This is going nowhere fast
In my last post, I described the two related classes of falsifying arguments that apply to NIST. They are the same as for any other hypothesis, about anything. This is just the standard tenets of the Scientific Method. If you're unsure about this, then please try to catch up on your own before posting further.
In the meantime, we've had a distracting argument that is, in effect, an attempt to shift the burden of proof. I don't know whether this applies to
jay's thinking, since he has understandably gone missing, but it certainly applies to
Gregory Urich:
Think of falsification criteria as claims by NIST, which, if shown to be false would invalidate the NIST theory.
Examples of falsification criteria: [...]
If those who are NIST supporters do a good job of this we will avoid straw-man arguments and accusations of straw-man arguments because we are in agreement on what the theory actually says.
This is different from: read it, thought about it, makes sense, believe it. Who has the guts to take an analytical look at the NIST theory they support?
So far, no one.
Emphasis added.
This is completely wrong.
To begin, it is
not the responsibility of NIST's proponents to derive specific means to falsify their own hypothesis, not unless they are comparing it against
another specific hypothesis or set of observations. There is, so far, no other competing hypothesis in sight. Instead, it is the responsibility of those with
the competing hypothesis, or any hypothesis coming later to the table, to come up with such falsifying criteria. This is for two reasons.
Imprimus, as a defender of NIST, I am likely to be biased. There is no reason why you should be restricted to my list, and no reason you should want to, either.
Secundus, those proposing the new hypothesis will be more versed in its detail. They will be inherently more capable of devising such criteria, as they have had the opportunity to study NIST, but not vice versa.
Furthermore, the NIST theory
has already demonstrated that it is falsifiable because it was compared against alternate hypotheses as it was developed. I speak primarily of "The Pancake Theory," as proposed by Eagar and others, but also the similar yet not identical results of the Weidlinger Associates, MIT, and Exponent Inc. studies. NIST describes in its report the distinctions -- that is to say, the "falsifying criteria" -- between all of these options, and gives its reasoning for why its result is the best fit to the observed data. Therefore, there is no doubt
at all that the NIST theory is falsifiable. It has already been exposed to, and survived, scientific comparison against at least four competing theories.
Q E D.
Before we go overboard in our criticism of
Gregory Urich and his misapprehensions of the basic tenets of science, we should remark that he has, usefully, provided us with two working examples of trivially refuted alternate hypotheses -- a "practice deal," if you will. These are the following:
First there is no evidence whatsoever of fireproofing being removed on the south side of WTC1. The theory NIST provides to support this claim is that the fireproofing was knocked off by debris during the impact.
Let's look at the SFRM on the floor trusses and ask the question: Could any debris possibly have impacted the floor trusses on the south side?
It would first have to get through 60 ft of the floor truss matrix (both primary and secondary trusses). Then there is the problem that gravity is pulling the debris downward toward the floor while it is traveling from the north side to the south edge of the core.
From NIST NCSTAR1-2B: According to the base case debris starts leaving the core on the far side (south side) at 0.40 seconds into the impact. The equation for distance with gravitational accelleration is d = (gt^2)/2 which means that the debris will fall downward 30" during that time. Since the truss system is 29" only deep, no debris can possibly hit the truss system on the south side of the building unless it is deflected upward in some way.
At this point (0.40 seconds into the impact) the momentum is less than 10% of the original momentum meaning that the velocity (43.3 mph) is also less than 10% of the original velocity (433 mph). Furthermore if the debris is deflected it will loose velocity so any deflected debris hitting the truss system will have a velocity significantly less the 43 mph.
Gregory's hypothetical competitor concerns the fireproofing behavior at impact. Contrasted against the NIST hypothesis, we have two different models:
Gregory's Model: Aircraft debris is treated as ballistic projectiles, affected only by gravity, but with a steeply decelerating horizontal velocity as predicted by NIST. These chunks of debris all follow uniform curves reminiscent of a parabola, caternary, or brachistochrone. There is no way for these curves to remove fireproofing in a wide area as predicted by NIST, as structure would interfere with the trajectories.
NIST Model: Aircraft debris is treated with a rigorous LS-DYNA simulation, accounting for aircraft size and impact geometry, inelastic and elastic impact, secondary impact, secondary debris, effects of material strength, fluid behavior and fluid erosion, at varying levels of fidelity (geometry being at high fidelity, fluid effects relatively low but still modeled). This model excludes deflagration effects and momentum from rotating machinery. The model shows that fireproofing that is screened or shielded from impact by structure can still be affected, according to the precise location and interior geometry.
Stacking these two models against each other reveals instantly which is superior. It is immediately clear, from photographs of the impact if not a basic understanding of impact and fracture mechanics, that
Gregory's Model is far too simple to be credible.
If a simplification was desired, perhaps the best analogue would not be to ballistics, but instead to the behavior of a turbulent fluid jet. It is immediately clear that vorticity can lead to such a jet affecting regions in the structure that are not line-of-sight from the jet's point of origin. This turbulent effect is but one of many that would have been present in the jet impacts, which are perhaps best described as turbulent heterogenous density flows at an initial speed of about 0.8 Mach.
Comparing the two theories,
Gregory's Model is therefore falsified. The NIST model remains the best known hypothesis.
For the second example,
Gregory provides us with an example of a logical error:
From NCSTAR1, NIST did not include the possibility of insulation damage or dislodgement from structural vibration.
In conclusion, very little if any damage could have been done to the floor truss fire-proofing on the south side of the building. The more severe case would not significantly affect this result.
This is, of course, incorrect. From NIST NCSTAR1-6A:
NIST NCSTAR1-6A said:
When a member is subjected to an impact, it will undergo various modes of vibration. These vibrations result in local cyclic accelerations that are transferred to the SFRM by forces at the interface between the steel and the SFRM. The forces are proportional to the mass of the SFRM, and if they exceed the adhesive or cohesive strength of the SFRM, the SFRM will separate from the member. Two limiting cases are considered:
- Case 1 is a planar element with SFRM applied to one face of the element. This would be representative of SFRM applied to large webs and flanges of beams and columns. In this case, adhesive strength or cohesive strength normal to the surface would be the controlling SFRM properties.
- Case 2 is a slender bar encased with SFRM. This would be representative of SFRM applied to the elements of the floor trusses. In this case, in-plane tensile strength and bond strength are the controlling SFRM properties.
[...]
The smallest required acceleration is about 40
g, which corresponds to a large bar having a thick layer of the higher density SFRM with low strength. At the other extreme, the required acceleration is about 730
g. For a 1.2 in. diameter bar with 2.5 in. thickness of SFRM and density of 19 pcf, which are representative of the conditions of the upgraded insulation on the floor trusses, the acceleration required to dislodge the SFRM would vary from 55
g to 230
g, depending on the strength characteristics within the assumed ranges given above.
The rest of the report goes on to demonstrate, by way of experiment, precisely what type of impact -- what projectile weight and speed -- sets up such a vibration. The
g-loading values are seen to be too low to be credibly shaken loose by the gross structural motion, but easily within the expected vibrations on individual structural members caused by impacts of minor primary and secondary debris.
Any hypothesis that makes such an easily demonstrated logical error, as
Gregory's second hypothesis does, is also falsified. Such a theory might be salvageable if correction of the logical reasoning leads to similar conclusions, but until it is fixed, it deserves no additional attention.
-----
Philosophical question for the board: Suppose we have a hypothesis that is "correct" -- somehow, through some twist in the fabric of space, we know that it is absolutely perfect in every detail. Is such a hypothesis falsifiable? Yes or no?
-----
Now, then, can we
please start, if we're going to? Anyone?
The horse is shod, the armor is polished, lances sharpened, pennons are flying... yet the Black Knight is nowhere to be found, and the onlookers are growing restless.
