North Tower Dust Cloud Calcs Prove Explosives

Hoffman allows posting of his material. I do not believe it was a ruile 4 violation.

The exapansion of the dust cloud is important, because a gravity-only collapse could not expand the cloud like that. Gravity will pressurize air to one atmosphere only. Somehow or another, there got to be about 3 times as much pressure inside the building. This requires energy. I hope that explains to some of the above posters why this is important.

If not explosvies then what? Gravity is insufficient.

Issuing ad hominem attacks against Hoffman does nothing for your scientific argument. I thought I had pasted version 4, but link to any version you like.
 
Hoffman allows posting of his material. I do not believe it was a ruile 4 violation.

The exapansion of the dust cloud is important, because a gravity-only collapse could not expand the cloud like that. Gravity will pressurize air to one atmosphere only. Somehow or another, there got to be about 3 times as much pressure inside the building. This requires energy. I hope that explains to some of the above posters why this is important.
Explain hurricanes. Tornados, and the average wind speed of 45mph in Lubbock, Texas year round?
If not explosvies then what? Gravity is insufficient.

Issuing ad hominem attacks against Hoffman does nothing for your scientific argument. I thought I had pasted version 4, but link to any version you like.

E=mgh=W*h=umpty million lb*1360/2 feet..
 
Um ... the building was not pulverized to dust. I have supplied you with the names, adresses, e-mails and phone numbers of the men who actually sorted through the remains of the towers. All you have to do is ask them. That's right, all you have to do is consult a primary source.

You won't, though. I believe you have a borderline personality disorder which makes it very difficult for you to interact in person with individuals, especially if you fear that they will reject you.

Your internet "friends" are no substitute for the real relationships you crave and the counseling you so desperately need.
 
The exapansion of the dust cloud is important, because a gravity-only collapse could not expand the cloud like that.

Can you please tell us what year, in what college or university and under wich professor you studied fluid dynamics?

Gravity will pressurize air to one atmosphere only.

Not entirely accurate, but the underlying principle is sound. This is why the air rushed out away from the collapse blowing the dust around rather than staying where it was and getting compressed.

The principle you describe explains the behavior of the dust cloud. You unsurprisingly applied the correct principle and get the exact opposite result from the correct one.

Next you'll be telling us gravity pushes rather than pulls and we are all held to the ground by the gravity of the rest of the universe pushing us against the earth. :p
 
I'm sorry but the statement
The exapansion of the dust cloud is important, because a gravity-only collapse could not expand the cloud like that
is just retarded.

Let's play pretend and assume there were explosives in the tower. What is your scenario for the use of those explosives?

In a typical demo by explosives the columns and building supports are severed by explosives. Then the building falls BY GRAVITY. Do you really think they use explosives to push the building down? That's just ignorant.

You've completely failed to prove the building fell faster than gravity could account for, but if it it then something had to push the building down. Did they mount rockets on the top floor to shove down?
 
Given the weight most CTers put in Hoffman's work, he must certainly be an expert in architecture, or structural or civil engineering, or a demolition expert...right....right?

Wrong.

TAM
 
........................

The exapansion of the dust cloud is important, because a gravity-only collapse could not expand the cloud like that. Gravity will pressurize air to one atmosphere only. Somehow or another, there got to be about 3 times as much pressure inside the building. This requires energy. I hope that explains to some of the above posters why this is important.

If not explosvies then what? Gravity is insufficient.

.......................

In fact in the treatment you have cited, Charles' Law behaviour is invoked. That is, the pressure is taken as a constant (in other words V1/T1 = V2/T2; I doubt this assumption is justified). The references the paper cites also admits that complete pulverization is highly unlikely. And they only get an error of an order of magnitude. I think this is pretty good.
 
Given the weight most CTers put in Hoffman's work, he must certainly be an expert in architecture, or structural or civil engineering, or a demolition expert...right....right?

Wrong.

TAM
Hoffman has only one qualification, but it's the one that matters. He's a believer.
 
So let me see if I understand this (I hope not or I am as crazy as TS is!). Gravity couldn't produce the dust cloud so enough explosives are going off on each floor of the buildings involved to pulverize the concrete and all other material on each floor and throw it out sideways WHILE LEAVING THE EXTERIOR WALLS TO FALL STRAIGHT DOWN AS THE BUILDINGS COLLAPSE! OK..... nope, still in the world of reality here, don't get that at all
 
New question on the SAT's.

"Pulverized into fine powder" is to TruthSeeker1234 as "3" rebar on 4'" centers is to _________________

Ooh, ooh! I know! Call on me!

Is the answer "Idiotera"? No wait...."Moronera"? No that's not it....but I know I'm close....
 
So let me see if I understand this (I hope not or I am as crazy as TS is!). Gravity couldn't produce the dust cloud so enough explosives are going off on each floor of the buildings involved to pulverize the concrete and all other material on each floor and throw it out sideways WHILE LEAVING THE EXTERIOR WALLS TO FALL STRAIGHT DOWN AS THE BUILDINGS COLLAPSE! OK..... nope, still in the world of reality here, don't get that at all

welcome to the boards, and I'm telling you there were rockets on top pushing all the non-dust things down. Only logical explanation.
 
If all the mass in the North Tower had fallen at free fall speed, there would have been zero energy left to do any other work. Estimate the amount of GPE actually available to do work, then subtract the amount needed to shred steel, then subtract the amount needed to pulverize all the concrete and desks and carpet and people, then consider Hoffman:
http://en.wikipedia.org/wiki/World_Trade_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="EPA particle WTC analysis"
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).

Code:
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.
 
By the forum rules, at what point are we allowed to put aside our obviously futile rational and observational arguments, and state what we're all thinking about TS1234?
 
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I would also like to point of that the claim of 1.5 kWh/ton concrete is taken out of context
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.
 
If all the mass in the North Tower had fallen at free fall speed, there would have been zero energy left to do any other work. Estimate the amount of GPE actually available to do work, then subtract the amount needed to shred steel, then subtract the amount needed to pulverize all the concrete and desks and carpet and people, then consider Hoffman:
I'd just like to point out the painfully obvious:

Kinetic energy is a temporary sink.

All of that KE is converted into heat, contributes to plastic deformation, and kicks up dust the instant it hits something. Energy is conserved.

Surely you've heard of conservation of energy? The towers falling is a temporary, fleeting state. So where do you think that energy goes by the time the rubble stops shaking?
 
I would also like to point of that the claim of 1.5 kWh/ton concrete is taken out of context


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.

So, being a good little armchair scientist, I continued digging.

It appears concrete is rated as standard 3000-5000 psi, or high stregth 5000-10000 psi (28 day compression test). So far, no luck in finding what the WTC towers were constructed with.

Frankly, I'm getting out of my league at this point trying to calculate how many joules are needed to exceed the respective psi ratings on 90000 tons of concrete. I'm hoping an engineer will step in at this point.
 
More denying the obvious. If all of that dust was mostly drywall, then where did all the concrete, carpet, desks, computers, and human beings go? We sure don't see them at ground zero. Remember the fireman in all the videos, the one who says that

"You have two 110-story office buildings: you don’t find a chair, you don’t find a telephone, a computer... the biggest piece of a telephone I found was half a keypad, and it was this big (holds up thumb and forefinger). The buildings collapsed to dust."



 
So far it seems like the biggest "discredit" to Hoffman is that he wrote his paper in 2003. AFAIK, nobody on the government team has come along and actually tried to model the collapses, or do these kinds of energy balance sheets. Hoffman's approach is not complicated really. Can anyone link us to a study like this, that does an energy balance sheet for the whole collapse and shows that GPE is enough?

I suppose before that happened we'd have to resolve this little issue of where all the intact concrete, and desks, and computers, and humans, where it all went since OCT's keep trying to say I'm wrong about the pulverization.

How about it OCT? If I'm wrong about near-complete pulverization of all non-metallic contents of the twin towers, then where is it? I'm sorry, you'll have to do better than some statement by the land fill operator. I want to see pictures of stacked up floors. And crunched desks. And busted computer monitors. And carpet.

But we don't see this. We see a pyroclastic flow, a mushroom cloud, and a crater full of smoldering dust and molten metal. If you ask me, you could drop a twin tower from twice its own height and it wouldn't get these kinds of observations.
 
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