Jones Beene wrote: > Stephen, > >> However, remote sensing can't "see" high temperatures through an opaque > mass of debris. At wavelengths emitted by very hot objects, which are > in the visible band, it can only read the *surface* temperature. > > Yes.... but... Here is a page with a tiny version of the same or a > similar image (second one down the page). > > http://www.historycommons.org/context.jsp?item=a091601hotspots > > My question is this: from the surface temperature which is indicated > from space, which as you say is NOT the true peak temperature in the > pool - but could that peak temp be computed backwards in time, since we > know the days which have lapsed, and the approximate size of the pool, > the approximate conductivity of the debris etc.and can plug in the other > constants ??
I will freely confess that I'm out of my depth here :-) I think it might be hard to conclude much from modeling the debris pile, for reasons I will go into below. > > Plus, since you can see from the color of the hot debris in the claw > (first image) which has been shedding heat for hundreds of hours, One would guess that would have been so, but on the other hand there were fires burning under the pile, so it's not a priori the case that things down there were cooling off. > all of > these things can be input for a meaningul simulation (assuming that you > have nothing to hide) ... and not an imaginary simulation which was > limited by the NIST contract terms so as to be effectively meaningless... > > ... anyway if you are going to do a computer simulation, why not also > simulate the original heat content of that debris on the day of the > disaster. That would be doable, no? The problem here is the same as the problem with the NIST models of all three of the the building collapses. NIST was attempting to figure out how a building could have collapsed due to the known causes. Ignore for the moment the question of whether you trust them, and let's just consider what the problem was like with the assumption that they were acting in good faith. The actual details of the collapse were unknown, the failure points were unknown, and the behavior of a lot of the materials under the conditions which occurred were unknown. In fact, the exact conditions inside the falling buildings were not known. They could *NOT* use a "pure physics" model to predict what would happen; there were far too many unknowns. Instead, they had to use a "calibrated" model, and fit the model to the observed behaviors. In fact, it is probably fair to say that the parameters which were adjusted to calibrate the model were EXACTLY the parameters that they were trying to learn the values of, in order to determine what apparently happened. Unfortunately, when modeling the debris pile, we've got the same problem: The exactly constituents of the pile are not known, the "texture" -- how finely pulverized -- the pile was is not known, possible air channels running through the pile due to incomplete collapse of the heap are no not known, and so ventilation (air supply) inside the pile was not known. In short, the parameters needed in order to predict how a fire would burn and how fast the heat would leak out are not known. The only way to model it would be to use a *calibrated* model, which we would need to calibrate by plugging in the known temperature of the top of the pile (known from satellite photos) along with the IR leakage rate (possibly known from satellite photos ??) along with *assumptions* about what was going on inside the pile. From that we could determine somewhat more about what happened, I suppose -- but the necessity to plug in assumptions about what was going on under the pile in order to get out any results might render the exercise useless from a "forensic" standpoint. Anyhow I'm racking up for the evening at this point; 'til tomorrow... > >
