New J of 9/11 Studies Paper

[RedIbis]

Lace up your debunking boots, this is a fairly brief analysis that REFUTES Woods' and Morgan's space beam theories. Instead, calculations are presented to conclude:

"Calculations using a range of estimates from observations show the destruction from these explosions range up to 1/4 mile or more in most directions. These strongly enhance the evidence presented in previous studies, such the photo in Figure 1 which shows the rapidly expanding huge dust clouds from the towers resulting from massive pulverization of the non-metallic parts of the towers in mid-air, along with hundreds of pieces of metal cladding and beams flying through the air on their rim. All of them provide dramatic examples of the devastation of the explosions in the World Trade
Center towers 6 years ago."

Direct Evidence for Explosions: Flying Projectiles and
Widespread Impact Damage
Dr. Crockett Grabbe
http://www.journalof911studies.com/volume/200704/GrabbeExplosionsEvidence.pdf

[Rahne Everson]

Gee, it's not like two 110 story building collapsing could do any of that, no sir.

[Gravy]

Oh. My. God. Stupidest Journal of 9/11 Stundies paper yet? It's certainly up there. What horrible incompetents these people are.

[RedIbis]

Oh. My. God. Stupidest Journal of 9/11 Stundies paper yet? It's certainly up there. What horrible incompetents these people are.

Your specificity, reasoning and logic are hard to argue with. At least you didn't disappoint by relying on nothing but a cheap ad hom attack. Well done.

[Cl1mh4224rd]

*yawn*

Let us know when it gets published in a reputable journal.

[einsteen]

I'm sure it is already stupid before a single line has been recalculated.
And about peer reviewing, ask your physics bozos and let them review it.

[9/11 Chewy Defense]

Conspiracists will do anything, I mean anything, to press their issues. If they want to take the Government to court without any evidence then why don't they just do it and be done with? What's taking them so long to accomplish this?

I would just die laughing when they do take the Government to court and then we'll see who are the clowns in the "circus" courtroom.

[Redtail]

Figures 5 and 6 show these high-speed squibs shot out material up to 1/4 mile or more from the towers. This ejection distance xhit is not all that sensitive to the height of origin: raising or lowereing the ejection height by over 800 feet changes xhit by less than 500 feet for the
low resistivty side, and just over 200 feet on the high resistivity side.

So the charges were powerful enough for the above mentioned to happen, yet were so quiet that none of the recording devices around that day picked anything that sounded like CD charges?

[Gravy]

I'm sure it is already stupid before a single line has been recalculated.You got it!

[Cl1mh4224rd]

So the charges were powerful enough for the above mentioned to happen, yet were so quiet that none of the recording devices around that day picked anything that sounded like CD charges?


Not to mention that these alleged explosives powerful enough to eject material 1/4 of a mile outward didn't even produce any vibrations that could be detected by the same seismographs that picked up the plane impacts...

[Mr. Skinny]

Dang, my computer seems to hate pdf documents at the moment.

Do they state what kind of weapon it supposedly is?

ETA: From the quote in the OP, they don't seem to state what their theory is as to what weapon/fairy dust brought down the towers.

[T.A.M.]

I love how the truthers HATE the concept of peer review...because they know it is something none of their "scientists/experts" will ever be successful at passing.

TAM:)

[T.A.M.]

If this is the guy, he seems to be legit, in terms of actually existing and being a scientist...even leaves you with his email...

http://www.physics.uiowa.edu/~cgrabbe/

Seems to be primarily an Astronomer.

TAM:)

[T.A.M.]

Seems he has some research experience in an area that might qualify him to refute the no-planer Space Beam theories...


C L Grabbe, Space Weapons and the Strategic Defense Initiative (Iowa State University Press, Ames, Iowa, 1991)

TAM:)

[Gravy]

Seems he has some research experience in an area that might qualify him to refute the no-planer Space Beam theories...

TAM:)There is a previous thread about him here, with video.

http://forums.randi.org/showthread.php?t=80357

[T.A.M.]

Thanks for the link...

Well he seems to be full blown truther, which makes me doubt anything he has to say, but according to his home page (which of course, could be along the lines of Torin Wolf in terms of exaggerated credentials), he does seem to have some knowledge/expertese that might make him qualified to denounce/refute the "Beam Weapons".

TAM:)

[Tony Szamboti]

Not to mention that these alleged explosives powerful enough to eject material 1/4 of a mile outward didn't even produce any vibrations that could be detected by the same seismographs that picked up the plane impacts...

You really have to explain the connection you are implying.

Are you saying an explosive in the upper stories would provide a similar effect on the building's lower levels as the aircraft impact at those upper stories?

Are you equating the aircraft energy with an explosive needed to take out a beam?

I thought I read where Crockett Grabbe says the high speed ejections were 1/3 of the width of the towers or approximately 70 feet from the tower perimeter. I think the remaining distance the material traveled was due to trajectory since it strated out at a great height not its initial force.

[Cl1mh4224rd]

You really have to explain the connection you are implying.

Are you saying an explosive in the upper stories would provide a similar effect on the building's lower levels as the aircraft impact at those upper stories?

Are you equating the aircraft energy with an explosive needed to take out a beam?

I thought I read where Crockett Grabbe says the high speed ejections were 1/3 of the width of the towers or approximately 70 feet from the tower perimeter. I think the remaining distance the material traveled was due to trajectory since it strated out at a great height not its initial force.


Please read the "paper", specifically the quote in post #8 of this thread, then get back to us.

[R.Mackey]

Please read the "paper", specifically the quote in post #8 of this thread, then get back to us.

There's a strong possibility (http://forums.randi.org/showthread.php?postid=2833119#post2833119) that "realcddeal" is Mr. Grabbe. But I could be wrong, if I'm not mistaken there are two such papers on the JONES that dispute the space-beam theories. It's not hard to do, I've done it here, myself.

Whomever assembled that... pamphlet, it's ruddy awful. Doesn't even resemble a proper whitepaper.

One of the key arguments against is that, if explosives were really to blame, drag works both ways in such a case. A smaller object will have a lower ballistic coefficient, and thus will be more affected by aerodynamic drag and differential pressure. This means, yes, a larger object with the same initial velocity will fly farther than a smaller object, but they don't start with the same initial velocity, if they're driven by explosives.

If the propulsion is caused by explosives, the smaller object will be accelerated much, much more than the larger one, by the same physics, and as a result we would see the smaller objects flying farther. Taking all other effects into account, there will be a "sweet spot" at extreme range where an intermediate-sized object, probably in the centimeter range, travels the farthest -- but this doesn't match what we saw at all.

If, on the other hand, the ejection is gravity-driven, then all pieces will have the same velocity, by virtue of falling the same distance or all being part of the same more-or-less cohesive collapse front until ejection. In this scenario, the larger pieces will fly farther, the larger the better. Oddly enough, this is exactly what we see, apart from pieces so small that they are effectively wind-borne and no longer ballistic in the first place.

This paper is just another poke in the eye for Dr. Jones and the "Scholars."

[LashL]

This paper is just another poke in the eye for Dr. Jones and the "Scholars."

Indeed. Yet, the "Scholars" don't even have enough sense to be embarrassed by such pathetic "scholarship" and that is actually sad.






Well, okay, it would be sad if it weren't so uproariously funny. :D

[Gravy]

realcddeal isn't Crockett Grabbe, for what it's worth.

[R.Mackey]

Good to know.

For what it's worth, I ran some calculations on how far a 100 kg blast of TNT would be expected to throw a 3m column section, originally located 15m from the blast (anything closer would probably destroy it). It works out to an initial velocity of only about 5 meters per second. If ejected in this fashion from the top of the Towers, this means a maximum distance of under 50 meters away from the footprint.

So, if Mr. Grabbe is right, we're talking about really, really big explosives. Funny that nobody saw them, including Protec and the LDEO.

[Gravy]

Good to know.

For what it's worth, I ran some calculations on how far a 100 kg blast of TNT would be expected to throw a 3m column section, originally located 15m from the blast (anything closer would probably destroy it). It works out to an initial velocity of only about 5 meters per second. If ejected in this fashion from the top of the Towers, this means a maximum distance of under 50 meters away from the footprint.

So, if Mr. Grabbe is right, we're talking about really, really big explosives. Funny that nobody saw them, including Protec and the LDEO.And you're talking only about the force to move the column, not to sever it from its connections, right?

[R.Mackey]

Yup. I'm assuming the column was free-standing and unattached when the pressure wave hits.

Much harder to estimate how it behaves if the explosive shears it off. There would probably be some elastic effect, but surely being hard-mounted would dissipate the blast, not actually make it fly farther.

[uk_dave]

You don't suppose that going through life with a name like "Crockett Grabbe" could have a profound psychological impact on a person?

Just sayin'....

[timhau]

I love how the truthers HATE the concept of peer review...

Hey, I'm sure the journal uses peer review. Nutters submit papers, other nutters review them.

[Gravy]

You don't suppose that going through life with a name like "Crockett Grabbe" could have a profound psychological impact on a person?

Just sayin'....I love the name. It may even be better than Buster Crabbe.

[LashL]

You don't suppose that going through life with a name like "Crockett Grabbe" could have a profound psychological impact on a person?

Just sayin'....

I have to admit, the first thing I thought when I saw the guy's name was, "Jesus, that poor guy had cruel parents."


(But he also goes by another name of his own choosing, which isn't a whole lot better, so.. who knows?)

In any event, his "paper" is complete crap and utterly meaningless; entirely in keeping with the pseudo-scholars' psuedo journal. Sad, no matter how you dissect it.

[DarkMagician]

Seems he has some research experience in an area that might qualify him to refute the no-planer Space Beam theories...

TAM:)

Oh god, he's being taught in IOWA.

I'm not drinking the water for a couple of weeks.

[Dave Rogers]

I'm sure it is already stupid before a single line has been recalculated.
And about peer reviewing, ask your physics bozos and let them review it.

Physics Bozo is on the case!!!!

OK, peer review coming.

The paper makes the assertion that certain photographs of the WTC collapse prove that explosions were responsible for the ejection of debris, but advances no evidence for the assertion. Pictures of damaged cars are produced more to refute the beam weapon theory than to promote the explosives theory; the damage is characterised as due to hot and possibly corrosive debris, but no evidence is advanced that this debris was not ejected as a result of glancing collisions in the collapse of the towers, or that the heating of the debris was not a result of the extensive pre-collapse fires.

In discussion of the "squibs", the key assertion that "overpressure is created by explosions" is not justified. The discussion of the radial distribution of debris is superfluous, as the ejection velocity has already been deduced from videos, and the comment that "it is likely that explosions are also occurring after the growing dust cloud envelopes the area" is pure speculation unsupported by evidence.

In summary, this paper is an attempt at proof by assertion, and no evidence is advanced to support its central thesis. Einsteen's characterisation of the paper as "already stupid before a single line has been recalculated" is a highly perceptive and accurate summary of the paper.

Refused for publication. Re-submission is not advised.

Dave

[Revolutionary91]

I love it when extremely qualified internet posters, such as tour guides, dismiss physicists papers without even reading them.

[Unsecured Coins]

I love it when people who still have to ask mom to stay up past 11 on a school night try to act like they're the reason the earth is still spinning.

[Alferd_Packer]

What is it with the university of Iowa?

Does Crokett do bong hits with Derrick Grimer?

[Unsecured Coins]

I thought Crokett worked with Tubbs.... :confused:

[T.A.M.]

I love it when extremely qualified internet posters, such as tour guides, dismiss physicists papers without even reading them.

Yes a tour guide that your entire movement is afraid do bebate!!!

TAM:)

[NDBoston]

I love it when extremely qualified internet posters, such as tour guides, dismiss physicists papers without even reading them.

You're 15 and seem to be a bright kid. I'm imploring you to do the following.

Call an engineering firm in your area and listen to a structural engineer. Perhaps you have a local college with a decent engineering department. Take the time to talk to people who actually know what they're talking about. It doesn't matter what a theology professor or former Friendly's worker thinks.

Why do I ask you this? I was actually at 7WTC for three years including 9-11. I experienced things that you can't see on You Tube or staring at pictures.

I felt the debris pounding the building on 9-11 and was forced to go out the back because of it. I was on almost every floor SSB had in my role on a daily basis and never saw any construction work being done.

Did you know 3 floors had people on it 24x 7 because they were trading floors? Most people were on there on the weekends too because of the pressures of the job. they paid us well but everyone had to bust their asses Did you know we were packed in like sardines after Salomon/Smith Barney merger? You Tube won't tell you that.

Guess what explanation I receive from "truthers". The building was pre-wired. PRE-WIRED!

Stop using 9-11 truth as a way of finding an identity and use the critical thinking skills I think you have. This isn't a joke for me. My best friend died that day and if I thought for even a second there was a chance of government involvement, I would be the first one storming the White House.

[Dave Rogers]

I love it when extremely qualified internet posters, such as tour guides, dismiss physicists papers without even reading them.

How do you feel when physicists with a quarter of a century's professional experience dismiss them after having read them?

Dave

[Sabrina]

You're 15 and seem to be a bright kid. I'm imploring you to do the following.

Call an engineering firm in your area and listen to a structural engineer. Perhaps you have a local college with a decent engineering department. Take the time to talk to people who actually know what they're talking about. It doesn't matter what a theology professor or former Friendly's worker thinks.

Why do I ask you this? I was actually at 7WTC for three years including 9-11. I experienced things that you can't see on You Tube or staring at pictures.

I felt the debris pounding the building on 9-11 and was forced to go out the back because of it. I was on almost every floor SSB had in my role on a daily basis and never saw any construction work being done.

Did you know 3 floors had people on it 24x 7 because they were trading floors? Most people were on there on the weekends too because of the pressures of the job. they paid us well but everyone had to bust their asses Did you know we were packed in like sardines after Salomon/Smith Barney merger? You Tube won't tell you that.

Guess what explanation I receive from "truthers". The building was pre-wired. PRE-WIRED!

Stop using 9-11 truth as a way of finding an identity and use the critical thinking skills I think you have. This isn't a joke for me. My best friend died that day and if I thought for even a second there was a chance of government involvement, I would be the first one storming the White House.

*applauds vigorously* Nothing more need be said.

[Revolutionary91]

Yes a tour guide that your entire movement is afraid do bebate!!!

TAM:)

Well, except that Jason and Dylan debated him, as did Fetzer. He was set to do the National 911 debate but nobody else from the OCT side would do it. Nobody is afraid to debate Gravy.

[funk de fino]

Well, except that Jason and Dylan debated him, as did Fetzer. He was set to do the National 911 debate but nobody else from the OCT side would do it. Nobody is afraid to debate Gravy.

not afraid to do it once, but they will not ever do it again

they were destroyed

[Revolutionary91]

not afraid to do it once, but they will not ever do it again

they were destroyed

Are you afraid of capital letters and periods?

They were not destroyed at all.

[Calcas]

Are you afraid of capital letters and periods?

They were not destroyed at all.

Johnathan, are you still going to NYC on 9-11 with your dad?

Why don't you plan to meet up with Gravy?

[funk de fino]

Are you afraid of capital letters and periods?

They were not destroyed at all.

uncle fester was made to look a fool

how many words did dylan actually utter? not counting the ones that he used to correct jasons mistakes

if those had been boxing matches the trainer would have thrown in the towel

we don't call then periods in my country short stuff

if i use capitals i may scare you off

[CHF]

Are you afraid of capital letters and periods?

They were not destroyed at all.

Well Uncle Fetzer and Jason were destroyed.

As for Dylan...well you can't lose if you don't play.

[nicepants]

Nobody is afraid to debate Gravy.

Kevin Ryan still refuses to debate him.

So does David Ray Griffin.

I think the reason for their refusals was pointed out nicely by CHF:

you can't lose if you don't play.

[T.A.M.]

Sorry Rev, but their patterns of behaviour on this matter leads me to believe they are all afraid to bebate him. They only have to read his papers, watch his debates with LTW and Fetzer to realize he is not some "out of the loop" scientist or beurocrat that they can bamboozle with the fog of 9/11 twoof.

TAM:)

[Anti-sophist]

I love it when extremely qualified internet posters, such as tour guides, dismiss physicists papers without even reading them.

What kind of asinine appeal to authority is this?

Do you really want me to start playing this game with you? Where'd you get your degree from?

[Corsair 115]

I love it when extremely qualified internet posters, such as tour guides, dismiss physicists papers without even reading them.I don't need to be an astonomer to know that a paper put out by an astronomer claiming that the Sun goes around the Earth is nonsensical.

[beachnut]

Lace up your debunking boots, this is a fairly brief analysis that REFUTES Woods' and Morgan's space beam theories. Instead, calculations are presented to conclude:

"Calculations using a range of estimates from observations show the destruction from these explosions range up to 1/4 mile or more in most directions. These strongly enhance the evidence presented in previous studies, such the photo in Figure 1 which shows the rapidly expanding huge dust clouds from the towers resulting from massive pulverization of the non-metallic parts of the towers in mid-air, along with hundreds of pieces of metal cladding and beams flying through the air on their rim. All of them provide dramatic examples of the devastation of the explosions in the World Trade
Center towers 6 years ago."

Direct Evidence for Explosions: Flying Projectiles and
Widespread Impact Damage
Dr. Crockett Grabbe
http://www.journalof911studies.com/volume/200704/GrabbeExplosionsEvidence.pdf
Your nonsense is garbage, only kids with no education fall for. If you had studied CD, you would know that explosives are not used to destroy the building but gravity is. You have failed to understand your world. I warn you now, if you are as poor in all aspects of your life, you could be in danger of making mistakes that risk your life. You must get better at understanding the real world and people. You have fallen for the biggest lies in modern history, the 9/11 truth movement. I can tell from your post you do not understand how gravity can do what you saw on 9/11 and that you did not know the primary energy used in CD is due to gravity.

Go get an education before you make serious mistakes in life. Being fooled by 9/11 truth only makes you look foolish. BTW, the idiot who wrote the paper is missing the blast effects to send object 1/4 of a mile. The sound alone would have been heard, but it was not. Sorry to debunk a paper without reading it, but you gave away the BS in your post. What has happened to rational thinking? Why are you so easily fooled?

[beachnut]

I love it when extremely qualified internet posters, such as tour guides, dismiss physicists papers without even reading them.
Pay attention young person of woo. When a paper is published in the journal of woo, you know it as, " Journal of 9/11 Studies", it is wrong and does not have to be read after one of the experts, like you, from LCF endorses it. I have found if you (R91) endorse something, it is 99.999999 percent BS. Not sure why this works but take any paper from the Journal of Woo, and you will find out too.

Go ahead, take a paper and show me one that is good for anything 9/11. Got one? This one is the biggest piles of junk, and I can see from just RedIbis and you, that it is woo too.

So should I read it? (1:25PST) (Kevin Ryan and Jones make it 99.99999999999999 Percent BS, you have more potential to become a real person who can think than these two clowns, but you have to start thinking for yourself and stop being a drone to 9/11 truth idiots)

Oops, read it! (1:28) It is total BS. What a bunch of BS, no comment is needed to mark this woo, with the mark of woo. Funny, he uses work of other truthers to make a paper of junk. Yes, from an engineer this is not very scientific, but get this real good. People who lie this bad and make up stuff this stupid do not deserve a critique. These people from 9/11 truth are so low, they are dumb as dirt. How can anyone push this tripe as science? You need to get help if you can not find enough information to debunk this yourself. If you can't do it yourself you are stuck in the 9/11 truth movement. Your problem.

I am sure other people with post the other scientific reasons, I am still laughing too much to even try.

[jhunter1163]

I love it when extremely qualified internet posters, such as tour guides, dismiss physicists papers without even reading them.

If Gravy is not qualified to comment on this paper because he's a tour guide, albeit one with encyclopedic knowledge of all things 9/11, then surely R.Mackey, who is a NASA scientist, is qualified. And he thinks it's garbage too.

You really shouldn't advertise your ignorance so.

[ihaunter]

Oh god, he's being taught in IOWA.

I'm not drinking the water for a couple of weeks.

It's worse than that, I believe he's the one teaching.

I knew that the Iowa City water could get bad sometimes, but I had no idea. I'm happy with Mississippi river mud water:D

[cmcaulif]

Good to know.

For what it's worth, I ran some calculations on how far a 100 kg blast of TNT would be expected to throw a 3m column section, originally located 15m from the blast (anything closer would probably destroy it). It works out to an initial velocity of only about 5 meters per second. If ejected in this fashion from the top of the Towers, this means a maximum distance of under 50 meters away from the footprint.

So, if Mr. Grabbe is right, we're talking about really, really big explosives. Funny that nobody saw them, including Protec and the LDEO.

Can you lay those calculations out in detail? It might be worthwhile to demonstrate this further, since the ejection of beams is such a major truther claim.

I believe there were reports of beams found 500 feet away, so if these came from the top floor they would need a horizontal velocity of 16.6m/s. Though that is just assuming they are ejected strait out and doesn't consider any kind of optimized trajectory. It still shows a huge difference while making ridiculous assumptions in favor of explosives though.

[R.Mackey]

Can you lay those calculations out in detail? It might be worthwhile to demonstrate this further, since the ejection of beams is such a major truther claim.

I believe there were reports of beams found 500 feet away, so if these came from the top floor they would need a horizontal velocity of 16.6m/s. Though that is just assuming they are ejected strait out and doesn't consider any kind of optimized trajectory. It still shows a huge difference while making ridiculous assumptions in favor of explosives though.
Those calculations appear in my upcoming re-bunk of Dr. Griffin. Basically I found a published paper that describes the pressure load of a 100 kg TNT reference explosion, which at 15 meters creates a wave of about 270 kPa (40 psi) for 17 milliseconds. Multiply that times the facing area of the column and you get total impulse, divided by mass and you get initial velocity. I used a 3m high box column, 20 cm on a side, with 4 cm thick walls for sake of argument. This gives an initial velocity of about 5 meters per second.

It's a rough figure, but there's little point trying to sharpen it. The exact pressure and duration are a factor of explosive geometry and how the wave is shaped and reflected by solid objects. What's important is that, in the collapse front, we already expect speeds of 20 m/s or even more just from gravity alone at places fairly high in the structure. To get higher speeds with explosives, you need very large explosives. 100 kg of TNT is enough to get your attention, even if detonated while the Towers were coming down.

[cmcaulif]

Those calculations appear in my upcoming re-bunk of Dr. Griffin. Basically I found a published paper that describes the pressure load of a 100 kg TNT reference explosion, which at 15 meters creates a wave of about 270 kPa (40 psi) for 17 milliseconds. Multiply that times the facing area of the column and you get total impulse, divided by mass and you get initial velocity. I used a 3m high box column, 20 cm on a side, with 4 cm thick walls for sake of argument. This gives an initial velocity of about 5 meters per second.

It's a rough figure, but there's little point trying to sharpen it. The exact pressure and duration are a factor of explosive geometry and how the wave is shaped and reflected by solid objects. What's important is that, in the collapse front, we already expect speeds of 20 m/s or even more just from gravity alone at places fairly high in the structure. To get higher speeds with explosives, you need very large explosives. 100 kg of TNT is enough to get your attention, even if detonated while the Towers were coming down.

I might be nitpicking, but I looked into it a bit further. I found a paper on the 1993 WTC bombing in the journal of impact engineering:

Shear failure of a steel member due to a blast (http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V3K-3YB4CXR-2&_user=605441&_coverDate=03%2F31%2F2000&_alid=608017195&_rdoc=2&_fmt=full&_orig=search&_cdi=5733&_sort=d&_docanchor=&_artOutline=Y&view=c&_ct=2&_acct=C000029138&_version=1&_urlVersion=0&_userid=605441&md5=a69f2e17e71b6eee2daa3afaec1039ce#appb)
T. Nonaka

From the equation in appendix A, it would give the reference charge you used would give a peak pressure of 189.02 kPA, which would then decrease monotonically, so the impulse you are using is likely to be a generous overestimate.

It is also interesting to note that the calculated Mu(ratio of peak blast load to plastic collapse load) for this blast load on the example beam used in the paper is less than one, equaling 0.63158. Not only that, but about 10 times more energy will be absorbed by shearing than by bending anyway. Although the members may not be comparable and a friend pilfered my AISC handbook.

[MIKILLINI]

I love it when extremely qualified internet posters, such as tour guides, dismiss physicists papers without even reading them.

I love it when internet posters dismiss 800 witness statements as not credible.

[R.Mackey]

I might be nitpicking, but I looked into it a bit further. I found a paper on the 1993 WTC bombing in the journal of impact engineering:

Shear failure of a steel member due to a blast (http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V3K-3YB4CXR-2&_user=605441&_coverDate=03%2F31%2F2000&_alid=608017195&_rdoc=2&_fmt=full&_orig=search&_cdi=5733&_sort=d&_docanchor=&_artOutline=Y&view=c&_ct=2&_acct=C000029138&_version=1&_urlVersion=0&_userid=605441&md5=a69f2e17e71b6eee2daa3afaec1039ce#appb)
T. Nonaka

From the equation in appendix A, it would give the reference charge you used would give a peak pressure of 189.02 kPA, which would then decrease monotonically, so the impulse you are using is likely to be a generous overestimate.

That's not a nitpick, it's true. It's a feature of my calculations. I'm attempting to show that the impulse from explosives, even with an extremely generous overestimate of the pressure and duration, still gives you unimpressive velocities. This is explained in my forthcoming report.

Thanks for the reference, by the way. It's not the same as mine but should give me a good basis for comparison. I high-balled the estimate because the other structure will give you a focusing effect -- possibly the upper and lower floors would increase the pressure at that distance, and also give you reflected waves that could add up making a longer pulse. It's going to be very difficult to calculate it precisely, so a generous estimate was good enough for my purposes.

So, in summary, you're quite right. And it drives the stake even deeper into the heart of the "CD" hypothesis.

[cmcaulif]

That's not a nitpick, it's true. It's a feature of my calculations. I'm attempting to show that the impulse from explosives, even with an extremely generous overestimate of the pressure and duration, still gives you unimpressive velocities. This is explained in my forthcoming report.

Thanks for the reference, by the way. It's not the same as mine but should give me a good basis for comparison. I high-balled the estimate because the other structure will give you a focusing effect -- possibly the upper and lower floors would increase the pressure at that distance, and also give you reflected waves that could add up making a longer pulse. It's going to be very difficult to calculate it precisely, so a generous estimate was good enough for my purposes.

So, in summary, you're quite right. And it drives the stake even deeper into the heart of the "CD" hypothesis.

All of that on top of the fact your velocity estimate will be even higher since you are neglecting the energy that will be dissipated by shearing and plastic bending, doing the CD hypothesis another favor. I guess that really makes it easy to see why the truth movement never got out of the 'just asking questions' phase and never formulated a coherent or quantifiable hypothesis.

Can't wait for your report though.

[Mangoose]

It's Beer Reviewed. http://www.goldenweb.it/software/immagini/icone/food/food_2/dark%20beer.gif http://www.goldenweb.it/software/immagini/icone/food/food_2/dark%20beer.gif

[Yaters]

You're 15 and seem to be a bright kid. I'm imploring you to do the following.

Call an engineering firm in your area and listen to a structural engineer. Perhaps you have a local college with a decent engineering department. Take the time to talk to people who actually know what they're talking about. It doesn't matter what a theology professor or former Friendly's worker thinks.

Why do I ask you this? I was actually at 7WTC for three years including 9-11. I experienced things that you can't see on You Tube or staring at pictures.

I felt the debris pounding the building on 9-11 and was forced to go out the back because of it. I was on almost every floor SSB had in my role on a daily basis and never saw any construction work being done.

Did you know 3 floors had people on it 24x 7 because they were trading floors? Most people were on there on the weekends too because of the pressures of the job. they paid us well but everyone had to bust their asses Did you know we were packed in like sardines after Salomon/Smith Barney merger? You Tube won't tell you that.

Guess what explanation I receive from "truthers". The building was pre-wired. PRE-WIRED!

Stop using 9-11 truth as a way of finding an identity and use the critical thinking skills I think you have. This isn't a joke for me. My best friend died that day and if I thought for even a second there was a chance of government involvement, I would be the first one storming the White House.

This is a bump for Rev. Great post, ND. Rev, what are your thoughts?

[johnny karate]

Rev was banned.

[cmcaulif]

That's not a nitpick, it's true. It's a feature of my calculations. I'm attempting to show that the impulse from explosives, even with an extremely generous overestimate of the pressure and duration, still gives you unimpressive velocities. This is explained in my forthcoming report.

Thanks for the reference, by the way. It's not the same as mine but should give me a good basis for comparison. I high-balled the estimate because the other structure will give you a focusing effect -- possibly the upper and lower floors would increase the pressure at that distance, and also give you reflected waves that could add up making a longer pulse. It's going to be very difficult to calculate it precisely, so a generous estimate was good enough for my purposes.

So, in summary, you're quite right. And it drives the stake even deeper into the heart of the "CD" hypothesis.

Can you link to your references? I'd like to check and compare as well.

[FactCheck]

I debunked some of this before it even came out.

http://www.debunking911.com/jones.htm

http://www.debunking911.com/collapse.htm

[simakperrce]

It's Beer Reviewed. http://www.goldenweb.it/software/immagini/icone/food/food_2/dark%20beer.gif http://www.goldenweb.it/software/immagini/icone/food/food_2/dark%20beer.gif

:dl:

[cmcaulif]

I debunked some of this before it even came out.

http://www.debunking911.com/jones.htm

http://www.debunking911.com/collapse.htm

I have read those links before, but using the equation given by Nonaka will further demonstrate how ridiculous the CD nonsense is. I'd like to see Mackey's sources as well though.

If we stick to Mackey's model, in which none of the impulse is dissipated through shearing or plastic bending, and using the same box column at the top of the tower, a constant pressure load of about 896.4 kPA is needed for 17 milliseconds to eject the member at the top floor of the WTC at the required velocity to travel 500 ft.

If the charge is detonated at 15 meters, it will have to be equal to about 1950 kg of TNT using Nonaka's equation in appendix B(which gives the peak pressure load, which then decreases monotonically, rather than remaining constant, as is being assumed here). And if you make the assumption that the massive charge would not be sitting in the middle of an office and would be hidden within the core at a minimum of 60ft, the size of the charge jumps up to approx 3500kg of TNT.

The smaller of the two explosions is 4 times the size of the explosion from the 93 WTC bombing.

[R.Mackey]

I have read those links before, but using the equation given by Nonaka will further demonstrate how ridiculous the CD nonsense is. I'd like to see Mackey's sources as well though.


Sorry for the delay, I was at the Cape all week.

The reference I used is "A Review of Methods for Predicting Bomb Blast Effects on Buildings", A. Rememnikov, Journal of Battlefield Technology, Vol. 6 No. 3, 2003. There is an archived copy readable here (http://ro.uow.edu.au/cgi/viewcontent.cgi?article=1360&context=engpapers). The example I use is taken verbatim from Page 3.

The reason I chose this reference is because of his correct usage of wave reflection, which is an important factor in actual impulse felt by a structure, and the "reasonable" size of his reference explosive. This paper is, after all, intended to directly address the question of explosives versus buildings, which is what we need to know.

Another reason is that the Journal of Battlefield Technology is about the coolest name for a Journal that I've ever seen. :tank:

[cmcaulif]

Thanks, thats pretty interesting, and definitely a great name for a journal.

Kind of wish he would info on the effects of distance and charge weight since his numbers are not in close agreement with the other reference, where these are given, but effects of wave reflection are not. Although I suppose the point is made easily enough with the reference charge used.

[TellyKNeasuss]

For us non-technical types, is it an accurate to say that Dr. Grabbe's paper is self-debunking because he estimates the speed of the "squib" in Figure 4 as between 100 and 200 feet/second (68-136 miles/hour), which would be way too slow for it to have been generated by an explosion?

[cmcaulif]

For us non-technical types, is it an accurate to say that Dr. Grabbe's paper is self-debunking because he estimates the speed of the "squib" in Figure 4 as between 100 and 200 feet/second (68-136 miles/hour), which would be way too slow for it to have been generated by an explosion?

I think 'an explosion' is not enough to characterize the event. The paper I linked to as well as RM's paper show that the blast loads from an explosion are dependent on scaled distance as well as the weight of the charge. Mackey's link includes the effect of reflected waves as well.

So I would say Dr. Grabbe should have attempted to show how much explosive was used, and where this charge was placed, in order to create the 'squib' observed, which is certainly reasonable. This way it can be seen if his claim has scientific merit, but as it stands, his work seems more like a collection of assumptions.