Jerry Russell estimated that the amount of energy required to crush concrete to 60 micron powder is about 1.5 KWH/ton. (See http://www.911-strike.com/powder.htm.)

1)      Russell’s estimate of 1.5 kWh/t is based off of http://www.b-i-m.de/public/ibac/mueller.htm  This is an erroneous estimate as the 1.5 kWh/t energy cost is of the impact crusher the paper is using for comparative purposes to a different method.  Specifically, “mechanical crushing methods (impact crusher: roughly 1.5 kWh/t concrete)” 

2)      Russell’s use of 60 microns is in response to Eric Hufschmid’s “concrete physics problem” challenge.  Hufschmid has been contacted and asked to provide a source for his use of 60 microns.  He has opted not to do so.

 

That paper incorrectly assumes there were 600,000 tons of concrete in each tower, but Russell later provided a more accurate estimate of 90,000 tons of concrete per tower, based on FEMA's description of the towers' construction.

1)      Neither Russell, nor Hoffman, provide a source for either estimate of the amount of concrete in each tower.

 

That estimate implies the energy sink of concrete pulverization was on the order of 135,000 KWH per tower, which is already larger than the energy source of gravitational energy.

1)      Given that the selection of 1.5 kWh/t is based off of the energy cost/efficiency of the impact crusher, and not the amount of energy needed to crush the concrete as calculated from a purely energy/work standpoint the 135,000 kWh estimated energy sink of the towers is wrong and is without doubt higher than the actual value.

 

 

 However, the size of this sink is critically dependent on the fineness of the concrete powder, and on mechanical characteristics of the lightweight concrete thought to have been used in the towers. Available statistics about particle sizes of the dust, such as the study by Paul J. Lioy, et al., characterize particle sizes of aggregate dust samples, not of its constituents, such as concrete, fiberglass, hydrocarbon soot, etc. Based on diverse evidence, 60 microns would appear to be a high estimate for average concrete particle size,

1)      The Paul J. Lioy, et al abstract (which is the cited source) states, “The largest mass concentrations were > 53 µm in diameter.”

2)      The full paper, http://www.ehponline.org/members/2002/110p703-714lioy/lioy-full.html , states that the estimated mass of material involved is “> 10 10⁶ tons”

3)      The sampling done for the Lioy paper dealt directly with the dust component of the debris, “These two samples were collected from 10-15 cm-thick deposits that were on the top of two automobiles about 0.7 km from the WTC site” and therefore their particle size is dealing specifically with the dust particles and is not a representation of the average particle size of all debris.

4)      Lioy used two methods for separating the particles, “a) a gravimetric sieving analysis that separated the mass of lint and nonfibrous material into fractions > 300 µm, 75-300 µm, and < 75 µm in diameter; and b) an aerodynamic separation for the particle size fractions of < 2.5 µm, 2.5-10 µm, and 10-53 µm in diameter, with a gravimetric sieving that separated the particles > 53 µm in diameter before the aerodynamic sizing of the samples. The separations were based on the design or availability of specific size separation techniques in the laboratories.”

5)      Lioy’s table here http://www.ehponline.org/members/2002/110p703-714lioy/tab1.jpg shows that the  “> 53 µm in diameter” statement in the abstract dealt specifically with the aerodynamically separated sample and accounted for 61.5%, 52.21% and 63.6% of the mass of the aerodynamically separated sample.  However, when looking at the first step of the separation process (sieved sample) we see that particles < 75 µm in diameter account for 38%, 30%, and 37% of the sample masses.  Particles between 75 µm and 300 µm in diameter account for 46%, 49%, and 42% of the samples and particles > 300 µm in diameter account for 16%, 23%, and 21% of the samples.  The use of 60 µm in diameter for the calculations is erroneous at best, and dishonest at worst.  To highlight what this table implies; in the three samples 62%, 72%, and 63% of the mass of the samples was > 75 µm in diameter.

 

suggesting 135,000 KWH is a conservative estimate for the magnitude of the sink.

At this point I am confident in saying that the estimate of 135,000 kWh is just plain wrong and entirely too high.

Couple the poor choice of particle size with my previous debunk means Hoffman’s entire paper is based upon a faulty premise.

 

I’m not going to analyze the paper further, because it would be a pointless exercise.  His premise if flawed.  His initial data is wrong.  His paper is crap.

A new loon at the JREF forums posted this tidbit to try to support his claim of controlled demolition of the Twin Towers:

"

 

This was not to go unanswered by me:

[QUOTE=Arkan_Wolfshade;1936951][url]http://en.wikipedia.org/wiki/World_Trade_Center[/url]

Height (m) 417 Height (ft) 1,368 Stories 110

http://www.house.gov/science/hot/wtc/wtc-report/WTC_ch2.pdf Section
2.2.1.1

American Airlines Flight 11 struck the north face of WTC 1 approximately between the 94th and
98th floors
2.2.1.5

2.2.2.1

For WTC 1, the top 12 floors of the tower translates into 8x10^9 joules of the total 4x10^11 joules.  So, the top ~10.9% of WTC 1 contained ~2% of the entire PE of WTC 1.  Extrapolating this on to WTC 2 (since the above mentioned report does not specify the amount PE contained above the WTC 2 impact point) we get the following:
WTC 2 => top 26 floors => ~23.6% of WTC 2.
If ~10.9% of WTC 1 translates into 8x10^9 joules PE
Then ~23.6% of WTC 2 translates into N joules PE
Therefore 10.9/8*10^9 = 23.6/N
=> 10.9*N/8*10^9 = 23.6
=> 10.9*N = 23.6*(8*10^9)
=> N = 23.6*(8*10^9)/10.9
=> N = 17321100917.431192660550458715596
=> N = 17.3*10^9 joules PE
=> ~34.7% of the entire PE of WTC 2

What does this mean?  It means for WTC 1, that ~2% (8x10^9 joules) of PE was converted to KE almost instantaneously upon structural failure at floors 94-98.  It means for WTC 2, that ~34.7% (17.3*10^9 joules) of PE was converted to KE almost instantaneously upon structural failure at floors 78-84.

Okay, so Hoffman wants to talk kWh.  What do our total, and our partials, convert into? (all per Google calculator)
4 x (10^11) joules = 111,111.111 kilowatt hours
8 x (10^9) joules = 2,222.22222 kilowatt hours
17.3 x (10^9) joules = 4,805.55556 kilowatt hours

Now, Hoffman cites [url]http://www.911-strike.com/powder.htm[/url] to support his claim that [b]all[/b] of the concrete was pulverized to 60 microns.  On Hoffman's reference Russell states

 

Russell's use of 60 microns appears to come from the nature of his article; that being a response to 

Eric Hufschmid's "concrete physics problem" challenge

  Russell does not link to Hufscmid's challenge, and, frankly, at this point I'm not going digging for it.  If someone has it, and it is relevant, they can post it.

Now, before delving too far into our 60 microns, let's look at the makeup of the dust after the collapses:
http://www.epa.gov/wtc/panel/pdfs/meeker-20041115.pdf#search=%22EPA%20particle%20WTC%20analysis%22
First, I highly suggest reading the short paper, as it describes the EPA's methodology in a very detailed manner.

Table 1. Range in area percent of major and minor components for all samples.
Particle Type Comment                                     Percent Range, Outdoor   Percent Range, Indoor
Gypsum        Includes all Ca sulfate particles           26.3 – 53.3              63.3 – 63.7
Concrete      All phases compatible with hydrated cement  19.3 – 30.8              14.0 – 21.0
MMVF*       Total                                         20.3 – 40.6               9.5 – 19.2
<snip>

 

Wait.  You read that too fast.  Let me reiterate
Particle Type
Gypsum
Percent Range, Outdoor
26.3 – 53.3
Percent Range, Indoor
63.3 – 63.7

Particle Type
Concrete     
Percent Range, Outdoor
19.3 – 30.8
Percent Range, Indoor
14.0 – 21.0

Let me put it another way.  In the EPA's sample, drywall dust accounted for more than ~15% more of the outdoor sample than concrete; and account for more than ~46% more of the indoor sample.

The bulk of the cloud seen from the collapse of the towers is drywall dust not concrete dust.  Hoffman is starting from a flawed premise.

QED.

 

Prof. Steven "Cold Fusion" Jones of "thermite brought the twin towers down!" fame has been placed on leave by BYU; they're getting tired of his shennanigans.  http://www.deseretnews.com/dn/view/0,1249,645199800,00.html

 

Over at the JREF forum we've been going around and around with Killtown over his analyis of Val McClatchey's photo, End of Serenity.  Seeing as how he has run away from the debunkings of his drek without responding in a meaningful way, I thought I would address a number of the points here.

 

Before delving into his pile of factoids and allegations I'd like to present the facts that are verifiable.

 

Here's Shanksville, PA and its surrounding area; including the crashsite of Flight 93 and Ms. McClatchey's house: 

Camera location: 40 03'00.33" N 78 52'28.37" W

Corner of fenceline meeting road in front, and south, of camera position: 40 02'59.99" N 78 52'29.65" W

Peak of house West-North-West of camera location: 40 03'02.30"N 78 52'35.01" W

Northern peak of red barn in picture: 40 03'01.15" N 78 52'34.43" W

Southern peak of red barn in picture: 40 03'00.43" N 78 52'34.40" W

Southern peak of red shed next to red barn in picture: 40 03'00.19" N 78 52'35.16" W

Northern peak of white barn in picture: 40 02'58.21" N 78 52'41.99" W

Southern peak of white barn in picture: 40 02'57.44" N 78 52'41.95" W

 

Let's look at the extended field of view of the camera.  We'll take it out past the longitude of the crashsite.

 

Now, let's look at Ms. McClatchey's photo with our reference points in place, and some indicators of where the smoke plume fits into the picture: 

So, let's overlay our new reference points in the field of view.  (widest angle is camera field of view, next is plume cap field of view, narrowest is plume stem field of view)