How WTC 7 was pulled down

[beachnut]

Heiwa and others (see cmatrix’s discussion “Open Letter to Dave Thomas”) seem to make a solid case for the collapse of WTC7 being a controlled demolition, and one that agrees with observable features, such as the three corners falling in unison with a high degree of symmetry.

To make matters worse for the skeptics, the NIST even concluded that WTC7 did not suffer significant structural damage due to WTC1's collapse.

In "The NIST WTC 7 Report: Bush Science reaches its peak" Kevin Ryan calculates that the thermal expansion in the NIST’s explanation is less than 3 inches. For those of you here who do not support the controlled demolition explanation, do you feel that 3 inches is enough thermal expansion to bring down WTC7 in the way that it did? Is there a way to verify the NIST's hypothesis?

Cmatrix can't do simple physics and has no clue what KE is or how it is related to E=mgh! Do you lack the skills to understand that?

Heiwa sent a letter with all his ideas to a real journal and his work was called nonsensical and delusional. Not a thing you can do will save Heiwa's claims from being moronic tripe.

Kevin Ryan is the world expert on structural engineering, you better break this story to ABC, CBS, and NBC. There has to be a Pulitzer Prize here, right?

Better take what you have to the FBI, if you think it is true, you are withholding evidence if you don't rush it to the FBI. Are you are committing a crime by withholding evidence!

Wait, do you have evidence? NO

Never mind!

 

[kylebisme]

http://www.internationalskeptics.com/forums/showpost.php?p=6434860&postcount=267

http://www.internationalskeptics.com/forums/showpost.php?p=6436568&postcount=272

Ah, that is what I suspected you were describing, but that applies to things toppling over rather than coming straight down as WTC 7 did for around the first 100 feet of global collapse. WTC 7 basically the same as if in this meter stick example both the hand and the table were pulled out from under the stick at around the same moment. So, that is the issue with WTC 7, it behaved as if about 100 feet of its supporting structure was pulled out from under it at around the same moment.

Is there a way to verify the NIST's hypothesis?

Well one tests hypotheses through experiment, and in that regard you could try building a physical or digital model, the latter being what NIST claims they used to verify their conclusions. They've never publicly shown their model come down beyond what is shown here though, and I've yet to see anyone else come close to demonstrating reproducibility of NIST's hypothesis either, so absent that it just comes down to a matter of faith.

 

[beachnut]

...
Well one tests hypotheses through experiment, and in that regard you could try building a physical or digital model, the latter being what NIST claims they used to verify their conclusions. They've never publicly shown their model come down beyond what is shown here though, and I've yet to see anyone else come close to demonstrating reproducibility of NIST's hypothesis either, so absent that it just comes down to a matter of faith.

You can't do engineering? It comes down to engineering and science. Your idiotic faith in 911 truth lies is based on your lack of knowledge.

You have zero knowledge and think the WTC tower would topple like a tree. You weakly attack a model, which you don't understand due to ignorance. You would attack those who said the earth was not flat; you have an anti-intellectual approach, and fail to grasp 911 after 9 years of fail claims. What brought down the WTC complex in your fantasy conspiracy?

 

[Clarrisani]

Maybe address this instead of using cheap one-liners?

http://www.internationalskeptics.com/forums/showpost.php?p=6478555&postcount=120

MM

I was being relevant. The term "pull" means to pull down with cables. Clearly this is not what happened with WTC7.

What we cannot see, unfortunately, is the interior of the building. However, the collapse of the east penthouse combined with the shattering of windows in this area indicate that there is structural failure within the building. With the interior structure collapsed and the building now lacking the interior support, the exterior of the building followed suit.

WTC7, after all, did not have the design and structure of an average skyscraper. This, combined with the fire and damage sustained from the collapse of the towers, ultimately lead to the buildings collapse.

 

[kylebisme]

You weakly attack a model, which you don't understand due to ignorance.

Tell me oh wise one; why is it that these guys can show buildings come down like their models predicted:



...yet NIST can't show similar split screen videos with their WTC 7 model, nor has anyone else managed to produce such experimental confirmation for either WTC 7 or the towers?

 

[Dave Rogers]

Tell me oh wise one; why is it that these guys can show buildings come down like their models predicted:



...yet NIST can't show similar split screen videos with their WTC 7 model, nor has anyone else managed to produce such experimental confirmation for either WTC 7 or the towers?

Because the exact placement of charges, their exact yield, and their effect on the supporting structures was very precisely known, so the initial conditions for modelling could be established very accurately. In WTC7, in contrast, observation of internal failures was impossible, so the models had to be extrapolated from a far more remote starting point, leading to greater cumulative errors.

So, yes, that's a very strong argument against WTC7 having been brought down by precisely controlled explosive demolition charges. Thank you for bringing it to our attention.

Dave

 

[triforcharity]

Because the exact placement of charges, their exact yield, and their effect on the supporting structures was very precisely known, so the initial conditions for modelling could be established very accurately. In WTC7, in contrast, observation of internal failures was impossible, so the models had to be extrapolated from a far more remote starting point, leading to greater cumulative errors.

So, yes, that's a very strong argument against WTC7 having been brought down by precisely controlled explosive demolition charges. Thank you for bringing it to our attention.

Dave

Damn, you beat me to it.

Thermodynamics is a science. But, it is NOT an exact science. Many things can affect fire. Time, humidity, wind direction, speed, contents of the building, placement of those items, volume of those items, etc etc.

 

[Edx]

Damn, you beat me to it.

Thermodynamics is a science. But, it is NOT an exact science. Many things can affect fire. Time, humidity, wind direction, speed, contents of the building, placement of those items, volume of those items, etc etc.

Im no scientist or expert by any means, but isnt it just as exact as the variables that can be predicted? Like, the law is always right its just not easily observed whats going on in every particular situation. Does that make sense?

 

[Edx]

Tell me oh wise one; why is it that these guys can show buildings come down like their models predicted:



...yet NIST can't show similar split screen videos with their WTC 7 model, nor has anyone else managed to produce such experimental confirmation for either WTC 7 or the towers?

What Dave said.

And you just proved how vacuous the truthers argument is, if these guys can do it, why cant you? Oh yes nevermind, I forgot, you dont know the properties of this mythical super secret quiet thermite explosives.

 

[triforcharity]

Im no scientist or expert by any means, but isnt it just as exact as the variables that can be predicted? Like, the law is always right its just not easily observed whats going on in every particular situation. Does that make sense?

Yes, absolutely.

We cannot predict if the wind will change directions from the east, to the SE for 5 minutes, then go back to the east for 10. It just is not possible. That is why fire science is not an exact science. We can always look back, and see what happened, but cannot predict what will happen before hand.

Also, in house fires, we will not know how good or bad the ventilation is. If the windows break, it adds more oxygen. If doors are open or closed can change the way a fire will spread. We can GUESS what is going to happen, but without knowing the exact variables beforehand, we can never know for certain. There are just too many variables.


Forrest fires are even worse, because of the fact that they can get so big, that they create their own wing. Even a large fire (1&2 WTC) will create it's own drafts.

 

[mzelinski]

In "The NIST WTC 7 Report: Bush Science reaches its peak" Kevin Ryan calculates that the thermal expansion in the NIST’s explanation is less than 3 inches. For those of you here who do not support the controlled demolition explanation, do you feel that 3 inches is enough thermal expansion to bring down WTC7 in the way that it did? Is there a way to verify the NIST's hypothesis?

Energy, Entropy, and the Collapse of WTC7

If a person holding a brick of mass m releases it, it will fall to the ground. Why? The force of gravity describes how it falls (central forces are symmetrical with respect to time-reversal), by why it falls is due to the Second Law of Thermodynamics, namely the whether the entropy increases. The change in entropy for the falling brick is ΔS = KE_brick/T, where KE_brick is the brick’s kinetic energy the moment before it hits the ground, and T is temperature. We can apply this concept to WTC7 to test whether the NIST’s explanation for the collapse is plausible. We do not need to know the causal relationship between the specific chain of events that took place internally during the collapse, because of the fact that the maximum work available to a system is the reversible work [1]. Furthermore, when the reversible work is maximized, the total change in entropy of the system is zero, and this allows us to relate the change in entropy associated with the initiating mechanism, to the change in entropy associated with the final collapse mechanism, provided both mechanisms can be clearly identified. Fortunately, the NIST chose an initiating mechanism – heating a girder – for which the “initial” change in entropy is easy to calculate. Also, the “free-fall” portion of the collapse provides a conveniently identifiable unit of measure to calculate the “final” change in entropy associated with the latter mechanism.

The final change in entropy ΔS_f associated with the WTC7’s 2.25s of free fall is, similar to the brick example, just the change in kinetic energy divided by temperature during the NIST's phase 2:

ΔS_f = (KE_{upper section})/T = ½ * M/T * (v_f² - v_i²)​

This is the amount of energy that is transformed into internal energy and transferred as heat into the surroundings.

Using dimensions from the NIST [2] and the trapezoid formula, we know that the area of floor plan of WTC7 is A = 3460 m², and the height is h_total = 186 m.
We can estimate the mass density of WTC7 to be roughly equal to that of the Twin Towers, as well as modern highrise buidings [3], ρ = 168.6 kg/m³, with the number of storeys = 35 (floors 13 through 47).
So the mass of the upper part of building is estimated to be M = 8.08E+07 kg.

The 2.25 sec of “free fall” (the NIST's phase 2) began with an initial velocity of v_i ~8ft/s = 2.4 m/s, and ended with a final velocity of v_f ~80ft/s = 24.4 m/s [4], and even include a factor 0.95 to allow a 5% deviation from pure free fall acceleration.
The kinetic energy of upper block during the 2.25s “free fall” phase is then

ΔS_f = (KE_{upper section})/T = 7.17E+07 J/K​

Now for the initial change in entropy, ΔS_i.
The change in entropy due to an addition of heat is

dS = dQ / T = (1/T) m * c_sp * dT​

And the total change in entropy due to fires heating the girder from T₁ to T₂ is:
ΔS_i = integrate (dS ) from T₁ to T₂ = m * c_sp * ln(T₂/T₁).
where m = mass of girder, c_sp = specific heat of steel.

The mass of the girder can be found from the volume and density. The cross-sectional area of a typical WTC7 girder is A = 38.3 in² = 0.0247 m² [5], and the length of girder is l = 15.8 m [6].
Given the density of steel, 7833 kg/m³, the mass of the girder is about m = 3058 kg.
The c_sp = 550 J/kg K for constant specific heat (for T < 600°C) [7]. T₁ = 300 K, T₂ = 750 °F = 400 °C = 672 K

ΔS_i = m * c_sp * ln(T₂/T₁) = 1.36E+06 J/K​

So, comparing the change in entropy associated with the initial and final mechanisms, the difference is:

ΔS_total = ΔS_f - ΔS_i = +7.03E+07 J/K​

This quantity should at most equal zero because the entropy of a system cannot be maximized more than the maximum available to the system. Therefore an additional source of energy had to have been present in order to deliver this extra amount of work to the system. In the language of thermodynamic potentials, the collapse process is not spontaneous, WTC7 is stable subjected to the thermal expansion, and the NIST’s explanation appears to violate the Second Law of Thermodynamics.

As we can see from this simple analysis [8] the thermal expansion of a girder is insufficient to cause the WTC7 to spontaneously collapse. We could extend this treatment to include additional beams and columns that may have been subjected to the heat from fires, and therefore somehow contribute to the collapse. However, the result would be the same because this exta amount of heat required to cause a change in entropy sufficient for collapse is equivalent to the amount required to raise two such girders to over 1400 °C. This is not possible from fires, although, coincidentally, it is consistent with the collapse mechanism of controlled demolition – the only hypothesis that can account for all the observable features. This is understandable, after all, because incendiaries and explosives are nothing more than a massive increase in entropy, which, if introduced to the system, would allow the collapse to proceed spontaneously.
_______________________

References

[1] H. Callen, Thermodynamics and an Introduction to Thermostatistics, pg 103

[2] NCSTAR1A - Final Report of Collapse of WTC7, pg 5

[3] Gregory Urich, "Analysis of the Mass and Potential Energy of World Trade Center Tower 1", pg. 25

[4] NCSTAR1A The Final Report on WTC7, pg 46

[5] NIST NCSTAR 1-9 Vol1 Draft for Public Comment, page 344

[6] Kevin Ryan, "The NIST WTC 7 Report: Bush Science reaches its peak",

[7] J.A. Purkiss, Fire Safety Engineering: Design of Structures, pg. 79

The present analysis uses the temperature-dependent specific heat of steel
c_sp(T) = c₀ + c₁ * T + c₂ * T² + c₃ * T³ [J/kg K], where
c₀ = -191.5 J/kg K
c₁ = 4.5 J/kg K
c₂ = -9.00E-03 J/kg K
c₃ = 6.00E-06 J/kg K
or, c_sp = (-191.5) + (4.5) * T + (-9E-03) * T² + (6E-06) * T³ [J/kg K]
​

[8] Bazant & Cedolin, Stability of Structures, chapter 10, “Stability of Inelastic Structures, Bifurcation and Thermodynamic Basis”

Here they present a much more rigorous thermodynamic analysis of structures (i.e. not limited to quasi-static states). Their formulation uses generalized forces and fluxes, second-order work, internal entropy production to do work of shearing bolts and fracturing beams, etc.​

 

[kylebisme]

Since the question in my previous post has been misinterpreted, I'll rephrase it. NIST repeatedly states throughout their WTC 7 report that their model is consistent with actual videos of WTC 7 coming down. One notable example is in NCSTAR 1A, chapter 3.6:

A more detailed examination of the same video led to a better understanding of the vertical motion of the building in the first several seconds of descent...

For discussion purposes, three stages were defined, as denoted in Figure 3-15:

• In Stage 1, the descent was slow and the acceleration was less than that of gravity. This stage corresponds to the initial buckling of the exterior columns in the lower stories of the north face. By 1.75 s, the north face had descended approximately 2.2 m (7 ft).
• In Stage 2, the north face descended at gravitational acceleration, as the buckled columns provided negligible support to the upper portion of the north face. This free fall drop continued for approximately 8 stories or 32.0 m (105 ft), the distance traveled between times t = 1.75 s and t = 4.0 s.
• In Stage 3, the acceleration decreased somewhat as the upper portion of the north face encountered increased resistance from the collapsed structure and the debris pile below. Between 4.0 and 5.4 s, the north face corner fell an additional 39.6 m (130 ft.)​

As noted above, the collapse time was approximately 40 percent longer than that of free fall for the first 18 stories of descent. The detailed analysis shows that this increase in time is due primarily to Stage 1. The three stages of collapse progression described above are consistent with the results of the global collapse analyses discussed in Chapter 12 of NIST NCSTAR 1-9.

So, why are we expected to to take NIST's claim of consistency between the video evidence and their model on faith, particularly when it seems nobody else as proven capable of producing a model to demonstrate fire induced free fall of a steel framed high-rise either?

 

[Newtons Bit]

Energy, Entropy, and the Collapse of WTC7

If a person holding a brick of mass m releases it, it will fall to the ground. Why? The force of gravity describes how it falls (central forces are symmetrical with respect to time-reversal), by why it falls is due to the Second Law of Thermodynamics, namely the whether the entropy increases. The change in entropy for the falling brick is ΔS = KE_brick/T, where KE_brick is the brick’s kinetic energy the moment before it hits the ground, and T is temperature. We can apply this concept to WTC7 to test whether the NIST’s explanation for the collapse is plausible. We do not need to know the causal relationship between the specific chain of events that took place internally during the collapse, because of the fact that the maximum work available to a system is the reversible work [1]. Furthermore, when the reversible work is maximized, the total change in entropy of the system is zero, and this allows us to relate the change in entropy associated with the initiating mechanism, to the change in entropy associated with the final collapse mechanism, provided both mechanisms can be clearly identified. Fortunately, the NIST chose an initiating mechanism – heating a girder – for which the “initial” change in entropy is easy to calculate. Also, the “free-fall” portion of the collapse provides a conveniently identifiable unit of measure to calculate the “final” change in entropy associated with the latter mechanism.

The final change in entropy ΔS_f associated with the WTC7’s 2.25s of free fall is, similar to the brick example, just the change in kinetic energy divided by temperature during the NIST's phase 2:

ΔS_f = (KE_{upper section})/T = ½ * M/T * (v_f² - v_i²)​

This is the amount of energy that is transformed into internal energy and transferred as heat into the surroundings.

Using dimensions from the NIST [2] and the trapezoid formula, we know that the area of floor plan of WTC7 is A = 3460 m², and the height is h_total = 186 m.
We can estimate the mass density of WTC7 to be roughly equal to that of the Twin Towers, as well as modern highrise buidings [3], ρ = 168.6 kg/m³, with the number of storeys = 35 (floors 13 through 47).
So the mass of the upper part of building is estimated to be M = 8.08E+07 kg.

The 2.25 sec of “free fall” (the NIST's phase 2) began with an initial velocity of v_i ~8ft/s = 2.4 m/s, and ended with a final velocity of v_f ~80ft/s = 24.4 m/s [4], and even include a factor 0.95 to allow a 5% deviation from pure free fall acceleration.
The kinetic energy of upper block during the 2.25s “free fall” phase is then

ΔS_f = (KE_{upper section})/T = 7.17E+07 J/K​

Now for the initial change in entropy, ΔS_i.
The change in entropy due to an addition of heat is

dS = dQ / T = (1/T) m * c_sp * dT​

And the total change in entropy due to fires heating the girder from T₁ to T₂ is:
ΔS_i = integrate (dS ) from T₁ to T₂ = m * c_sp * ln(T₂/T₁).
where m = mass of girder, c_sp = specific heat of steel.

The mass of the girder can be found from the volume and density. The cross-sectional area of a typical WTC7 girder is A = 38.3 in² = 0.0247 m² [5], and the length of girder is l = 15.8 m [6].
Given the density of steel, 7833 kg/m³, the mass of the girder is about m = 3058 kg.
The c_sp = 550 J/kg K for constant specific heat (for T < 600°C) [7]. T₁ = 300 K, T₂ = 750 °F = 400 °C = 672 K

ΔS_i = m * c_sp * ln(T₂/T₁) = 1.36E+06 J/K​

So, comparing the change in entropy associated with the initial and final mechanisms, the difference is:

ΔS_total = ΔS_f - ΔS_i = +7.03E+07 J/K​

This quantity should at most equal zero because the entropy of a system cannot be maximized more than the maximum available to the system. Therefore an additional source of energy had to have been present in order to deliver this extra amount of work to the system. In the language of thermodynamic potentials, the collapse process is not spontaneous, WTC7 is stable subjected to the thermal expansion, and the NIST’s explanation appears to violate the Second Law of Thermodynamics.

As we can see from this simple analysis [8] the thermal expansion of a girder is insufficient to cause the WTC7 to spontaneously collapse. We could extend this treatment to include additional beams and columns that may have been subjected to the heat from fires, and therefore somehow contribute to the collapse. However, the result would be the same because this exta amount of heat required to cause a change in entropy sufficient for collapse is equivalent to the amount required to raise two such girders to over 1400 °C. This is not possible from fires, although, coincidentally, it is consistent with the collapse mechanism of controlled demolition – the only hypothesis that can account for all the observable features. This is understandable, after all, because incendiaries and explosives are nothing more than a massive increase in entropy, which, if introduced to the system, would allow the collapse to proceed spontaneously.
_______________________

References

[1] H. Callen, Thermodynamics and an Introduction to Thermostatistics, pg 103

[2] NCSTAR1A - Final Report of Collapse of WTC7, pg 5

[3] Gregory Urich, "Analysis of the Mass and Potential Energy of World Trade Center Tower 1", pg. 25

[4] NCSTAR1A The Final Report on WTC7, pg 46

[5] NIST NCSTAR 1-9 Vol1 Draft for Public Comment, page 344

[6] Kevin Ryan, "The NIST WTC 7 Report: Bush Science reaches its peak",

[7] J.A. Purkiss, Fire Safety Engineering: Design of Structures, pg. 79

The present analysis uses the temperature-dependent specific heat of steel
c_sp(T) = c₀ + c₁ * T + c₂ * T² + c₃ * T³ [J/kg K], where
c₀ = -191.5 J/kg K
c₁ = 4.5 J/kg K
c₂ = -9.00E-03 J/kg K
c₃ = 6.00E-06 J/kg K
or, c_sp = (-191.5) + (4.5) * T + (-9E-03) * T² + (6E-06) * T³ [J/kg K]
​

[8] Bazant & Cedolin, Stability of Structures, chapter 10, “Stability of Inelastic Structures, Bifurcation and Thermodynamic Basis”

Here they present a much more rigorous thermodynamic analysis of structures (i.e. not limited to quasi-static states). Their formulation uses generalized forces and fluxes, second-order work, internal entropy production to do work of shearing bolts and fracturing beams, etc.​

That is deliciously insane. Thanks, I needed a chortle.

 

[Miragememories]

Energy, Entropy, and the Collapse of WTC7

If a person holding a brick of mass m releases it, it will fall to the ground. Why? The force of gravity describes how it falls (central forces are symmetrical with respect to time-reversal), by why it falls is due to the Second Law of Thermodynamics, namely the whether the entropy increases. The change in entropy for the falling brick is ΔS = KE_brick/T, where KE_brick is the brick’s kinetic energy the moment before it hits the ground, and T is temperature. We can apply this concept to WTC7 to test whether the NIST’s explanation for the collapse is plausible. We do not need to know the causal relationship between the specific chain of events that took place internally during the collapse, because of the fact that the maximum work available to a system is the reversible work [1]. Furthermore, when the reversible work is maximized, the total change in entropy of the system is zero, and this allows us to relate the change in entropy associated with the initiating mechanism, to the change in entropy associated with the final collapse mechanism, provided both mechanisms can be clearly identified. Fortunately, the NIST chose an initiating mechanism – heating a girder – for which the “initial” change in entropy is easy to calculate. Also, the “free-fall” portion of the collapse provides a conveniently identifiable unit of measure to calculate the “final” change in entropy associated with the latter mechanism.

The final change in entropy ΔS_f associated with the WTC7’s 2.25s of free fall is, similar to the brick example, just the change in kinetic energy divided by temperature during the NIST's phase 2:

ΔS_f = (KE_{upper section})/T = ½ * M/T * (v_f² - v_i²)​

This is the amount of energy that is transformed into internal energy and transferred as heat into the surroundings.

Using dimensions from the NIST [2] and the trapezoid formula, we know that the area of floor plan of WTC7 is A = 3460 m², and the height is h_total = 186 m.
We can estimate the mass density of WTC7 to be roughly equal to that of the Twin Towers, as well as modern highrise buidings [3], ρ = 168.6 kg/m³, with the number of storeys = 35 (floors 13 through 47).
So the mass of the upper part of building is estimated to be M = 8.08E+07 kg.

The 2.25 sec of “free fall” (the NIST's phase 2) began with an initial velocity of v_i ~8ft/s = 2.4 m/s, and ended with a final velocity of v_f ~80ft/s = 24.4 m/s [4], and even include a factor 0.95 to allow a 5% deviation from pure free fall acceleration.
The kinetic energy of upper block during the 2.25s “free fall” phase is then

ΔS_f = (KE_{upper section})/T = 7.17E+07 J/K​

Now for the initial change in entropy, ΔS_i.
The change in entropy due to an addition of heat is

dS = dQ / T = (1/T) m * c_sp * dT​

And the total change in entropy due to fires heating the girder from T₁ to T₂ is:
ΔS_i = integrate (dS ) from T₁ to T₂ = m * c_sp * ln(T₂/T₁).
where m = mass of girder, c_sp = specific heat of steel.

The mass of the girder can be found from the volume and density. The cross-sectional area of a typical WTC7 girder is A = 38.3 in² = 0.0247 m² [5], and the length of girder is l = 15.8 m [6].
Given the density of steel, 7833 kg/m³, the mass of the girder is about m = 3058 kg.
The c_sp = 550 J/kg K for constant specific heat (for T < 600°C) [7]. T₁ = 300 K, T₂ = 750 °F = 400 °C = 672 K

ΔS_i = m * c_sp * ln(T₂/T₁) = 1.36E+06 J/K​

So, comparing the change in entropy associated with the initial and final mechanisms, the difference is:

ΔS_total = ΔS_f - ΔS_i = +7.03E+07 J/K​

This quantity should at most equal zero because the entropy of a system cannot be maximized more than the maximum available to the system. Therefore an additional source of energy had to have been present in order to deliver this extra amount of work to the system. In the language of thermodynamic potentials, the collapse process is not spontaneous, WTC7 is stable subjected to the thermal expansion, and the NIST’s explanation appears to violate the Second Law of Thermodynamics.

As we can see from this simple analysis [8] the thermal expansion of a girder is insufficient to cause the WTC7 to spontaneously collapse. We could extend this treatment to include additional beams and columns that may have been subjected to the heat from fires, and therefore somehow contribute to the collapse. However, the result would be the same because this exta amount of heat required to cause a change in entropy sufficient for collapse is equivalent to the amount required to raise two such girders to over 1400 °C. This is not possible from fires, although, coincidentally, it is consistent with the collapse mechanism of controlled demolition – the only hypothesis that can account for all the observable features. This is understandable, after all, because incendiaries and explosives are nothing more than a massive increase in entropy, which, if introduced to the system, would allow the collapse to proceed spontaneously.
_______________________

References

[1] H. Callen, Thermodynamics and an Introduction to Thermostatistics, pg 103

[2] NCSTAR1A - Final Report of Collapse of WTC7, pg 5

[3] Gregory Urich, "Analysis of the Mass and Potential Energy of World Trade Center Tower 1", pg. 25

[4] NCSTAR1A The Final Report on WTC7, pg 46

[5] NIST NCSTAR 1-9 Vol1 Draft for Public Comment, page 344

[6] Kevin Ryan, "The NIST WTC 7 Report: Bush Science reaches its peak",

[7] J.A. Purkiss, Fire Safety Engineering: Design of Structures, pg. 79

The present analysis uses the temperature-dependent specific heat of steel
c_sp(T) = c₀ + c₁ * T + c₂ * T² + c₃ * T³ [J/kg K], where
c₀ = -191.5 J/kg K
c₁ = 4.5 J/kg K
c₂ = -9.00E-03 J/kg K
c₃ = 6.00E-06 J/kg K
or, c_sp = (-191.5) + (4.5) * T + (-9E-03) * T² + (6E-06) * T³ [J/kg K]
​

[8] Bazant & Cedolin, Stability of Structures, chapter 10, “Stability of Inelastic Structures, Bifurcation and Thermodynamic Basis”

Here they present a much more rigorous thermodynamic analysis of structures (i.e. not limited to quasi-static states). Their formulation uses generalized forces and fluxes, second-order work, internal entropy production to do work of shearing bolts and fracturing beams, etc.​

That is deliciously insane. Thanks, I needed a chortle.

Rather than chortle, why not display your structural engineer prowess and actually debunk mzelinski's work?

MM

 

[Cl1mh4224rd]

I like how Truthers are starting to refer to the presumed demolition of buildings as "pulling"; like if they make the reference often enough, the term "pulling" might actually begin to become connected in any way with building demolition to the rest of the world.

It's 2006 all over again. Just like fashion, conspiracy theories work in cycles. Bell bottoms were big at one point, then died out, then grew in popularity again in recent years. They never quite reached the same height as their initial popularity, but there it is.

Apparently, the "'pull' = explosive demolition" claim is on its upswing.

 

[Sabretooth]

Been there.

Already responded.

Already been ignored.

I would rather you addressed this Al;

The videos show WTC7 perimeter collapsing in unison.

The NIST agree that 8 storeys, 105 feet of collapse occurred as free fall.

Well, for all 4 sides to be dropping in unison at free fall speed for 105 feet, they have to be falling through a vertical path of zero resistance. Any disagreement in the timing of this zero resistance would show up as asymmetry in the observed collapse.

So how did the north, the east, the west and the south walls, all have 105 feet removed simultaneously?

MM

OMFG

MM - Everything you just said here has been discussed and debunked in other threads multiple times...

You abandon those conversations the second you get backed into a corner, and then find new threads to dump your garbage so we can start all over?

You are wrong...no amount of ignore/repeat/ignore/repeat/ignore/repeat is going to change that.

9+ years...WTG!!!

 

[Miragememories]

"Been there.

Already responded.

Already been ignored.

I would rather you addressed this Al;

The videos show WTC7 perimeter collapsing in unison.

The NIST agree that 8 storeys, 105 feet of collapse occurred as free fall.

Well, for all 3 sides to be dropping in unison at free fall speed for 105 feet, they have to be falling through a vertical path of zero resistance.
Any disagreement in the timing of this zero resistance would show up as asymmetry in the observed collapse.

So how did the north, the east, and the west walls, all have 105 feet removed simultaneously?"

OMFG

MM - Everything you just said here has been discussed and debunked in other threads multiple times...

You abandon those conversations the second you get backed into a corner, and then find new threads to dump your garbage so we can start all over?

You are wrong...no amount of ignore/repeat/ignore/repeat/ignore/repeat is going to change that.

9+ years...WTG!!!

If that is the case, then it should be very easy for you to present the argument that closed the discussion?

MM

 

[beachnut]

...
As we can see from this simple analysis [8] the thermal expansion of a girder is insufficient to cause the WTC7 to spontaneously collapse. ...

Wow, you wave your hands, post nonsense and declare victory. When will you publish this nonsense? You sound just like Jones, but with delusional science at work. Jones has the delusion of thermite, you have the delusion you can do, holy thermite, what did you do? It is funny.

Quick, send this to the same journal Heiwa sent his idiotic claims. Hurry before you figure out you have nothing.

Does anyone believe your failed work besides 911 truth professional followers?

Rather than chortle, why not display your structural engineer prowess and actually debunk mzelinski's work?

MM

MM, it was total nonsense! mzelinski's work debunks itself, it is pure fantasy, poppycock, dumber than dirt junk. It can be used effectively to expose those who have no clue.

 

[Sabretooth]

If that is the case, then it should be very easy for you to present the argument that closed the discussion?

MM

You're right...and so can you. But I'm not wasting my time so you can handwave facts and spout your spam for all of eternity...

 

[Furcifer]

Rather than chortle, why not display your structural engineer prowess and actually debunk mzelinski's work?

MM

There's nothing to debunk, it's nonsense.

My best guess is that the poster intended to show how clueless people are and willing to believe just about anything.