I wonder why Agloco didn't come in here to defend his Science pals?
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Its ok you proved already to be a coward by avoiding a live debate with me.
http://www.spurstalk.com/forums/showthread.php?t=203428
Has anyone replicated the tests Jones, et. al., did on that dust?
If not, that's really serious if you're in the sciences.
Yeah they did. The considered the controlled demolition hypothesis and rejected it giving their reasoning in their report.
If anyone is not considering another hypothesis --or any other hypothesis for that matter-- it's you.
I am sure you are a Clinton fan. Remember where he talks about coming to conclusions and making decisions based on ideology instead of what the actual facts are? Think about that for awhile. Quit being like WC and trying to fit the way you want things to be rather than how they actually are.
Who comparing? I stated that NIST never contemplated that the building could have been brought down by any other scenario than they outlined....is that true or not?
Answer the question.
Oh, so you were just trying to avoid answering the question I asked. Understood.Fuzzy already answered that. I would add that if nutters had evidence of thermite, they would be falling over themselves to have others duplicate their test results on the dust.Quote:
I stated that NIST never contemplated that the building could have been brought down by any other scenario than they outlined....is that true or not?
Answer the question.
Answer my question.
Has anyone replicated the tests Jones, et. al., did on that dust?
Don't try to change the subject again.
O'Relly?
Did the NIST investigation look for evidence of the WTC towers being brought down by controlled demolition? Was the steel tested for explosives or thermite residues?
http://www.nist.gov/el/disasterstudi..._wtctowers.cfmQuote:
NIST did not test for the residue of these compounds in the steel.
The responses to previous questions demonstrate why NIST concluded that there were no explosives or controlled demolition involved in the collapses of the WTC towers.
As for thermite (a mixture of powdered or granular aluminum metal and powdered iron oxide that burns at extremely high temperatures when ignited), it burns slowly relative to explosive materials and would require several minutes in contact with a massive steel section to heat it to a temperature that would result in substantial weakening. Separate from the WTC towers investigation, NIST researchers estimated that at least 0.13 pounds of thermite would be required to heat each pound of a steel section to approximately 700 degrees Celsius (the temperature at which steel weakens substantially). Therefore, while a thermite reaction can cut through large steel columns, many thousands of pounds of thermite would need to have been placed inconspicuously ahead of time, remotely ignited, and somehow held in direct contact with the surface of hundreds of massive structural components to weaken the building. This makes it an unlikely substance for achieving a controlled demolition.
Analysis of the WTC steel for the elements in thermite/thermate would not necessarily have been conclusive. The metal compounds also would have been present in the construction materials making up the WTC towers, and sulfur is present in the gypsum wallboard that was prevalent in the interior partitions.
You didn't even answer your own question.
But go ahead and answer mine now.
Has anyone replicated the tests Jones, et. al., did on that dust.
Quit stalling.
Selling Progressive Collapse
Quote:
The (911 commission) Report mentions "progressive collapse" 16 times, mostly in sections describing recommendations. It defines progressive collapse as when "a building or portion of a building collapses due to disproportionate spread of an initial local failure" but does not mention how rare the phenomenon is or that there are no examples of total progressive collapse of steel-framed buildings outside of 9/11/01.
By repeatedly invoking the specter of "progressive collapse" while concealing the phenomenon's lack of repeatability outside of "terrorist incidents," the Report surreptitiously bolsters its supposition that "global collapse" automatically follows from "collapse initiation."
Quote:
A key technique the Report uses to add realism to its theory is to mix observational data with speculation, while failing to note the difference. For example, in numerous places the Report juxtaposes its estimates of core column damage (which are highly speculative) next to estimates of perimeter column damage (which can be inferred directly from photographic evidence).
http://911research.wtc7.net/wtc/offi...ers_draft.htmlQuote:
The debris cut a shallow path through the west and center array of trusses, damaging the insulation up to the north wall of the building core. This devastation took 0.7 s. The structural and insulation damage was considerable and was estimated to be:
35 exterior columns severed, 2 heavily damaged.
6 core columns severed, 3 heavily damaged.
43 of 47 core columns stripped of insulation on one or more floors.
Insulation stripped from trusses covering 60,000 ft2 of floor area.
As noted below, the Report asserts that infernos raged in the Towers' cores with quantitative detail that could easily mislead the reader into thinking that there is evidence to support it. Elsewhere the Report admits that there is no visual evidence for fires close to or in the cores.
http://911research.wtc7.net/wtc/offi...ers_draft.htmlQuote:
Fires deeper than a few meters inside the building could not be seen because of the smoke obscuration and the steep viewing angle of nearly all the photographs. (p 127/177)
The Report repeatedly makes claims that amazingly high fire temperatures were extant in the Towers, without any evidence. The Report itself contains evidence contradicting the claims.
Observations of paint cracking due to thermal expansion. Of the more than 170 areas examined on 16 perimeter column panels, only three columns had evidence that the steel reached temperatures above 250 ºC: east face, floor 98, inner web; east face, floor 92, inner web; and north face, floor 98, floor truss connector. Only two core column specimens had sufficient paint remaining to make such an analysis, and their temperatures did not reach 250 ºC. ... Using metallographic analysis, NIST determined that there was no evidence that any of the samples had reached temperatures above 600 ºC. (p 90/140)
The highest temperatures estimated for the samples was 250 ºC (482 ºF). That's consistent with the results of fire tests in uninsulated steel-framed parking garages, which showed maximum steel temperatures of 360 ºC (680 ºF). How interesting then, that NIST's sagging truss model has the truss heated to 700 ºC (1292 ºF).
Where does NIST get the idea that steel temperatures should be more than 450 degrees Celsius (or 842 degrees Fahrenheit) higher than their own evidence indicates? This passage provides some insight into their experimental method.Quote:
A floor section was modeled to investigate failure modes and sequences of failures under combined gravity and thermal loads. The floor section was heated to 700 ºC (with a linear thermal gradient through the slab thickness from 700 ºC to 300 ºC at the top surface of the slab) over a period of 30 min. Initially the thermal expansion of the floor pushed the columns outward, but with increased temperatures, the floor sagged and the columns were pulled inward. (p 98/148)
Quote:
A spray burner generating 1.9 MW or 3.4 MW of power was ignited in a 23 ft by 11.8 ft by 12.5 ft high compartment. The temperatures near the ceiling approached 900 ºC. (p 123/173)
1.9 to 3.4 MW (megawatts) is the heat output of about 500 wood stoves -- that in a living-room-sized space!
Temperatures of 800 ºC to 1,100 ºC (1472 ºF to 2012 ºF) are normally observed only for brief times in building fires, in a phenomenon known as flashover. Flashover occurs when uncombusted gases accumulate near the ceilings and then suddenly ignite. Since flame consumes the pre-heated fuel-air mixture in an instant, very high temperatures are produced for a few seconds. Note that this temperature range includes the 900 ºC recorded using the megawatt super-burner, so they must have had to pour on quite a lot of jet fuel.Quote:
The jet fuel greatly accelerated the fire growth. Only about 60 percent of the combustible mass of the rubblized workstations was consumed. The near-ceiling temperatures varied between 800 ºC and 1,100 ºC. (p 125-6/175-6)
The first section of the Report describing the fires deceptively implies that 1,000 ºC (1832 ºF) temperatures (rarely seen in even momentary flashovers) were sustained, and that they were in the building's core.
http://911research.wtc7.net/essays/nist/Quote:
Aside from isolated areas, perhaps protected by surviving gypsum walls, the cooler parts of this upper layer were at about 500 ºC, and in the vicinity of the active fires, the upper layer air temperatures reached 1,000 ºC. The aircraft fragments had broken through the core walls on the 94th through the 97th floors, and temperatures in the upper layers there were similar to those in the tenant spaces. (p 28/78)
These guys are structural engineers.
http://www.civil.northwestern.edu/pe...Papers/466.pdf
http://www.nist.gov/customcf/get_pdf.cfm?pub_id=861610Quote:
Originally Posted by NIST Report, p26
And quit being like WC with shitty napkin math. If you want to attempt to look at how to model building collape and thermodynamics go to the first link.
You are completely out of your element and make yourself seem the ignorant fool, dan. Don't be a WC.
This is clearly designed to be compelling to ignorant fools. That you give it credence is sad.Quote:
A spray burner generating 1.9 MW or 3.4 MW of power was ignited in a 23 ft by 11.8 ft by 12.5 ft high compartment. The temperatures near the ceiling approached 900 ºC. (p 123/173)
1.9 to 3.4 MW (megawatts) is the heat output of about 500 wood stoves -- that in a living-room-sized space!
Eh, dan has successfully engaged someone else on the subject of not my question. I'll still ask it though.
Has anyone replicated the tests Jones, et. al., did on that dust?
:sleep
The entire premise of the paper rests on claiming the simplifying assumptions employed describe an extreme case which favors survival, therefore all other scenarios must also lead to total collapse.
But the paper actually does not assume conditions most optimistic for survival as I'll explain.
To understand why these conditions are not most optimistic for survival we need to understand how he formulates the problem.
We have discovered many things in the last two years which show the initial collapse scenario of Bazant to be outdated. His probable collapse scenario from pg 1:
Limpy's bogus proofQuote:
In stage 1 ~Fig. 1!, the conflagration, caused by the aircraft fuel
spilled into the structure, causes the steel of the columns to be
exposed to sustained temperatures apparently exceeding 800°C.
The heating is probably accelerated by a loss of the protective
thermal insulation of steel during the initial blast. At such temperatures,
structural steel suffers a decrease of yield strength and
exhibits significant viscoplastic deformation ~i.e., creep—an increase
of deformation under sustained load!. This leads to creep
buckling of columns ~Bazˇant and Cedolin 1991, Sec. 9!, which
consequently lose their load carrying capacity ~stage 2!. Once
more than half of the columns in the critical floor that is heated
most suffer buckling ~stage 3!, the weight of the upper part of the
structure above this floor can no longer be supported, and so the
upper part starts falling down onto the lower part below the critical
floor, gathering speed until it impacts the lower part. At that
moment, the upper part has acquired an enormous kinetic energy
and a significant downward velocity. The vertical impact of the
mass of the upper part onto the lower part ~stage 4! applies enormous
vertical dynamic load on the underlying structure, far exceeding
its load capacity, even though it is not heated. This causes
failure of an underlying multifloor segment of the tower ~stage 4!,
in which the failure of the connections of the floor-carrying
trusses to the columns is either accompanied or quickly followed
by buckling of the core columns and overall buckling of the
framed tube, with the buckles probably spanning the height of
many floors ~stage 5, at right!, and the upper part possibly getting
wedged inside an emptied lower part of the framed tube ~stage 5,
at left!. The buckling is initially plastic but quickly leads to fracture
in the plastic hinges. The part of building lying beneath is
then impacted again by an even larger mass falling with a greater
velocity, and the series of impacts and failures then proceeds all
the way down ~stage 5!.
This is his formulation of the physics problem. It is not the only way to describe the first impact.
Notice his description of the first collision: At that
moment, the upper part has acquired an enormous kinetic energy
and a significant downward velocity. The vertical impact of the
mass of the upper part onto the lower part ~stage 4! applies enormous
vertical dynamic load on the underlying structure, far exceeding
its load capacity, even though it is not heated.
He formulates the physics as the KE of the entire upper block striking the structure below with no justification. This is only an assumption and certainly does not favor survival.
A more realistic understanding of the first significant collision as being between 2 floor slabs, both held to their respective structures by finite connections. Considering the upper floor slab to be connected to the rest of the upper block only through connections of finite strength, there is no physical justification to include the entire upper block mass or KE in the first collision.
It is by treating the upper block as a rigid body and misrepresenting the nature of the first impact as column-to-column impacts rather than floor-to-floor impacts that he can apply an overwhelming amount of KE at the first impact while claiming that such a massive jolt is actually the most optimistic case for survival.
Notice his description of perimeter buckling which has been shown to be totally wrong.
In short, it is the way in which he formulates the physics of the first impact and all subsequent impacts that allows him to overestimate the destructive nature of the collisions. We see absolutely no evidence that single floor failure inevitably leads to total collapse in actual demolitions (in, like, real buildings) studied nor do we see any guarantee that there is an ever increasing capacity for destruction at the collapse front as the front progresses downwards as BZ claims.
Website
http://the911forum.freeforums.org/li...s-t106-45.html
Remember the thread that got started about guys testing dust from the site of the 9/11 attacks?
Has anyone replicated the tests Jones, et. al., did on that dust?