QUOTE (NEU-FONZE+Jul 19 2007, 02:41 PM)
Arthur/Chainsaw:
Here is a simple calculation that illustrates the difference between generalized heating of a building vs. localized heating of a structure within the building:
Let's assume the fire in a WTC tower released 8000 GJ of heat and, (being very generous), also assume that ALL this heat was absorbed by the upper 15 floors having a total mass of 50,000 tonnes. In addition let's assume that the average heat capacity, Cp, of the building's structural materials was 1000 J/kg. The resultant temperature increase, Delta(T), is given by:
Delta(T) = [Total Heat Released] / [Mass x Cp]
= 8 x 10^12 / [50,000,000 x 1000] = 160 deg C
Now consider the case of 50 GJ of chemical reaction heat being delivered directly to the steel in the truss assemblies on one floor. The heat capacity of iron is about 500 J/kg and we shall take the mass of steel in the trusses on one floor as 75 tonnes. In this case:
Delta(T) = 50 x 10^9 / [75,000 x 500] = 1333 deg C
These numbers are, of course, very approximate but they do show that a little bit of LOCALIZED heating is much more effective than GENERALIZED heating and could easily heat a single building component to a temperature sufficient to melt steel.
Neu,
I don't have time to go over your figures right now, but quickly, using 15 floors is a bit of a stretch don't you think, the majority of that heat was released on less than half that many floors.
(Of course a LOT of the heat was vented, but ....
It would appear that chemical reactions don't have a preference for structural steel and there are plenty of OTHER steel objects in the towers, thus I think the amount of localized effect has to reflect that PERCENT of surface area that structural steel represents vs other reactive materials. I believe it is this factor alone that vastly diminishes the impact over the length of time we are talking about. (max 101 minutes)
Still it would appear that what is missing more than anything is RATE of release.
I don't think one can even approximate temp rise without it.
Finally, Note the many examples of steel analysis they did based on mud-cracking of the PRIMER on structural steel from the fire zone. I have a hard time reconciling that the structural steel in the towers were suffering massive chemical attack when NIST spent so much time examaining structural steel that still has its primer intact.
Arthur
Here is a simple calculation that illustrates the difference between generalized heating of a building vs. localized heating of a structure within the building:
Let's assume the fire in a WTC tower released 8000 GJ of heat and, (being very generous), also assume that ALL this heat was absorbed by the upper 15 floors having a total mass of 50,000 tonnes. In addition let's assume that the average heat capacity, Cp, of the building's structural materials was 1000 J/kg. The resultant temperature increase, Delta(T), is given by:
Delta(T) = [Total Heat Released] / [Mass x Cp]
= 8 x 10^12 / [50,000,000 x 1000] = 160 deg C
Now consider the case of 50 GJ of chemical reaction heat being delivered directly to the steel in the truss assemblies on one floor. The heat capacity of iron is about 500 J/kg and we shall take the mass of steel in the trusses on one floor as 75 tonnes. In this case:
Delta(T) = 50 x 10^9 / [75,000 x 500] = 1333 deg C
These numbers are, of course, very approximate but they do show that a little bit of LOCALIZED heating is much more effective than GENERALIZED heating and could easily heat a single building component to a temperature sufficient to melt steel.
Neu,
I don't have time to go over your figures right now, but quickly, using 15 floors is a bit of a stretch don't you think, the majority of that heat was released on less than half that many floors.
(Of course a LOT of the heat was vented, but ....
It would appear that chemical reactions don't have a preference for structural steel and there are plenty of OTHER steel objects in the towers, thus I think the amount of localized effect has to reflect that PERCENT of surface area that structural steel represents vs other reactive materials. I believe it is this factor alone that vastly diminishes the impact over the length of time we are talking about. (max 101 minutes)
Still it would appear that what is missing more than anything is RATE of release.
I don't think one can even approximate temp rise without it.
Finally, Note the many examples of steel analysis they did based on mud-cracking of the PRIMER on structural steel from the fire zone. I have a hard time reconciling that the structural steel in the towers were suffering massive chemical attack when NIST spent so much time examaining structural steel that still has its primer intact.
Arthur
QUOTE (adoucette+Jul 19 2007, 07:06 PM)
Neu,
I don't have time to go over your figures right now, but quickly, using 15 floors is a bit of a stretch don't you think, the majority of that heat was released on less than half that many floors.
(Of course a LOT of the heat was vented, but ....
It would appear that chemical reactions don't have a preference for structural steel and there are plenty of OTHER steel objects in the towers, thus I think the amount of localized effect has to reflect that PERCENT of surface area that structural steel represents vs other reactive materials. I believe it is this factor alone that vastly diminishes the impact over the length of time we are talking about. (max 101 minutes)
Still it would appear that what is missing more than anything is RATE of release.
I don't think one can even approximate temp rise without it.
Finally, Note the many examples of steel analysis they did based on mud-cracking of the PRIMER on structural steel from the fire zone. I have a hard time reconciling that the structural steel in the towers were suffering massive chemical attack when NIST spent so much time examaining structural steel that still has its primer intact.
Arthur
There was a lot of steel however with no primer intact, as it says measurements of steel perimeter columns where there was primer to measure. How about the ones with no primer at all?
Also the trusses and the floor pans?
Your correct about other steel, Aluminum and magnesium being in the buildings but this might be impossible to quantify.
http://www.ingentaconnect.com/content/asm/...000005/art00014
I don't have time to go over your figures right now, but quickly, using 15 floors is a bit of a stretch don't you think, the majority of that heat was released on less than half that many floors.
(Of course a LOT of the heat was vented, but ....
It would appear that chemical reactions don't have a preference for structural steel and there are plenty of OTHER steel objects in the towers, thus I think the amount of localized effect has to reflect that PERCENT of surface area that structural steel represents vs other reactive materials. I believe it is this factor alone that vastly diminishes the impact over the length of time we are talking about. (max 101 minutes)
Still it would appear that what is missing more than anything is RATE of release.
I don't think one can even approximate temp rise without it.
Finally, Note the many examples of steel analysis they did based on mud-cracking of the PRIMER on structural steel from the fire zone. I have a hard time reconciling that the structural steel in the towers were suffering massive chemical attack when NIST spent so much time examaining structural steel that still has its primer intact.
Arthur
There was a lot of steel however with no primer intact, as it says measurements of steel perimeter columns where there was primer to measure. How about the ones with no primer at all?
Also the trusses and the floor pans?
Your correct about other steel, Aluminum and magnesium being in the buildings but this might be impossible to quantify.
http://www.ingentaconnect.com/content/asm/...000005/art00014
QUOTE
"Recovered structural steel from the World Trade Center was examined as part of the National Institute of Standards and Technology investigation to provide data on potential temperature excursions seen by the steel for input and validation of the fire and thermal finite element models. While numerous experimental techniques were appraised for use during this study, two proved to be practical: assessment of the primer paint on the structural elements and examination of the steel microstructure. Results from these two techniques are presented. Evaluation of primer paint from 21 exterior panel sections, which represent approximately 3% of the panels from fire-involved floors, was conducted and indicated that only three locations may have experienced temperatures over 250 °C. Steel microstructures taken from these and other areas on exterior panels exposed to pre-collapse fires showed no evidence of exposure to temperatures exceeding 625 °C for times longer than the detectable lower limit of 15 min. The lack of high-temperature excursions observed during this analysis may be related to the protection afforded by intact spray-applied fire-resistant material on the components at the time of exposure. "
Remember that NIST had so little steel to experiment with that the results are not statistically meaningful, in the slightest.
The only exception was finding unheated examples of all the different grades of steel in the towers. This was important in setting up the correct parameters in the FEA analysis.
The only exception was finding unheated examples of all the different grades of steel in the towers. This was important in setting up the correct parameters in the FEA analysis.
QUOTE (David B. Benson+Jul 19 2007, 08:10 PM)
Remember that NIST had so little steel to experiment with that the results are not statistically meaningful, in the slightest.
The only exception was finding unheated examples of all the different grades of steel in the towers. This was important in setting up the correct parameters in the FEA analysis.
I agree DBB. the heating seemed to be localized, not as had been suggested widely distributed.
However there was no way to Quantify it really.
The only exception was finding unheated examples of all the different grades of steel in the towers. This was important in setting up the correct parameters in the FEA analysis.
I agree DBB. the heating seemed to be localized, not as had been suggested widely distributed.
However there was no way to Quantify it really.
QUOTE (Hambone+Jul 18 2007, 07:28 PM)
1. I haven't looked at the appendix. I'll have to check that out.
2. I have found no detailed data on the actual members included in the hat truss.
1. NCSTAR1--2A, page 192 (226 ordinal) ff. When you do you'll find that several of your assumptions about floor plans are in need of revision. For example, the mechanical mezz at floors 8, 42, 76, and 109 were all type 13, with about 1/2 beamed floor outside the core. (I assume that smaller mechanical equipment sat on those.)
2. I haven't either, but connection locations and tension strengths are found in NCSTAR1-6D. Figure 4--3, page 170 (234 ordinal) shows connections (notice the unusual orientation of the graphic). Tables 4--27, page 242 (306 ordinal) and 4--29, page 244 (308 ordinal) give strengths. In any case the floor 105 load data ought to be enough to figure out how to add more mass at the top.
Another question: Did you attempt to include the in-service live loads? That is, I believe what NIST has done.
I am quite interested in this since I have two computer programs which model the collapses. To be accurate, these need a good building model. It looks to me that you have a good start, but I opine that the total mass ought to be closer to about 350,000 tonnes, with the in-service live loads included.
In any case, it is easy to check the N-S and E-W fundamental vibration modes (approximately) against the values given in NCSTAR1--2A to see if you are in the ballpark.
2. I have found no detailed data on the actual members included in the hat truss.
1. NCSTAR1--2A, page 192 (226 ordinal) ff. When you do you'll find that several of your assumptions about floor plans are in need of revision. For example, the mechanical mezz at floors 8, 42, 76, and 109 were all type 13, with about 1/2 beamed floor outside the core. (I assume that smaller mechanical equipment sat on those.)
2. I haven't either, but connection locations and tension strengths are found in NCSTAR1-6D. Figure 4--3, page 170 (234 ordinal) shows connections (notice the unusual orientation of the graphic). Tables 4--27, page 242 (306 ordinal) and 4--29, page 244 (308 ordinal) give strengths. In any case the floor 105 load data ought to be enough to figure out how to add more mass at the top.
Another question: Did you attempt to include the in-service live loads? That is, I believe what NIST has done.
I am quite interested in this since I have two computer programs which model the collapses. To be accurate, these need a good building model. It looks to me that you have a good start, but I opine that the total mass ought to be closer to about 350,000 tonnes, with the in-service live loads included.
In any case, it is easy to check the N-S and E-W fundamental vibration modes (approximately) against the values given in NCSTAR1--2A to see if you are in the ballpark.
Chainsaw:
Here's the thing:
Combustion of 1/5th of the mass of aluminium in a Boeing 767 would release 4.8x10^12 Joules of energy (Which over here is 480 Gigajoules).
And yes, I can provide figures to back that claim up.
There was somethign else I was going to add, but I forgot what it was... =_=
Here's the thing:
Combustion of 1/5th of the mass of aluminium in a Boeing 767 would release 4.8x10^12 Joules of energy (Which over here is 480 Gigajoules).
And yes, I can provide figures to back that claim up.
There was somethign else I was going to add, but I forgot what it was... =_=
QUOTE (Chainsaw+,Jul 19 2007, 01:19 PM)
the heating seemed to be localized ...
By floor. So obtaining exterior wall panels from floors not affected by fires was not only possible, but actually done.
On floors 97 and 98 of WTC 1, from NIST's fire study it appears that little was left unconsumed after 102 minutes of burning. This agrees with NIST's careful observations of fire behavior via the several videos available.
By floor. So obtaining exterior wall panels from floors not affected by fires was not only possible, but actually done.
On floors 97 and 98 of WTC 1, from NIST's fire study it appears that little was left unconsumed after 102 minutes of burning. This agrees with NIST's careful observations of fire behavior via the several videos available.
QUOTE (Trippy+Jul 19 2007, 09:05 PM)
Chainsaw:
Here's the thing:
Combustion of 1/5th of the mass of aluminium in a Boeing 767 would release 4.8x10^12 Joules of energy (Which over here is 480 Gigajoules).
And yes, I can provide figures to back that claim up.
There was somethign else I was going to add, but I forgot what it was... =_=
Thats to high I may have way over estimated how much aluminum combusted on impact, my test are a little more high energy than the trade center plane impact, but I do know that only 3 Gigajoules of energy are necessary to catalyze the reactions in the crash .
This points out the energy released by the plane at impact might actually be way higher than I have estimated. However the release has a theoretical limit, to how much Light energy would be absorbed by the carbon black and reraditated in the inferred.
Thanks Trippy that was very helpful I will work on this some more.
anything you have to add please do so.
Here's the thing:
Combustion of 1/5th of the mass of aluminium in a Boeing 767 would release 4.8x10^12 Joules of energy (Which over here is 480 Gigajoules).
And yes, I can provide figures to back that claim up.
There was somethign else I was going to add, but I forgot what it was... =_=
Thats to high I may have way over estimated how much aluminum combusted on impact, my test are a little more high energy than the trade center plane impact, but I do know that only 3 Gigajoules of energy are necessary to catalyze the reactions in the crash .
This points out the energy released by the plane at impact might actually be way higher than I have estimated. However the release has a theoretical limit, to how much Light energy would be absorbed by the carbon black and reraditated in the inferred.
Thanks Trippy that was very helpful I will work on this some more.
anything you have to add please do so.
QUOTE (Chainsaw,+Jul 19 2007, 03:28 PM)
There was a lot of steel however with no primer intact, as it says measurements of steel perimeter columns where there was primer to measure. How about the ones with no primer at all?
Also the trusses and the floor pans?
I believe that all the structural steel was primed, including the Trusses.
The Trusses were shop primed by an electro-deposition process at Laclede Steel.
See NIST NCSTAR 1-6B pg 21
(The 20 ga steel in the pans was galvanized, not primed, but it wasn't structural)
Also see http://i117.photobucket.com/albums/o72/ard...ionimage017.jpg
Note how all of the steel has the same primer coat.
So, I'm thinking there would be no structural steel that wouldn't have STARTED out with a primer coat.
Based on the mud cracking tests, I'd say that was ONE TOUGH PRIMER (handles 625 C for 15 minutes!).
Now those FLOOR PANs would most certainly be more susceptible, particularly since they weren't covered with SFRM to start with, and I'd suggest that they also far exceed the structural steel in exposed surface area (~ 30,000 sq ft per floor), so I'm guessing that, besides other light steel in the furnishings (Computer cases, file cabinets, lighting fixtures, duct work etc) they would take the brunt of any chemical reactions.
Arthur
Also the trusses and the floor pans?
I believe that all the structural steel was primed, including the Trusses.
The Trusses were shop primed by an electro-deposition process at Laclede Steel.
See NIST NCSTAR 1-6B pg 21
(The 20 ga steel in the pans was galvanized, not primed, but it wasn't structural)
Also see http://i117.photobucket.com/albums/o72/ard...ionimage017.jpg
Note how all of the steel has the same primer coat.
So, I'm thinking there would be no structural steel that wouldn't have STARTED out with a primer coat.
Based on the mud cracking tests, I'd say that was ONE TOUGH PRIMER (handles 625 C for 15 minutes!).
Now those FLOOR PANs would most certainly be more susceptible, particularly since they weren't covered with SFRM to start with, and I'd suggest that they also far exceed the structural steel in exposed surface area (~ 30,000 sq ft per floor), so I'm guessing that, besides other light steel in the furnishings (Computer cases, file cabinets, lighting fixtures, duct work etc) they would take the brunt of any chemical reactions.
Arthur
QUOTE (adoucette+Jul 19 2007, 03:17 PM)
Now those FLOOR PANs would most certainly be more susceptible, ...
And so few survived that a truck driver, who drove truck loads of mangled trusses to the NJ recycler, was reported as wondering just where the floor pans were. He hadn't seen any.
In all the photographs of Ground Zero I have seen, there are only four in which floor pans are visible.
And so few survived that a truck driver, who drove truck loads of mangled trusses to the NJ recycler, was reported as wondering just where the floor pans were. He hadn't seen any.
In all the photographs of Ground Zero I have seen, there are only four in which floor pans are visible.
QUOTE
In all the photographs of Ground Zero I have seen, there are only four in which floor pans are visible.
Obviously, government agents stole them while they were planting the thermate.
QUOTE (Chainsaw+,Jul 20 2007, 09:50 AM)
Thanks Trippy that was very helpful I will work on this some more.
anything you have to add please do so.
This is what I've been tying to do. I still do not believe that 'exotic chemistry' is neccessary to explain whats-his-faces spehrules, but...
Oh.
Correction.
Combustion of 1/5th of the mass of the aircraft's aluminium would release 480 Megajoules, not 480 Gigajoules (I think I pressed the . to quickly, thus it didn't register when I did the initial caclulation).
Oops.
Production of 3 Gigajoules of energy requires that 1.18x mass of the available aluminium be combusted.
Even if we take the combustion of Magnesium into account, we only get an extra 5.5 Mega Joules (for 1/5th the mass of the aircraft combusted)
But that's still less then 0.1 Giga Joules.
If we incinerate the entire mass of metal on the aircraft (Magnesium and Aluminium) that's still only 2.5 Gigajoules.
EDIT: CORRECTED 48 MEGAJOULES TO 480 MEGAJOULES
anything you have to add please do so.
This is what I've been tying to do. I still do not believe that 'exotic chemistry' is neccessary to explain whats-his-faces spehrules, but...
Oh.
Correction.
Combustion of 1/5th of the mass of the aircraft's aluminium would release 480 Megajoules, not 480 Gigajoules (I think I pressed the . to quickly, thus it didn't register when I did the initial caclulation).
Oops.
Production of 3 Gigajoules of energy requires that 1.18x mass of the available aluminium be combusted.
Even if we take the combustion of Magnesium into account, we only get an extra 5.5 Mega Joules (for 1/5th the mass of the aircraft combusted)
But that's still less then 0.1 Giga Joules.
If we incinerate the entire mass of metal on the aircraft (Magnesium and Aluminium) that's still only 2.5 Gigajoules.
EDIT: CORRECTED 48 MEGAJOULES TO 480 MEGAJOULES
QUOTE (Chainsaw+,Jul 19 2007, 05:50 PM)
This points out the energy released by the plane at impact might actually be way higher than I have estimated. However the release has a theoretical limit, to how much Light energy would be absorbed by the carbon black and reraditated in the inferred.
But there is little carbon black at impact because at impact is the one time there is plenty of oxygen.
See seconds 4-6 of this video:
http://www.youtube.com/watch?v=JoL_-geEIV4...related&search=
How can you claim that any significant amount of the Aluminum burnt during these two seconds, but that it wasn't observable?
Further, if it didn't burn during the most energetic part of the crash, why would we expect a significant part to burn later?
Arthur
But there is little carbon black at impact because at impact is the one time there is plenty of oxygen.
See seconds 4-6 of this video:
http://www.youtube.com/watch?v=JoL_-geEIV4...related&search=
How can you claim that any significant amount of the Aluminum burnt during these two seconds, but that it wasn't observable?
Further, if it didn't burn during the most energetic part of the crash, why would we expect a significant part to burn later?
Arthur
QUOTE (carterelliott+Jul 19 2007, 03:53 PM)
Obviously, government agents stole them ...
QUOTE (David B. Benson+Jul 19 2007, 09:05 PM)
1. NCSTAR1--2A, page 192 (226 ordinal) ff. When you do you'll find that several of your assumptions about floor plans are in need of revision. For example, the mechanical mezz at floors 8, 42, 76, and 109 were all type 13, with about 1/2 beamed floor outside the core. (I assume that smaller mechanical equipment sat on those.)
2. I haven't either, but connection locations and tension strengths are found in NCSTAR1-6D. Figure 4--3, page 170 (234 ordinal) shows connections (notice the unusual orientation of the graphic). Tables 4--27, page 242 (306 ordinal) and 4--29, page 244 (308 ordinal) give strengths. In any case the floor 105 load data ought to be enough to figure out how to add more mass at the top.
Another question: Did you attempt to include the in-service live loads? That is, I believe what NIST has done.
I am quite interested in this since I have two computer programs which model the collapses. To be accurate, these need a good building model. It looks to me that you have a good start, but I opine that the total mass ought to be closer to about 350,000 tonnes, with the in-service live loads included.
In any case, it is easy to check the N-S and E-W fundamental vibration modes (approximately) against the values given in NCSTAR1--2A to see if you are in the ballpark.
The in-service live loads are in columns SLL. They are the same as NIST with the possible exception of the mechanical floors. I'll check it again.
I'll get back to you on the other points.
2. I haven't either, but connection locations and tension strengths are found in NCSTAR1-6D. Figure 4--3, page 170 (234 ordinal) shows connections (notice the unusual orientation of the graphic). Tables 4--27, page 242 (306 ordinal) and 4--29, page 244 (308 ordinal) give strengths. In any case the floor 105 load data ought to be enough to figure out how to add more mass at the top.
Another question: Did you attempt to include the in-service live loads? That is, I believe what NIST has done.
I am quite interested in this since I have two computer programs which model the collapses. To be accurate, these need a good building model. It looks to me that you have a good start, but I opine that the total mass ought to be closer to about 350,000 tonnes, with the in-service live loads included.
In any case, it is easy to check the N-S and E-W fundamental vibration modes (approximately) against the values given in NCSTAR1--2A to see if you are in the ballpark.
The in-service live loads are in columns SLL. They are the same as NIST with the possible exception of the mechanical floors. I'll check it again.
I'll get back to you on the other points.
A very interesting quantity to consider is the AVERAGE MASS OF THE AIRCRAFT ALUMINUM DEBRIS produced by the impacts on WTC 1 & 2.
If you look at a typical published simulation of an aircraft break up and debris distribution it looks like an average debris mass of 50 kg might be what the NIST and Perdue images are suggesting.
HOWEVER, are these realistic estimates or simply a measure of the "resolution" of the simulations?
See for example Figure E-37 in NIST NCSTAR 1-2B, page lxxx, of the executive summary, or Figure E-35 in the same document, page lxxviii.
We also have on page lxviii:
"...the aircraft was broken into thousands of debris fragments of various size and mass...."
Comments?
If you look at a typical published simulation of an aircraft break up and debris distribution it looks like an average debris mass of 50 kg might be what the NIST and Perdue images are suggesting.
HOWEVER, are these realistic estimates or simply a measure of the "resolution" of the simulations?
See for example Figure E-37 in NIST NCSTAR 1-2B, page lxxx, of the executive summary, or Figure E-35 in the same document, page lxxviii.
We also have on page lxviii:
"...the aircraft was broken into thousands of debris fragments of various size and mass...."
Comments?
QUOTE (Hambone+Jul 19 2007, 04:17 PM)
The in-service live loads are in columns SLL. They are the same as NIST with the possible exception of the mechanical floors.
Thank you. I did not completely follow what I read in NCSTAR1--2A regarding the loadings on the mechanical floors. And worse, I couldn't determine whether the mechanical floors in-service live loads were actually much less than the maximum live load. (Not really understanding why there is such a big difference between in-service live loads and maximum live loads for ordinary office floors...)
Thank you. I did not completely follow what I read in NCSTAR1--2A regarding the loadings on the mechanical floors. And worse, I couldn't determine whether the mechanical floors in-service live loads were actually much less than the maximum live load. (Not really understanding why there is such a big difference between in-service live loads and maximum live loads for ordinary office floors...)
Oops. heh heh. Either I miscounted, or dropped a zero in my last post.
Oh well.
Oh well.
QUOTE (adoucette+Jul 20 2007, 11:01 AM)
But there is little carbon black at impact because at impact is the one time there is plenty of oxygen.
See seconds 4-6 of this video:
http://www.youtube.com/watch?v=JoL_-geEIV4...related&search=
How can you claim that any significant amount of the Aluminum burnt during these two seconds, but that it wasn't observable?
Further, if it didn't burn during the most energetic part of the crash, why would we expect a significant part to burn later?
Arthur
Which is related to one of the other points that I was going to raise.
The presence of big black billowing clouds of smoke tends to suggest a strongly reducing environment. Those big black billowing clouds of smoke aren't just carbon black, they're mostly PAH's, especially seeing as how there are polymers involved in the combustion.
The next point i'm going to raise is that the reaction that produces Aluminium carbide requires temperatures on the order of 1000°C (IIRC) - unless you're dealing with the production of aluminium, in which case it occurs as a corrosive byproduct of the electrolysis.
Combustion at those sorts of temperatures tends to produce little or no smoke, and requires a more oxygen rich environment then is suggested by the evidence. The change from light grey to dark black smoke, is, IIRC, generally indicative of the source of primary combustion shifting from the jet fuel to the combustables in the offices.
See seconds 4-6 of this video:
http://www.youtube.com/watch?v=JoL_-geEIV4...related&search=
How can you claim that any significant amount of the Aluminum burnt during these two seconds, but that it wasn't observable?
Further, if it didn't burn during the most energetic part of the crash, why would we expect a significant part to burn later?
Arthur
Which is related to one of the other points that I was going to raise.
The presence of big black billowing clouds of smoke tends to suggest a strongly reducing environment. Those big black billowing clouds of smoke aren't just carbon black, they're mostly PAH's, especially seeing as how there are polymers involved in the combustion.
The next point i'm going to raise is that the reaction that produces Aluminium carbide requires temperatures on the order of 1000°C (IIRC) - unless you're dealing with the production of aluminium, in which case it occurs as a corrosive byproduct of the electrolysis.
Combustion at those sorts of temperatures tends to produce little or no smoke, and requires a more oxygen rich environment then is suggested by the evidence. The change from light grey to dark black smoke, is, IIRC, generally indicative of the source of primary combustion shifting from the jet fuel to the combustables in the offices.
.
QUOTE (Trippy+Jul 19 2007, 09:05 AM)
And suddenly my motivation for trying to discuss this, and inject some 'rationality' into the conversation.
Once again, YOU RC are heading, once again, down the road of "You've been indoctrinated into the cult of science, you only know the textbooks, therefore everything you know is wrong", and frankly it's bugging the heck out of me.
The fact that I may be able to quote things chapter and verse from textbooks is a reflection of the depth of my understanding of chemistry and chemical processes.
My intrest is in APPLIED chemistry, not PURE chemistry, as you seem to be implying.
The fact that I have in my lap while I type this the course material for the postgrad paper I am doing this semester that deals with things such as chemical weapons of mass destruction, and how to deal with them should they be released into the environment should tell you something.
I have been discussing things in this thread in GOOD FAITH.
Right now, you are showing very BAD FAITH RC, and I am NOT impressed.
Once again, you are demonstrating that you are unwilling to listen to someone who actually knows what they're talking about on the subject, apparently preferring to believe whatever is convenient.
First point: You are, and have been adovacting Furnace like conditions in the floors, the heat held in the steel and the concrete of the walls and floor doesn't simply 'vanish' the hot air doesn't simply vanish, it doesn't work that way. You can't invoke furnace like conditions for part of the scenario, and then have them 'vanish' when it's convenient. The comment in relation to the photo is that it was taken between the impact and the collapse, and it was taken early, rather then late in the footage. Also, it's in the first tower to stand, which survived 55 minutes between the impact and collapse.
Second point: Close inspection of the impact footage reveals three flashes when the aircraft strikes the cladding, the three flashes are when the three densest parts of the aircraft strike the cladding. These flashes are the Al powder generated by the impact igniting.
Third point: Heating due to friction would be extremely localized, and it's obvious from the footage that the plane did not (appear) to slow down significantly as it entered the building, so it's fairly safe to assume that most of the impact energy would have been released in the impacts with the central columns.
Fourth point: Combustion of Hydrocarbons does not release super heated steam, it releases water in the gas phase. Steam is water in the liquid phase (in very small droplets). This is why it's possible to superheat it, and before you go and try and contradict this point, take a careful look at pictures of steam being vented at Geothermal plants, there is a space between the steam and the nozzle, in this space, water exists in the gas phase.
Fifth point: I don't have the data at my fingertips right at this instant, and to be honest, given the responses I have received, I'm feeling far from motivated to go and look it up, but you're assigning much higher explosion velocities to the fireball then 1. Are generally observed in comparable fireballs, and 2. Were observed in this particular fireball.
Sixth point: Did I, or did I not explicitly state, or at least imply in one of my posts to chainsaw about his experiments that there is/was the posibility for small scale localized thermite reactions.
Seventh point: I'm aware of the reactions between Aluminium and Silicates.
Eighth point: I'm feeling to lazy to go and look up the thermochemical data on Aluminium carbide and it's reactions, I may do it later, but there's something that seems not quite right about what you've said in that respect - but i'm not able to put my finger on it right now.
Ninth point: Most of what you say about the Carbon or what ever swamping any light or effects from whatever explosions, is, IMO, bogus. One of the aircraft effectively occupied a corner of the building, some fragments even exited IIRC, this means that all of the effects that you are claiming should have been noticable, but, nothing.
10th point: I'm not sure how to address what you 'claim' wrt the splattering/flowing Aluminium, again, there's something in there that strikes me as being wrong, but i can't quite put my finger on it.
11th point: I don't think that the aqueous processes you're talking about are as important as you seem to think they are. Agaom, there seems to me to be something inherently wrong with some of those things, but I can'r put my finger on it.
Question.
Where's the information? It's not that hard to find. Take the PVC discussion, what use is all this discussion about HCl, if you don't know how fast it's generated, and you don't know how much was generated.
I've already pointed out some of the potential problems with the experiments chainsaw's doing, and I get criticized for doing this? What's the deal with that? How is Chainsaw supposed to conduct better experiments to prove his point my reliably and more emphaticaly, if nobody points out the (potential) problems in his experiments? (Or anyone elses experiments). You know? You're so quick to jump on the 'thinking outside the box' bandwagon that you manage to completely overlook the simple, obvious truths.
And you overlook the obvious questions:
Why is it that the tower that took the most glancing blow fell first?
Why is it that the tower with the shortest lived fires fell first?
I can offer explanations for both of those without invoking exotic chemistry, but, if the fire was responsible, then the other tower should have collapsed first. It really is that simple.
I have other observations I can offer, but I find myself asking it is really worth it? Because so far, nobody (except maybe Arthur, and one or two others) actually seems interested in having a seriouse and rational discussion.
Hi Trippy!
No mate, I never said your or the textbooks were WRONG.
I merely tried to point to all the facts about aluminium/other metals/materials and thermo-chemical and thermophysical properties/process which probably were involkved on a mass scale and multi level UNCONTROLLED inferno set initially by the Kero jet fuel ALL AT ONCE in an impact/fuel-explosion damaged scenario as 9/11 produced.
So THIS is what I have said in my posts to you and everyone:
The textbooks and some of your own references are based on historical experience/experiments/data that is almost uniformly "smaller scale", "less chaotic" and "clean" and "controlled" and cross-isolated" in some way so as to give to give 'specialised' data for texts/reference books.
9/11 is a NEW 'experience'. It is a NEW terrible/unwanted 'experiment'. It has NEW 'data' to provide for the text/reference books. It was 'humongous scale'. It was 'dirty'. It was 'uncontrolled'. It was mixed and not isolated' as to materials, thermodynamics, structures and COMPLICATING/EXACERBATING/CATALYTIC/CYCLING etc processes that will probably be difficult to recreate unless the exact same thing happens at the exact same impact/plne/fuels/scale/dirtyness etc. of parameters.
So again, I did NOT say your or the texts are wrong. I said that because of the unusual 9/11 scenario, the texts may be ENHANCED to take in all that MAY perhaps be learned from the behaviour/processes/chemical-effects etc in such UNCONTROLLED and MASSIVE and CATASTROPHIC scenarios.
That's all, mate. No more. No less. Certainly NO aspersions on you or the texts as they are. But I hope you agree with me that EVERY text may be improved to cover such UNUSUAL and UNCONTROLLED scenarios that were not even CONTEMPLATED let alone 'treated' in detail for the compilation of the data set IN REAL WORLD EVENTS like 9/11.
So no offence meant. And I hope I have now explained why no offense should be taken by anyone.
Once again, YOU RC are heading, once again, down the road of "You've been indoctrinated into the cult of science, you only know the textbooks, therefore everything you know is wrong", and frankly it's bugging the heck out of me.
The fact that I may be able to quote things chapter and verse from textbooks is a reflection of the depth of my understanding of chemistry and chemical processes.
My intrest is in APPLIED chemistry, not PURE chemistry, as you seem to be implying.
The fact that I have in my lap while I type this the course material for the postgrad paper I am doing this semester that deals with things such as chemical weapons of mass destruction, and how to deal with them should they be released into the environment should tell you something.
I have been discussing things in this thread in GOOD FAITH.
Right now, you are showing very BAD FAITH RC, and I am NOT impressed.
Once again, you are demonstrating that you are unwilling to listen to someone who actually knows what they're talking about on the subject, apparently preferring to believe whatever is convenient.
First point: You are, and have been adovacting Furnace like conditions in the floors, the heat held in the steel and the concrete of the walls and floor doesn't simply 'vanish' the hot air doesn't simply vanish, it doesn't work that way. You can't invoke furnace like conditions for part of the scenario, and then have them 'vanish' when it's convenient. The comment in relation to the photo is that it was taken between the impact and the collapse, and it was taken early, rather then late in the footage. Also, it's in the first tower to stand, which survived 55 minutes between the impact and collapse.
Second point: Close inspection of the impact footage reveals three flashes when the aircraft strikes the cladding, the three flashes are when the three densest parts of the aircraft strike the cladding. These flashes are the Al powder generated by the impact igniting.
Third point: Heating due to friction would be extremely localized, and it's obvious from the footage that the plane did not (appear) to slow down significantly as it entered the building, so it's fairly safe to assume that most of the impact energy would have been released in the impacts with the central columns.
Fourth point: Combustion of Hydrocarbons does not release super heated steam, it releases water in the gas phase. Steam is water in the liquid phase (in very small droplets). This is why it's possible to superheat it, and before you go and try and contradict this point, take a careful look at pictures of steam being vented at Geothermal plants, there is a space between the steam and the nozzle, in this space, water exists in the gas phase.
Fifth point: I don't have the data at my fingertips right at this instant, and to be honest, given the responses I have received, I'm feeling far from motivated to go and look it up, but you're assigning much higher explosion velocities to the fireball then 1. Are generally observed in comparable fireballs, and 2. Were observed in this particular fireball.
Sixth point: Did I, or did I not explicitly state, or at least imply in one of my posts to chainsaw about his experiments that there is/was the posibility for small scale localized thermite reactions.
Seventh point: I'm aware of the reactions between Aluminium and Silicates.
Eighth point: I'm feeling to lazy to go and look up the thermochemical data on Aluminium carbide and it's reactions, I may do it later, but there's something that seems not quite right about what you've said in that respect - but i'm not able to put my finger on it right now.
Ninth point: Most of what you say about the Carbon or what ever swamping any light or effects from whatever explosions, is, IMO, bogus. One of the aircraft effectively occupied a corner of the building, some fragments even exited IIRC, this means that all of the effects that you are claiming should have been noticable, but, nothing.
10th point: I'm not sure how to address what you 'claim' wrt the splattering/flowing Aluminium, again, there's something in there that strikes me as being wrong, but i can't quite put my finger on it.
11th point: I don't think that the aqueous processes you're talking about are as important as you seem to think they are. Agaom, there seems to me to be something inherently wrong with some of those things, but I can'r put my finger on it.
Question.
Where's the information? It's not that hard to find. Take the PVC discussion, what use is all this discussion about HCl, if you don't know how fast it's generated, and you don't know how much was generated.
I've already pointed out some of the potential problems with the experiments chainsaw's doing, and I get criticized for doing this? What's the deal with that? How is Chainsaw supposed to conduct better experiments to prove his point my reliably and more emphaticaly, if nobody points out the (potential) problems in his experiments? (Or anyone elses experiments). You know? You're so quick to jump on the 'thinking outside the box' bandwagon that you manage to completely overlook the simple, obvious truths.
And you overlook the obvious questions:
Why is it that the tower that took the most glancing blow fell first?
Why is it that the tower with the shortest lived fires fell first?
I can offer explanations for both of those without invoking exotic chemistry, but, if the fire was responsible, then the other tower should have collapsed first. It really is that simple.
I have other observations I can offer, but I find myself asking it is really worth it? Because so far, nobody (except maybe Arthur, and one or two others) actually seems interested in having a seriouse and rational discussion.
Hi Trippy!
No mate, I never said your or the textbooks were WRONG.
I merely tried to point to all the facts about aluminium/other metals/materials and thermo-chemical and thermophysical properties/process which probably were involkved on a mass scale and multi level UNCONTROLLED inferno set initially by the Kero jet fuel ALL AT ONCE in an impact/fuel-explosion damaged scenario as 9/11 produced.
So THIS is what I have said in my posts to you and everyone:
The textbooks and some of your own references are based on historical experience/experiments/data that is almost uniformly "smaller scale", "less chaotic" and "clean" and "controlled" and cross-isolated" in some way so as to give to give 'specialised' data for texts/reference books.
9/11 is a NEW 'experience'. It is a NEW terrible/unwanted 'experiment'. It has NEW 'data' to provide for the text/reference books. It was 'humongous scale'. It was 'dirty'. It was 'uncontrolled'. It was mixed and not isolated' as to materials, thermodynamics, structures and COMPLICATING/EXACERBATING/CATALYTIC/CYCLING etc processes that will probably be difficult to recreate unless the exact same thing happens at the exact same impact/plne/fuels/scale/dirtyness etc. of parameters.
So again, I did NOT say your or the texts are wrong. I said that because of the unusual 9/11 scenario, the texts may be ENHANCED to take in all that MAY perhaps be learned from the behaviour/processes/chemical-effects etc in such UNCONTROLLED and MASSIVE and CATASTROPHIC scenarios.
That's all, mate. No more. No less. Certainly NO aspersions on you or the texts as they are. But I hope you agree with me that EVERY text may be improved to cover such UNUSUAL and UNCONTROLLED scenarios that were not even CONTEMPLATED let alone 'treated' in detail for the compilation of the data set IN REAL WORLD EVENTS like 9/11.
So no offence meant. And I hope I have now explained why no offense should be taken by anyone.
QUOTE (Trippy+Jul 19 2007, 11:23 AM)
Oh, and one other thing.
I was talking to a Fireman with twenty+ years experience in the service who has dealt first hand with Metal fires.
It's his recollection that they used water to cool molten aluminium without any explosions or mishaps, so...
This demonstrates what I was pointing to above, Trip.
What you and your source are presenting is data/observations produced UNDER CONTROLLED CONDITIONS and in a very LIMITED scenario as to scale, entrained additives/processes.
These piecemeal, controlled data bear no relation to what ACTUALLY MIGHT HAVE OCCURRED under the chaos and enormity o 9/11 events/processes.
See what I mean?
I and others do NOT say you are wrong PER SE in the information presented. Only that what you put forth MAY not be the full story; and thus MAY not be directly applicable in the uncontrolled/extreme conditions in 9/11 event.
Hence the need for further study. I hope that suggestion for further study does not anger you or offend you in some way?
Please take the time to ask adoucette what my position has been from day one in this and all other 9/11 threads. You will soon find that what CTers have put, I and others have REFUTED with ACTUAL relevant science/information.
So your impression that I am in bad faith is going a bit far. I suggest you cool doen and be less defensive and get actually ACQUAINTED with who's who and where they stand in these 9/11 threads. You will be pleasantly surprised; and I hope will not in future be so ready to 'knee-jerk' accusations about bad faith....and also others' ACTUAL stance overall in these discussions.
I'm not on anybody's 'side, mate.....I just follow the science AS IS in situ.......and not just in theory.
As a further demonstration of my good faith; and what I'm considering that you and the texts may not have considered in such cases as 9/11, let me point to just A FEW physical DYNAMIC effects that may 'continually compromise' a small metallic aluminium shred that has reacted/been heated or otherwise put into a molten state under the VIOLENT and TURBULENT conditions in 9/11 impact explosion/inferno:
- Any molten globules would be oxidising as you have described.....BUT when such globules are set SPINNING and WOBBLING in-mid-air and in other media (either by violent drafts/shock-fronts or impact/falling processes, the LOWER SPECIFIC GRAVITY of the less dense crystal oxide coat (that would otherwise protect that globules bulk) is continually under STRESS and being broken by
.........CENTRIFUGAL forces (which can 'centrifugally' SEPARATE oxide as it forms from the metal underneath)....
....... AIR/STEEL SHOCKWAVES (which can 'blast' the oxide layers off as they form, and even 'splatter/disintegrate' the globule to finer globules).....
........JET-FUEL BLAST-IMPREGNATION of foreign material into (even the near-molten) aluminium globule/shred.....
.......All the materials and processes for even THESE FEW straightforward events were present (let alone the ALUMINIUM-GLASS reaction which I mentioned in my last post that occurs WELL BELOW the melting point of aluminium.
So Trippy, please don't be offended.....because I have NOT said you are wrong....merely that there may be more to be learned through Chainsaw's and NF's researches which may be relevant to future safety standards/precautions in high rise steel structure design/construction.
Repeat, you are NOT 'wrong'. BUT....the actual 9/11 processes being researched by Chainsaw/NF seem to be REFUTING CD conspiracies, by actually hypothesising other NATURAL (given plane impact/fire) mechanisms/processes to explain MORE than was already explained.
Whether any SIGNIFICANT contribution to collapse either way of these yet to be quantified/identified 'unknowns', well in my opinion, they would have only had a marginal effect....but in a critically damaged building, EVEN A MARGINAL EFFECT MAY MAKE THE DIFFERENCE BETWEEN SURVIVAL AND DEATH for those needing the 'extra minutes' to evacuate. See? Onle safety and future design is being affected by these researches....no matter WHO is conducting them (as long as they don't 'twist' their data to suit their conspiracy, hehehe...which I don't think NF and Chainsaw are ih the business of doing....since they are presenting their findings here OPENLY for review by all!).
Peace, Bros!
PS: adoucette....I myself see NF's and Chainsaw's work not so much as the quantification/identification of TOTAL ENERGY made available by whatever they are looking into, bur rather through the perspective of CYCLING and ADDITIONAL DWELL-TIME for whatever energy WAS released by ALL 'fuels' at and minutes after plane impact/conflgration. Basically because I see the plane impact 'removing' or 'compromising MUCH spray-on fireproofing....and so leaving open the widespread pathways/sites for further damage/weakening/stressing by fire (and then 'cooling' of course) AND any chemical legacies of the initial fireball inferno/processes involving ALL the shredded components present. So the chemical/catalytic/cycling/as described earlier MAY have [b]INCREASED the DWELL TIME for the INTIAL (and not so much requiring any ADDITIONAL) energy that WAS released at the earliest stages. See? NOT 'additional' input' so much as 'additional' dwell-time and cycling of EXISTING energy released (which would be more damaging than if the energy flows were 'truncated' by quick dissipation without such -recycling and greater dwell-time reaction chains/processes.
Cheers all!
RC.
.
I was talking to a Fireman with twenty+ years experience in the service who has dealt first hand with Metal fires.
It's his recollection that they used water to cool molten aluminium without any explosions or mishaps, so...
This demonstrates what I was pointing to above, Trip.
What you and your source are presenting is data/observations produced UNDER CONTROLLED CONDITIONS and in a very LIMITED scenario as to scale, entrained additives/processes.
These piecemeal, controlled data bear no relation to what ACTUALLY MIGHT HAVE OCCURRED under the chaos and enormity o 9/11 events/processes.
See what I mean?
I and others do NOT say you are wrong PER SE in the information presented. Only that what you put forth MAY not be the full story; and thus MAY not be directly applicable in the uncontrolled/extreme conditions in 9/11 event.
Hence the need for further study. I hope that suggestion for further study does not anger you or offend you in some way?
Please take the time to ask adoucette what my position has been from day one in this and all other 9/11 threads. You will soon find that what CTers have put, I and others have REFUTED with ACTUAL relevant science/information.
So your impression that I am in bad faith is going a bit far. I suggest you cool doen and be less defensive and get actually ACQUAINTED with who's who and where they stand in these 9/11 threads. You will be pleasantly surprised; and I hope will not in future be so ready to 'knee-jerk' accusations about bad faith....and also others' ACTUAL stance overall in these discussions.
I'm not on anybody's 'side, mate.....I just follow the science AS IS in situ.......and not just in theory.
As a further demonstration of my good faith; and what I'm considering that you and the texts may not have considered in such cases as 9/11, let me point to just A FEW physical DYNAMIC effects that may 'continually compromise' a small metallic aluminium shred that has reacted/been heated or otherwise put into a molten state under the VIOLENT and TURBULENT conditions in 9/11 impact explosion/inferno:
- Any molten globules would be oxidising as you have described.....BUT when such globules are set SPINNING and WOBBLING in-mid-air and in other media (either by violent drafts/shock-fronts or impact/falling processes, the LOWER SPECIFIC GRAVITY of the less dense crystal oxide coat (that would otherwise protect that globules bulk) is continually under STRESS and being broken by
.........CENTRIFUGAL forces (which can 'centrifugally' SEPARATE oxide as it forms from the metal underneath)....
....... AIR/STEEL SHOCKWAVES (which can 'blast' the oxide layers off as they form, and even 'splatter/disintegrate' the globule to finer globules).....
........JET-FUEL BLAST-IMPREGNATION of foreign material into (even the near-molten) aluminium globule/shred.....
.......All the materials and processes for even THESE FEW straightforward events were present (let alone the ALUMINIUM-GLASS reaction which I mentioned in my last post that occurs WELL BELOW the melting point of aluminium.
So Trippy, please don't be offended.....because I have NOT said you are wrong....merely that there may be more to be learned through Chainsaw's and NF's researches which may be relevant to future safety standards/precautions in high rise steel structure design/construction.
Repeat, you are NOT 'wrong'. BUT....the actual 9/11 processes being researched by Chainsaw/NF seem to be REFUTING CD conspiracies, by actually hypothesising other NATURAL (given plane impact/fire) mechanisms/processes to explain MORE than was already explained.
Whether any SIGNIFICANT contribution to collapse either way of these yet to be quantified/identified 'unknowns', well in my opinion, they would have only had a marginal effect....but in a critically damaged building, EVEN A MARGINAL EFFECT MAY MAKE THE DIFFERENCE BETWEEN SURVIVAL AND DEATH for those needing the 'extra minutes' to evacuate. See? Onle safety and future design is being affected by these researches....no matter WHO is conducting them (as long as they don't 'twist' their data to suit their conspiracy, hehehe...which I don't think NF and Chainsaw are ih the business of doing....since they are presenting their findings here OPENLY for review by all!).
Peace, Bros!
PS: adoucette....I myself see NF's and Chainsaw's work not so much as the quantification/identification of TOTAL ENERGY made available by whatever they are looking into, bur rather through the perspective of CYCLING and ADDITIONAL DWELL-TIME for whatever energy WAS released by ALL 'fuels' at and minutes after plane impact/conflgration. Basically because I see the plane impact 'removing' or 'compromising MUCH spray-on fireproofing....and so leaving open the widespread pathways/sites for further damage/weakening/stressing by fire (and then 'cooling' of course) AND any chemical legacies of the initial fireball inferno/processes involving ALL the shredded components present. So the chemical/catalytic/cycling/as described earlier MAY have [b]INCREASED the DWELL TIME for the INTIAL (and not so much requiring any ADDITIONAL) energy that WAS released at the earliest stages. See? NOT 'additional' input' so much as 'additional' dwell-time and cycling of EXISTING energy released (which would be more damaging than if the energy flows were 'truncated' by quick dissipation without such -recycling and greater dwell-time reaction chains/processes.
Cheers all!
RC.
.
QUOTE (NEU-FONZE+Jul 19 2007, 04:23 PM)
... an average debris mass of 50 kg might be what the NIST and Perdue[sic] images are suggesting.
"...the aircraft was broken into thousands of debris fragments of various size and mass...."
one thousand: average is about 50 kg.
two thousand: average is about 25 kg.
etc.
But this average isn't a very good measure when landing struts and engines stay largely in one piece.
I have no idea what sort of particle size distribution to attempt to fit to the data, even if I had the data.
"...the aircraft was broken into thousands of debris fragments of various size and mass...."
one thousand: average is about 50 kg.
two thousand: average is about 25 kg.
etc.
But this average isn't a very good measure when landing struts and engines stay largely in one piece.
I have no idea what sort of particle size distribution to attempt to fit to the data, even if I had the data.
RC: How is a warehouse fire a controlled environment?
Take a warehouse full of lawnmower parts and set it on fire, then you've got Aluminium, Magnesium, and god knows what else all burning together.
Take the ICI fire in Auckland (NZ) some years ago - big stainless steel drums with Paraquat and Pool chemicals.
Take the warehouse fire in Brazil (I think it was) that burned so hot that it reduced Concrete to a powder (the sorts of temperatures that have been suggested btw) the only fuel there was paper.
I could name a bunch of others as well.
None of these are controled circumstances.
The point that is being made is that the fire wasn't neccessarily as unique as it's being made out to be, I don't think that even the ignition is as widespread or instantaneous as it's being made out to be.
Take a warehouse full of lawnmower parts and set it on fire, then you've got Aluminium, Magnesium, and god knows what else all burning together.
Take the ICI fire in Auckland (NZ) some years ago - big stainless steel drums with Paraquat and Pool chemicals.
Take the warehouse fire in Brazil (I think it was) that burned so hot that it reduced Concrete to a powder (the sorts of temperatures that have been suggested btw) the only fuel there was paper.
I could name a bunch of others as well.
None of these are controled circumstances.
The point that is being made is that the fire wasn't neccessarily as unique as it's being made out to be, I don't think that even the ignition is as widespread or instantaneous as it's being made out to be.
QUOTE (RealityCheck+Jul 20 2007, 11:45 AM)
These piecemeal, controlled data bear no relation to what ACTUALLY MIGHT HAVE OCCURRED under the chaos and enormity o 9/11 events/processes.
And this statement, without wanting to sound like i'm being rude, or making an adhominem attack, is as funny as it is blatantly wrong.
The ionization energy (the main govering factor in ignition temperature) of Aluminium doesn't change just because it's burning in a warehouse instead of a lab.
And this statement, without wanting to sound like i'm being rude, or making an adhominem attack, is as funny as it is blatantly wrong.
The ionization energy (the main govering factor in ignition temperature) of Aluminium doesn't change just because it's burning in a warehouse instead of a lab.
DBB:
Well we know the engine and parts of the undercarriage were quite massive and, in the case of WTC 2, made it all the way through the building and out the other side.... but I was thinking more about the aluminum "skin" of the fuselage.
Surely this was totally shredded...
At least, that's what I am getting from the NIST and Perdue simulations.
Well we know the engine and parts of the undercarriage were quite massive and, in the case of WTC 2, made it all the way through the building and out the other side.... but I was thinking more about the aluminum "skin" of the fuselage.
Surely this was totally shredded...
At least, that's what I am getting from the NIST and Perdue simulations.
QUOTE (adoucette+Jul 19 2007, 11:01 PM)
But there is little carbon black at impact because at impact is the one time there is plenty of oxygen.
See seconds 4-6 of this video:
http://www.youtube.com/watch?v=JoL_-geEIV4...related&search=
How can you claim that any significant amount of the Aluminum burnt during these two seconds, but that it wasn't observable?
Further, if it didn't burn during the most energetic part of the crash, why would we expect a significant part to burn later?
Arthur
Hi adoucette!
I'm not so sure, mate. I think the tons and tons of liquid/atomised Kerosene and shredded plane/office material particulates would have mixed with a VASTLY LESSER molecule to molecule ratio of AIR.
So even thogh the initial billows of the fireball was 'redddish orange/yellow', it may have been the pyrolysed Kero fuel's Carbon (soot) and the pyrolised office plastics/organics particulate 'sooty-ash' AT INCANDESCENT TEMPERATURES that constituted the bulk of what went out and was observed through the windows.
In which case, even though all that carbon was HOT and red/yellow, it WAS still a humongous quantity of CARBON and carbon-containing smoke that could easily 'hide' and 'swamp' any other LESSER 'white' light radiation form diffuse reaction sites within that SEA of glowing carbon.
That's my take.
I can see no real objection to Chainsaw's contention that such clouds within and without the building at or soon after impact COULD hide such 'flashes' as metal reactions might produce INSIDE that building/fireball.
Still, as NIST showed, and I agree, the collapse would have happened sooner or later by a few minutes either way.
So the only thing I am interested in NOW is to determnine whether precious EVACUATION/FIREFIGHTING MINUTES could be gained in such events by applying anything that NF/Chain may come up with.
That's all that really is left to discuss, in my opinion. Everything else has been covered and the 'conspiracy' theories well and truly DEBUNKED by you, grumpy, Schneibster, DBB, Shagster, Common Sense, Alex Elevator man and others...including myself.
Cheers mate, all!
RC.
.
See seconds 4-6 of this video:
http://www.youtube.com/watch?v=JoL_-geEIV4...related&search=
How can you claim that any significant amount of the Aluminum burnt during these two seconds, but that it wasn't observable?
Further, if it didn't burn during the most energetic part of the crash, why would we expect a significant part to burn later?
Arthur
Hi adoucette!
I'm not so sure, mate. I think the tons and tons of liquid/atomised Kerosene and shredded plane/office material particulates would have mixed with a VASTLY LESSER molecule to molecule ratio of AIR.
So even thogh the initial billows of the fireball was 'redddish orange/yellow', it may have been the pyrolysed Kero fuel's Carbon (soot) and the pyrolised office plastics/organics particulate 'sooty-ash' AT INCANDESCENT TEMPERATURES that constituted the bulk of what went out and was observed through the windows.
In which case, even though all that carbon was HOT and red/yellow, it WAS still a humongous quantity of CARBON and carbon-containing smoke that could easily 'hide' and 'swamp' any other LESSER 'white' light radiation form diffuse reaction sites within that SEA of glowing carbon.
That's my take.
I can see no real objection to Chainsaw's contention that such clouds within and without the building at or soon after impact COULD hide such 'flashes' as metal reactions might produce INSIDE that building/fireball.
Still, as NIST showed, and I agree, the collapse would have happened sooner or later by a few minutes either way.
So the only thing I am interested in NOW is to determnine whether precious EVACUATION/FIREFIGHTING MINUTES could be gained in such events by applying anything that NF/Chain may come up with.
That's all that really is left to discuss, in my opinion. Everything else has been covered and the 'conspiracy' theories well and truly DEBUNKED by you, grumpy, Schneibster, DBB, Shagster, Common Sense, Alex Elevator man and others...including myself.
Cheers mate, all!
RC.
.
QUOTE (NEU-FONZE+Jul 19 2007, 05:25 PM)
Surely this was totally shredded...
Well, I know more about the wings than the fuselage. There is a steel beam, tapered, running the entire length. Attached to that are the spars. Riveted to the spars are the aluminum panels making up the skin. The strongest aluminum alloy components are the spars, followed by the leading edge.
Without really knowing, I would expect the spars to retain some structural identity, not be totally shredded. The skin might be, dunno.
If we can use the average, say 20 kg apiece, that's a big chuck of skin, but not much of a wing spar.
(With regard to the fuselage, recall that an easily recognizable, substantial, portion of the forward right fuselage survived in WTC 1 and appears in a Ground Zero photograph.)
Well, I know more about the wings than the fuselage. There is a steel beam, tapered, running the entire length. Attached to that are the spars. Riveted to the spars are the aluminum panels making up the skin. The strongest aluminum alloy components are the spars, followed by the leading edge.
Without really knowing, I would expect the spars to retain some structural identity, not be totally shredded. The skin might be, dunno.
If we can use the average, say 20 kg apiece, that's a big chuck of skin, but not much of a wing spar.
(With regard to the fuselage, recall that an easily recognizable, substantial, portion of the forward right fuselage survived in WTC 1 and appears in a Ground Zero photograph.)
RC:
I am inclined to agree with you.... But there is almost too much to explore and too many variables to consider!!!!
One thing I am wondering about is the extent of shredding of the aircraft's aluminum. This looks to be a very important piece of data, especially with regard to Chainsaw's ideas.
The NIST and Perdue simulations would say that the aircraft FUSELAGE, at least, was totally fragmented.
This immediately raises many questions:
Was each fragment formed with a thermite spark?
How hot was each fragment?
How did the aviation fuel itself "fragment" and mix with the air and the aluminum?
Etc, etc...
I am inclined to agree with you.... But there is almost too much to explore and too many variables to consider!!!!
One thing I am wondering about is the extent of shredding of the aircraft's aluminum. This looks to be a very important piece of data, especially with regard to Chainsaw's ideas.
The NIST and Perdue simulations would say that the aircraft FUSELAGE, at least, was totally fragmented.
This immediately raises many questions:
Was each fragment formed with a thermite spark?
How hot was each fragment?
How did the aviation fuel itself "fragment" and mix with the air and the aluminum?
Etc, etc...
.
QUOTE (Trippy+Jul 20 2007, 12:01 AM)
RC: How is a warehouse fire a controlled environment?
Take a warehouse full of lawnmower parts and set it on fire, then you've got Aluminium, Magnesium, and god knows what else all burning together.
Take the ICI fire in Auckland (NZ) some years ago - big stainless steel drums with Paraquat and Pool chemicals.
Take the warehouse fire in Brazil (I think it was) that burned so hot that it reduced Concrete to a powder (the sorts of temperatures that have been suggested btw) the only fuel there was paper.
I could name a bunch of others as well.
None of these are controled circumstances.
The point that is being made is that the fire wasn't neccessarily as unique as it's being made out to be, I don't think that even the ignition is as widespread or instantaneous as it's being made out to be.
I see what you're getting at, mate. And you're RIGHT.
But please try to see what I and others are getting at:
-. None of these things tou mention are anywhere near the VAST and WIDESPREAD all-at once fires over multilevel 'stack' conditions and mix of materials.
-. None of these involved a TALL building the size of WTC1/2.
-. None of these involve widespread all-at-once fireproofing removal and total neautralising of active firefighting systems/firemen.
-. None of these involve the quantities and SCALE-EFFECTS of the processes.
-. None of these had the PLANE and OFFICE fuels/materials SHREDDED and piled up and blasted up/down shafts (and into critical crevices/boltholes that were CUT and otherwise ALREADY compromised by the plane impact-expolosion) as in 9/11.
One could go on and on, mate.
Just ask grumpy and adoucette to complete the list of what was UNIQUE AND DISASTROUS about WTC1/2 events/scenariuos that didn't need any CD to make the towers collapse.
Hi adoucette!
I'm not so sure, mate. I think the tons and tons of liquid/atomised Kerosene and shredded plane/office material particulates would have mixed with a VASTLY LESSER molecule to molecule ratio of AIR.
So even thogh the initial billows of the fireball was 'redddish orange/yellow', it may have been the pyrolysed Kero fuel's Carbon (soot) and the pyrolised office plastics/organics particulate 'sooty-ash' AT INCANDESCENT TEMPERATURES that constituted the bulk of what went out and was observed through the windows.
In which case, even though all that carbon was HOT and red/yellow, it WAS still a humongous quantity of CARBON and carbon-containing smoke that could easily 'hide' and 'swamp' any other LESSER 'white' light radiation form diffuse reaction sites within that SEA of glowing carbon.
That's my take.
I can see no real objection to Chainsaw's contention that such clouds within and without the building at or soon after impact COULD hide such 'flashes' as metal reactions might produce INSIDE that building/fireball.
Still, as NIST showed, and I agree, the collapse would have happened sooner or later by a few minutes either way.
So the only thing I am interested in NOW is to determnine whether precious EVACUATION/FIREFIGHTING MINUTES could be gained in such events by applying anything that NF/Chain may come up with.
That's all that really is left to discuss, in my opinion. Everything else has been covered and the 'conspiracy' theories well and truly DEBUNKED by you, grumpy, Schneibster, DBB, Shagster, Common Sense, Alex Elevator man and others...including myself.
Cheers mate, all!
RC.
.
Hi RC,
I hope your eyesight is better.
Could you watch the Video I linked to?
The reason I chose this video is because it was of WTC 2.
In WTC 2 the plane impacted at the HIGHER speed (~ 100 MPH greater than the plane impacted in WTC 1) so if aluminum was going to burn, this is the tower most likely to have it do so.
Also, in WTC 2 the plane impacted at somewhat of an angle and quite a bit of the plane exited the building (you can see some of the larger pieces) NIST estimated in the less severe case (Case C) that 10,600 lbs of fuel and 55,000 lbs of aircraft debris exited the building. See NIST NCSTAR 1-2 Table 7-7 pg 241.
IF the aluminum was burning (in even moderate quantities) than that 55,000 lbs of aircraft debris would have included burning pieces of aluminum which would have made the impact look a bit like a Fireworks SPARKLER.
But not a SINGLE piece of burning aluminum is seen exiting the building.
NOT ONE
Anyone suggesting that a substantial amount of that plane's structure combusted on impact has to explain the lack of supporting visual evidence in that video.
Personally I think people are ignoring the cooling and lubricating effects of the 20,000 lbs of Jet A fuel that shortly after the initial impact OUTRUNS the plane and coats nearly all of the interior contents PRIOR to most of it being impacted by bits of the plane. I suspect that would prevent most of the friction induced oxide layer damage and/or heat buildup that otherwise MIGHT have led to combustion of some of the aluminum.
Arthur
Take a warehouse full of lawnmower parts and set it on fire, then you've got Aluminium, Magnesium, and god knows what else all burning together.
Take the ICI fire in Auckland (NZ) some years ago - big stainless steel drums with Paraquat and Pool chemicals.
Take the warehouse fire in Brazil (I think it was) that burned so hot that it reduced Concrete to a powder (the sorts of temperatures that have been suggested btw) the only fuel there was paper.
I could name a bunch of others as well.
None of these are controled circumstances.
The point that is being made is that the fire wasn't neccessarily as unique as it's being made out to be, I don't think that even the ignition is as widespread or instantaneous as it's being made out to be.
I see what you're getting at, mate. And you're RIGHT.
But please try to see what I and others are getting at:
-. None of these things tou mention are anywhere near the VAST and WIDESPREAD all-at once fires over multilevel 'stack' conditions and mix of materials.
-. None of these involved a TALL building the size of WTC1/2.
-. None of these involve widespread all-at-once fireproofing removal and total neautralising of active firefighting systems/firemen.
-. None of these involve the quantities and SCALE-EFFECTS of the processes.
-. None of these had the PLANE and OFFICE fuels/materials SHREDDED and piled up and blasted up/down shafts (and into critical crevices/boltholes that were CUT and otherwise ALREADY compromised by the plane impact-expolosion) as in 9/11.
One could go on and on, mate.
Just ask grumpy and adoucette to complete the list of what was UNIQUE AND DISASTROUS about WTC1/2 events/scenariuos that didn't need any CD to make the towers collapse.
QUOTE (Trippy+Jul 20 2007, 12:09 AM)
And this statement, without wanting to sound like i'm being rude, or making an adhominem attack, is as funny as it is blatantly wrong.
The ionization energy (the main govering factor in ignition temperature) of Aluminium doesn't change just because it's burning in a warehouse instead of a lab.
Mate, really, it seems like you WANT someone to offend you in some way, and you will read everything in that light, hehehe.
Take it easy with the readiness to see insults where there are none.
There was nothing in that except the pointing out of the OTHER WAYS TO IGNITE ALUMINIUM that has been pre-shredded and pre-heated/molten, and otherwise READY (even WELL below melting point) to reacrt with Silicates (glass) and other catalysing/accelerating/compromising materials/processes.
That's all anyone is saying, mate. just look FURTHER than just straight 'fire temps heating' for all the OTHER things possibly going on.
Anyway, ask adoucette to tell you how MUCH evidence presented in pastb threads by himself, myself and others has PROVED that 1000+C is VERY usual in even 'normal' office/building fires, let alone in the towers on 9/11.
I'm with you. Just try to be less quick to feel slighted. I am NOT doing any such thing. Honest. I am deeply sorry and apologise if I came across that way.
Cheers Trip!
RC.
.
The ionization energy (the main govering factor in ignition temperature) of Aluminium doesn't change just because it's burning in a warehouse instead of a lab.
Mate, really, it seems like you WANT someone to offend you in some way, and you will read everything in that light, hehehe.
Take it easy with the readiness to see insults where there are none.
There was nothing in that except the pointing out of the OTHER WAYS TO IGNITE ALUMINIUM that has been pre-shredded and pre-heated/molten, and otherwise READY (even WELL below melting point) to reacrt with Silicates (glass) and other catalysing/accelerating/compromising materials/processes.
That's all anyone is saying, mate. just look FURTHER than just straight 'fire temps heating' for all the OTHER things possibly going on.
Anyway, ask adoucette to tell you how MUCH evidence presented in pastb threads by himself, myself and others has PROVED that 1000+C is VERY usual in even 'normal' office/building fires, let alone in the towers on 9/11.
I'm with you. Just try to be less quick to feel slighted. I am NOT doing any such thing. Honest. I am deeply sorry and apologise if I came across that way.
Cheers Trip!
RC.
.
QUOTE (RealityCheck+Jul 19 2007, 08:26 PM)
Hi adoucette!
I'm not so sure, mate. I think the tons and tons of liquid/atomised Kerosene and shredded plane/office material particulates would have mixed with a VASTLY LESSER molecule to molecule ratio of AIR.
So even thogh the initial billows of the fireball was 'redddish orange/yellow', it may have been the pyrolysed Kero fuel's Carbon (soot) and the pyrolised office plastics/organics particulate 'sooty-ash' AT INCANDESCENT TEMPERATURES that constituted the bulk of what went out and was observed through the windows.
In which case, even though all that carbon was HOT and red/yellow, it WAS still a humongous quantity of CARBON and carbon-containing smoke that could easily 'hide' and 'swamp' any other LESSER 'white' light radiation form diffuse reaction sites within that SEA of glowing carbon.
That's my take.
I can see no real objection to Chainsaw's contention that such clouds within and without the building at or soon after impact COULD hide such 'flashes' as metal reactions might produce INSIDE that building/fireball.
Still, as NIST showed, and I agree, the collapse would have happened sooner or later by a few minutes either way.
So the only thing I am interested in NOW is to determnine whether precious EVACUATION/FIREFIGHTING MINUTES could be gained in such events by applying anything that NF/Chain may come up with.
That's all that really is left to discuss, in my opinion. Everything else has been covered and the 'conspiracy' theories well and truly DEBUNKED by you, grumpy, Schneibster, DBB, Shagster, Common Sense, Alex Elevator man and others...including myself.
Cheers mate, all!
RC.
.
Hi RC,
I hope your eyesight is better.
Could you watch the Video I linked to?
The reason I chose this video is because it was of WTC 2.
In WTC 2 the plane impacted at the HIGHER speed (~ 100 MPH greater than the plane impacted in WTC 1) so if aluminum was going to burn, this is the tower most likely to have it do so.
Also, in WTC 2 the plane impacted at somewhat of an angle and quite a bit of the plane exited the building (you can see some of the larger pieces) NIST estimated in the less severe case (Case C) that 10,600 lbs of fuel and 55,000 lbs of aircraft debris exited the building. See NIST NCSTAR 1-2 Table 7-7 pg 241.
IF the aluminum was burning (in even moderate quantities) than that 55,000 lbs of aircraft debris would have included burning pieces of aluminum which would have made the impact look a bit like a Fireworks SPARKLER.
But not a SINGLE piece of burning aluminum is seen exiting the building.
NOT ONE
Anyone suggesting that a substantial amount of that plane's structure combusted on impact has to explain the lack of supporting visual evidence in that video.
Personally I think people are ignoring the cooling and lubricating effects of the 20,000 lbs of Jet A fuel that shortly after the initial impact OUTRUNS the plane and coats nearly all of the interior contents PRIOR to most of it being impacted by bits of the plane. I suspect that would prevent most of the friction induced oxide layer damage and/or heat buildup that otherwise MIGHT have led to combustion of some of the aluminum.
Arthur
QUOTE (RealityCheck+Jul 19 2007, 08:51 PM)
Anyway, ask adoucette to tell you how MUCH evidence presented in pastb threads by himself, myself and others has PROVED that 1000+C is VERY usual in even 'normal' office/building fires, let alone in the towers on 9/11.
True enough, but those very high temps are predominately peak CEILING temperatures (unfortunately for the trusses) and Aluminum debris from the crash wouldn't tend to be found near the ceilings. Floor level temps, where the majority of the debris would have accumulated, would tend to be hundreds of degrees cooler.
Arthur
True enough, but those very high temps are predominately peak CEILING temperatures (unfortunately for the trusses) and Aluminum debris from the crash wouldn't tend to be found near the ceilings. Floor level temps, where the majority of the debris would have accumulated, would tend to be hundreds of degrees cooler.
Arthur
QUOTE (adoucette+Jul 20 2007, 01:28 AM)
Hi RC,
I hope your eyesight is better.
Could you watch the Video I linked to?
The reason I chose this video is because it was of WTC 2.
In WTC 2 the plane impacted at the HIGHER speed (~ 100 MPH greater than the plane impacted in WTC 1) so if aluminum was going to burn, this is the tower most likely to have it do so.
Also, in WTC 2 the plane impacted at somewhat of an angle and quite a bit of the plane exited the building (you can see some of the larger pieces) NIST estimated in the less severe case (Case C) that 10,600 lbs of fuel and 55,000 lbs of aircraft debris exited the building. See NIST NCSTAR 1-2 Table 7-7 pg 241.
IF the aluminum was burning (in even moderate quantities) than that 55,000 lbs of aircraft debris would have included burning pieces of aluminum which would have made the impact look a bit like a Fireworks SPARKLER.
But not a SINGLE piece of burning aluminum is seen exiting the building.
NOT ONE
Anyone suggesting that a substantial amount of that plane's structure combusted on impact has to explain the lack of supporting visual evidence in that video.
Personally I think people are ignoring the cooling and lubricating effects of the 20,000 lbs of Jet A fuel that shortly after the initial impact OUTRUNS the plane and coats nearly all of the interior contents PRIOR to most of it being impacted by bits of the plane. I suspect that would prevent most of the friction induced oxide layer damage and/or heat buildup that otherwise MIGHT have led to combustion of some of the aluminum.
Arthur
Two points jet fuel would not reduce the friction on impact, and second, the initial impact caused thermite reactions on Impact with the core will cause reactions as well but by the time the plane parts are exiting the building the oxidants might well be depleted and the aluminum cooling.
Aluminum is very good at conducting heat away and very reactive to oxygen, by the time the aluminum reach the exterior of the building it would be in the form of aluminum oxide.
I am thinking like Neu it is the small shredded parts of the skin that are oxidized along with fines from the fuselage and the aluminum on the buildings.
From what I have seen that would be about 1/5th the planes mass at most.
That hot and extremely strong material Aluminum oxide would cause the floor pans to be shredded leaving an increased surface area for reactions.
Basically it is the heavier non shredded parts that are exiting the buildings.
I hope your eyesight is better.
Could you watch the Video I linked to?
The reason I chose this video is because it was of WTC 2.
In WTC 2 the plane impacted at the HIGHER speed (~ 100 MPH greater than the plane impacted in WTC 1) so if aluminum was going to burn, this is the tower most likely to have it do so.
Also, in WTC 2 the plane impacted at somewhat of an angle and quite a bit of the plane exited the building (you can see some of the larger pieces) NIST estimated in the less severe case (Case C) that 10,600 lbs of fuel and 55,000 lbs of aircraft debris exited the building. See NIST NCSTAR 1-2 Table 7-7 pg 241.
IF the aluminum was burning (in even moderate quantities) than that 55,000 lbs of aircraft debris would have included burning pieces of aluminum which would have made the impact look a bit like a Fireworks SPARKLER.
But not a SINGLE piece of burning aluminum is seen exiting the building.
NOT ONE
Anyone suggesting that a substantial amount of that plane's structure combusted on impact has to explain the lack of supporting visual evidence in that video.
Personally I think people are ignoring the cooling and lubricating effects of the 20,000 lbs of Jet A fuel that shortly after the initial impact OUTRUNS the plane and coats nearly all of the interior contents PRIOR to most of it being impacted by bits of the plane. I suspect that would prevent most of the friction induced oxide layer damage and/or heat buildup that otherwise MIGHT have led to combustion of some of the aluminum.
Arthur
Two points jet fuel would not reduce the friction on impact, and second, the initial impact caused thermite reactions on Impact with the core will cause reactions as well but by the time the plane parts are exiting the building the oxidants might well be depleted and the aluminum cooling.
Aluminum is very good at conducting heat away and very reactive to oxygen, by the time the aluminum reach the exterior of the building it would be in the form of aluminum oxide.
I am thinking like Neu it is the small shredded parts of the skin that are oxidized along with fines from the fuselage and the aluminum on the buildings.
From what I have seen that would be about 1/5th the planes mass at most.
That hot and extremely strong material Aluminum oxide would cause the floor pans to be shredded leaving an increased surface area for reactions.
Basically it is the heavier non shredded parts that are exiting the buildings.
QUOTE (adoucette+Jul 20 2007, 01:45 AM)
True enough, but those very high temps are predominately peak CEILING temperatures (unfortunately for the trusses) and Aluminum debris from the crash wouldn't tend to be found near the ceilings. Floor level temps, where the majority of the debris would have accumulated, would tend to be hundreds of degrees cooler.
Arthur
Temperature is almost irrelevent as the combination of the fuel, and the Aluminum would most definately cause reactions along with thermite sparking.
It after all is the friction of the fast moving jet fuel that strips the fire proofing off the steel.
Lets not forget also that thermite sparks occur at room temps.
http://www.energyinst.org.uk/content/files/file374.pdf
Arthur
Temperature is almost irrelevent as the combination of the fuel, and the Aluminum would most definately cause reactions along with thermite sparking.
It after all is the friction of the fast moving jet fuel that strips the fire proofing off the steel.
Lets not forget also that thermite sparks occur at room temps.
http://www.energyinst.org.uk/content/files/file374.pdf
.
QUOTE (adoucette+Jul 20 2007, 01:28 AM)
Hi RC,
I hope your eyesight is better.
Could you watch the Video I linked to?
The reason I chose this video is because it was of WTC 2.
In WTC 2 the plane impacted at the HIGHER speed (~ 100 MPH greater than the plane impacted in WTC 1) so if aluminum was going to burn, this is the tower most likely to have it do so.
Also, in WTC 2 the plane impacted at somewhat of an angle and quite a bit of the plane exited the building (you can see some of the larger pieces) NIST estimated in the less severe case (Case C) that 10,600 lbs of fuel and 55,000 lbs of aircraft debris exited the building. See NIST NCSTAR 1-2 Table 7-7 pg 241.
IF the aluminum was burning (in even moderate quantities) than that 55,000 lbs of aircraft debris would have included burning pieces of aluminum which would have made the impact look a bit like a Fireworks SPARKLER.
But not a SINGLE piece of burning aluminum is seen exiting the building.
NOT ONE
Anyone suggesting that a substantial amount of that plane's structure combusted on impact has to explain the lack of supporting visual evidence in that video.
Personally I think people are ignoring the cooling and lubricating effects of the 20,000 lbs of Jet A fuel that shortly after the initial impact OUTRUNS the plane and coats nearly all of the interior contents PRIOR to most of it being impacted by bits of the plane. I suspect that would prevent most of the friction induced oxide layer damage and/or heat buildup that otherwise MIGHT have led to combustion of some of the aluminum.
Arthur
Yeah, mate, I see what you're getting at.
Even so, though, the parts that do make it through the 'sieve' of the perimeter/core shredder would SELF-SELECTIVELY be the BULKIER/SOLIDER and more stable and sections.....which, if they WERE burning, would be doing so only at their 'margins'....while their GREATER bulk would be still cool enough (not yet having had time to heat up much....since they did nort dwell in the floor inferno/explosion zone long at all) to allow the oxidising layers to STAY on over a cool bulk substrate.
theh cooler outside air would cool the bulk further.....and so without the propensity for the bulk to 'join in' the oxidising at the edges, it would soon hit ground and resemble smoldering airplane debris as in 'normal' open field crashes.
It is what's going on with what's LEFT of the plane inside the multi-tier inferno; and the additional cladding and glass 'entrained' in from the building by the plane ingress, that is interesting to me....and of course, all that office panels/equipment and other reactive metals and catalytic/corrosive chemicals/processes that over many minutes could further exacerbate/compromise the connections (not the bulk components) in the 'integrated' system, that really interests me at this stage.[/b]
Simply because the jet-fuel and foffice fuel fires overall would OBVIOUSLY have been severe enough to produce collapse. No question.
It's these other interesting details that make the event even MORE unique.....and possibly even MORE sobering for the assumptions that allowed these towers to be designed/constructed such that their vulnerabilities could easily be exacerbated by ALL SORTS of previously ignored factors that SHOULD and COULD in future be taken into account and minimised where possible.
No it can preheat and melt the aluminum weakening the oxide layer, it also provides more fine particle of aluminum that ignite in the fuel.
No it can preheat and melt the aluminum weakening the oxide layer, it also provides more fine particle of aluminum that ignite in the fuel.
Actually Jet fuel is a fairly decent lubricant and will make a nice surface layer on anything it touches, anything else that hits it after that has to get past this surface layer.
Not a problem with the energies were considering, diesel engines are ignited by the fiction of diesel fuel in air, Jet fuel is not as good a lubricant as diesel. It would not provide much protection at those energy levels.
Of course, no arguement there.
Of course, no arguement there.
If the aluminum is going to burn it would be visible in those first two seconds.
It would occur when the plane hits the interior core.
oxidize more than 20,000 lbs of aluminum, but CLEARLY a LOT of the Oxygen wasn't consuI explained that, the expanding fire ball can obscure and swamp the white light.
oxidize more than 20,000 lbs of aluminum, but CLEARLY a LOT of the Oxygen wasn't consuI explained that, the expanding fire ball can obscure and swamp the white light.
Further, the TOTAL Oxygen on one floor is only about ~ 7,000 lbs.
The majority of the fuselage & wings impacted on three floors.
If it consumed ALL the oxygen on three floors you couldn't med in the impact and CLEARLY a lot that was, was consumed with combusting hydrocarbons.
There simply wasn't sufficient free oxygen available for combusting a significant part of the plane during impact.
Could Oxygen be liberated from other compounds?
Yes, but NOT quickly enough to generate large releases of energy.
The aluminum-water reaction that produces hydrogen is instantanious as is the CO2 reaction or the thermite reaction. If what your saying is true than thermite should not work at all.
Hi adoucette!
About that 'preferred combustion with the available air. In fact, the aluminium and magnesium would ignite much faster than the hydrocarons. So the immediate air oin contact with both would be scooped into Al2O3 faster.
And even AFTER any Kero HAS combusted, the by products (now HOT H2O and CO and CO2) would ALSO be 'recycled' as to OXYGEN for the aluminium and other reactive metal oxidations.
And of course, as the H2O and CO2 component is dissociated and their oxygen stolen by metals, the Hydrogen and CO (from part-stolen CO2 molecule's oxygen) and 'Carbon black' would then re-ignite as they met air near/out the windows.
Hi RC
But you can't get these mass transfer reactions to proceed that quickly.
And even if Al is more reactive than Jet A, that doesn't mean that all Al reacts first, its only when the two are competing for the same molecule that reactiveness need be considered. All in all, probably a non-issue.
Again remember that not ALL of the 7,000 lbs of O2 on a floor is going to be involved in any of this (it happens to fast, and in WTC 2, most of these reactions occur on just one side of the building)
Now for every 1,000 lbs of Jet A that burns, 2,800 lbs of O2 are required.
This will result in ~ 2,000 lbs of CO2 and only 800 lbs of H20 (less O2 is used up as more CO is formed, but then much less energy is released).
While some of that H20 might recycle, I doubt you will get much of the CO2 (or CO to recycle, the energy levels would drop too quickly.
Again, we can speculate all we want on the POSSIBILITY of some small quantity of these reactions occuring, there certainly were enough variables for most anything to occur, but there is NO EVIDENCE that any significant quantity of Aluminum burned in the towers.
Chainsaw:
They are QUICK, but NOT instantaneous, the fact is for ANY of these reactions to take place the specific materials have to come together, that limits the reaction rates.
The reason I picked that video is because you see it from the side of the core that the plane hit on.
There would be NOTHING between the major columns the plane took out and those windows facing the video camera.
If any quantity of aluminum ignited during the time it took out those columns it WOULD HAVE BEEN VISIBLE.
It wasn't.
Arthur
I hope your eyesight is better.
Could you watch the Video I linked to?
The reason I chose this video is because it was of WTC 2.
In WTC 2 the plane impacted at the HIGHER speed (~ 100 MPH greater than the plane impacted in WTC 1) so if aluminum was going to burn, this is the tower most likely to have it do so.
Also, in WTC 2 the plane impacted at somewhat of an angle and quite a bit of the plane exited the building (you can see some of the larger pieces) NIST estimated in the less severe case (Case C) that 10,600 lbs of fuel and 55,000 lbs of aircraft debris exited the building. See NIST NCSTAR 1-2 Table 7-7 pg 241.
IF the aluminum was burning (in even moderate quantities) than that 55,000 lbs of aircraft debris would have included burning pieces of aluminum which would have made the impact look a bit like a Fireworks SPARKLER.
But not a SINGLE piece of burning aluminum is seen exiting the building.
NOT ONE
Anyone suggesting that a substantial amount of that plane's structure combusted on impact has to explain the lack of supporting visual evidence in that video.
Personally I think people are ignoring the cooling and lubricating effects of the 20,000 lbs of Jet A fuel that shortly after the initial impact OUTRUNS the plane and coats nearly all of the interior contents PRIOR to most of it being impacted by bits of the plane. I suspect that would prevent most of the friction induced oxide layer damage and/or heat buildup that otherwise MIGHT have led to combustion of some of the aluminum.
Arthur
Yeah, mate, I see what you're getting at.
Even so, though, the parts that do make it through the 'sieve' of the perimeter/core shredder would SELF-SELECTIVELY be the BULKIER/SOLIDER and more stable and sections.....which, if they WERE burning, would be doing so only at their 'margins'....while their GREATER bulk would be still cool enough (not yet having had time to heat up much....since they did nort dwell in the floor inferno/explosion zone long at all) to allow the oxidising layers to STAY on over a cool bulk substrate.
theh cooler outside air would cool the bulk further.....and so without the propensity for the bulk to 'join in' the oxidising at the edges, it would soon hit ground and resemble smoldering airplane debris as in 'normal' open field crashes.
It is what's going on with what's LEFT of the plane inside the multi-tier inferno; and the additional cladding and glass 'entrained' in from the building by the plane ingress, that is interesting to me....and of course, all that office panels/equipment and other reactive metals and catalytic/corrosive chemicals/processes that over many minutes could further exacerbate/compromise the connections (not the bulk components) in the 'integrated' system, that really interests me at this stage.[/b]
Simply because the jet-fuel and foffice fuel fires overall would OBVIOUSLY have been severe enough to produce collapse. No question.
It's these other interesting details that make the event even MORE unique.....and possibly even MORE sobering for the assumptions that allowed these towers to be designed/constructed such that their vulnerabilities could easily be exacerbated by ALL SORTS of previously ignored factors that SHOULD and COULD in future be taken into account and minimised where possible.
QUOTE (adoucette+Jul 20 2007, 01:45 AM)
True enough, but those very high temps are predominately peak CEILING temperatures (unfortunately for the trusses) and Aluminum debris from the crash wouldn't tend to be found near the ceilings. Floor level temps, where the majority of the debris would have accumulated, would tend to be hundreds of degrees cooler.
Arthur
As Trip pointed out, the cracked floor membrane allowed aluminium and other debris liquid/particulate mixes to cascade through into lower levels from the highest levels....and these would meet the 1000+C under-ceiling temperatures and REACT THERE as they get enmeshed in the strutwork and forming mesh under the rubblised slabs....as well as along the wall-to-floor gaps/connection line.
Perfect location and mixes of molten aluminium, entrained glass and other debris and the HOT concrete crack surfaces themselves.
But again, there are more ways than one (other than ordinary fire temps/processes) to ignite/react aluminium and all the other metals present in 9/11.
And again, at this stage, I see it as highly localised, marginally damaging/predisposing reactions in cracks and starting-points for later failure/fissure effects bginning/propagating SLIGHT;Y faster/sooner than otherwise. How much so, I don't know. But in such situations MINUTES COUNT where evacuation is still in progress.....especially if no firefighting at all is active.
So I don't see the overall energy budget has anything to do with it as such.
It is the specific marginal effects that may have reduced time to collapse by unforeseen 'selective exacerbation' at critical/vulnerable points by even one or two minutes that may in future make the difference between human life and death, structure survivability and catastrophe. That's all.
Good luck to everyone concerned in the OBJECTIVE SCIENTIFIC and not the CTer/CDer POLITICAL/CONSPIRATORIAL researches.
PS: Yeah! Thanks! My optic nerve etc are almost fully recovered...and most importantly, the inflammation, blurring and headaches have abated to almost 'gone', hehehe! Like a new lease on vision and light, mate. Great feeling! Thanks again for your concern!
How are you? OK and fit as a fiddle, I hope!
Cheers adoucette!
RC.
.
Arthur
As Trip pointed out, the cracked floor membrane allowed aluminium and other debris liquid/particulate mixes to cascade through into lower levels from the highest levels....and these would meet the 1000+C under-ceiling temperatures and REACT THERE as they get enmeshed in the strutwork and forming mesh under the rubblised slabs....as well as along the wall-to-floor gaps/connection line.
Perfect location and mixes of molten aluminium, entrained glass and other debris and the HOT concrete crack surfaces themselves.
But again, there are more ways than one (other than ordinary fire temps/processes) to ignite/react aluminium and all the other metals present in 9/11.
And again, at this stage, I see it as highly localised, marginally damaging/predisposing reactions in cracks and starting-points for later failure/fissure effects bginning/propagating SLIGHT;Y faster/sooner than otherwise. How much so, I don't know. But in such situations MINUTES COUNT where evacuation is still in progress.....especially if no firefighting at all is active.
So I don't see the overall energy budget has anything to do with it as such.
It is the specific marginal effects that may have reduced time to collapse by unforeseen 'selective exacerbation' at critical/vulnerable points by even one or two minutes that may in future make the difference between human life and death, structure survivability and catastrophe. That's all.
Good luck to everyone concerned in the OBJECTIVE SCIENTIFIC and not the CTer/CDer POLITICAL/CONSPIRATORIAL researches.
PS: Yeah! Thanks! My optic nerve etc are almost fully recovered...and most importantly, the inflammation, blurring and headaches have abated to almost 'gone', hehehe! Like a new lease on vision and light, mate. Great feeling! Thanks again for your concern!
How are you? OK and fit as a fiddle, I hope!
Cheers adoucette!
RC.
.
QUOTE (Chainsaw,+Jul 19 2007, 10:36 PM)
Two points jet fuel would not reduce the friction on impact, and second, the initial impact caused thermite reactions on Impact with the core will cause reactions as well but by the time the plane parts are exiting the building the oxidants might well be depleted and the aluminum cooling.
Aluminum is very good at conducting heat away and very reactive to oxygen, by the time the aluminum reach the exterior of the building it would be in the form of aluminum oxide.
I am thinking like Neu it is the small shredded parts of the skin that are oxidized along with fines from the fuselage and the aluminum on the buildings.
From what I have seen that would be about 1/5th the planes mass at most.
That hot and extremely strong material Aluminum oxide would cause the floor pans to be shredded leaving an increased surface area for reactions.
Basically it is the heavier non shredded parts that are exiting the buildings.
I'm ignoring the initial EXTERNAL impact since ALL of those columns were taken out by the impact anyway, so any natural thermite type damage is pretty irrelevant.
Actually Jet fuel is a fairly decent lubricant and will make a nice surface layer on anything it touches, anything else that hits it after that has to get past this surface layer.
One can time the crash.
If the aluminum is going to burn it would be visible in those first two seconds.
It would also be VISIBLE THROUGH the WINDOWS.
It wasn't.
Further, the TOTAL Oxygen on one floor is only about ~ 7,000 lbs.
The majority of the fuselage & wings impacted on three floors.
If it consumed ALL the oxygen on three floors you couldn't oxidize more than 20,000 lbs of aluminum, but CLEARLY a LOT of the Oxygen wasn't consumed in the impact and CLEARLY a lot that was, was consumed with combusting hydrocarbons.
There simply wasn't sufficient free oxygen available for combusting a significant part of the plane during impact.
Could Oxygen be liberated from other compounds?
Yes, but NOT quickly enough to generate large releases of energy.
Arthur
Aluminum is very good at conducting heat away and very reactive to oxygen, by the time the aluminum reach the exterior of the building it would be in the form of aluminum oxide.
I am thinking like Neu it is the small shredded parts of the skin that are oxidized along with fines from the fuselage and the aluminum on the buildings.
From what I have seen that would be about 1/5th the planes mass at most.
That hot and extremely strong material Aluminum oxide would cause the floor pans to be shredded leaving an increased surface area for reactions.
Basically it is the heavier non shredded parts that are exiting the buildings.
I'm ignoring the initial EXTERNAL impact since ALL of those columns were taken out by the impact anyway, so any natural thermite type damage is pretty irrelevant.
Actually Jet fuel is a fairly decent lubricant and will make a nice surface layer on anything it touches, anything else that hits it after that has to get past this surface layer.
One can time the crash.
If the aluminum is going to burn it would be visible in those first two seconds.
It would also be VISIBLE THROUGH the WINDOWS.
It wasn't.
Further, the TOTAL Oxygen on one floor is only about ~ 7,000 lbs.
The majority of the fuselage & wings impacted on three floors.
If it consumed ALL the oxygen on three floors you couldn't oxidize more than 20,000 lbs of aluminum, but CLEARLY a LOT of the Oxygen wasn't consumed in the impact and CLEARLY a lot that was, was consumed with combusting hydrocarbons.
There simply wasn't sufficient free oxygen available for combusting a significant part of the plane during impact.
Could Oxygen be liberated from other compounds?
Yes, but NOT quickly enough to generate large releases of energy.
Arthur
QUOTE (adoucette to Chainsaw+Jul 20 2007, 03:01 AM)
I'm ignoring the initial EXTERNAL impact since ALL of those columns were taken out by the impact anyway, so any natural thermite type damage is pretty irrelevant.
Actually Jet fuel is a fairly decent lubricant and will make a nice surface layer on anything it touches, anything else that hits it after that has to get past this surface layer.
One can time the crash.
If the aluminum is going to burn it would be visible in those first two seconds.
It would also be VISIBLE THROUGH the WINDOWS.
It wasn't.
Further, the TOTAL Oxygen on one floor is only about ~ 7,000 lbs.
The majority of the fuselage & wings impacted on three floors.
If it consumed ALL the oxygen on three floors you couldn't oxidize more than 20,000 lbs of aluminum, but CLEARLY a LOT of the Oxygen wasn't consumed in the impact and CLEARLY a lot that was, was consumed with combusting hydrocarbons.
There simply wasn't sufficient free oxygen available for combusting a significant part of the plane during impact.
Could Oxygen be liberated from other compounds?
Yes, but NOT quickly enough to generate large releases of energy.
Arthur
Hi adoucette!
About that 'preferred combustion with the available air. In fact, the aluminium and magnesium would ignite much faster than the hydrocarons. So the immediate air oin contact with both would be scooped into Al2O3 faster.
And even AFTER any Kero HAS combusted, the by products (now HOT H2O and CO and CO2) would ALSO be 'recycled' as to OXYGEN for the aluminium and other reactive metal oxidations.
And of course, as the H2O and CO2 component is dissociated and their oxygen stolen by metals, the Hydrogen and CO (from part-stolen CO2 molecule's oxygen) and 'Carbon black' would then re-ignite as they met air near/out the windows.
So since the hydrogen flame is too weak to notice, the heat from that would be heating the burning CO and C and making the rest of the partially-burnt Kero and the soot and ash glow orange/yellow until cooling stopped further combustion outside.
There is more to the possible energy cycling/reactions caused by the plane and scale and mixes than meets the eye at first glance....especially INSIDE the awful mix of materials and reactions in gaps ans crevices and fissures and vital connection systems/organics etc where metallic reactions and corrosive/catalytic reactions could take minutes off the time to inevitable collapse.
See what I mean? Not much difference, but possibly crucial to someone/somebuilding in the future to sort out and learn what we can from this staghtforward plane-fire catastrophe the towers were vulnerable to....irrespective of what these interesting 'details' contibuted to it or not.
PS: I stress again: The total energy budget is plenty from plane fuel and office fuel for collapse. And I don't think the additional plane body and cladding aluminium energy PER SE added much to that energy budget. HOWEVER, the reaction types, cycles and locations involving reactive metals and catalyttic and corrosive element/compounds MIGHT have done some damage in SMALL but critical places like welds/bolts connector systems. That is a marginal difference in EFFECT rather than ENERGY per se, in my opinion.
Cheers!
RC.
.
Actually Jet fuel is a fairly decent lubricant and will make a nice surface layer on anything it touches, anything else that hits it after that has to get past this surface layer.
One can time the crash.
If the aluminum is going to burn it would be visible in those first two seconds.
It would also be VISIBLE THROUGH the WINDOWS.
It wasn't.
Further, the TOTAL Oxygen on one floor is only about ~ 7,000 lbs.
The majority of the fuselage & wings impacted on three floors.
If it consumed ALL the oxygen on three floors you couldn't oxidize more than 20,000 lbs of aluminum, but CLEARLY a LOT of the Oxygen wasn't consumed in the impact and CLEARLY a lot that was, was consumed with combusting hydrocarbons.
There simply wasn't sufficient free oxygen available for combusting a significant part of the plane during impact.
Could Oxygen be liberated from other compounds?
Yes, but NOT quickly enough to generate large releases of energy.
Arthur
Hi adoucette!
About that 'preferred combustion with the available air. In fact, the aluminium and magnesium would ignite much faster than the hydrocarons. So the immediate air oin contact with both would be scooped into Al2O3 faster.
And even AFTER any Kero HAS combusted, the by products (now HOT H2O and CO and CO2) would ALSO be 'recycled' as to OXYGEN for the aluminium and other reactive metal oxidations.
And of course, as the H2O and CO2 component is dissociated and their oxygen stolen by metals, the Hydrogen and CO (from part-stolen CO2 molecule's oxygen) and 'Carbon black' would then re-ignite as they met air near/out the windows.
So since the hydrogen flame is too weak to notice, the heat from that would be heating the burning CO and C and making the rest of the partially-burnt Kero and the soot and ash glow orange/yellow until cooling stopped further combustion outside.
There is more to the possible energy cycling/reactions caused by the plane and scale and mixes than meets the eye at first glance....especially INSIDE the awful mix of materials and reactions in gaps ans crevices and fissures and vital connection systems/organics etc where metallic reactions and corrosive/catalytic reactions could take minutes off the time to inevitable collapse.
See what I mean? Not much difference, but possibly crucial to someone/somebuilding in the future to sort out and learn what we can from this staghtforward plane-fire catastrophe the towers were vulnerable to....irrespective of what these interesting 'details' contibuted to it or not.
PS: I stress again: The total energy budget is plenty from plane fuel and office fuel for collapse. And I don't think the additional plane body and cladding aluminium energy PER SE added much to that energy budget. HOWEVER, the reaction types, cycles and locations involving reactive metals and catalyttic and corrosive element/compounds MIGHT have done some damage in SMALL but critical places like welds/bolts connector systems. That is a marginal difference in EFFECT rather than ENERGY per se, in my opinion.
Cheers!
RC.
.
QUOTE
I'm ignoring the initial EXTERNAL impact since ALL of those columns were taken out by the impact anyway, so any natural thermite type damage is pretty irrelevant.
No it can preheat and melt the aluminum weakening the oxide layer, it also provides more fine particle of aluminum that ignite in the fuel.
QUOTE (->
| QUOTE |
| I'm ignoring the initial EXTERNAL impact since ALL of those columns were taken out by the impact anyway, so any natural thermite type damage is pretty irrelevant. |
No it can preheat and melt the aluminum weakening the oxide layer, it also provides more fine particle of aluminum that ignite in the fuel.
Actually Jet fuel is a fairly decent lubricant and will make a nice surface layer on anything it touches, anything else that hits it after that has to get past this surface layer.
Not a problem with the energies were considering, diesel engines are ignited by the fiction of diesel fuel in air, Jet fuel is not as good a lubricant as diesel. It would not provide much protection at those energy levels.
QUOTE
One can time the crash.
Of course, no arguement there.
QUOTE (->
| QUOTE |
| One can time the crash. |
Of course, no arguement there.
If the aluminum is going to burn it would be visible in those first two seconds.
It would occur when the plane hits the interior core.
QUOTE
It would also be VISIBLE THROUGH the WINDOWS.
It wasn't.
It wasn't.
oxidize more than 20,000 lbs of aluminum, but CLEARLY a LOT of the Oxygen wasn't consuI explained that, the expanding fire ball can obscure and swamp the white light.
QUOTE (->
| QUOTE |
| It would also be VISIBLE THROUGH the WINDOWS. It wasn't. |
oxidize more than 20,000 lbs of aluminum, but CLEARLY a LOT of the Oxygen wasn't consuI explained that, the expanding fire ball can obscure and swamp the white light.
Further, the TOTAL Oxygen on one floor is only about ~ 7,000 lbs.
The majority of the fuselage & wings impacted on three floors.
If it consumed ALL the oxygen on three floors you couldn't med in the impact and CLEARLY a lot that was, was consumed with combusting hydrocarbons.
There simply wasn't sufficient free oxygen available for combusting a significant part of the plane during impact.
Could Oxygen be liberated from other compounds?
Yes, but NOT quickly enough to generate large releases of energy.
The aluminum-water reaction that produces hydrogen is instantanious as is the CO2 reaction or the thermite reaction. If what your saying is true than thermite should not work at all.
QUOTE (RealityCheck+Jul 19 2007, 11:16 PM)
Hi adoucette!
About that 'preferred combustion with the available air. In fact, the aluminium and magnesium would ignite much faster than the hydrocarons. So the immediate air oin contact with both would be scooped into Al2O3 faster.
And even AFTER any Kero HAS combusted, the by products (now HOT H2O and CO and CO2) would ALSO be 'recycled' as to OXYGEN for the aluminium and other reactive metal oxidations.
And of course, as the H2O and CO2 component is dissociated and their oxygen stolen by metals, the Hydrogen and CO (from part-stolen CO2 molecule's oxygen) and 'Carbon black' would then re-ignite as they met air near/out the windows.
Hi RC
But you can't get these mass transfer reactions to proceed that quickly.
And even if Al is more reactive than Jet A, that doesn't mean that all Al reacts first, its only when the two are competing for the same molecule that reactiveness need be considered. All in all, probably a non-issue.
Again remember that not ALL of the 7,000 lbs of O2 on a floor is going to be involved in any of this (it happens to fast, and in WTC 2, most of these reactions occur on just one side of the building)
Now for every 1,000 lbs of Jet A that burns, 2,800 lbs of O2 are required.
This will result in ~ 2,000 lbs of CO2 and only 800 lbs of H20 (less O2 is used up as more CO is formed, but then much less energy is released).
While some of that H20 might recycle, I doubt you will get much of the CO2 (or CO to recycle, the energy levels would drop too quickly.
Again, we can speculate all we want on the POSSIBILITY of some small quantity of these reactions occuring, there certainly were enough variables for most anything to occur, but there is NO EVIDENCE that any significant quantity of Aluminum burned in the towers.
Chainsaw:
QUOTE
The aluminum-water reaction that produces hydrogen is instantanious as is the CO2 reaction or the thermite reaction. If what your saying is true than thermite should not work at all.
They are QUICK, but NOT instantaneous, the fact is for ANY of these reactions to take place the specific materials have to come together, that limits the reaction rates.
The reason I picked that video is because you see it from the side of the core that the plane hit on.
There would be NOTHING between the major columns the plane took out and those windows facing the video camera.
If any quantity of aluminum ignited during the time it took out those columns it WOULD HAVE BEEN VISIBLE.
It wasn't.
Arthur
QUOTE (adoucette+Jul 20 2007, 04:55 AM)
Hi RC
But you can't get these mass transfer reactions to proceed that quickly.
And even if Al is more reactive than Jet A, that doesn't mean that all Al reacts first, its only when the two are competing for the same molecule that reactiveness need be considered. All in all, probably a non-issue.
Again remember that not ALL of the 7,000 lbs of O2 on a floor is going to be involved in any of this (it happens to fast, and in WTC 2, most of these reactions occur on just one side of the building)
Now for every 1,000 lbs of Jet A that burns, 2,800 lbs of O2 are required.
This will result in ~ 2,000 lbs of CO2 and only 800 lbs of H20 (less O2 is used up as more CO is formed, but then much less energy is released).
While some of that H20 might recycle, I doubt you will get much of the CO2 (or CO to recycle, the energy levels would drop too quickly.
Again, we can speculate all we want on the POSSIBILITY of some small quantity of these reactions occuring, there certainly were enough variables for most anything to occur, but there is NO EVIDENCE that any significant quantity of Aluminum burned in the towers.
Chainsaw:
They are QUICK, but NOT instantaneous, the fact is for ANY of these reactions to take place the specific materials have to come together, that limits the reaction rates.
The reason I picked that video is because you see it from the side of the core that the plane hit on.
There would be NOTHING between the major columns the plane took out and those windows facing the video camera.
If any quantity of aluminum ignited during the time it took out those columns it WOULD HAVE BEEN VISIBLE.
It wasn't.
Arthur
Yeah, I see what you're getting at about the actual open area ignition/reaction of aluminium. That's between you and Chainsaw, I think.
The aspect interesting me is what is happening in the hidden cracks/ducts and connectors/bolt/weld points in the building structure out of direct view.
And like you said, it would take a couple of seconds for BOTH the jet kero and the reactive metals to ignite and chain up to vastly visible proportions.
That is the point, I think.
The delay you mention would mean that the actual main ignition/reaction 'en masse' would occur after enough of the plane shreds and kero fuel were sufficiently particulated/atomised and mixed so as to BEGIN the fireball....which would then produce all the effects and dynamics (both thermo and physical) that would distribute those materials/reactions/effects within the vast interior TURBULENTLY and forcefully for the rest of the train of corrosive/catalytic processes to occur.
And as to oxygen supply per se.
It must be remembered that the fuel fireball then created an expansion of the interior air/gas volume which when 'spent' would have left a lower pressure area that would have drawn in the air from the surroundings in addition to the 'stack effect from the multi-floor immediate inferno.
But again, all that is details. Only a very close analysis of possible events will get anywhere near answering the 'places/extent' to which any of these things might or might have not done any effective, if marginal, damage. And of course, it bears repeating that the collapses were inevitable given the plane impact damage and all the kero and office fuel fires.
I know what you mean about the main impact. But these other things may have occurred very soon after, and for some minutes until all the 'reactants' eventually went to neutralisation states.
Hehehe. If nothing else, Chainsaw's and NF's researches have been a salutary eyeopener about what can happen in such vast acreages full of so many massive and varied reactants.
Don't do this at home! hehehe.
Cheers!
RC.
.
But you can't get these mass transfer reactions to proceed that quickly.
And even if Al is more reactive than Jet A, that doesn't mean that all Al reacts first, its only when the two are competing for the same molecule that reactiveness need be considered. All in all, probably a non-issue.
Again remember that not ALL of the 7,000 lbs of O2 on a floor is going to be involved in any of this (it happens to fast, and in WTC 2, most of these reactions occur on just one side of the building)
Now for every 1,000 lbs of Jet A that burns, 2,800 lbs of O2 are required.
This will result in ~ 2,000 lbs of CO2 and only 800 lbs of H20 (less O2 is used up as more CO is formed, but then much less energy is released).
While some of that H20 might recycle, I doubt you will get much of the CO2 (or CO to recycle, the energy levels would drop too quickly.
Again, we can speculate all we want on the POSSIBILITY of some small quantity of these reactions occuring, there certainly were enough variables for most anything to occur, but there is NO EVIDENCE that any significant quantity of Aluminum burned in the towers.
Chainsaw:
They are QUICK, but NOT instantaneous, the fact is for ANY of these reactions to take place the specific materials have to come together, that limits the reaction rates.
The reason I picked that video is because you see it from the side of the core that the plane hit on.
There would be NOTHING between the major columns the plane took out and those windows facing the video camera.
If any quantity of aluminum ignited during the time it took out those columns it WOULD HAVE BEEN VISIBLE.
It wasn't.
Arthur
Yeah, I see what you're getting at about the actual open area ignition/reaction of aluminium. That's between you and Chainsaw, I think.
The aspect interesting me is what is happening in the hidden cracks/ducts and connectors/bolt/weld points in the building structure out of direct view.
And like you said, it would take a couple of seconds for BOTH the jet kero and the reactive metals to ignite and chain up to vastly visible proportions.
That is the point, I think.
The delay you mention would mean that the actual main ignition/reaction 'en masse' would occur after enough of the plane shreds and kero fuel were sufficiently particulated/atomised and mixed so as to BEGIN the fireball....which would then produce all the effects and dynamics (both thermo and physical) that would distribute those materials/reactions/effects within the vast interior TURBULENTLY and forcefully for the rest of the train of corrosive/catalytic processes to occur.
And as to oxygen supply per se.
It must be remembered that the fuel fireball then created an expansion of the interior air/gas volume which when 'spent' would have left a lower pressure area that would have drawn in the air from the surroundings in addition to the 'stack effect from the multi-floor immediate inferno.
But again, all that is details. Only a very close analysis of possible events will get anywhere near answering the 'places/extent' to which any of these things might or might have not done any effective, if marginal, damage. And of course, it bears repeating that the collapses were inevitable given the plane impact damage and all the kero and office fuel fires.
I know what you mean about the main impact. But these other things may have occurred very soon after, and for some minutes until all the 'reactants' eventually went to neutralisation states.
Hehehe. If nothing else, Chainsaw's and NF's researches have been a salutary eyeopener about what can happen in such vast acreages full of so many massive and varied reactants.
Don't do this at home! hehehe.
Cheers!
RC.
.
QUOTE (RealityCheck+Jul 20 2007, 12:51 PM)
But please try to see what I and others are getting at:
-. None of these things tou mention are anywhere near the VAST and WIDESPREAD all-at once fires over multilevel 'stack' conditions and mix of materials.
-. None of these involved a TALL building the size of WTC1/2.
-. None of these involve widespread all-at-once fireproofing removal and total neautralising of active firefighting systems/firemen.
-. None of these involve the quantities and SCALE-EFFECTS of the processes.
-. None of these had the PLANE and OFFICE fuels/materials SHREDDED and piled up and blasted up/down shafts (and into critical crevices/boltholes that were CUT and otherwise ALREADY compromised by the plane impact-expolosion) as in 9/11.
I'm gonna address these point by point:
"None of these things tou mention are anywhere near the VAST and WIDESPREAD all-at once fires over multilevel 'stack' conditions and mix of materials."
This may (or may not) be true, I don't know, I haven't exactly found the motivation to go digging through the inernet, but, there have been fires with aspects that are comparable or identical to of the WTC fires.
There have been Fires involving 6-15 story buildings.
There have (I believe) been fires in buildings with floor plans and square footage comparable to the WTC fires.
"None of these involved a TALL building the size of WTC1/2."
The height of the WTC is irrelevant. You know something about the composition of the air 415m above sea level that nobody else does?
"None of these involve widespread all-at-once fireproofing removal and total neautralising of active firefighting systems/firemen."
There have been office or warehouse fires with wide spread ignition over comparable temporal periods (I gave one method this could happen).
"None of these involve the quantities and SCALE-EFFECTS of the processes."
Untrue, see above points.
"None of these had the PLANE and OFFICE fuels/materials SHREDDED and piled up and blasted up/down shafts (and into critical crevices/boltholes that were CUT and otherwise ALREADY compromised by the plane impact-expolosion) as in 9/11."
Not neccessarily accurate, I'm sure a C-130 crashing into an 8 story apartment block, or the Concorde SST crashing into an apartment block is comparable in many respects - just two examples I can offer.
One of the points that I have tried to make is that some of what you're talking about is not without precedent - take for example the reputation that the particular style of trussing they used in the WTC has a reputation as being a death trap, because it was well known by the NY fire brigade that during the course of a normal office fire they would bow and collapse. As I understand it, this is one of the reasons that particular style of flooring was stopped being used.
My point is that NONE of this information can be simply disregarded, and all of it should be used as a guideline to work out how likely reactions are.
-. None of these things tou mention are anywhere near the VAST and WIDESPREAD all-at once fires over multilevel 'stack' conditions and mix of materials.
-. None of these involved a TALL building the size of WTC1/2.
-. None of these involve widespread all-at-once fireproofing removal and total neautralising of active firefighting systems/firemen.
-. None of these involve the quantities and SCALE-EFFECTS of the processes.
-. None of these had the PLANE and OFFICE fuels/materials SHREDDED and piled up and blasted up/down shafts (and into critical crevices/boltholes that were CUT and otherwise ALREADY compromised by the plane impact-expolosion) as in 9/11.
I'm gonna address these point by point:
"None of these things tou mention are anywhere near the VAST and WIDESPREAD all-at once fires over multilevel 'stack' conditions and mix of materials."
This may (or may not) be true, I don't know, I haven't exactly found the motivation to go digging through the inernet, but, there have been fires with aspects that are comparable or identical to of the WTC fires.
There have been Fires involving 6-15 story buildings.
There have (I believe) been fires in buildings with floor plans and square footage comparable to the WTC fires.
"None of these involved a TALL building the size of WTC1/2."
The height of the WTC is irrelevant. You know something about the composition of the air 415m above sea level that nobody else does?
"None of these involve widespread all-at-once fireproofing removal and total neautralising of active firefighting systems/firemen."
There have been office or warehouse fires with wide spread ignition over comparable temporal periods (I gave one method this could happen).
"None of these involve the quantities and SCALE-EFFECTS of the processes."
Untrue, see above points.
"None of these had the PLANE and OFFICE fuels/materials SHREDDED and piled up and blasted up/down shafts (and into critical crevices/boltholes that were CUT and otherwise ALREADY compromised by the plane impact-expolosion) as in 9/11."
Not neccessarily accurate, I'm sure a C-130 crashing into an 8 story apartment block, or the Concorde SST crashing into an apartment block is comparable in many respects - just two examples I can offer.
One of the points that I have tried to make is that some of what you're talking about is not without precedent - take for example the reputation that the particular style of trussing they used in the WTC has a reputation as being a death trap, because it was well known by the NY fire brigade that during the course of a normal office fire they would bow and collapse. As I understand it, this is one of the reasons that particular style of flooring was stopped being used.
My point is that NONE of this information can be simply disregarded, and all of it should be used as a guideline to work out how likely reactions are.
QUOTE (RealityCheck+Jul 20 2007, 12:51 PM)
There was nothing in that except the pointing out of the OTHER WAYS TO IGNITE ALUMINIUM that has been pre-shredded and pre-heated/molten, and otherwise READY (even WELL below melting point) to reacrt with Silicates (glass) and other catalysing/accelerating/compromising materials/processes.
Take a moment to look up what Ionization Energy means, and you'll realize that from the point of view of a physical chemist, this statement is kind of silly.
It DOESN'T MATTER how you do it, it still takes 5138.8 kJ/Mol to remove those three electrons from Elemental Aluminium, which is what we're dealing with. This is NOT something that can be gotten around by finding some other way of igniting Aluminium, this is one of those fundamental things that boils down, more or less to atomic structure. The fact that it has been pre-heated, pre-shredded, pre basted, or pre whatever is completely irrelevant. The only use any of the above would do is heating it, and all that does is provide it with some of the energy required to remove those electrons.
Not exactly true, 1st: 577.5 kJ·mol−1
2nd: 1816.7 kJ·mol−1
3rd: 2744.8 kJ·mol−1
The reaction of the first electron releases energy, the second reaction is theirfore more likely, the third reactions likelyhood is increased by the energy released by the second electron.
Your dealing with total Ionization energy what I have found is aluminum is so reactive it, because one reaction state releases energy that continues likelyhood of the next electrons state.
If what your saying were true then magnesium would not burn in simular fires.
1st: 737.7 kJ·mol−1
2nd: 1450.7 kJ·mol−1
3rd: 7732.7 kJ·mol−1
As you have said there is not getting around Quantum mechanics so you have some explaining of how magnesium does it.
Also what about Carbon?
1st: 1086.5 kJ·mol−1
2nd: 2352.6 kJ·mol−1
3rd: 4620.5 kJ·mol−1
So carbon was not buring in the fire because the ionization energy totals are higher than for Aluminum My god it is and inside job where did those 8000Gj come from.
This is one point I aready raised with Dr. Jones I believe he used the same arguement you have.
Please Trippy go back and read old threads on this.
Aluminums reactivity is directly based on the oxidants present and the energy to disrupt the Crystaline structure of the oxide layer.
Aluminum is so reactive that it forms an oxide layer over itself even while flowing Almost instantly. That oxide layer helps protect the Aluminum from combustion.
The strong reducing environment is what I am counting on, I understand that but it is really a matter of the individual reactions in the environments not an overall single condition that is an over simplification of the issue.
I enjoy your imput Trippy I need people like you and Arthur, Rc, and Frank to keep me strait and point out my mistakes and I do make a lot of mistakes.
Oh god.
This is turning into a chemistry lecture.
You're completely wrong in many of your suppositions, and you can't even see it.
But you have been to wikipedia, but apparently not understood what you have read.
Two examples:
1. Carbon doesn't ionize when it reacts. If you had understood what you were reading, you would have realized this, thus that part of your argument is completely irrelevant (this of course is ignoring Carbanions and carbocations which are beyond the depth of this discussion.
2. As I have already said. It's irrelevant where the energy comes from, it still takes that amount of energy to remove all three electrons. THIS is the point that I was trying to make, and that you've gotten side tracked from.
I'll post some more shortly.
*EDIT:
The main thrust of the point that I have been trying to make is that the reactivity of Aluminium is not as strongly dependent on the Oxide layer as some of the posts in this thread seem to be representing it as. Yes, it is an influence, but it is not the only influence to consider, THIS is the point that I have been trying to make.
Dampers won't affect the period of the oscillation, they only act to attenuate the oscillation (so it dies down quicker and won't build up like the Tacoma bridge did).
If the primary period is 11.4 seconds, that's the primary period, period.
I would also be interested in seeing what happens when a transverse-mode shockwave propagates down to the foundation level. In theory, a large fraction of the energy of the aircraft's impact would either be transmitted into the foundation (which, due to a huge impedance mismatch, isn't where most of the energy goes) or it'd have to be reflected back up the tower, making it ring like a bell (which wasn't observed) or the energy coupled to the concrete/steel interface, rupturing the concrete and shearing the steel (which seems likeliest to me). That would cause significant damage to the basement, which would explain a lot of the anecdotal reports of same that the CDiots seem to prove their case.
My point is that most of this absorbed kinetic energy would've gotten transmitted to the base of the tower, and would've done extensive damage when it got there due to the sudden impedance mismatch.
My point is that most of this absorbed kinetic energy would've gotten transmitted to the base of the tower, and would've done extensive damage when it got there due to the sudden impedance mismatch.
The Pallisades Seismograph record might be able to give you some usefull information about that. If IIRC, what you're talking about might have registered, not sure though, it depends on the modes of the energy, and how efficiently it was transfered into the surrounding strata.
The key point here is that steel is flexible, and concrete isn't. Where steel gets imbedded in concrete, you have a problem if the steel has an energetic transverse shockwave travelling through it. The concrete will tend to pulverize. Depending on the specifics of the design, this could've led to signficant destruction at the base of the towers immediately following the impact of the plane(s).
The key point here is that steel is flexible, and concrete isn't. Where steel gets imbedded in concrete, you have a problem if the steel has an energetic transverse shockwave travelling through it. The concrete will tend to pulverize. Depending on the specifics of the design, this could've led to signficant destruction at the base of the towers immediately following the impact of the plane(s).
Yes, but compressive shockwaves are more efficiently transferred from the super structure, to the bedrock, thus more likely to be detected, which is the point that I was trying to make.
Anyway, the one estimate I have seen for the spring constant for the section below the impact zone (not sure if its WTC 1 or 2) is 71 GN/m.
I am looking for a reference for this....
71 GN/m was stated in the BZ paper.
If my understanding of the mechanism of the collapse is correct, you should *expect* most of the material to land in the building's footprint.
On a floor-by-floor basis, I'd expect that the perimeter columns would flex outward after the floor-perimeter-column brackets fail, making the outer perimeter columns act like a funnel.
The breaking perimeter-floor brackets release the floors from the outside first, causing them to drape towards the core columns initially, until those core-floor brackets themselves fail, providing a "pull" on the floors towards the center of the buildings.
One could see that those two effects, combined, would turn the collapsing tower(s) into a funnel that directs the bulk of the debris down the middle of the tower, with the funnel itself disintegrating after it's no longer in-play.
Take a moment to look up what Ionization Energy means, and you'll realize that from the point of view of a physical chemist, this statement is kind of silly.
It DOESN'T MATTER how you do it, it still takes 5138.8 kJ/Mol to remove those three electrons from Elemental Aluminium, which is what we're dealing with. This is NOT something that can be gotten around by finding some other way of igniting Aluminium, this is one of those fundamental things that boils down, more or less to atomic structure. The fact that it has been pre-heated, pre-shredded, pre basted, or pre whatever is completely irrelevant. The only use any of the above would do is heating it, and all that does is provide it with some of the energy required to remove those electrons.
QUOTE (RealityCheck+Jul 20 2007, 12:51 PM)
Anyway, ask adoucette to tell you how MUCH evidence presented in pastb threads by himself, myself and others has PROVED that 1000+C is VERY usual in even 'normal' office/building fires, let alone in the towers on 9/11.
Perhaps as peek temperatures, or ceiling temperatures, or core temperatures, or even localized temperatures, all of which are gass temperatures to boot, but, as I think you pointed out, irrespective of cracks in the concrete, Concrete is an excellent insulator, which means it doesn't get very hot very easily, and it doesn't change the fact that as I understand it, no evidence was found for (average/wide spread) temps above 550-650°C
I'm sure there was otherstuff, and i'm probably going to make another couple of posts.
Perhaps as peek temperatures, or ceiling temperatures, or core temperatures, or even localized temperatures, all of which are gass temperatures to boot, but, as I think you pointed out, irrespective of cracks in the concrete, Concrete is an excellent insulator, which means it doesn't get very hot very easily, and it doesn't change the fact that as I understand it, no evidence was found for (average/wide spread) temps above 550-650°C
I'm sure there was otherstuff, and i'm probably going to make another couple of posts.
QUOTE (Chainsaw+,Jul 20 2007, 03:50 PM)
oxidize more than 20,000 lbs of aluminum, but CLEARLY a LOT of the Oxygen wasn't consuI explained that, the expanding fire ball can obscure and swamp the white light.
Actually, 7,000 lbs of Oxygen can consume 7,800 lbs of Aluminium, so Arthurs estimate is pretty much bang on (23,600 lbs), and this represents just 12% of the mass of Aluminium available for consumption, which falls well short of the '1/5th' you mentioned earlier.
Incidentaly this is ONE Of the reasons why I mentioned a while ago that the conditions in the fire would have been strongly reducing - this also affects what reactions will and wont take place, and is yet another reason why I say that some of what's being talked about is wrong.
*Edit
For example:
In a reducing environment the reactions:
Fe203 + 3CO -> 2Fe + 3CO2 and
Fe2O3 + 3C -> 2Fe + 3CO
Become more likely (I'm using this as an example because it's the easiest I can think of to follow). Comparable reaction exist for all metal oxides - you can refine Lead oxide into lead using a block of charred wood and a blow torch.
Actually, 7,000 lbs of Oxygen can consume 7,800 lbs of Aluminium, so Arthurs estimate is pretty much bang on (23,600 lbs), and this represents just 12% of the mass of Aluminium available for consumption, which falls well short of the '1/5th' you mentioned earlier.
Incidentaly this is ONE Of the reasons why I mentioned a while ago that the conditions in the fire would have been strongly reducing - this also affects what reactions will and wont take place, and is yet another reason why I say that some of what's being talked about is wrong.
*Edit
For example:
In a reducing environment the reactions:
Fe203 + 3CO -> 2Fe + 3CO2 and
Fe2O3 + 3C -> 2Fe + 3CO
Become more likely (I'm using this as an example because it's the easiest I can think of to follow). Comparable reaction exist for all metal oxides - you can refine Lead oxide into lead using a block of charred wood and a blow torch.
Quote: you can refine Lead oxide into lead using a block of charred wood and a blow torch.
However open the widows in your joint because lead fumes owfen dumb down peoples brain functions permantly.
However open the widows in your joint because lead fumes owfen dumb down peoples brain functions permantly.
RC:
The other thing that you don't seem to realize is that you're effectively shooting yourself in the foot, and chainsaw, among others, do you know why?
You mentioned the thing about WTC 7 coming up in the near future.
Tell me RC, here's a little scenario for you to think about.
We have two chainsaws. Chainsaw 1, and Chainsaw 2.
Chainsaw 1 chooses to listen to what you say, assumes that the WTC fire was wholly unlike any other fire ever, goes to the commision, and presents a bunch of flawed, or potentially flawed experimental evidence to the commission.
Or.
Chainsaw 2 who chooses to listen to what I (or others) say, sorts out the bugs in their experiments, and constrains some variables, but equally important does some research into some of the kinds of fires that i've been talking about and saying that WTC is similar to, and presents not only experimental evidence but cited literature providing precedents, and verifying that this chemistry is likely to have occured in the way being described.
I know which I'D rather be.
The other thing that you don't seem to realize is that you're effectively shooting yourself in the foot, and chainsaw, among others, do you know why?
You mentioned the thing about WTC 7 coming up in the near future.
Tell me RC, here's a little scenario for you to think about.
We have two chainsaws. Chainsaw 1, and Chainsaw 2.
Chainsaw 1 chooses to listen to what you say, assumes that the WTC fire was wholly unlike any other fire ever, goes to the commision, and presents a bunch of flawed, or potentially flawed experimental evidence to the commission.
Or.
Chainsaw 2 who chooses to listen to what I (or others) say, sorts out the bugs in their experiments, and constrains some variables, but equally important does some research into some of the kinds of fires that i've been talking about and saying that WTC is similar to, and presents not only experimental evidence but cited literature providing precedents, and verifying that this chemistry is likely to have occured in the way being described.
I know which I'D rather be.
QUOTE (Trippy+Jul 20 2007, 07:44 AM)
RC:
The other thing that you don't seem to realize is that you're effectively shooting yourself in the foot, and chainsaw, among others, do you know why?
You mentioned the thing about WTC 7 coming up in the near future.
Tell me RC, here's a little scenario for you to think about.
We have two chainsaws. Chainsaw 1, and Chainsaw 2.
Chainsaw 1 chooses to listen to what you say, assumes that the WTC fire was wholly unlike any other fire ever, goes to the commision, and presents a bunch of flawed, or potentially flawed experimental evidence to the commission.
Or.
Chainsaw 2 who chooses to listen to what I (or others) say, sorts out the bugs in their experiments, and constrains some variables, but equally important does some research into some of the kinds of fires that i've been talking about and saying that WTC is similar to, and presents not only experimental evidence but cited literature providing precedents, and verifying that this chemistry is likely to have occured in the way being described.
I know which I'D rather be.
Trippy
I have looked into fires that are similar to the world trade center and did find evidence of these reactions on a smaller scale in air craft fires, Into buildings but no aircraft fire into a building has been of this magnitude, the C130 crashed into a concrete apartment building, the concord hit mostly houses.
Both incidents were not steel framed structures.
Trippy have you ever heard of Sono Chemistry?
The other thing that you don't seem to realize is that you're effectively shooting yourself in the foot, and chainsaw, among others, do you know why?
You mentioned the thing about WTC 7 coming up in the near future.
Tell me RC, here's a little scenario for you to think about.
We have two chainsaws. Chainsaw 1, and Chainsaw 2.
Chainsaw 1 chooses to listen to what you say, assumes that the WTC fire was wholly unlike any other fire ever, goes to the commision, and presents a bunch of flawed, or potentially flawed experimental evidence to the commission.
Or.
Chainsaw 2 who chooses to listen to what I (or others) say, sorts out the bugs in their experiments, and constrains some variables, but equally important does some research into some of the kinds of fires that i've been talking about and saying that WTC is similar to, and presents not only experimental evidence but cited literature providing precedents, and verifying that this chemistry is likely to have occured in the way being described.
I know which I'D rather be.
Trippy
I have looked into fires that are similar to the world trade center and did find evidence of these reactions on a smaller scale in air craft fires, Into buildings but no aircraft fire into a building has been of this magnitude, the C130 crashed into a concrete apartment building, the concord hit mostly houses.
Both incidents were not steel framed structures.
Trippy have you ever heard of Sono Chemistry?
QUOTE (Trippy+Jul 20 2007, 06:09 AM)
I'm gonna address these point by point:
"None of these things tou mention are anywhere near the VAST and WIDESPREAD all-at once fires over multilevel 'stack' conditions and mix of materials."
This may (or may not) be true, I don't know, I haven't exactly found the motivation to go digging through the inernet, but, there have been fires with aspects that are comparable or identical to of the WTC fires.
There have been Fires involving 6-15 story buildings.
There have (I believe) been fires in buildings with floor plans and square footage comparable to the WTC fires.
"None of these involved a TALL building the size of WTC1/2."
The height of the WTC is irrelevant. You know something about the composition of the air 415m above sea level that nobody else does?
"None of these involve widespread all-at-once fireproofing removal and total neautralising of active firefighting systems/firemen."
There have been office or warehouse fires with wide spread ignition over comparable temporal periods (I gave one method this could happen).
"None of these involve the quantities and SCALE-EFFECTS of the processes."
Untrue, see above points.
"None of these had the PLANE and OFFICE fuels/materials SHREDDED and piled up and blasted up/down shafts (and into critical crevices/boltholes that were CUT and otherwise ALREADY compromised by the plane impact-expolosion) as in 9/11."
Not neccessarily accurate, I'm sure a C-130 crashing into an 8 story apartment block, or the Concorde SST crashing into an apartment block is comparable in many respects - just two examples I can offer.
One of the points that I have tried to make is that some of what you're talking about is not without precedent - take for example the reputation that the particular style of trussing they used in the WTC has a reputation as being a death trap, because it was well known by the NY fire brigade that during the course of a normal office fire they would bow and collapse. As I understand it, this is one of the reasons that particular style of flooring was stopped being used.
My point is that NONE of this information can be simply disregarded, and all of it should be used as a guideline to work out how likely reactions are.
Take a moment to look up what Ionization Energy means, and you'll realize that from the point of view of a physical chemist, this statement is kind of silly.
It DOESN'T MATTER how you do it, it still takes 5138.8 kJ/Mol to remove those three electrons from Elemental Aluminium, which is what we're dealing with. This is NOT something that can be gotten around by finding some other way of igniting Aluminium, this is one of those fundamental things that boils down, more or less to atomic structure. The fact that it has been pre-heated, pre-shredded, pre basted, or pre whatever is completely irrelevant. The only use any of the above would do is heating it, and all that does is provide it with some of the energy required to remove those electrons.
Perhaps as peek temperatures, or ceiling temperatures, or core temperatures, or even localized temperatures, all of which are gass temperatures to boot, but, as I think you pointed out, irrespective of cracks in the concrete, Concrete is an excellent insulator, which means it doesn't get very hot very easily, and it doesn't change the fact that as I understand it, no evidence was found for (average/wide spread) temps above 550-650°C
I'm sure there was otherstuff, and i'm probably going to make another couple of posts.
Not exactly true, 1st: 577.5 kJ·mol−1
2nd: 1816.7 kJ·mol−1
3rd: 2744.8 kJ·mol−1
The reaction of the first electron releases energy, the second reaction is theirfore more likely, the third reactions likelyhood is increased by the energy released by the second electron.
Your dealing with total Ionization energy what I have found is aluminum is so reactive it, because one reaction state releases energy that continues likelyhood of the next electrons state.
If what your saying were true then magnesium would not burn in simular fires.
1st: 737.7 kJ·mol−1
2nd: 1450.7 kJ·mol−1
3rd: 7732.7 kJ·mol−1
As you have said there is not getting around Quantum mechanics so you have some explaining of how magnesium does it.
Also what about Carbon?
1st: 1086.5 kJ·mol−1
2nd: 2352.6 kJ·mol−1
3rd: 4620.5 kJ·mol−1
So carbon was not buring in the fire because the ionization energy totals are higher than for Aluminum My god it is and inside job where did those 8000Gj come from.
This is one point I aready raised with Dr. Jones I believe he used the same arguement you have.
Please Trippy go back and read old threads on this.
Aluminums reactivity is directly based on the oxidants present and the energy to disrupt the Crystaline structure of the oxide layer.
Aluminum is so reactive that it forms an oxide layer over itself even while flowing Almost instantly. That oxide layer helps protect the Aluminum from combustion.
The strong reducing environment is what I am counting on, I understand that but it is really a matter of the individual reactions in the environments not an overall single condition that is an over simplification of the issue.
I enjoy your imput Trippy I need people like you and Arthur, Rc, and Frank to keep me strait and point out my mistakes and I do make a lot of mistakes.
"None of these things tou mention are anywhere near the VAST and WIDESPREAD all-at once fires over multilevel 'stack' conditions and mix of materials."
This may (or may not) be true, I don't know, I haven't exactly found the motivation to go digging through the inernet, but, there have been fires with aspects that are comparable or identical to of the WTC fires.
There have been Fires involving 6-15 story buildings.
There have (I believe) been fires in buildings with floor plans and square footage comparable to the WTC fires.
"None of these involved a TALL building the size of WTC1/2."
The height of the WTC is irrelevant. You know something about the composition of the air 415m above sea level that nobody else does?
"None of these involve widespread all-at-once fireproofing removal and total neautralising of active firefighting systems/firemen."
There have been office or warehouse fires with wide spread ignition over comparable temporal periods (I gave one method this could happen).
"None of these involve the quantities and SCALE-EFFECTS of the processes."
Untrue, see above points.
"None of these had the PLANE and OFFICE fuels/materials SHREDDED and piled up and blasted up/down shafts (and into critical crevices/boltholes that were CUT and otherwise ALREADY compromised by the plane impact-expolosion) as in 9/11."
Not neccessarily accurate, I'm sure a C-130 crashing into an 8 story apartment block, or the Concorde SST crashing into an apartment block is comparable in many respects - just two examples I can offer.
One of the points that I have tried to make is that some of what you're talking about is not without precedent - take for example the reputation that the particular style of trussing they used in the WTC has a reputation as being a death trap, because it was well known by the NY fire brigade that during the course of a normal office fire they would bow and collapse. As I understand it, this is one of the reasons that particular style of flooring was stopped being used.
My point is that NONE of this information can be simply disregarded, and all of it should be used as a guideline to work out how likely reactions are.
Take a moment to look up what Ionization Energy means, and you'll realize that from the point of view of a physical chemist, this statement is kind of silly.
It DOESN'T MATTER how you do it, it still takes 5138.8 kJ/Mol to remove those three electrons from Elemental Aluminium, which is what we're dealing with. This is NOT something that can be gotten around by finding some other way of igniting Aluminium, this is one of those fundamental things that boils down, more or less to atomic structure. The fact that it has been pre-heated, pre-shredded, pre basted, or pre whatever is completely irrelevant. The only use any of the above would do is heating it, and all that does is provide it with some of the energy required to remove those electrons.
Perhaps as peek temperatures, or ceiling temperatures, or core temperatures, or even localized temperatures, all of which are gass temperatures to boot, but, as I think you pointed out, irrespective of cracks in the concrete, Concrete is an excellent insulator, which means it doesn't get very hot very easily, and it doesn't change the fact that as I understand it, no evidence was found for (average/wide spread) temps above 550-650°C
I'm sure there was otherstuff, and i'm probably going to make another couple of posts.
QUOTE
It DOESN'T MATTER how you do it, it still takes 5138.8 kJ/Mol to remove those three electrons from Elemental Aluminium, which is what we're dealing with. This is NOT something that can be gotten around by finding some other way of igniting Aluminium, this is one of those fundamental things that boils down, more or less to atomic structure. The fact that it has been pre-heated, pre-shredded, pre basted, or pre whatever is completely irrelevant. The only use any of the above would do is heating it, and all that does is provide it with some of the energy required to remove those electrons.
Not exactly true, 1st: 577.5 kJ·mol−1
2nd: 1816.7 kJ·mol−1
3rd: 2744.8 kJ·mol−1
The reaction of the first electron releases energy, the second reaction is theirfore more likely, the third reactions likelyhood is increased by the energy released by the second electron.
Your dealing with total Ionization energy what I have found is aluminum is so reactive it, because one reaction state releases energy that continues likelyhood of the next electrons state.
If what your saying were true then magnesium would not burn in simular fires.
1st: 737.7 kJ·mol−1
2nd: 1450.7 kJ·mol−1
3rd: 7732.7 kJ·mol−1
As you have said there is not getting around Quantum mechanics so you have some explaining of how magnesium does it.
Also what about Carbon?
1st: 1086.5 kJ·mol−1
2nd: 2352.6 kJ·mol−1
3rd: 4620.5 kJ·mol−1
So carbon was not buring in the fire because the ionization energy totals are higher than for Aluminum My god it is and inside job where did those 8000Gj come from.
This is one point I aready raised with Dr. Jones I believe he used the same arguement you have.
Please Trippy go back and read old threads on this.
Aluminums reactivity is directly based on the oxidants present and the energy to disrupt the Crystaline structure of the oxide layer.
Aluminum is so reactive that it forms an oxide layer over itself even while flowing Almost instantly. That oxide layer helps protect the Aluminum from combustion.
The strong reducing environment is what I am counting on, I understand that but it is really a matter of the individual reactions in the environments not an overall single condition that is an over simplification of the issue.
I enjoy your imput Trippy I need people like you and Arthur, Rc, and Frank to keep me strait and point out my mistakes and I do make a lot of mistakes.
QUOTE (Chainsaw,+Jul 20 2007, 10:45 AM)
Not exactly true, 1st: 577.5 kJ·mol−1
2nd: 1816.7 kJ·mol−1
3rd: 2744.8 kJ·mol−1
The reaction of the first electron releases energy, the second reaction is theirfore more likely, the third reactions likelyhood is increased by the energy released by the second electron.
Your dealing with total Ionization energy what I have found is aluminum is so reactive it, because one reaction state releases energy that continues likelyhood of the next electrons state.
If what your saying were true then magnesium would not burn in simular fires.
1st: 737.7 kJ·mol−1
2nd: 1450.7 kJ·mol−1
3rd: 7732.7 kJ·mol−1
As you have said there is not getting around Quantum mechanics so you have some explaining of how magnesium does it.
Also what about Carbon?
1st: 1086.5 kJ·mol−1
2nd: 2352.6 kJ·mol−1
3rd: 4620.5 kJ·mol−1
So carbon was not buring in the fire because the ionization energy totals are higher than for Aluminum My god it is and inside job where did those 8000Gj come from.
couple of points, (from someone whose chemistry is a tad rusty)
The third electron in Mg typically doesn't get to play outside with his more distant cousins.
The removal of the two outer electons leaves the next inner shell filled.
Which is why the energy level jumps 5X to get the next electron away.
(Atoms like to attain a noble gas configuration)
But that energy level is higher than any chemical reaction can provide so you won't find Mg3+ ions running around.
The two Mg electrons though have lower overall potential than the two Al electrons, and unlike Mg the third Al electron can and does play, but ONLY with a LARGE energy input.
As to the Carbon issue, I believe you are mistaking the combustion of HYDROCARBONS with the Ionization of ELEMENTS.
The ionization energy of Carbon was overcome when the various Carbon compounds were originally created, while when talking ionization energies we are dealing with elements.
Arthur
2nd: 1816.7 kJ·mol−1
3rd: 2744.8 kJ·mol−1
The reaction of the first electron releases energy, the second reaction is theirfore more likely, the third reactions likelyhood is increased by the energy released by the second electron.
Your dealing with total Ionization energy what I have found is aluminum is so reactive it, because one reaction state releases energy that continues likelyhood of the next electrons state.
If what your saying were true then magnesium would not burn in simular fires.
1st: 737.7 kJ·mol−1
2nd: 1450.7 kJ·mol−1
3rd: 7732.7 kJ·mol−1
As you have said there is not getting around Quantum mechanics so you have some explaining of how magnesium does it.
Also what about Carbon?
1st: 1086.5 kJ·mol−1
2nd: 2352.6 kJ·mol−1
3rd: 4620.5 kJ·mol−1
So carbon was not buring in the fire because the ionization energy totals are higher than for Aluminum My god it is and inside job where did those 8000Gj come from.
couple of points, (from someone whose chemistry is a tad rusty)
The third electron in Mg typically doesn't get to play outside with his more distant cousins.
The removal of the two outer electons leaves the next inner shell filled.
Which is why the energy level jumps 5X to get the next electron away.
(Atoms like to attain a noble gas configuration)
But that energy level is higher than any chemical reaction can provide so you won't find Mg3+ ions running around.
The two Mg electrons though have lower overall potential than the two Al electrons, and unlike Mg the third Al electron can and does play, but ONLY with a LARGE energy input.
As to the Carbon issue, I believe you are mistaking the combustion of HYDROCARBONS with the Ionization of ELEMENTS.
The ionization energy of Carbon was overcome when the various Carbon compounds were originally created, while when talking ionization energies we are dealing with elements.
Arthur
Terminology correction: The steel beam the length of a wing is the spar. The aluminum attached to it forms the ribs. The aluminum skin is attached by rivets to the ribs.
There are thousands of rivets. I would expect a great many of these to come loose to form small projectiles. Suitable for removing fireproofing, IMHO.
There are thousands of rivets. I would expect a great many of these to come loose to form small projectiles. Suitable for removing fireproofing, IMHO.
QUOTE (David B. Benson+Jul 20 2007, 02:34 PM)
Terminology correction: The steel beam the length of a wing is the spar. The aluminum attached to it forms the ribs. The aluminum skin is attached by rivets to the ribs.
There are thousands of rivets. I would expect a great many of these to come loose to form small projectiles. Suitable for removing fireproofing, IMHO.
The 767 has TWO spars. A front Spar and A Rear Spar.
Spars run the width of the wing (SPAN)
Spars on 767s are Aluminum, not Steel.
Ribs run between the Front Spar and Rear Spar (Chord wise).
Stringers run Span wise over the ribs and the wing skin is riveted to the stringers, not the ribs.
The area in front of the front spar is the leading edge. In a 767 it is mostly made of composite material.
The area behind the rear spar is the trailing edge. In a 767 it is mostly made of composite material.
A good visual of this is in NIST NCSTAR 1-2b Fig 4-18 and Fig 4-20 pg 76-78
Arthur
.
There are thousands of rivets. I would expect a great many of these to come loose to form small projectiles. Suitable for removing fireproofing, IMHO.
The 767 has TWO spars. A front Spar and A Rear Spar.
Spars run the width of the wing (SPAN)
Spars on 767s are Aluminum, not Steel.
Ribs run between the Front Spar and Rear Spar (Chord wise).
Stringers run Span wise over the ribs and the wing skin is riveted to the stringers, not the ribs.
The area in front of the front spar is the leading edge. In a 767 it is mostly made of composite material.
The area behind the rear spar is the trailing edge. In a 767 it is mostly made of composite material.
A good visual of this is in NIST NCSTAR 1-2b Fig 4-18 and Fig 4-20 pg 76-78
Arthur
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QUOTE (adoucette+Jul 20 2007, 01:42 PM)
The 767 has TWO spars. A front Spar and A Rear Spar.
Thanks for the corrections. However, I'm having a hard time believing that the front spar was not made of steel. (Although my direct knowledge doesn't go past early model 747s.)
Thanks for the corrections. However, I'm having a hard time believing that the front spar was not made of steel. (Although my direct knowledge doesn't go past early model 747s.)
QUOTE (adoucette+Jul 20 2007, 05:25 PM)
couple of points, (from someone whose chemistry is a tad rusty)
The third electron in Mg typically doesn't get to play outside with his more distant cousins.
The removal of the two outer electons leaves the next inner shell filled.
Which is why the energy level jumps 5X to get the next electron away.
(Atoms like to attain a noble gas configuration)
But that energy level is higher than any chemical reaction can provide so you won't find Mg3+ ions running around.
The two Mg electrons though have lower overall potential than the two Al electrons, and unlike Mg the third Al electron can and does play, but ONLY with a LARGE energy input.
As to the Carbon issue, I believe you are mistaking the combustion of HYDROCARBONS with the Ionization of ELEMENTS.
The ionization energy of Carbon was overcome when the various Carbon compounds were originally created, while when talking ionization energies we are dealing with elements.
Arthur
As to the Carbon issue, I believe you are mistaking the combustion of HYDROCARBONS with the Ionization of ELEMENTS.
The ionization energy of Carbon was overcome when the various Carbon compounds were originally created, while when talking ionization energies we are dealing with elements.
I understand all that, that was kind of the point, question what bonds have to be broken for aluminum to oxidize?
It is also not that simple as I believe Neu will tell you other things are at play.
http://www.physorg.com/news98556080.html
It might even involve some stored energy, although I do not believe this is the case.
http://www.cbe.buffalo.edu/research_areas4.htm
It is a very complicated issue, it also has more to do with Metallic bonding that with Ionic bonding.
http://en.wikipedia.org/wiki/Metallic_bond
Take carbon for instance, it burns as Carbon black, as Graphite, and as Diamond, but the energy to break the bonds is different in each.
The third electron in Mg typically doesn't get to play outside with his more distant cousins.
The removal of the two outer electons leaves the next inner shell filled.
Which is why the energy level jumps 5X to get the next electron away.
(Atoms like to attain a noble gas configuration)
But that energy level is higher than any chemical reaction can provide so you won't find Mg3+ ions running around.
The two Mg electrons though have lower overall potential than the two Al electrons, and unlike Mg the third Al electron can and does play, but ONLY with a LARGE energy input.
As to the Carbon issue, I believe you are mistaking the combustion of HYDROCARBONS with the Ionization of ELEMENTS.
The ionization energy of Carbon was overcome when the various Carbon compounds were originally created, while when talking ionization energies we are dealing with elements.
Arthur
As to the Carbon issue, I believe you are mistaking the combustion of HYDROCARBONS with the Ionization of ELEMENTS.
The ionization energy of Carbon was overcome when the various Carbon compounds were originally created, while when talking ionization energies we are dealing with elements.
I understand all that, that was kind of the point, question what bonds have to be broken for aluminum to oxidize?
It is also not that simple as I believe Neu will tell you other things are at play.
http://www.physorg.com/news98556080.html
It might even involve some stored energy, although I do not believe this is the case.
http://www.cbe.buffalo.edu/research_areas4.htm
It is a very complicated issue, it also has more to do with Metallic bonding that with Ionic bonding.
http://en.wikipedia.org/wiki/Metallic_bond
Take carbon for instance, it burns as Carbon black, as Graphite, and as Diamond, but the energy to break the bonds is different in each.
Its aluminum.
Here's a pic of the front spar
http://www.boeing.com/news/releases/1999/p...ase/990209b.jpg
Arthur
Here's a pic of the front spar
http://www.boeing.com/news/releases/1999/p...ase/990209b.jpg
Arthur
QUOTE (David B. Benson+Jul 19 2007, 11:26 PM)
Thank you. I did not completely follow what I read in NCSTAR1--2A regarding the loadings on the mechanical floors. And worse, I couldn't determine whether the mechanical floors in-service live loads were actually much less than the maximum live load. (Not really understanding why there is such a big difference between in-service live loads and maximum live loads for ordinary office floors...)
We had quite a discussion about this one over at JREF. There are a couple of sources that have done statistical analysis based on sampling office buildings. NIST cites Culver 1976. I found another article from the 80's. It turns out the in-service live loads are on average less than 25% of design loads. This make sense because the whole floor must be able to hande a "crowding" condition but these are temporary phenomena.
We had quite a discussion about this one over at JREF. There are a couple of sources that have done statistical analysis based on sampling office buildings. NIST cites Culver 1976. I found another article from the 80's. It turns out the in-service live loads are on average less than 25% of design loads. This make sense because the whole floor must be able to hande a "crowding" condition but these are temporary phenomena.
QUOTE (Hambone+Jul 20 2007, 05:14 PM)
... the whole floor must be able to hande[sic] a "crowding" condition but these are temporary phenomena.
Aha!
But maybe not so on the mechanical floors?
Aha!
But maybe not so on the mechanical floors?
QUOTE (Chainsaw+,Jul 21 2007, 02:45 AM)
Not exactly true, 1st: 577.5 kJ·mol−1
2nd: 1816.7 kJ·mol−1
3rd: 2744.8 kJ·mol−1
The reaction of the first electron releases energy, the second reaction is theirfore more likely, the third reactions likelyhood is increased by the energy released by the second electron.
Your dealing with total Ionization energy what I have found is aluminum is so reactive it, because one reaction state releases energy that continues likelyhood of the next electrons state.
If what your saying were true then magnesium would not burn in simular fires.
1st: 737.7 kJ·mol−1
2nd: 1450.7 kJ·mol−1
3rd: 7732.7 kJ·mol−1
As you have said there is not getting around Quantum mechanics so you have some explaining of how magnesium does it.
Also what about Carbon?
1st: 1086.5 kJ·mol−1
2nd: 2352.6 kJ·mol−1
3rd: 4620.5 kJ·mol−1
So carbon was not buring in the fire because the ionization energy totals are higher than for Aluminum My god it is and inside job where did those 8000Gj come from.
This is one point I aready raised with Dr. Jones I believe he used the same arguement you have.
Please Trippy go back and read old threads on this.
Aluminums reactivity is directly based on the oxidants present and the energy to disrupt the Crystaline structure of the oxide layer.
Aluminum is so reactive that it forms an oxide layer over itself even while flowing Almost instantly. That oxide layer helps protect the Aluminum from combustion.
The strong reducing environment is what I am counting on, I understand that but it is really a matter of the individual reactions in the environments not an overall single condition that is an over simplification of the issue.
I enjoy your imput Trippy I need people like you and Arthur, Rc, and Frank to keep me strait and point out my mistakes and I do make a lot of mistakes.
Oh god.
This is turning into a chemistry lecture.
You're completely wrong in many of your suppositions, and you can't even see it.
But you have been to wikipedia, but apparently not understood what you have read.
Two examples:
1. Carbon doesn't ionize when it reacts. If you had understood what you were reading, you would have realized this, thus that part of your argument is completely irrelevant (this of course is ignoring Carbanions and carbocations which are beyond the depth of this discussion.
2. As I have already said. It's irrelevant where the energy comes from, it still takes that amount of energy to remove all three electrons. THIS is the point that I was trying to make, and that you've gotten side tracked from.
I'll post some more shortly.
*EDIT:
The main thrust of the point that I have been trying to make is that the reactivity of Aluminium is not as strongly dependent on the Oxide layer as some of the posts in this thread seem to be representing it as. Yes, it is an influence, but it is not the only influence to consider, THIS is the point that I have been trying to make.
QUOTE (adoucette+Jul 21 2007, 05:25 AM)
The third electron in Mg typically doesn't get to play outside with his more distant cousins.
The removal of the two outer electons leaves the next inner shell filled.
Which is why the energy level jumps 5X to get the next electron away.
(Atoms like to attain a noble gas configuration)
But that energy level is higher than any chemical reaction can provide so you won't find Mg3+ ions running around.
The two Mg electrons though have lower overall potential than the two Al electrons, and unlike Mg the third Al electron can and does play, but ONLY with a LARGE energy input.
As to the Carbon issue, I believe you are mistaking the combustion of HYDROCARBONS with the Ionization of ELEMENTS.
The ionization energy of Carbon was overcome when the various Carbon compounds were originally created, while when talking ionization energies we are dealing with elements.
This is all mostly true.
Elements also like configurations that are half, or one short (Oddly enough,a lthough the one short applies mostly from the third row down (inclusive)).
The removal of the two outer electons leaves the next inner shell filled.
Which is why the energy level jumps 5X to get the next electron away.
(Atoms like to attain a noble gas configuration)
But that energy level is higher than any chemical reaction can provide so you won't find Mg3+ ions running around.
The two Mg electrons though have lower overall potential than the two Al electrons, and unlike Mg the third Al electron can and does play, but ONLY with a LARGE energy input.
As to the Carbon issue, I believe you are mistaking the combustion of HYDROCARBONS with the Ionization of ELEMENTS.
The ionization energy of Carbon was overcome when the various Carbon compounds were originally created, while when talking ionization energies we are dealing with elements.
This is all mostly true.
Elements also like configurations that are half, or one short (Oddly enough,a lthough the one short applies mostly from the third row down (inclusive)).
QUOTE (Chainsaw,+Jul 21 2007, 09:30 AM)
Take carbon for instance, it burns as Carbon black, as Graphite, and as Diamond, but the energy to break the bonds is different in each.
Carbon Black is a complex mixture of PAH's, including things such as Benzene, the energy it releases when combusted is closer to that of a Hydrocarbon then carbon, because although carbon black is mostly carbon, it does contain significant amounts of H, N, S, O, and I believe P. Without looking up the data, I'm going to say that combustion of Carbon Black releases the least amount of energy.
Graphite is an elemental form of carbon (as you already know) but it contains sandwiched layers of sheets of carbon atoms arranged in a hexagonal arrangement. Each carbon is SP2 hybridized, and there exist delocalized electrons above and below each plane of carbons. It is these electrons that give Graphite it's metallic wualities - the reflectivity, and conductivity, and it is the plabes rgar give Graphite the abilkity to be used as a lubricant. Without looking up the data, I'm going to say that Combustion of Graphite releases an intermediate amount of energy, more then that of Carbon Black, and more then that of Alkenes, but less then that of Diamond.
Diamond is an elemental for of Carbon (as you already know) But it contains SP3 Hybridized carbons, and in a perfect crystal, every carbon is bonded to 4 other carbon atoms. This is what gives it it's strength, the fact that every diamond you look at is basically one giant molecule. The one (posisble) exception to this is black diamonds. Black diamonds are porous, and (potentially) glassy, they also only form in very extreme circumstances - they are generally considered to be Supernova remnants. Without looking up the data, I'm predicting that Diamonds release the most energy when Combusted (And they do combust, they just have a very high activation energy, but they combuts before they melt).
Carbon Black is a complex mixture of PAH's, including things such as Benzene, the energy it releases when combusted is closer to that of a Hydrocarbon then carbon, because although carbon black is mostly carbon, it does contain significant amounts of H, N, S, O, and I believe P. Without looking up the data, I'm going to say that combustion of Carbon Black releases the least amount of energy.
Graphite is an elemental form of carbon (as you already know) but it contains sandwiched layers of sheets of carbon atoms arranged in a hexagonal arrangement. Each carbon is SP2 hybridized, and there exist delocalized electrons above and below each plane of carbons. It is these electrons that give Graphite it's metallic wualities - the reflectivity, and conductivity, and it is the plabes rgar give Graphite the abilkity to be used as a lubricant. Without looking up the data, I'm going to say that Combustion of Graphite releases an intermediate amount of energy, more then that of Carbon Black, and more then that of Alkenes, but less then that of Diamond.
Diamond is an elemental for of Carbon (as you already know) But it contains SP3 Hybridized carbons, and in a perfect crystal, every carbon is bonded to 4 other carbon atoms. This is what gives it it's strength, the fact that every diamond you look at is basically one giant molecule. The one (posisble) exception to this is black diamonds. Black diamonds are porous, and (potentially) glassy, they also only form in very extreme circumstances - they are generally considered to be Supernova remnants. Without looking up the data, I'm predicting that Diamonds release the most energy when Combusted (And they do combust, they just have a very high activation energy, but they combuts before they melt).
.
Hi adoucette, everyone!
Sorry I haven't been able to reply to some outstanding posts, but yesterday (Friday here in Aus) I was getting ready to go to Sydney for the weekend.
But it's been postponed, so here I am to say 'hello'.
But that's all, though, because I want to take this unexpected extra time to sort out once anf for all if I can get this fancy new technology (scanner) to work with my very old (but safe) beast.
And THEN I will be trying to compile ready for posting, something that I promised TRoc, Good Elf, Zephir et al......a very long time ago now!
So please excuse my not responding to you for a couple of days at least.
PS: A special 'hello' to adoucette: Keep on keeping on, and Respice Finem, mate!
Cheers all until I speak with you again.
RC.
.
Hi adoucette, everyone!
Sorry I haven't been able to reply to some outstanding posts, but yesterday (Friday here in Aus) I was getting ready to go to Sydney for the weekend.
But it's been postponed, so here I am to say 'hello'.
But that's all, though, because I want to take this unexpected extra time to sort out once anf for all if I can get this fancy new technology (scanner) to work with my very old (but safe) beast.
And THEN I will be trying to compile ready for posting, something that I promised TRoc, Good Elf, Zephir et al......a very long time ago now!
So please excuse my not responding to you for a couple of days at least.
PS: A special 'hello' to adoucette: Keep on keeping on, and Respice Finem, mate!
Cheers all until I speak with you again.
RC.
.
QUOTE (David B. Benson+Jul 20 2007, 06:43 PM)
That's a 767--400ER.
Major Assembly Begins on First Boeing 767-400RT
All 767s are derivatives of each other, all have Aluminum Spars.
According to Simon, tooling changes were minimized and are proceeding on schedule. Boeing recently completed one entirely new tool, which will be used during the second stage of building up the airplane spars and will accommodate all 767 versions.
Arthur
Major Assembly Begins on First Boeing 767-400RT
All 767s are derivatives of each other, all have Aluminum Spars.
According to Simon, tooling changes were minimized and are proceeding on schedule. Boeing recently completed one entirely new tool, which will be used during the second stage of building up the airplane spars and will accommodate all 767 versions.
Arthur
QUOTE (Trippy+Jul 21 2007, 02:21 AM)
Carbon Black is a complex mixture of PAH's, including things such as Benzene, the energy it releases when combusted is closer to that of a Hydrocarbon then carbon, because although carbon black is mostly carbon, it does contain significant amounts of H, N, S, O, and I believe P. Without looking up the data, I'm going to say that combustion of Carbon Black releases the least amount of energy.
Graphite is an elemental form of carbon (as you already know) but it contains sandwiched layers of sheets of carbon atoms arranged in a hexagonal arrangement. Each carbon is SP2 hybridized, and there exist delocalized electrons above and below each plane of carbons. It is these electrons that give Graphite it's metallic wualities - the reflectivity, and conductivity, and it is the plabes rgar give Graphite the abilkity to be used as a lubricant. Without looking up the data, I'm going to say that Combustion of Graphite releases an intermediate amount of energy, more then that of Carbon Black, and more then that of Alkenes, but less then that of Diamond.
Diamond is an elemental for of Carbon (as you already know) But it contains SP3 Hybridized carbons, and in a perfect crystal, every carbon is bonded to 4 other carbon atoms. This is what gives it it's strength, the fact that every diamond you look at is basically one giant molecule. The one (posisble) exception to this is black diamonds. Black diamonds are porous, and (potentially) glassy, they also only form in very extreme circumstances - they are generally considered to be Supernova remnants. Without looking up the data, I'm predicting that Diamonds release the most energy when Combusted (And they do combust, they just have a very high activation energy, but they combuts before they melt).
Take it up with Oxford, http://www.iop.org/EJ/abstract/0268-1242/18/3/311.
Black diamonds are more numerous in the earths crust, and easier to grow they are not super nova products they are formed in igneous rock they are the most common form of industrial diamond.
However if your referring to carbonado Diamonds the theory of Super Nova Creation is no longer the predominate theory.
http://www.pbs.org/wgbh/nova/diamond/sky2.html
Carbon Black in the pure form is elemental carbon, no Pah's, it can be produce from acetylene gas and can be used to create pure carbon nano fibers, its ignition temperature is significantly lower than graphite or Diamond because there are no Ionic bonds that have to be broken down to allow combustion to take place.
Diamonds take so much heat to break the Ionic bonds that the energy produced vs the energy to break the bonds means that they are worthless as a fuel source because they have to be broken down into Graphite first the highest sustainable temperature for them is limited by the amount of diamond that can be converted to Graphite.
http://www.nanomedicine.com/NMI/9.3.5.3.4.htm
In aluminum oxide the third electron is bonded in an ionic bond that bond must be broken for the crystalline structure of Aluminum oxide to break down, the metallic bonds however are weaker and would allow the crystals to vibrate at about 1000c allowing limited Oxidation to occur.
Both Diamond and Aluminum oxide, Diamond (ten) and Aluminum oxide (nine) on the hardness scale, have a similar Crystalline structure.
Stored energy in Graphite or aluminum particles is a direct result of damage to the bonds within the solid materials resulting in a decrease in the energy level needed to brake the bonds and release the potential energy. So damage to the bonding equals less energy in, more energy out.
This is a well known factor, first discovered with Irradiated carbon in Nuclear reactors in the 1950s.
Graphite is an elemental form of carbon (as you already know) but it contains sandwiched layers of sheets of carbon atoms arranged in a hexagonal arrangement. Each carbon is SP2 hybridized, and there exist delocalized electrons above and below each plane of carbons. It is these electrons that give Graphite it's metallic wualities - the reflectivity, and conductivity, and it is the plabes rgar give Graphite the abilkity to be used as a lubricant. Without looking up the data, I'm going to say that Combustion of Graphite releases an intermediate amount of energy, more then that of Carbon Black, and more then that of Alkenes, but less then that of Diamond.
Diamond is an elemental for of Carbon (as you already know) But it contains SP3 Hybridized carbons, and in a perfect crystal, every carbon is bonded to 4 other carbon atoms. This is what gives it it's strength, the fact that every diamond you look at is basically one giant molecule. The one (posisble) exception to this is black diamonds. Black diamonds are porous, and (potentially) glassy, they also only form in very extreme circumstances - they are generally considered to be Supernova remnants. Without looking up the data, I'm predicting that Diamonds release the most energy when Combusted (And they do combust, they just have a very high activation energy, but they combuts before they melt).
Take it up with Oxford, http://www.iop.org/EJ/abstract/0268-1242/18/3/311.
Black diamonds are more numerous in the earths crust, and easier to grow they are not super nova products they are formed in igneous rock they are the most common form of industrial diamond.
However if your referring to carbonado Diamonds the theory of Super Nova Creation is no longer the predominate theory.
http://www.pbs.org/wgbh/nova/diamond/sky2.html
Carbon Black in the pure form is elemental carbon, no Pah's, it can be produce from acetylene gas and can be used to create pure carbon nano fibers, its ignition temperature is significantly lower than graphite or Diamond because there are no Ionic bonds that have to be broken down to allow combustion to take place.
Diamonds take so much heat to break the Ionic bonds that the energy produced vs the energy to break the bonds means that they are worthless as a fuel source because they have to be broken down into Graphite first the highest sustainable temperature for them is limited by the amount of diamond that can be converted to Graphite.
http://www.nanomedicine.com/NMI/9.3.5.3.4.htm
In aluminum oxide the third electron is bonded in an ionic bond that bond must be broken for the crystalline structure of Aluminum oxide to break down, the metallic bonds however are weaker and would allow the crystals to vibrate at about 1000c allowing limited Oxidation to occur.
Both Diamond and Aluminum oxide, Diamond (ten) and Aluminum oxide (nine) on the hardness scale, have a similar Crystalline structure.
Stored energy in Graphite or aluminum particles is a direct result of damage to the bonds within the solid materials resulting in a decrease in the energy level needed to brake the bonds and release the potential energy. So damage to the bonding equals less energy in, more energy out.
This is a well known factor, first discovered with Irradiated carbon in Nuclear reactors in the 1950s.
Carbon black is produced by the incomplete combustion of petroleum products, and contains Oxygen complexes (Carboxylic, Quinonic, Lactonic, and Phenolic, to name a few).
The presents of Phenolic groups means there are cyclic, or polycyclic aromatic components present in Carbon Black.
And finally, the conidtions that produce Carbon Black also produce PAH's.
Carbon Black is also a Group 2B Carcinogen.
The presents of Phenolic groups means there are cyclic, or polycyclic aromatic components present in Carbon Black.
And finally, the conidtions that produce Carbon Black also produce PAH's.
Carbon Black is also a Group 2B Carcinogen.
To further back my point up:
This is from the MSDS for Carbon Black:
Toxicology
IARC evaluation: possible human carcinogen (Group 2B). May be harmful by ingestion or inhalation. Respiratory irritant. Typical STEL 7 mg/m3. Note: Carbon black is generally made under controlled conditions, and has a high carbon content. By contrast, soot usually contains additional complex organic molecules, some of which may be carcinogenic. Thus, industrial and domestic soot may be presumed to present a greater risk to human health than commercially-produced carbon black.
Commercially produced Carbon Black is "generally made under controlled conditions", where as the WTC fires were most definitely NOT 'carefully controlled conditions' and to try and claim that they're comparable to a monitored and controlled furnace, especially with all these other reactions you claim to have been going on in the background, kinda contradicts everything else you've been saying.
This is from the MSDS for Carbon Black:
QUOTE
Toxicology
IARC evaluation: possible human carcinogen (Group 2B). May be harmful by ingestion or inhalation. Respiratory irritant. Typical STEL 7 mg/m3. Note: Carbon black is generally made under controlled conditions, and has a high carbon content. By contrast, soot usually contains additional complex organic molecules, some of which may be carcinogenic. Thus, industrial and domestic soot may be presumed to present a greater risk to human health than commercially-produced carbon black.
Commercially produced Carbon Black is "generally made under controlled conditions", where as the WTC fires were most definitely NOT 'carefully controlled conditions' and to try and claim that they're comparable to a monitored and controlled furnace, especially with all these other reactions you claim to have been going on in the background, kinda contradicts everything else you've been saying.
QUOTE (Trippy+Jul 21 2007, 10:22 PM)
To further back my point up:
This is from the MSDS for Carbon Black:
Commercially produced Carbon Black is "generally made under controlled conditions", where as the WTC fires were most definitely NOT 'carefully controlled conditions' and to try and claim that they're comparable to a monitored and controlled furnace, especially with all these other reactions you claim to have been going on in the background, kinda contradicts everything else you've been saying.
DA that is Carbon Black in a fire such as the world trade center and I never disagreed with the point that the carbon Black at the World Trade Center contained pahs.
In fact I know the carbon black at the World Trade Center contained pahs.
I was talking about the energy stored in the preassembled bonding of the electrons in pure elemental Assemblies, Thus I was referring to pure carbon black, pure Graphite, and pure Carbon in Diamonds, All three can have impurities as you have said but in each form the reaction conditions are different for the carbons dependent on the energy necessary to disrupt the pre assembled bonds.
This is from the MSDS for Carbon Black:
Commercially produced Carbon Black is "generally made under controlled conditions", where as the WTC fires were most definitely NOT 'carefully controlled conditions' and to try and claim that they're comparable to a monitored and controlled furnace, especially with all these other reactions you claim to have been going on in the background, kinda contradicts everything else you've been saying.
DA that is Carbon Black in a fire such as the world trade center and I never disagreed with the point that the carbon Black at the World Trade Center contained pahs.
In fact I know the carbon black at the World Trade Center contained pahs.
I was talking about the energy stored in the preassembled bonding of the electrons in pure elemental Assemblies, Thus I was referring to pure carbon black, pure Graphite, and pure Carbon in Diamonds, All three can have impurities as you have said but in each form the reaction conditions are different for the carbons dependent on the energy necessary to disrupt the pre assembled bonds.
QUOTE (Chainsaw,+Jul 22 2007, 12:27 PM)
DA that is Carbon Black in a fire such as the world trade center and I never disagreed with the point that the carbon Black at the World Trade Center contained pahs.
In fact I know the carbon black at the World Trade Center contained pahs.
I was talking about the energy stored in the preassembled bonding of the electrons in pure elemental Assemblies, Thus I was referring to pure carbon black, pure Graphite, and pure Carbon in Diamonds, All three can have impurities as you have said but in each form the reaction conditions are different for the carbons dependent on the energy necessary to disrupt the pre assembled bonds.
See...
Now this is the perfect example of exactly what I've been talking about. When it comes to comparing Carbon Black and Graphite to Diamond, it's not as simple as you seem to be making it out to be.
Basically, one of the other things that governs activation energy (remember that I did say there were many things, and that the whole ting was complicated) is how stable reaction intermediates are. Reactions with stable intermediates require less energy to proceed then those without them.
Carbon Black, if we're dealing with an ordinary sample outside of a laborotory contains PAH's, even analytical grade carbon black has some volatile content, although admittedly not very miuch, otherwise it wouldn't be very good as analytical grade Carbon Black, now would it. The other thing they both has is a wide spread network of delocalized electrons, a whole bunch of conjugated double bonds. Basically, what this does, is it stabilizes radicles that form during combustion (and if you've studied combustion and metabolism, you know that they're all about radicles, among other things). The fact that this network of conjugated carbon-carbon double bonds is present, and can stabilize radicles lowers the activation energy required for the combustion (or at least is one of the factors responsible for doing so).
This extended network is not present when dealing with Diamond, therefore there are no stabilizing intermediates, and this is one of the reasons for the differences between the three compounds.
In fact I know the carbon black at the World Trade Center contained pahs.
I was talking about the energy stored in the preassembled bonding of the electrons in pure elemental Assemblies, Thus I was referring to pure carbon black, pure Graphite, and pure Carbon in Diamonds, All three can have impurities as you have said but in each form the reaction conditions are different for the carbons dependent on the energy necessary to disrupt the pre assembled bonds.
See...
Now this is the perfect example of exactly what I've been talking about. When it comes to comparing Carbon Black and Graphite to Diamond, it's not as simple as you seem to be making it out to be.
Basically, one of the other things that governs activation energy (remember that I did say there were many things, and that the whole ting was complicated) is how stable reaction intermediates are. Reactions with stable intermediates require less energy to proceed then those without them.
Carbon Black, if we're dealing with an ordinary sample outside of a laborotory contains PAH's, even analytical grade carbon black has some volatile content, although admittedly not very miuch, otherwise it wouldn't be very good as analytical grade Carbon Black, now would it. The other thing they both has is a wide spread network of delocalized electrons, a whole bunch of conjugated double bonds. Basically, what this does, is it stabilizes radicles that form during combustion (and if you've studied combustion and metabolism, you know that they're all about radicles, among other things). The fact that this network of conjugated carbon-carbon double bonds is present, and can stabilize radicles lowers the activation energy required for the combustion (or at least is one of the factors responsible for doing so).
This extended network is not present when dealing with Diamond, therefore there are no stabilizing intermediates, and this is one of the reasons for the differences between the three compounds.
QUOTE (Trippy+Jul 22 2007, 09:11 AM)
See...
Now this is the perfect example of exactly what I've been talking about. When it comes to comparing Carbon Black and Graphite to Diamond, it's not as simple as you seem to be making it out to be.
Basically, one of the other things that governs activation energy (remember that I did say there were many things, and that the whole ting was complicated) is how stable reaction intermediates are. Reactions with stable intermediates require less energy to proceed then those without them.
Carbon Black, if we're dealing with an ordinary sample outside of a laborotory contains PAH's, even analytical grade carbon black has some volatile content, although admittedly not very miuch, otherwise it wouldn't be very good as analytical grade Carbon Black, now would it. The other thing they both has is a wide spread network of delocalized electrons, a whole bunch of conjugated double bonds. Basically, what this does, is it stabilizes radicles that form during combustion (and if you've studied combustion and metabolism, you know that they're all about radicles, among other things). The fact that this network of conjugated carbon-carbon double bonds is present, and can stabilize radicles lowers the activation energy required for the combustion (or at least is one of the factors responsible for doing so).
This extended network is not present when dealing with Diamond, therefore there are no stabilizing intermediates, and this is one of the reasons for the differences between the three compounds.
Which is what I know, however Aluminum can store energy in the structure that can lead to a greater reaction rate at a lower temperature.
Well it really does not actually store energy what it does is reduce the energy of the metallic bonding leading to more reactivity and a lower ignition temperature.
A lot of energy in Aluminum goes into disrupting the oxide layer even before the aluminum can react, that is accomplished by the expansion of the aluminum to break the oxide when heated to above 1000c.
Reduce the energy that goes into breaking the oxide layer by disrupting the metallic bonding of the oxide and improve the Oxidation properties of the materials.
I must also point out that Aluminum oxidizes as in more forms than Al2O3 although that is the most energetic form.
Each oxidation state of aluminum also produces heat.
Let us not forget that there are other forms of energy involve other than thermal.
http://www.europeansocietysonochemistry.eu...stry_theory.doc
Now this is the perfect example of exactly what I've been talking about. When it comes to comparing Carbon Black and Graphite to Diamond, it's not as simple as you seem to be making it out to be.
Basically, one of the other things that governs activation energy (remember that I did say there were many things, and that the whole ting was complicated) is how stable reaction intermediates are. Reactions with stable intermediates require less energy to proceed then those without them.
Carbon Black, if we're dealing with an ordinary sample outside of a laborotory contains PAH's, even analytical grade carbon black has some volatile content, although admittedly not very miuch, otherwise it wouldn't be very good as analytical grade Carbon Black, now would it. The other thing they both has is a wide spread network of delocalized electrons, a whole bunch of conjugated double bonds. Basically, what this does, is it stabilizes radicles that form during combustion (and if you've studied combustion and metabolism, you know that they're all about radicles, among other things). The fact that this network of conjugated carbon-carbon double bonds is present, and can stabilize radicles lowers the activation energy required for the combustion (or at least is one of the factors responsible for doing so).
This extended network is not present when dealing with Diamond, therefore there are no stabilizing intermediates, and this is one of the reasons for the differences between the three compounds.
Which is what I know, however Aluminum can store energy in the structure that can lead to a greater reaction rate at a lower temperature.
Well it really does not actually store energy what it does is reduce the energy of the metallic bonding leading to more reactivity and a lower ignition temperature.
A lot of energy in Aluminum goes into disrupting the oxide layer even before the aluminum can react, that is accomplished by the expansion of the aluminum to break the oxide when heated to above 1000c.
Reduce the energy that goes into breaking the oxide layer by disrupting the metallic bonding of the oxide and improve the Oxidation properties of the materials.
I must also point out that Aluminum oxidizes as in more forms than Al2O3 although that is the most energetic form.
Each oxidation state of aluminum also produces heat.
Let us not forget that there are other forms of energy involve other than thermal.
http://www.europeansocietysonochemistry.eu...stry_theory.doc
QUOTE (David B. Benson+Jul 19 2007, 09:05 PM)
1. NCSTAR1--2A, page 192 (226 ordinal) ff. When you do you'll find that several of your assumptions about floor plans are in need of revision. For example, the mechanical mezz at floors 8, 42, 76, and 109 were all type 13, with about 1/2 beamed floor outside the core. (I assume that smaller mechanical equipment sat on those.)
2. I haven't either, but connection locations and tension strengths are found in NCSTAR1-6D. Figure 4--3, page 170 (234 ordinal) shows connections (notice the unusual orientation of the graphic). Tables 4--27, page 242 (306 ordinal) and 4--29, page 244 (308 ordinal) give strengths. In any case the floor 105 load data ought to be enough to figure out how to add more mass at the top.
Another question: Did you attempt to include the in-service live loads? That is, I believe what NIST has done.
I am quite interested in this since I have two computer programs which model the collapses. To be accurate, these need a good building model. It looks to me that you have a good start, but I opine that the total mass ought to be closer to about 350,000 tonnes, with the in-service live loads included.
In any case, it is easy to check the N-S and E-W fundamental vibration modes (approximately) against the values given in NCSTAR1--2A to see if you are in the ballpark.
Do you know how to calculate the fundametal vibration mode? Is that the same as the natural frequency of ocillation of the tower?
2. I haven't either, but connection locations and tension strengths are found in NCSTAR1-6D. Figure 4--3, page 170 (234 ordinal) shows connections (notice the unusual orientation of the graphic). Tables 4--27, page 242 (306 ordinal) and 4--29, page 244 (308 ordinal) give strengths. In any case the floor 105 load data ought to be enough to figure out how to add more mass at the top.
Another question: Did you attempt to include the in-service live loads? That is, I believe what NIST has done.
I am quite interested in this since I have two computer programs which model the collapses. To be accurate, these need a good building model. It looks to me that you have a good start, but I opine that the total mass ought to be closer to about 350,000 tonnes, with the in-service live loads included.
In any case, it is easy to check the N-S and E-W fundamental vibration modes (approximately) against the values given in NCSTAR1--2A to see if you are in the ballpark.
Do you know how to calculate the fundametal vibration mode? Is that the same as the natural frequency of ocillation of the tower?
QUOTE (Hambone+Jul 22 2007, 09:58 AM)
Do you know how to calculate the fundametal[sic] vibration mode?
Is that the same as the natural frequency of ocillation[sic] of the tower?
Approximately, yes.
The towers had several vibration modes, see NCSTAR1--2A. But the fundamental sways back and forth without torsion, so can be treated approximately as a distributed mass-spring system.
Is that the same as the natural frequency of ocillation[sic] of the tower?
Approximately, yes.
The towers had several vibration modes, see NCSTAR1--2A. But the fundamental sways back and forth without torsion, so can be treated approximately as a distributed mass-spring system.
About the swaying of the Twin Towers. I believe NIST, using a moire analysis of a video, measured the primary period to be 11.4 +/- 0.1 seconds with an amplitude of about one foot.
My question is: how do you include the effect of the visco-elastic dampers in any calculation of the mass of a tower based on this vibrational period?
My question is: how do you include the effect of the visco-elastic dampers in any calculation of the mass of a tower based on this vibrational period?
QUOTE (NEU-FONZE+Jul 23 2007, 08:09 AM)
My question is: how do you include the effect of the visco-elastic dampers in any calculation of the mass of a tower based on this vibrational period?
Ignore the dampers.
There is a worse problem: I don't know how to determine the horizontal stiffness of the tower. Without that, the method is hopeless.
I didn't think it though enough before posting.
Ignore the dampers.
There is a worse problem: I don't know how to determine the horizontal stiffness of the tower. Without that, the method is hopeless.
I didn't think it though enough before posting.
QUOTE (David B. Benson+Jul 24 2007, 07:06 AM)
Ignore the dampers.
There is a worse problem: I don't know how to determine the horizontal stiffness of the tower. Without that, the method is hopeless.
I didn't think it though enough before posting.
That should be relatively easy to find - the horizontal stiffness of the towers should be listed with the other physical characteristics of the tower, because it's a factor in calculating resistance to windspeeds, something that should predate the construction of the towers. Maybe someone else will be able to tell specifically where to look, but that should be a helpful start (I hope).
There is a worse problem: I don't know how to determine the horizontal stiffness of the tower. Without that, the method is hopeless.
I didn't think it though enough before posting.
That should be relatively easy to find - the horizontal stiffness of the towers should be listed with the other physical characteristics of the tower, because it's a factor in calculating resistance to windspeeds, something that should predate the construction of the towers. Maybe someone else will be able to tell specifically where to look, but that should be a helpful start (I hope).
QUOTE (Trippy+Jul 23 2007, 01:27 PM)
That should be relatively easy to find - the horizontal stiffness of the towers should be listed ...
NCSTAR1--2, page 306, point 5 states to the effect that the towers were sixteen times as stiff as a conventional structure.
But that appears to be all that is said in either NCSTAR1--2 or NCSTAR1--2A.
Ah me...
Edited to add: NCSTAR1--2A, page 35 (69 ordinal):
In the as-designed drawings, there were strap anchors connecting the core columns to the concrete floor slab to provide lateral bracing for the column[sic].
NCSTAR1--2, page 306, point 5 states to the effect that the towers were sixteen times as stiff as a conventional structure.
But that appears to be all that is said in either NCSTAR1--2 or NCSTAR1--2A.
Ah me...
Edited to add: NCSTAR1--2A, page 35 (69 ordinal):
In the as-designed drawings, there were strap anchors connecting the core columns to the concrete floor slab to provide lateral bracing for the column[sic].
QUOTE (David B. Benson+Jul 24 2007, 10:32 AM)
NCSTAR1--2, page 306, point 5 states to the effect that the towers were sixteen times as stiff as a conventional structure.
But that appears to be all that is said in either NCSTAR1--2 or NCSTAR1--2A.
Ah me...
Maybe try looking for some of the 'original' documentation surrounding their construction?
But that appears to be all that is said in either NCSTAR1--2 or NCSTAR1--2A.
Ah me...
Maybe try looking for some of the 'original' documentation surrounding their construction?
QUOTE (Trippy+Jul 23 2007, 07:10 PM)
Maybe try looking for some of the 'original' documentation surrounding their construction?
I believe most of that was stored in the towers.
Keep in mind though that these towers were built before the use of computers.
Any calculations you might find were done by hand.
Arthur
I believe most of that was stored in the towers.
Keep in mind though that these towers were built before the use of computers.
Any calculations you might find were done by hand.
Arthur
QUOTE (adoucette+Jul 23 2007, 04:26 PM)
I believe most of that was stored in the towers.
PANYNJ's copy was in the emergency center in WTC 7 and so lost. LERA had a copy as well, which only became accessible two days later.
NIST used LERA's copy by contracting with LERA to build the SAP2000 FEA elements and doing the wind load studies, etc. (NCSTAR1--2A, which I re-reading more carefully just now.)
PANYNJ's copy was in the emergency center in WTC 7 and so lost. LERA had a copy as well, which only became accessible two days later.
NIST used LERA's copy by contracting with LERA to build the SAP2000 FEA elements and doing the wind load studies, etc. (NCSTAR1--2A, which I re-reading more carefully just now.)
QUOTE (NEU-FONZE+Jul 23 2007, 08:09 AM)
My question is: how do you include the effect of the visco-elastic dampers in any calculation of the mass of a tower based on this vibrational period?
NCSTAR1--2A, page 76 (110 ordinal):
"The wind loads were calculated n the basis of 2.5 percent total damping. The value includes the intrinsic damping of the structural systems plus the supplemental damping provided by the dampers."
NCSTAR1--2A, page 76 (110 ordinal):
"The wind loads were calculated n the basis of 2.5 percent total damping. The value includes the intrinsic damping of the structural systems plus the supplemental damping provided by the dampers."
QUOTE
My question is: how do you include the effect of the visco-elastic dampers in any calculation of the mass of a tower based on this vibrational period?
Dampers won't affect the period of the oscillation, they only act to attenuate the oscillation (so it dies down quicker and won't build up like the Tacoma bridge did).
If the primary period is 11.4 seconds, that's the primary period, period.
I would also be interested in seeing what happens when a transverse-mode shockwave propagates down to the foundation level. In theory, a large fraction of the energy of the aircraft's impact would either be transmitted into the foundation (which, due to a huge impedance mismatch, isn't where most of the energy goes) or it'd have to be reflected back up the tower, making it ring like a bell (which wasn't observed) or the energy coupled to the concrete/steel interface, rupturing the concrete and shearing the steel (which seems likeliest to me). That would cause significant damage to the basement, which would explain a lot of the anecdotal reports of same that the CDiots seem to prove their case.
I believe this topic was raised because it has been suggested that the measured oscillations of WTC 2 after the aircraft impact could be used to determine the mass of the tower. This may be true but the calculation is far from trivial!
When the aircraft hit the towers not all of the impact kinetic energy went into the towers. First off, for WTC 2, NIST estimate that about 30,000 kg of aircraft debris exited the towers. Then, of course, a lot of energy was expended in fragmenting the aircraft. Wierzibicki at MIT has a couple of papers on this. I believe he estimates that only 28 % of the impact KE was absorbrd by the core columns and 53 % by the floor structure.
When the aircraft hit the towers not all of the impact kinetic energy went into the towers. First off, for WTC 2, NIST estimate that about 30,000 kg of aircraft debris exited the towers. Then, of course, a lot of energy was expended in fragmenting the aircraft. Wierzibicki at MIT has a couple of papers on this. I believe he estimates that only 28 % of the impact KE was absorbrd by the core columns and 53 % by the floor structure.
QUOTE
I believe he estimates that only 28 % of the impact KE was absorbrd by the core columns and 53 % by the floor structure.
My point is that most of this absorbed kinetic energy would've gotten transmitted to the base of the tower, and would've done extensive damage when it got there due to the sudden impedance mismatch.
Einsteen:
Is that supposed to represent the Twin Towers?
A "concert pitch A" tuning fork is 440 Hz I believe...
Anyway, the one estimate I have seen for the spring constant for the section below the impact zone (not sure if its WTC 1 or 2) is 71 GN/m.
I am looking for a reference for this....
Is that supposed to represent the Twin Towers?
A "concert pitch A" tuning fork is 440 Hz I believe...
Anyway, the one estimate I have seen for the spring constant for the section below the impact zone (not sure if its WTC 1 or 2) is 71 GN/m.
I am looking for a reference for this....
sorry, that was a typical nonsense post, once in a while..
On National geographic I recently saw a documentary about the sears tower and they spoke some people working very high up there about the swaying. Can't remember any stats...
On National geographic I recently saw a documentary about the sears tower and they spoke some people working very high up there about the swaying. Can't remember any stats...
QUOTE (wcelliott+Jul 25 2007, 03:07 AM)
My point is that most of this absorbed kinetic energy would've gotten transmitted to the base of the tower, and would've done extensive damage when it got there due to the sudden impedance mismatch.
The Pallisades Seismograph record might be able to give you some usefull information about that. If IIRC, what you're talking about might have registered, not sure though, it depends on the modes of the energy, and how efficiently it was transfered into the surrounding strata.
QUOTE
it depends on the modes of the energy, and how efficiently it was transfered into the surrounding strata.
The key point here is that steel is flexible, and concrete isn't. Where steel gets imbedded in concrete, you have a problem if the steel has an energetic transverse shockwave travelling through it. The concrete will tend to pulverize. Depending on the specifics of the design, this could've led to signficant destruction at the base of the towers immediately following the impact of the plane(s).
QUOTE (wcelliott+Jul 25 2007, 08:14 AM)
The key point here is that steel is flexible, and concrete isn't. Where steel gets imbedded in concrete, you have a problem if the steel has an energetic transverse shockwave travelling through it. The concrete will tend to pulverize. Depending on the specifics of the design, this could've led to signficant destruction at the base of the towers immediately following the impact of the plane(s).
Yes, but compressive shockwaves are more efficiently transferred from the super structure, to the bedrock, thus more likely to be detected, which is the point that I was trying to make.
QUOTE (Trippy+Jul 24 2007, 12:32 PM)
The Pallisades[sic] Seismograph record ...
registered both aircraft impacts as small events.
On a previous thread, the first as I recall it, there is a link to a seismologist explaining that these events were (primarily) Love waves, transverse surface waves.
Nonetheless, the reflection coefficient is -0.662 so only 0.338 of the amplitude of the transverse waves in the towers goes onwards to the concrete.
Upon reflection, Carter Elliot's point is a good one. Willy R. first spoke of hearing the noise from the sub-basement below his, sounding like furniture being dragged across the floor. This well could be (most likely is) the response to the initial peak. After that, the wave was sufficiently attenuated that no one else noticed anything. (Although, with fireballs racing down the voids in the core, attention was certainly directed elsewhere.)
The only generally noticed wave was the fundamental period of the tower swaying. Details regarding the first eight modes can be found in NCSTAR1--2A.
registered both aircraft impacts as small events.
On a previous thread, the first as I recall it, there is a link to a seismologist explaining that these events were (primarily) Love waves, transverse surface waves.
Nonetheless, the reflection coefficient is -0.662 so only 0.338 of the amplitude of the transverse waves in the towers goes onwards to the concrete.
Upon reflection, Carter Elliot's point is a good one. Willy R. first spoke of hearing the noise from the sub-basement below his, sounding like furniture being dragged across the floor. This well could be (most likely is) the response to the initial peak. After that, the wave was sufficiently attenuated that no one else noticed anything. (Although, with fireballs racing down the voids in the core, attention was certainly directed elsewhere.)
The only generally noticed wave was the fundamental period of the tower swaying. Details regarding the first eight modes can be found in NCSTAR1--2A.
Energy from the plane impact is easily transferred to the bottom... but when the building starts moving nothing... even not in the slightest way. I don't get it.
QUOTE (einsteen+Jul 24 2007, 02:51 PM)
Energy from the plane impact is easily transferred to the bottom... but when the building starts moving nothing... even not in the slightest way. I don't get it.
Some does. But very little until exterior wall panels, falling freely, begin to impact the ground. The largest signal is at the end of crush-down.
Very little of the energy associated with the collapse went down the walls or core columns as pressure waves. Hence the small signal before impact.
(By the way, I sent you an e-mail several days ago.)
Some does. But very little until exterior wall panels, falling freely, begin to impact the ground. The largest signal is at the end of crush-down.
Very little of the energy associated with the collapse went down the walls or core columns as pressure waves. Hence the small signal before impact.
(By the way, I sent you an e-mail several days ago.)
Apologize, I have too much e-mails, and I had to check with which one I signed up here, I'm going to reply
QUOTE (Trippy+Jul 24 2007, 08:33 PM)
Yes, but compressive shockwaves are more efficiently transferred from the super structure, to the bedrock, thus more likely to be detected, which is the point that I was trying to make.
I have to agree also let us not forget the towers main interior Columns were basically hollow steel beams, they dissipate some energy as wave energy.
sound.
Think of he dampeners as a thermal link they convert movement into heat, if you know how much heat was produced by the dampeners for how much movement, then you would have a clue as to how to model them.
The best way is as an energy converting fluid shock absorber which is what they are. They simply cancel out energy traveling from the perimeter to the core.
I have to agree also let us not forget the towers main interior Columns were basically hollow steel beams, they dissipate some energy as wave energy.
sound.
Think of he dampeners as a thermal link they convert movement into heat, if you know how much heat was produced by the dampeners for how much movement, then you would have a clue as to how to model them.
The best way is as an energy converting fluid shock absorber which is what they are. They simply cancel out energy traveling from the perimeter to the core.
QUOTE (NEU-FONZE+Jul 24 2007, 06:04 PM)
Anyway, the one estimate I have seen for the spring constant for the section below the impact zone (not sure if its WTC 1 or 2) is 71 GN/m.
I am looking for a reference for this....
71 GN/m was stated in the BZ paper.
Anyone happen to know what the dampers' ratings were?
How much of the impact kinetic energy got dampened-out before the shockwave reached the basement?
I kinda doubt that they were rated to absorb the impact of an aircraft going 500mph.
How much of the impact kinetic energy got dampened-out before the shockwave reached the basement?
I kinda doubt that they were rated to absorb the impact of an aircraft going 500mph.
A total damping of 2.5% will have little effect on the natural frequency.
A NIST paper by Kathryn Butler shows the results of the measured sway using video of the aircraft impact of WTC2 and a Moire technique. The translational sway was still measurable after 30 cycles, which would be expected for a damping of 2.5%. The first and second translational modes and torsional modes were measured and agreed closely with those predicted by modal analysis in the SAP2000 global model of the towers.
http://i134.photobucket.com/albums/q91/sha...000/butler1.jpg
A NIST paper by Kathryn Butler shows the results of the measured sway using video of the aircraft impact of WTC2 and a Moire technique. The translational sway was still measurable after 30 cycles, which would be expected for a damping of 2.5%. The first and second translational modes and torsional modes were measured and agreed closely with those predicted by modal analysis in the SAP2000 global model of the towers.
http://i134.photobucket.com/albums/q91/sha...000/butler1.jpg
I ran the WTC global models on SAP2000. Here are some of the animations I captured after doing modal analysis on WTC1. SAP2000 adds in some percussion sound effects. I forgot to edit them out for some of the videos.
fundamental translational:
http://s134.photobucket.com/albums/q91/sha...=wtc1bend11.flv
second translational:
http://s134.photobucket.com/albums/q91/sha...t=wtc1bend3.flv
fundamental torsional:
http://s134.photobucket.com/albums/q91/sha...t=WTC1mode3.flv
second torsional:
http://s134.photobucket.com/albums/q91/sha...=wtc1mode6b.flv
Still image from fundamental translational:
fundamental translational:
http://s134.photobucket.com/albums/q91/sha...=wtc1bend11.flv
second translational:
http://s134.photobucket.com/albums/q91/sha...t=wtc1bend3.flv
fundamental torsional:
http://s134.photobucket.com/albums/q91/sha...t=WTC1mode3.flv
second torsional:
http://s134.photobucket.com/albums/q91/sha...=wtc1mode6b.flv
Still image from fundamental translational:
Then add those shear forces onto the shear forces caused by what was simply an asymetric loading, and pply those forces to structural members that were never designed to withstand shear forces...
QUOTE (shagster+Jul 25 2007, 10:00 AM)
A total damping of 2.5% will have little effect on the natural frequency.
It might be better to say that the damped frequency won't be very different than the natural frequency for small damping. The natural frequency is usually defined as being the frequency with no damping.
It might be better to say that the damped frequency won't be very different than the natural frequency for small damping. The natural frequency is usually defined as being the frequency with no damping.
Thank you, shagster!
Recognize that this means the loads on the foundations were oscillating back and forth every few seconds, which they weren't designed for. This could've caused failures in the basement where the steel columns came into contact with the concrete.
Recognize that this means the loads on the foundations were oscillating back and forth every few seconds, which they weren't designed for. This could've caused failures in the basement where the steel columns came into contact with the concrete.
In a lot of books it is often mentioned that for a pendulum the frequency is independent of the amplitude, that is simply wrong. As far as I remember it is only an approach for small amplitudes, it had to do with a sin(x) that is approximately x for small x and that leads to the harmonic equation, for small amplitudes if you damp it it will also not really affect the period.
Nice shakin' building Shagster, sap2000 sounds professional, could you also simulate a collapse, i.e. take N masses with N-1 functions f(u) between that are lineair in the beginning, constant later and zero after a certain u> u_critical ?
Nice shakin' building Shagster, sap2000 sounds professional, could you also simulate a collapse, i.e. take N masses with N-1 functions f(u) between that are lineair in the beginning, constant later and zero after a certain u> u_critical ?
What do you folks here think about the implosionworld paper, author Brent Blanchard (from Protec I believe) ? If I understand it right he said that 95% fell over the footprint, that implies that for wtc1 that even if the top block's mass stays above the footprint we have even less, i.e. 87%. Now assume we then use Dr. Greening's first stage of collapse where all mass of floor i (after i-1 floors collide with it) is not taking part of the collapse process then I find using his model that
the end velocity is 22.3 m/s, the first stage of collapse takes 17.67 seconds. Then the 2nd stage of collapse would add 2.2 seconds giving a total of 19.9 seconds
the end velocity is 22.3 m/s, the first stage of collapse takes 17.67 seconds. Then the 2nd stage of collapse would add 2.2 seconds giving a total of 19.9 seconds
QUOTE
If I understand it right he said that 95% fell over the footprint, that implies that for wtc1 that even if the top block's mass stays above the footprint we have even less, i.e. 87%.
If my understanding of the mechanism of the collapse is correct, you should *expect* most of the material to land in the building's footprint.
On a floor-by-floor basis, I'd expect that the perimeter columns would flex outward after the floor-perimeter-column brackets fail, making the outer perimeter columns act like a funnel.
The breaking perimeter-floor brackets release the floors from the outside first, causing them to drape towards the core columns initially, until those core-floor brackets themselves fail, providing a "pull" on the floors towards the center of the buildings.
One could see that those two effects, combined, would turn the collapsing tower(s) into a funnel that directs the bulk of the debris down the middle of the tower, with the funnel itself disintegrating after it's no longer in-play.
I don't believe in the funnel theory because it is the whole block that falls as a whole with all floors and trusses still connected. It couldn't funnel.
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