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Ignatz
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Joined: 14 Sep 2006
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Posted: Wed Oct 11, 2006 12:25 am Post subject: The question for chek

(splitting this)

chek wrote:

Anyroad up, ask your question and I shall try to answer, although if it's much more scientific than the formula for salt, you may be disappointed..

Hoffman (and others) performed a complex calculation on the 'energy sink' of the Twin Towers. In this, they calculate the total potential energy in that building and the amount of energy required to pulverise its 600,000 tons of concrete content into 60 micron dust and heat it, and the energy remaining to continue the collapse of the building. They conclude that the potential energy contained with the towers was insufficient to cause the observed collapse.

They take the 60 micron figure from a (worthy) study at

http://www.ehponline.org/docs/2002/110p703-714lioy/abstract.html (abstract)
http://www.ehponline.org/members/2002/110p703-714lioy/EHP110p703PDF.PD F (full version)

that sampled fine dust and smoke residues at 3 protected locations downwind of GZ.

Those researchers found only fine particles, recovered from a distance (we might need to discuss terminal velocity of objects of various size/shape/density here, but I believe you'll get the gist).

In fact there was no way they could detect larger pieces of mineral residue, as such pieces could not drift that far.

The samples contained 50% by mass of fibrous materials, mostly fibreglass but also cellulose and asbestos.

Mineral deposits were partly bound to fibrous material.

Non-fibrous material included soot particles, paint, gypsum and glass fragments as well as cement and calcium carbonate

Conclusion :

The "60micron average" figure for pulverised concrete is inadmissible to the calculations of Hoffman et al.

Therefore :

a) Hoffman et al were guilty of gross scientific negligence.

or

b) They set out to mislead the unwary reader.

Your comments are invited on Hoffman's scientific plausibility.

(the above barely does justice to Hoffman's misrepresentation of the research, but it's a start. I recommend you read the quoted study sometime.)
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Last edited by Ignatz on Wed Oct 11, 2006 7:40 am; edited 1 time in total

Anti-sophist
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Posted: Wed Oct 11, 2006 12:37 am Post subject:

Also, keep in mind, 600,000 tons is a gross overestimate of the amount of concrete in each tower.

chek
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Location: North Down, N. Ireland

Posted: Wed Oct 11, 2006 10:02 am Post subject:

Anti-sophist wrote:

Also, keep in mind, 600,000 tons is a gross overestimate of the amount of concrete in each tower.

That is debateable, as arriving at a figure is difficult from published sources. Although figures quoted by Eager roughly agree with Hoffman's.

"The land-filling of 700,000 t of concrete and stone rubble is more problematic. However, the volume is equivalent to six football fields, 6–9 m deep, so it is manageable."

"Interestingly, the approximately 300,000 t of steel is fully recyclable and represents only one day’s production of the U.S. steel industry."

http://www.tms.org/pubs/journals/JOM/0112/Eagar/Eagar-0112.html

Eager doesn't specifically state it, but the figure matches the approx 500,000t per tower often quoted. As Eager can in no way be considered
a 'truther', his and Hoffman's figures are roughly in agreement.

The Bazant-Zhou calculation appears somewhat less, but the maths are beyond me - and given that it was published on 13 Sept 2001, may not be that reliable in any case.

http://209.85.129.104/search?q=cache:eDrYJFHI2QQJ:www-math.mit.edu/~ba zant/WTC/WTC-asce.pdf+Bazant+and+Zhou+WTC+weight&hl=en&gl=uk&ct=clnk&c d=3

ComfortablyNumb
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Posted: Wed Oct 11, 2006 10:17 am Post subject:

Can I just clarify something. Is your concern that Hoffmann 'chose' this data to report the 60 micron average or is the problem in the make up of the samples themselves?

Quote:

In fact there was no way they could detect larger pieces of mineral residue, as such pieces could not drift that far.

Just wanted to point out that Cortlandt Street (one of the sample locations) is in the next block from GZ.

What is fascinating is the make up of the three samples. They are very similar. This, despite the fact that the Cherry Street and Market Street samples were taken an approximate (took a very rough mesurement from GZ centre to middle distance of each street) 5000ft distance from GZ whereas Cortlandt Street is aproximately 500ft - 10 times closer.

I'm assuming this is due to the debris not been transported by the downwind but by the force of the pyroclastic flow.

I think you are dead right to encourage people to read and research the source material no matter which side of the fence you stand.

Ignatz
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Posts: 918

Posted: Wed Oct 11, 2006 10:51 am Post subject:

chek wrote:

Anti-sophist wrote:

Also, keep in mind, 600,000 tons is a gross overestimate of the amount of concrete in each tower.

"The land-filling of 700,000 t of concrete and stone rubble is more problematic. However, the volume is equivalent to six football fields, 6–9 m deep, so it is manageable."

"Interestingly, the approximately 300,000 t of steel is fully recyclable and represents only one day’s production of the U.S. steel industry."

http://www.tms.org/pubs/journals/JOM/0112/Eagar/Eagar-0112.html

Eager doesn't specifically state it, but the figure matches the approx 500,000t per tower often quoted. As Eager can in no way be considered
a 'truther', his and Hoffman's figures are roughly in agreement.

Eager's figures would lead to 350,000 tons of concrete per tower, which is far from "roughly in agreement" with Hoffman (1,000,000 total debris for 2 towers, minus 300,000 tons total steel = 700,000 tons total concrete. Divide by 2 for the concrete in a single tower)

500,000t total weight per tower is a very commonly accepted approximation, and 350,000t of concrete per tower would appear to be a significant over-estimate as it doesn't consider glass, aluminium, plasterboarding and other building materials.

How do you feel about Hoffman's "pulverisation to 60 microns" calculations?
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Ignatz
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Posted: Wed Oct 11, 2006 11:16 am Post subject:

ComfortablyNumb wrote:

Can I just clarify something. Is your concern that Hoffmann 'chose' this data to report the 60 micron average or is the problem in the make up of the samples themselves?

Quote:

In fact there was no way they could detect larger pieces of mineral residue, as such pieces could not drift that far.

Hi - my problem is that Hoffman chose a study that was bound to report small particle sizes and then extrapolated the findings to cover the whole concrete load of the buildings. Which is approximately like me taking measurements from the kids of 3 primary schools to arrive at conclusions about the stature of 21st century Brits in general.

The sites they decribe were "undisturbed sheltered locations". Non-exposure to rain appears to have been vital so it seems reasonable to suppose that the locations were not subject to falling debris, but only drifting debris (however caused) which is scientically bound to be very small and/or light.

cheers
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chek
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Posted: Wed Oct 11, 2006 11:59 am Post subject:

Ignatz wrote:

ComfortablyNumb wrote:

Can I just clarify something. Is your concern that Hoffmann 'chose' this data to report the 60 micron average or is the problem in the make up of the samples themselves?

Quote:

In fact there was no way they could detect larger pieces of mineral residue, as such pieces could not drift that far.

Two points need clarified.
Hoffmans 600,000t and Eager's 700,000t estimates seem 'roughly in agreement for estimates - I'm not aware Hoffman's figure is per tower - but I'll double check that.
Secondly - Hoffman was measuring the expansion of the dustcloud - not doing a rubble count, which therefore will pertain to the dust.

This is not unreasonable given the very fine powder that covered Manhattan from coast to coast and for several miles inland.

While you will no doubt kneejerk dispute it, that is also in basic agreement with anecdotal evidence.
Taken from various locations the dust particle size - which is as low as 5 microns in places he has averaged out at 60.

Interestingly this is something nobody else, including EPA, seems to have attempted to quantify.

Bushwacker
Relentless Limpet Shill

Joined: 07 Sep 2006
Posts: 1628

Posted: Wed Oct 11, 2006 12:49 pm Post subject:

Intuitively one would expect the concrete debris to range in size from dust to large pieces, and include some still attached to the steel on which it was poured. Studying samples taken from even as close as 500 feet from the site does nothing to refute that. Certainly the size of the dust clouds was huge, but anyone who has taken down a wall or ceiling knows how much dust that generates. Without more data no conclusions can be drawn, and Hoffman's result cannot be accepted.

aggle-rithm
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Joined: 22 Aug 2006
Posts: 557

Posted: Wed Oct 11, 2006 1:04 pm Post subject:

ComfortablyNumb wrote:

I'm assuming this is due to the debris not been transported by the downwind but by the force of the pyroclastic flow.

Of course, that would mean there was a volcano in the vicinity, which would throw the investigation into an entirely new direction.

chek
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Posted: Wed Oct 11, 2006 1:11 pm Post subject:

Bushwacker wrote:

Intuitively one would expect the concrete debris to range in size from dust to large pieces, and include some still attached to the steel on which it was poured. Studying samples taken from even as close as 500 feet from the site does nothing to refute that. Certainly the size of the dust clouds was huge, but anyone who has taken down a wall or ceiling knows how much dust that generates. Without more data no conclusions can be drawn, and Hoffman's result cannot be accepted.

I can see why such a conclusion would be attractive to certain parties, but Hoffman doesn't agree and is currently working on v.4 of his paper. It's an important related indicator of the heat and energy released during collapse from whatever source it originated.

The dust clouds weren't just 'huge' - they were dense enough to lift a man off his feet and transport him for a block. Thats one survivor's testimony.
How many didn't survive that hellish trip will never be known.

In the meantime any examples of buildings anytime anywhere which have powderised themselves while collapsing would be welcome.
I won't hold my breath.

Ignatz
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Posts: 918

Posted: Wed Oct 11, 2006 1:13 pm Post subject:

chek wrote:

1) "Since I have better photographs for North Tower dust, I did the calculation for it" - Hoffman. He was calculating for the N Tower only.

Hoffman uses the 60micron figure to calculate the energy required to pulverise 600,000t of concrete from WTC1. The 600,000t is wrong. The 60micron figure is wrong, as it's gleaned from a study that was bound to report low particle sizes. That very report showed >50% non-concrete particles (by mass).

2) "- 900,000 KWh - crushing of concrete - (0.5e12 g to 60 micron powder) "
Hoffman

( 0.5e^12g = 500,000 metric tonnes )

3) If Hoffman were trying to calculate the mass of the dustcloud you might have a point. He wasn't - he was calculating the energy 'used up' (energy sink) in various aspects of the collapse, in this case the crushing of the concrete. Even so he would need to factor in the extreme natural fineness and weakness of plasterboard gypsum, pulverised paper, insulating fibres etc (as actually found in the dust) in his estimates of the cloud's makeup. He doesn't.
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Bushwacker
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Posted: Wed Oct 11, 2006 2:10 pm Post subject:

I have just seen that version 3 of Hoffman's paper uses a weight of 90,000 tons of concrete per tower, instead of 600,000 tons. This gives him an energy figure of 135,000 KWh, which becomes almost insignificant alongside his other calculated figures, which total 14,382,000 KWh.

ComfortablyNumb
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Joined: 14 Sep 2006
Posts: 86
Location: Flintshire

Posted: Wed Oct 11, 2006 2:45 pm Post subject:

aggle-rithm wrote:

ComfortablyNumb wrote:

I'm assuming this is due to the debris not been transported by the downwind but by the force of the pyroclastic flow.

Of course, that would mean there was a volcano in the vicinity, which would throw the investigation into an entirely new direction.

I wasn't aware that the term was exclusive to volcanoes. I was pointing out that the debris analysed at the three sites could not have been distributed by natural wind conditions (downwind as described) but by the 'debris surges' created by the tower collapses.

My assumption being that in natual condtions lighter particals would travel further than heavier ones.

Is 'debris surges' a more acceptible term?

Ignatz
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Joined: 14 Sep 2006
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Posted: Wed Oct 11, 2006 3:00 pm Post subject:

Bushwacker wrote:

I have just seen that version 3 of Hoffman's paper uses a weight of 90,000 tons of concrete per tower, instead of 600,000 tons. This gives him an energy figure of 135,000 KWh, which becomes almost insignificant alongside his other calculated figures, which total 14,382,000 KWh.

Those figures can't be added up - the "ignoring water..." and "assuming water..." are alternative cases.

v3.1 does adjust the concrete figure. He also retracts the 1000k cloud temperature that was in v3, it being "implausible", yet bizarrely puts it back in under "ignoring water vaporization".

ignoring water vaporization
- 400,000 heating of gasses (2e9 g air from 300 to 1020 K)
- 11,300,000 heating of suspended concrete (9e10 g from 300 to 1020 K)

Yet he clings to the "total pulverisation to 60 micron dust" theory. And requires 28,000,000 litres of water to be boiled along the way under "including water vaporization"

assuming water vaporization sink was not supply-limited
- 1,496,000 vaporization of water (2.38e9 g water)
- 41,000 heating of gasses (2e9 g air from 300 to 373 K)
- 1,145,000 heating of suspended concrete (9e10 g from 300 to 373 K)

V4 is "currently under development, taking into consideration critiques by various reviewers". I bet. My guess is the 60micron dust and that volume of water don't stand scrutiny. Chip away long enough and his fine calculations fall to shreds.

And how many people have been polluted by this pseudo-science meanwhile? How many go back to see v3.0/3.1/4.0 having "learnt" all the v2 stuff about the "impossibility" of the collapse?
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ComfortablyNumb
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Posted: Wed Oct 11, 2006 3:11 pm Post subject:

I'm sorry if these questions have been asked before, but I've got ask them because it’s what bothers me the most about the WTC collpases. This is non-partisan question so I want a non-partisan answer! Why do the towers continue to collapse? 1. As the towers collapse and the non-steel contents is pulverised to dust (60 microns or not) where's the weight to continue the process on the undamaged lower floors? 2. As I understand it, the 47 steel central columns were stronger on lower floors than the upper floors to carry more weight. Does this mean the energy to continue the process would need to increase? Compounds with 1 above? 3. The sky lobbies were constructed differently to normal floors and 're-enforced' But they offer no apparent resistance. Why?

chek
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Posted: Wed Oct 11, 2006 3:52 pm Post subject:

It is puzzling, to say the least. As photos show, a huge proportion of the falling dust is outside the perimeter of the building, yet the collapse does not appreciably slow down. It is also apparent that the material inside the perimeter is falling as fast as that outside. Call it intuitive or whatever, but that does not make sense, without other factors coming into play. (I'm trying to avoid saying explosives. Ooops.).

Ignatz
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Posted: Wed Oct 11, 2006 4:09 pm Post subject:

chek wrote:

It is puzzling, to say the least.

As photos show, a huge proportion of the falling dust is outside the perimeter of the building, yet the collapse does not appreciably slow down.
It is also apparent that the material inside the perimeter is falling as fast as that outside.

Same answer as before. Those assertions aren't justified unless you believe Hoffman and those like him. Which you do, even though his science is shown to be faulty.
But just for old time's sake - here's some material falling contrary to your description

And why would anyone expect to see one concrete floor slamming into the next, with that much dust+debris flying around?
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chek
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Posted: Wed Oct 11, 2006 4:22 pm Post subject:

Bushwacker wrote:

It's a while since I checked his papers and he has significantly adjusted his figures in the light of better evidence.
The 135,000KWh relates only to the grinding energy required and even that exceeds the potential energy, without adding the dust cloud expansion volume/speed energy requirement.

Most people would accept that the figures are estimates due to lack of solid evidence (such as a known water content of the concrete, and a known temperature of the debris flows) but given the absence of alternative calculations they at least give a framework to conceive the energy deficiency due to gravity alone.

While critics will argue the exact percentage, the amount of solid concrete chunks is noticeably lacking even at GZ, discounting rubble from WTC5 & 6).

chek
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Posted: Wed Oct 11, 2006 4:37 pm Post subject:

Ignatz wrote:

chek wrote:

And why would anyone expect to see one concrete floor slamming into the next, with that much dust+debris flying around?

If that photo was at all representative, there would not have been several inches thickness of fine dust deposited from coast to coast and one end of Manhattan to the other.

Nobody claims all the concrete (and other non-ferrous material) was powderised but vast quantities were, and that is not deniable.

Arkan_Wolfshade
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Joined: 20 Jul 2006
Posts: 31

Posted: Wed Oct 11, 2006 5:13 pm Post subject: Hoffman's paper has several serious flaws

Hoffman's paper has several serious flaws:

Part I of my analysis

Quote:

[QUOTE=Arkan_Wolfshade;1936951]http://en.wikipedia.org/wiki/World_Trad e_Center
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
Construction of WTC 1 resulted in the storage of more than 4x10^11 joules of potential energy over the
1,368-foot height of the structure. Of this, approximately 8x10^9 joules of potential energy were stored in the
upper part of the structure, above the impact floors, relative to the lowest point of impact.
2.2.2.1
United Airlines Flight 175 struck the south face of WTC 2 approximately between the 78th and 84th
floors.

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 http://www.911-strike.com/powder.htm to support his claim that all of the concrete was pulverized to 60 microns. On Hoffman's reference Russell states
The energy required to crush rock is roughly proportional to 1/sqrt(powder diameter), so the exact amount of energy required is critically dependent on the fineness of the powder. The energy required to reduce solid rock to 60 micron powder is about 20 kwh/ton:
http://www.elorantaassoc.com/eob97.htm

However, concrete is softer than rock, and a round number for the energy required to crush concrete is around 1.5 kwh/ton:
http://www.b-i-m.de/public/ibac/mueller.htm

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%20 particle%20WTC%20analysis%22
First, I highly suggest reading the short paper, as it describes the EPA's methodology in a very detailed manner.
Component analysis for the six WTC bulk samples is summarized in Table 1 and Figures 2 - 7. All of the samples show three primary components – gypsum, phases compatible with concrete, and MMVF. The additional particle types shown in Table 1 were found in most samples. The data demonstrate that the most consistent particle-type abundance ratios occur within the MMVF, i.e., slag wool, rock wool, and soda-lime glass. In all samples, slag wool is the dominant MMVF component while rock wool and soda-lime glass fibers occur in all samples at similar relative abundances below approximately 10 to less than 1 percent total MMVF (Table 1).

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.

I would also like to point of that the claim of 1.5 kWh/ton concrete is taken out of context

Quote:
At the moment digestion rates of around 60 % can be attained with electro-mechanical crushing methods (sonic impulse). This method is nevertheless not competitive compared to common mechanical crushing methods (impact crusher: roughly 1.5 kWh/t concrete) because of its high energy consumption (around 12 kWh/t).

The 1.5 kWh/t is the energy consumption of the impact crusher, not a calculated value of the amount of energy to pulverize the concrete in an ideal setting.

http://arkanwolfshade.spaces.live.com/blog/cns!9E151F6EB6C7A35D!304.e ntry

Part II of my analysis

Quote:

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 nonsense.

http://arkanwolfshade.spaces.live.com/blog/cns!9E151F6EB6C7A35D!306.e ntry

aggle-rithm
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Posted: Wed Oct 11, 2006 5:58 pm Post subject:

ComfortablyNumb wrote:

I think the investigators used the term "compression wave". It was essentially the compressed air pushed down the the ground and outward by the collapsing building.

This is interesting because many CT'ers deny that such a compression wave existed, because it is an alternate explanation for the "squibs" seen shooting out the sides of the towers as they collapsed.

chek
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Posted: Wed Oct 11, 2006 6:43 pm Post subject:

Ignatz wrote:

And why would anyone expect to see one concrete floor slamming into the next, with that much dust+debris flying around?

That view may be a supportable opinion later in the collapse sequence, but those exploding clouds of dust were evident within 3 seconds, by which time they are twice th ediameter of th building.

Which of course you already know, thereby proving this thread is a complete waste of time purporting to demonstrate nothing to see here, move along.

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Posted: Wed Oct 11, 2006 7:26 pm Post subject:

chek wrote:

Ignatz wrote:

And why would anyone expect to see one concrete floor slamming into the next, with that much dust+debris flying around?

In fact it proves you didn't even read the opening post of the thread, which relates to the viability of Hoffman's "science" (and have paid little attention to it for the duration of the thread). "Science" which even he had amended dramatically and then withdrawn since you last read it, as demonstrated by my having to point this out to you in a different thread. And still you'd forgotten. Keep up now chek.
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chek
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Posted: Wed Oct 11, 2006 7:26 pm Post subject:

And here we have what may be the only dust and smoke plume from collapsed buildings that were ever visble from orbit. (http://www-misr.jpl.nasa.gov).

Ignatz
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Posted: Wed Oct 11, 2006 8:45 pm Post subject:

chek wrote:

And here we have what may be the only dust and smoke plume from collapsed buildings that were ever visble from orbit.
(http://www-misr.jpl.nasa.gov).

Fortunately you said "may be".
Actually, you never take any kind of fixed position at all and can therefore always avoid being wrong (are you a politician chek?) ... but anyhow looks like Buncefield has to be included.

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Posted: Wed Oct 11, 2006 8:46 pm Post subject:

aggle-rithm wrote:

ComfortablyNumb wrote:

The sight of those 'debris flows' not dispersing into the surrounding air, but 'boiling' as if a separate entity would suggest that there is more going on than compressed air blowing dust out of the way.

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Posted: Wed Oct 11, 2006 9:15 pm Post subject:

he he

Nice 1 Wiki

Quote:

http://en.wikipedia.org/wiki/Pyroclastic_flow

Pyroclastic flow
From Wikipedia, the free encyclopedia

Pyroclastic flows are a common and devastating result of some volcanic eruptions. They are fast-moving fluidized bodies of hot gas, ash and rock (collectively known as tephra) which can travel away from the vent at up to 150 km/h. The gas is usually at a temperature of 100-800 degrees Celsius. The flows normally hug the ground and travel downhill under gravity, their speed depending upon the gradient of the slope and the size of the flow.

Volumes range from a few hundred cubic metres to more than a thousand cubic kilometres, and the larger ones can travel for hundreds of kilometres although none on that scale have occurred for several hundred thousand years. Most flows are around one to ten cubic kilometres and travel for several kilometres. Flows usually consist of two parts: the basal flow hugs the ground and contains larger, coarse boulders and rock fragments, while an ash cloud rises above it because of the turbulence between the flow and the overlying air.

While moving, the kinetic energy of the boulders will flatten trees and buildings in their path. The hot gases and high speed make them particularly lethal. For example, the towns of Pompeii and Herculaneum in Italy were famously engulfed by pyroclastic flows in 79 AD with heavy loss of life, and in June 1997 flows killed 20 people on the Caribbean island of Montserrat.

The word pyroclast is derived from the Greek πῦρ, meaning fire, and κλαστός, meaning broken. Another name for a pyroclastic flow is a nuée ardente (French for "burning cloud"), which was first used to describe the disastrous 1902 eruption of Mount Pelée on Martinique. A pyroclastic flow has a red glow in the dark.

Flows containing a high proportion of gas to rock are known as pyroclastic surges. The lower density sometimes allows them to flow over higher topographic features such as ridges and hills. They may also be "cold," containing steam, water and rock at less than 100 degrees Celsius. Cold surges can occur when the eruption is from a vent under a lake or the sea.

Hot pyroclastic surges may form ahead of flows, for example during the eruption of Mount Pelée in 1902 a surge overwhelmed the city of Saint-Pierre and killed nearly 30,000 people.

A pyroclastic flow is a type of gravity current; in scientific literature they are sometimes abbreviated to PDC (pyroclastic density current).

There are several scenarios which can produce a pyroclastic flow:

Collapse of the ash column from a plinian eruption (e.g., Mount Vesuvius's destruction of Pompeii, see Pliny the Younger). In such an eruption, the material ejected from the vent heats the surrounding air and the turbulent mixture rises for many kilometres through convection. If the erupted jet is unable to heat the surrounding air sufficiently, there will not be enough convection to carry the plume upwards and it will fall back down the flanks of the volcano. This is known as base surge. It was first documented from observations of underwater nuclear explosions, in which a cloud rolls outward from the bottom of the column as it rises through the air, and subsequently applied to volcanology.

Frothing at the mouth of the vent during degassing of the erupted lava at the mouth. This can lead to the production of a type of igneous rock called ignimbrite. This occurred during the eruption of Mount Katmai in 1912 which produced the largest flows to be generated during recorded history.

Collapse of a lava dome and its subsequent flow down a steep slope (e.g. Montserrat's Soufriere Hills volcano).
The directional blast when part of a volcano explodes or collapses (e.g. the May 18, 1980 eruption of Mount St. Helens)

The use of high explosives in the demolition of skyscrapers and other buildings (e.g. the pyroclastic flows of concrete dust present in Manhattan on September 11, 2001 following the collapse of the World Trade Center Towers 1 and 2.)

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chek
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Posted: Wed Oct 11, 2006 9:51 pm Post subject:

Ignatz wrote:

Can a blazing oil storage depot roughly with an area approx. ten times bigger than the WTC site really be considered comparable to 3 buildings collapsing into dust and smouldering fires?

Ignatz
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Posted: Wed Oct 11, 2006 9:51 pm Post subject:

chek wrote:

aggle-rithm wrote:

ComfortablyNumb wrote:

You still haven't addressed the point that even Hoffman's latest published calculation would require 250,000 litres of available water on every floor to produce the steam to generate this so-called pyroclastic flow (which it wasn't, despite John White wetting himself because somebody has slipped it into Wikipedia unnoticed)
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Posted: Wed Oct 11, 2006 9:56 pm Post subject:

chek wrote:

Can a blazing oil storage depot roughly with an area approx. ten times bigger than the WTC site really be considered comparable to 3 buildings collapsing into dust and smouldering fires?

We started where I asked you whether dust collected from sheltered spots well away from GZ could give an accurate picture of the size and amount of concrete debris at GZ. So far you've skirted the issue.
You first ....
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