pgwenthold
Penultimate Amazing
- Joined
- Sep 19, 2001
- Messages
- 21,829
I haven't seen anyone follow up on this, but it is important, because it seriously affects mutton-head's calculations.
If I use the numbers listed on this site, which are apparently from the original reference, I get the following average composition
< 2.5 1.1%
2.5-10 .35%
10 - 53 39.4%
> 53 59.1%
With the makeup of the >53 components something like
75 micron 35%
75 - 300 micron 45%
> 300 20%
Now, if I call the average <2.5 particle 1 micron, the 2.5-10 is 6 microns, the 10 - 53 is 30 microns, the 75 - 300 is 185 microns, and using only 300 for greater than 300, I estimate an average particle size of 113 microns.
At the ABSOLUTELY LOWEST LIMIT, where particles 10 - 53 are all estimated to be 10 micron, and 75 - 300 are all estimated to be 75, I get an average of 75 microns. The average particle size from the dust, if I am reading the data right, MUST BE greater than 75. 110 is even toward the low end of a realistic estimate. 120 is perfectly justified.
That means that the LOWER LIMIT to the average particle size is 75, 25% greater than Hoffman's supposed conservative estimate. A more realistic estimate is 120, twice the size.
Now, because these are particle diameters, the amount of material in them goes as the radius cubed. That means in terms of volume, a particle that is 60 microns is half the volume of one that is 75 microns. That means it takes _twice_ as much energy to "pulverize" the concrete into 60 micron pieces than 75 micron pieces. Therefore, if Hoffman used 60 microns as the average particle size, then his energy estimate is twice as large as the upper possible limit, and is EIGHT times higher than a more realistic estimate of the energy that would be needed.
So Mutton-Head, if the energy required is only half of that Hoffman claimed was needed, how does that change his conclusions?
And this analysis ignores the fact that this is only an analysis of the pulverized material, and does not take into account the possibility of non-pulverized material.
