite that blew up the mine went off on accident, or was deliberately set off in an act of vandalism, you could calculate the change in entropy.

If you could somehow pick up all the pieces and put them back together again and determine the amount of energy required to spread them over the scene you could theoretically determine if someone lit the fuse. The extra energy of the lit match would violate the second law and you could say for certain it was deliberate.

But the energy of the lit match is so small in comparison, if you missed a single piece evidence, the smallest rock moved 4 feet from the blast area instead of 3 feet your analysis would be flawed.

In an open system, all it takes is the slightest breeze to blow the unstable dynamite off the shelf and cause the accident. Miss that and again your analysis is flawed.

In the WTC there are litterally trillions of pieces you would have to put back together painstakingly to analyze the entropy of the system."

With such a giant example as the WTC7, how precise must energy accountability be to reach a determination?

"Many of them we hidden from view, I have no idea how you would determine if a ream of paper was from the 9th floor or the 29th floor."

Maybe by tracing the manufacturer's sku, bar code etc.

"It's such a mind boggling proposition. I don't think this poster even realizes how ridiculous it is. It's like a child looking up into the night sky and saying with authority they are going to count all the stars in the heavens. So cute!"

Only we aren't counting the stars in the sky.

MM

 

[excaza]

Maybe by tracing the manufacturer's sku, bar code etc.

You could tell precisely where a soda bottle was on my desk by scanning the bar code? Fascinating.

Only we aren't counting the stars in the sky.

That would be much easier.

 

[Sabretooth]

How do you determine such success vs failure?



With such a giant example as the WTC7, how precise must energy accountability be to reach a determination?



Maybe by tracing the manufacturer's sku, bar code etc.



Only we aren't counting the stars in the sky.

MM

Wow. You just have no idea on how the real-world operates, do you?

Out of curiosity, what's your favorite brand of aluminum foil?

 

[Furcifer]

With such a giant example as the WTC7, how precise must energy accountability be to reach a determination?

All it takes is a carelessly thrown cigarette butt to burn down a forest and a few hundred homes.

 

[Newtons Bit]

All it takes is a carelessly thrown cigarette butt to burn down a forest and a few hundred homes.

Good luck trying to back compute the entropy change of that

 

[Oystein]

How do you determine such success vs failure?

Success: Getting it right
Failure: Getting it wrong

In the WTC there are litterally trillions of pieces you would have to put back together painstakingly to analyze the entropy of the system."

With such a giant example as the WTC7, how precise must energy accountability be to reach a determination?

You really don't understand, do you?
The ridiculously difficult method is to account for entropy.
It is MUCH more easy to account for energy to get determinate and reliable results.

...
Only we aren't counting the stars in the sky.

MM

In a very real sense, mzelinski is.

 

[mzelinski]

regarding posts #1, #151, #252, #333, #345, #378

Ok, I had to look up what the term "isentropic" meant. The definitions I'm finding basically amount to "with unchanging entropy; at constant entropy".

And to this, I must go "Treat WTC 7 isentropically?? Buh"? [qimg]http://i110.photobucket.com/albums/n94/elmondohummus/buh.gif[/qimg]

Maybe I'm ignorant here, but: Given that the 7 World trade went from a highly ordered to a disordered system, and that it went from having elements of itself having a gravitational PE built up (from the process of constructing the tower) to having those components have far less due to being on or very near the ground, how can anyone posit that there is no entropy change? That simply makes no sense to me. It seems to me that, if you try to make an analysis describe 7 World Trade's collapse as having constant entropy, you're going to fail because clearly energy was dispersed in the collapse. Treating it "isentropically" seems to me to posit a sort of collapse that's reversible without an additional input of energy. And clearly, that has no chance in hell of happening. So why use the term? Or am I, the layman, misunderstanding the concept here?

. . . .

Ok, that’s good, it is a critical piece of the puzzle.
Perhaps presenting the case in installments makes the argument difficult to follow. We may summarize it as follows.

The highly symmetric, nearly instantaneous, nearly free fall collapse of WTC7 represents release from a highly ordered – or relative low entropy – state. Fortunately for us, due to the relatively isolated free fall Phase 2, we are able to quantify this entropy change by identifying it with the kinetic energy of the upper section of the building, ΔS_f = -KE/T. The overall entropy of the system must increase, and in order for the collapse to be spontaneous, this low entropy state at the output must have been accompanied by a larger increase in entropy ΔS > +KE/T elsewhere prior to collapse. But recall, ΔS > 0 is our condition for instability, and at no point do we see a loss of symmetry significant enough to indicate the onset of instability. Therefore, since ΔS appears to be never greater than zero, at best the condition is ΔS = 0. This implies no change of state, and that the output energy is the same as the input energy, E_f = E_i , where E_i is the work done by thermal expansion of the girder. Or, if you prefer, the potential energy of the system changes by no more than the amount of the input energy, ΔΠ = E_i , in which case we may expect to see the roofline sink a few centimeters, establish a new equilibrium position, and remain stable.

But in reality the output response, rather than being the amount of energy E_f = E_i as we would expect given the conditions, is in fact the kinetic energy of the upper section of the building, E_f = KE. This discrepancy suggests that a large amount of entropy had to have been added to the system in order to satisfy the overall entropy requirement, and for the building to spontaneously collapse in accordance with the Second Law of Thermodynamics. This additional entropy is introduced, of course, in the form of an energy input.

The Phase 2’s departure from perfect free fall acceleration, the collapse’s departure from perfect symmetry, the energy consumed in Phase 1, etc. will each introduce some uncertainty into the energy deficit, but to a first order approximation, that additional quantity is ΔE = KE - E_i . This is a large energy input.

The NIST attempts to resolve this paradox by postulating a cascade of internal damage hollowed out the building prior to the final collapse of the remaining shell, as seen in the simulation. In this case, the proportions of ΔS_f and ΔS may vary relative to each other, and therefore have different values than in the case above, but the lack of loss of symmetry still establishes ΔS = 0 as the dominant condition that must be satisfied. This again limits the extent of internal damage to ΔΠ = E_i , and, based on the same arguments as above, suggests that the NIST explanation did not occur.

 

[kylebisme]

No one has produced a model to serve as experimental confirmation that CD could bring a building down anywhere near as quickly and completely as WTC 7 came down.

There's not only many models to substantiate that fact, but plenty of real world examples too. You can see some side by sides of both here:



Again, where's even a simulation to support the notion that impact damage and fire bringing down a building anywhere near as quickly and completely as that? You've got squat because such notions have no basis any reality.

 

[Furcifer]

The highly symmetric, nearly instantaneous, nearly free fall collapse of WTC7 represents release from a highly ordered – or relative low entropy – state.

We could say that.

Fortunately for us, due to the relatively isolated free fall Phase 2, we are able to quantify this entropy change by identifying it with the kinetic energy of the upper section of the building, ΔS_f = -KE/T.

We can't say that. "Relatively isolated" is nonsense. It's like "a little bit pregnant". The system is either isolated or it isn't. Given the fact that there were fires burning all over the place, and fires need oxygen, the system wasn't isolated. Not even close.

But recall, ΔS > 0 is our condition for instability, and at no point do we see a loss of symmetry significant enough to indicate the onset of instability.

ΔS was greater than 0 well before the onset of instability.

Therefore, since ΔS appears to be never greater than zero, at best the condition is ΔS = 0.

You just said the condition for instability was ΔS > 0, but now it's never greater than 0. Why don't you make up your mind

This implies no change of state, and that the output energy is the same as the input energy, E_f = E_i , where E_i is the work done by thermal expansion of the girder.

Wha? The work done by the expansion of the girder is equal to the output energy?

Or, if you prefer, the potential energy of the system changes by no more than the amount of the input energy, ΔΠ = E_i , in which case we may expect to see the roofline sink a few centimeters, establish a new equilibrium position, and remain stable.

But in reality the output response, rather than being the amount of energy E_f = E_i as we would expect given the conditions, is in fact the kinetic energy of the upper section of the building, E_f = KE.

Now the kinetic energy of the upper section is equal to the work done by the thermal expansion of the girder. Hilarious.

This discrepancy suggests that a large amount of entropy had to have been added to the system in order to satisfy the overall entropy requirement, and for the building to spontaneously collapse in accordance with the Second Law of Thermodynamics. This additional entropy is introduced, of course, in the form of an energy input.

Yah, fires have a crazy way of making things hot and throwing entropy all over the rug.

The Phase 2’s departure from perfect free fall acceleration, the collapse’s departure from perfect symmetry, the energy consumed in Phase 1, etc. will each introduce some uncertainty into the energy deficit, but to a first order approximation, that additional quantity is ΔE = KE - E_i . This is a large energy input.

I have a wild idea, how about the change in chemical potential due to combustion?

The NIST attempts to resolve this paradox by postulating a cascade of internal damage hollowed out the building prior to the final collapse of the remaining shell, as seen in the simulation.

What paradox? "Which came first; the fires or the failure?" you mean that paradox

In this case, the proportions of ΔS_f and ΔS may vary relative to each other, and therefore have different values than in the case above, but the lack of loss of symmetry still establishes ΔS = 0 as the dominant condition that must be satisfied.

I'd say the fires were the dominant condition, they made ΔS way not zero. Way.

This again limits the extent of internal damage to ΔΠ = E_i , and, based on the same arguments as above, suggests that the NIST explanation did not occur.

Now the internal damage is limited to the drop in the roof line

This is idiotic rambling and pure nonsense. It reminds me of when the Lion gets his brain in the Wizard of OZ, but he actually made sense.

 

[GlennB]

Or, if you prefer, the potential energy of the system changes by no more than the amount of the input energy, ΔΠ = E_i , in which case we may expect to see the roofline sink a few centimeters, establish a new equilibrium position, and remain stable.

There's a common belief (I don't know if it's true) that an avalanche can be triggered by shouting too loudly. Or by the fall of a single pebble.

So - go find an avalanche just waiting to happen. Toss a pebble at it. According to your analysis the avalanche will progress such that the loss of GPE (of the pile of stuff) will equal the input KE of the pebble, then stabilise.

In fact this reminds me of school physics experiments regarding static and dynamic coefficients of friction. You know the one, where a tiny nudge can overcome the higher coefficient of static friction and get the wooden block sliding down the slope, releasing all that GPE ?

I'm not sure if I've ever read such atrocious sophism as yours, mzelinski. You are intoxicated with the exuberance of your own verbosity (as the man said).

 

[triforcharity]

Maybe by tracing the manufacturer's sku, bar code etc.
MM

You're kidding, right? LOL!!! HILARIOUS!!

 

[triforcharity]

There's not only many models to substantiate that fact, but plenty of real world examples too. You can see some side by sides of both here:



Again, where's even a simulation to support the notion that impact damage and fire bringing down a building anywhere near as quickly and completely as that? You've got squat because such notions have no basis any reality.

Yes, explosives provide an EXACT amount of energy, and can be directed at an EXACT point.

FIRE, on the other hand, is an organic process. There are so many variables.

Time, Temperature, humidity, wind speed, wind direction, window failure causing additional ventilation, material placement, etc. etc. etc.

Now, predict where fire will effect a building, accounting for those variables, and you will win a Nobel Prize and an honorary PhD from every single college in the world.

Let us know how that works out for you.

 

[kylebisme]

Now, predict where fire will effect a building, accounting for those variables...

The issue isn't one of "where", but again, nobody has produced even a simulation to support the notion that any combination of such variables can bring down a building anywhere near as quickly and completely as WTC 7 came down, let alone a real world example. On the other hand, there are plenty of real world examples that show high-rise fires resulting in nothing of the sort, along with plenty of real world examples showing controlled demolitions doing do bring buildings down as quickly and completely as WTC 7 came down.

 

[Furcifer]

The issue isn't one of "where", but again, nobody has produced even a simulation to support the notion that any combination of such variables can bring down a building anywhere near as quickly and completely as WTC 7 came down, let alone a real world example. On the other hand, there are plenty of real world examples that show high-rise fires resulting in nothing of the sort, along with plenty of real world examples showing controlled demolitions doing do bring buildings down as quickly and completely as WTC 7 came down.

Again I'll reiterate how it works, you want to challenge the system, the man, the way it is, it's up to you to build the model and show how it really happened.

You plot the path of the sun and the stars and show how the Earth revolves around the sun.

If you want to show how an iceberg couldn't have sank the Titantic, guess what? it's up to you to build the model and run the simulation.

Shall I continue or do you understand how it works and why yours is a hopelessly failed cause?

 

[triforcharity]

The issue isn't one of "where", but again, nobody has produced even a simulation to support the notion that any combination of such variables can bring down a building anywhere near as quickly and completely as WTC 7 came down, let alone a real world example. On the other hand, there are plenty of real world examples that show high-rise fires resulting in nothing of the sort, along with plenty of real world examples showing controlled demolitions doing do bring buildings down as quickly and completely as WTC 7 came down.

You missed what I said. Too many big words?

You can get as close as possible. We have that with NIST's damage collapse model.

You cannot get any closer.

Yes, there are plenty of high rise fires that did not result in global collapse. Now, what is one thing that you will notice is common to all of those fires?

Most, if not all, were concrete framed, or had concrete cores.
Most also did not have 7 hours of completly unfought fires either.

Just because YOU don't believe it, doesn't mean it's not possible.

That is called an argument from incredulity.

BTW, define quickly. Thanks.

 

[Furcifer]

BTW, define quickly. Thanks.

def. quickly; "faster than I think it should be"; from the gut, based on that innate sense of knowing the collapse acceleration of two of the rarest buildings on the planet.

 

[Grizzly Bear]

On the other hand, there are plenty of real world examples that show high-rise fires resulting in nothing of the sort, along with plenty of real world examples showing controlled demolitions doing do bring buildings down as quickly and completely as WTC 7 came down.

By that same token there has been no such thing as a controlled demolition in which a large uncrontrolled fire was sparked intentionally while using a large projectile to cause serious structural damage on multiple floors before the detonation of any kind of explosives. See, we can play this game too.

 

[ElMondoHummus]

Ok, that’s good, it is a critical piece of the puzzle.
Perhaps presenting the case in installments makes the argument difficult to follow. We may summarize it as follows.

The highly symmetric, nearly instantaneous, nearly free fall collapse of WTC7 represents release from a highly ordered – or relative low entropy – state. Fortunately for us, due to the relatively isolated free fall Phase 2, we are able to quantify this entropy change by identifying it with the kinetic energy of the upper section of the building, ΔS_f = -KE/T. The overall entropy of the system must increase, and in order for the collapse to be spontaneous, this low entropy state at the output must have been accompanied by a larger increase in entropy ΔS > +KE/T elsewhere prior to collapse. But recall, ΔS > 0 is our condition for instability, and at no point do we see a loss of symmetry significant enough to indicate the onset of instability. Therefore, since ΔS appears to be never greater than zero, at best the condition is ΔS = 0. This implies no change of state, and that the output energy is the same as the input energy, E_f = E_i , where E_i is the work done by thermal expansion of the girder. Or, if you prefer, the potential energy of the system changes by no more than the amount of the input energy, ΔΠ = E_i , in which case we may expect to see the roofline sink a few centimeters, establish a new equilibrium position, and remain stable.

But in reality the output response, rather than being the amount of energy E_f = E_i as we would expect given the conditions, is in fact the kinetic energy of the upper section of the building, E_f = KE. This discrepancy suggests that a large amount of entropy had to have been added to the system in order to satisfy the overall entropy requirement, and for the building to spontaneously collapse in accordance with the Second Law of Thermodynamics. This additional entropy is introduced, of course, in the form of an energy input.

The Phase 2’s departure from perfect free fall acceleration, the collapse’s departure from perfect symmetry, the energy consumed in Phase 1, etc. will each introduce some uncertainty into the energy deficit, but to a first order approximation, that additional quantity is ΔE = KE - E_i . This is a large energy input.

The NIST attempts to resolve this paradox by postulating a cascade of internal damage hollowed out the building prior to the final collapse of the remaining shell, as seen in the simulation. In this case, the proportions of ΔS_f and ΔS may vary relative to each other, and therefore have different values than in the case above, but the lack of loss of symmetry still establishes ΔS = 0 as the dominant condition that must be satisfied. This again limits the extent of internal damage to ΔΠ = E_i , and, based on the same arguments as above, suggests that the NIST explanation did not occur.

Stop. I mean seriously, just stop. You're exercising your inner word salad chef in front of an audience who's common, unifying characteristic is the ability to tell pseudoscientific charlatanism when we see it.

I actually suspect you realize this as well as the fact that your premise is full of it and are just trying to mess with people for fun. I suspect this because nobody is so oblivious they set up energy equivalences like you do. I absolutely suck at physics, was no more than a middling student at it in college, only took undergraduate courses in it, and I still see what's wrong with your analysis: Saying that KE= E_f = E_i. That is utterly absurd because all E_i can ever do is stress or break connections between structural elements. It does not provide the energy for the fall. Gravity does that. KE is the result of gravity pulling the structure down, and the two are not equivalent, and indeed cannot be equivalent. Newton's Bit already told you this:

I wonder what mzelinski thinks would happen if one were to attach a large heavy weight on a crane over the Grand Canyon and then light the rope on fire with a match. Would he inevitably conclude that it took explosives to propel the weight downwards because the final kinetic energy of the weight far exceeds the thermal energy of the rope?

Maybe you're just screwing around to have fun, but whether or not that's the case, your suppositions fail and will continue to fail for as long as you equivocate the energy that goes into thermal expansion with the energy gravity provides to bring the building down once connections fail. There is zero reason to create that equivalence.

 

[ElMondoHummus]

The issue isn't one of "where", but again, nobody has produced even a simulation to support the notion that any combination of such variables can bring down a building anywhere near as quickly and completely as WTC 7 came down, let alone a real world example. On the other hand, there are plenty of real world examples that show high-rise fires resulting in nothing of the sort, along with plenty of real world examples showing controlled demolitions doing do bring buildings down as quickly and completely as WTC 7 came down.

How many real world examples were unfought fires? There is only one, single case I can think of where a structure fire was even worse - the Bejing TVCC tower - and that building was designed with the lessons learned from the September 11th tragedy in mind.

It's a red herring to frame things that way. 7 World Trade came down due to a combination of factors converging, so comparison to other fires should take those factors into account. Not doing so is the equivalent of saying a cancer patient shouldn't have died because people recover from the flu all the time: The fact that both were sick is only one of the factors that are comparable, and the ones being ignored are the ones that distinguish the cases from each other.