QUOTE (einsteen+May 3 2007, 09:06 AM)
Funneling is better, but its almost the law of conservation of problems. How would that happen, an intact top block cannot funnel into the perimeter columns because that top block also still has perimeter and inner core columns, almost like you cut a piece of coax cable.
Who says the top blocks remains intact? It's pretty obvious that the funneling or wedging was going on above and below the collapse fronts. Think of the collapse front as a double sided fruit juicer, extracting mostly floor elements from the upper and lower blocks as it descended to the bottom.
I think this would be a valid non-tilting-E1 model
there is a crush up and crush down until the floors (thick black) have
sufficient mass/energy/momentum to do the 1st stage of collapse.
However something that one should not forgot is that since the acceleration
is <g the block wants to follow the avalanche with a near g speed, but that means that during the 1st stage of collapse there is also a crush up but since the force between the following block and the crushed part is not large it will be a small crush-up. But if I understand Greening's famous paper then a funneling or wedging is not needed because E1 includes the perimeter and core columns.
The problem that I have is that some people mentioned an effective E1 factor that is much lower, maybe 0.001 GJ because it totally takes no energy to detach the floors, but that is indeed only valid for a model in which the core is still standing after the collapse and also the core part within the initial falling block, that would imply that the floors are detached from the falling block and its core will independently topple away at the top because it has almost no mass compared with the floors.
Assume you have the same building and all floors have zero mass then a collapse will be impossible (there is no proof needed for that because it is trivial).
There are only two possibilities
1) all floors detached from the core(s)
2) all floors still fixed with the core but the core breaks in sequences during global collapse
Both of them are ridiculous.
You make me thirsty with that picture!
there is a crush up and crush down until the floors (thick black) have
sufficient mass/energy/momentum to do the 1st stage of collapse.
However something that one should not forgot is that since the acceleration
is <g the block wants to follow the avalanche with a near g speed, but that means that during the 1st stage of collapse there is also a crush up but since the force between the following block and the crushed part is not large it will be a small crush-up. But if I understand Greening's famous paper then a funneling or wedging is not needed because E1 includes the perimeter and core columns.
The problem that I have is that some people mentioned an effective E1 factor that is much lower, maybe 0.001 GJ because it totally takes no energy to detach the floors, but that is indeed only valid for a model in which the core is still standing after the collapse and also the core part within the initial falling block, that would imply that the floors are detached from the falling block and its core will independently topple away at the top because it has almost no mass compared with the floors.
Assume you have the same building and all floors have zero mass then a collapse will be impossible (there is no proof needed for that because it is trivial).
There are only two possibilities
1) all floors detached from the core(s)
2) all floors still fixed with the core but the core breaks in sequences during global collapse
Both of them are ridiculous.
You make me thirsty with that picture!
Reading this thread is like watching Days of Our Lives. You can miss a load of episodes and easily pick up on the story again. It goes round and round and round and round. Haven't seen hardly any new facts while I have been away.
The dust research from the last thread seems to have been forgotten - a large amount of fine dust (6 micro mean from memory) more than 400m from ground zero.
The energy analysis shows a big black hole just counting concrete comminution energy, and we hadn't even included energy to make short segments of glass fiber due to lack of understanding.
Metamars' discovered paper of steel fracture is interesting. We aren't far off knowing how much energy was required.
Building mass I think was 380,000 tonnes above ground per tower (Omika quoting Tanaka I recall).
Maybe it would be easier to just dig up the old posts and replay them.....again here.
The dust research from the last thread seems to have been forgotten - a large amount of fine dust (6 micro mean from memory) more than 400m from ground zero.
The energy analysis shows a big black hole just counting concrete comminution energy, and we hadn't even included energy to make short segments of glass fiber due to lack of understanding.
Metamars' discovered paper of steel fracture is interesting. We aren't far off knowing how much energy was required.
Building mass I think was 380,000 tonnes above ground per tower (Omika quoting Tanaka I recall).
Maybe it would be easier to just dig up the old posts and replay them.....again here.
QUOTE (Capracus+May 3 2007, 12:12 PM)
Who says the top blocks remains intact? It's pretty obvious that the funneling or wedging was going on above and below the collapse fronts. Think of the collapse front as a double sided fruit juicer, extracting mostly floor elements from the upper and lower blocks as it descended to the bottom.
The Bazant et al. crush down, crush up model relies on an intact upper block during the crush down phase. If the upper block is losing mass at a similar rate to the lower block then the collapse will slow and stop when the upper block has run out of mass!
The Bazant et al. crush down, crush up model relies on an intact upper block during the crush down phase. If the upper block is losing mass at a similar rate to the lower block then the collapse will slow and stop when the upper block has run out of mass!
No I don't think it will stop for a mass ejection model, because even if all mass from the block is lost then in the mean time there is still enough mass collected below the top block to continue. It will be a very different collapse time indeed. But I still think the discussion about energy absorption is not finished for the simple reason that for wtc1 a stepwise 0.6 GJ absorption is inconsistent with the top block that provides 2.4GJ of kinetic energy. But if you add some crush-up in the beginning (and maybe a slower one during the fall) that problem is solved.
I'm wondering if you place the top on ground zero and drop it then the energy laws say that the drop of one story doesn't provide enough energy to collapse the whole block but in classical CDs they also only blow up the floors at the bottom, if you then get a total collapse from bottom-up then it is indeed a stepwise process. If there is not sufficient energy in the beginning the collapse will stop, but I'm wondering if that is only valid if E_kin<E1 or if that is valid for E_kin<(n-1)E1.
The story at the bottom will in general be the strongest because it needs to lift most of the statical mass but when it falls it also gets the most dynamical mass.
The per story absorption is then maybe indeed valid.
I'm wondering if you place the top on ground zero and drop it then the energy laws say that the drop of one story doesn't provide enough energy to collapse the whole block but in classical CDs they also only blow up the floors at the bottom, if you then get a total collapse from bottom-up then it is indeed a stepwise process. If there is not sufficient energy in the beginning the collapse will stop, but I'm wondering if that is only valid if E_kin<E1 or if that is valid for E_kin<(n-1)E1.
The story at the bottom will in general be the strongest because it needs to lift most of the statical mass but when it falls it also gets the most dynamical mass.
The per story absorption is then maybe indeed valid.
E1 not a constant: E1 consists of the energy required to do several things. This changes, getting generally larger, as the collapse progresses. It includes the energy required to detach the trusses from the seats. This is less than 50 MJ out of the 500+ MJ consumed per story during the first few seconds of collapse.
B & V divide a collapsing tower into the top block, zone A, the crushed part, zone B, and the lower intact part, zone C. As long as zones A+B possess enough kinetic energy the collapse will continue even if mass is shed from zone A or zone B.
Recent video/audio evidence collected by shagster demonstrates that the collapse of both towers took much longer than anybody previously estimated, 18 seconds for WTC 1 and perhaps as long for WTC 2. If correct, both imply that E! grows to much larger than 500 MJ in the latter stages of collapse or considerable mass is lost from A+B (or both).
Finally, a substantial portion of the lower cores of both towers did not participate in the progressive collapse, but fell down a few seconds later. Similarly, the lower west wall of WTC 1 did not participate in the progressive collapse but rather fell over, producing the definite bang at the end of the audio, according to shagster.
B & V divide a collapsing tower into the top block, zone A, the crushed part, zone B, and the lower intact part, zone C. As long as zones A+B possess enough kinetic energy the collapse will continue even if mass is shed from zone A or zone B.
Recent video/audio evidence collected by shagster demonstrates that the collapse of both towers took much longer than anybody previously estimated, 18 seconds for WTC 1 and perhaps as long for WTC 2. If correct, both imply that E! grows to much larger than 500 MJ in the latter stages of collapse or considerable mass is lost from A+B (or both).
Finally, a substantial portion of the lower cores of both towers did not participate in the progressive collapse, but fell down a few seconds later. Similarly, the lower west wall of WTC 1 did not participate in the progressive collapse but rather fell over, producing the definite bang at the end of the audio, according to shagster.
einsteen
1) all floors detached from the core(s)
2) all floors still fixed with the core but the core breaks in sequences during global collapse
Or
3) those floors in the lower, intact section pancake into the subbasements, leaving behind the mostly intact core columns and outer frame which the top block falls into, pushing the outer frame outwards and causing the core columns to snap at their weakest points(the welds). This matches the distribution and condition of the frame members, floor rubble and the core columns. The top block does not undergo much deteriation or loss until the resistence of the GROUND becomes great enough to overcome the resistence of the top to disintegration(something pushing over outer frame members could not do). Some of the core columns were seen to still be standing after the collapses, but were not able to continue to stand unbraced horizontally.
blue74
Or
3) those floors in the lower, intact section pancake into the subbasements, leaving behind the mostly intact core columns and outer frame which the top block falls into, pushing the outer frame outwards and causing the core columns to snap at their weakest points(the welds). This matches the distribution and condition of the frame members, floor rubble and the core columns. The top block does not undergo much deteriation or loss until the resistence of the GROUND becomes great enough to overcome the resistence of the top to disintegration(something pushing over outer frame members could not do). Some of the core columns were seen to still be standing after the collapses, but were not able to continue to stand unbraced horizontally.
blue74
The energy analysis shows a big black hole just counting concrete comminution energy, and we hadn't even included energy to make short segments of glass fiber due to lack of understanding.
The amount of glass fibers in the gypsum board and insulation accounts for the fibers found in the dust. Very little of the concrete of the twin towers was crushed into dust. So what about this do you have such a lack of understanding of, hmmm???
Grumpy
Hi,
there's a pdf here which has in the reference list some sources where the numbers have been estimated.
http://journalof911studies.com/letters/wtc..._and_energy.pdf
http://journalof911studies.com/letters.html
3) those floors in the lower, intact section pancake into the subbasements, leaving behind the mostly intact core columns and outer frame which the top block falls into, pushing the outer frame outwards and causing the core columns to snap at their weakest points(the welds). This matches the distribution and condition of the frame members, floor rubble and the core columns. The top block does not undergo much deteriation or loss until the resistence of the GROUND becomes great enough to overcome the resistence of the top to disintegration(something pushing over outer frame members could not do). Some of the core columns were seen to still be standing after the collapses, but were not able to continue to stand unbraced horizontally.
Grumpy,
I try to visualize your point 3) but I have no idea to do that. Maybe it is really easy but I have no idea how to do that, if
anyone has an idea I'm very happy.
You said the top block funnels through the building and the welded core below breaks into pieces. I think it is a little
bit strange because that implies that the floors below are indeed not detached from the building but still one part
with the trusses and the trusses are still connected at the core which breaks stepwise. This is no pancaking.
And it probably requires more energy to break the core than detaching the trusses from the cores.
Isn't the whole pancaking idea that a core still stands and floors are detached, from video evidence we clearly see
that the whole top block falls down dramatically without any resistance, the top floors are not detached from the core columns because we then would clearly see that in the videos. But again as I said before I don't understand why a
modified Greening model isn't good enough. If I understand this paper it is not a real pancaking in which floors are detached but complete stories are compressed. Maybe a core part left at the bottom can be explained by the fact that
the E1's are higher at the bottom and the mass becomes more chaotically.
QUOTE
1) all floors detached from the core(s)
2) all floors still fixed with the core but the core breaks in sequences during global collapse
Or
3) those floors in the lower, intact section pancake into the subbasements, leaving behind the mostly intact core columns and outer frame which the top block falls into, pushing the outer frame outwards and causing the core columns to snap at their weakest points(the welds). This matches the distribution and condition of the frame members, floor rubble and the core columns. The top block does not undergo much deteriation or loss until the resistence of the GROUND becomes great enough to overcome the resistence of the top to disintegration(something pushing over outer frame members could not do). Some of the core columns were seen to still be standing after the collapses, but were not able to continue to stand unbraced horizontally.
blue74
QUOTE (->
| QUOTE |
1) all floors detached from the core(s) 2) all floors still fixed with the core but the core breaks in sequences during global collapse |
Or
3) those floors in the lower, intact section pancake into the subbasements, leaving behind the mostly intact core columns and outer frame which the top block falls into, pushing the outer frame outwards and causing the core columns to snap at their weakest points(the welds). This matches the distribution and condition of the frame members, floor rubble and the core columns. The top block does not undergo much deteriation or loss until the resistence of the GROUND becomes great enough to overcome the resistence of the top to disintegration(something pushing over outer frame members could not do). Some of the core columns were seen to still be standing after the collapses, but were not able to continue to stand unbraced horizontally.
blue74
The energy analysis shows a big black hole just counting concrete comminution energy, and we hadn't even included energy to make short segments of glass fiber due to lack of understanding.
The amount of glass fibers in the gypsum board and insulation accounts for the fibers found in the dust. Very little of the concrete of the twin towers was crushed into dust. So what about this do you have such a lack of understanding of, hmmm???
Grumpy
QUOTE (blue74+May 3 2007, 01:55 PM)
Reading this thread is like watching Days of Our Lives.
The energy analysis shows a big black hole ...
Building mass I think was 380,000 tonnes above ground per tower (Omika quoting Tanaka I recall).
(1) You said it!
(2) Not with the newest estimates of the total collapse time.
(3) Thanks for the reminder. I'm certainly more comfortable with this figure.
The energy analysis shows a big black hole ...
Building mass I think was 380,000 tonnes above ground per tower (Omika quoting Tanaka I recall).
(1) You said it!
(2) Not with the newest estimates of the total collapse time.
(3) Thanks for the reminder. I'm certainly more comfortable with this figure.
QUOTE (einsteen+May 3 2007, 09:06 AM)
... if A wedges B then B wedges A, ...
ps. The NIST spokesman really said the core failed first, this will make the story even more difficult.
(1) This appears to make sense right at the beginning of collapse of WTC 1. However, a crushed mass, zone B, develops then the symmetry is no longer obvious since the crushed mass is already, well, crushed.
(2) The NCSTAR1 report makes it clear (to me, anyway) that the exterior walls failed first, at least for WTC 1.
ps. The NIST spokesman really said the core failed first, this will make the story even more difficult.
(1) This appears to make sense right at the beginning of collapse of WTC 1. However, a crushed mass, zone B, develops then the symmetry is no longer obvious since the crushed mass is already, well, crushed.
(2) The NCSTAR1 report makes it clear (to me, anyway) that the exterior walls failed first, at least for WTC 1.
QUOTE (lozenge124+May 3 2007, 03:06 PM)
The Bazant et al. crush down, crush up model relies on an intact upper block during the crush down phase. If the upper block is losing mass at a similar rate to the lower block then the collapse will slow and stop when the upper block has run out of mass!
Crush up on the upper block does not translate into a loss of mass, only the configuration of it. For the upper block to add mass to the collapse front, it had to experience its resistance also. Whenever this resistance exceeded to strength of the lower elements of the top block, they became disassociated. As the collapse front descended, the strength of the core and perimeter columns increased, adding more resistance to the upper block elements, and increasing the rate of crush up.
Crush up on the upper block does not translate into a loss of mass, only the configuration of it. For the upper block to add mass to the collapse front, it had to experience its resistance also. Whenever this resistance exceeded to strength of the lower elements of the top block, they became disassociated. As the collapse front descended, the strength of the core and perimeter columns increased, adding more resistance to the upper block elements, and increasing the rate of crush up.
QUOTE (Capracus+May 4 2007, 01:16 AM)
Crush up on the upper block does not translate into a loss of mass, only the configuration of it. For the upper block to add mass to the collapse front, it had to experience its resistance also...
Previously this week I posed about what B & V had to say regarding crush-up during crush-down. Under the four assumptions of their paper, other than at the beginning of crush-down, no crush-up is possible during crush-down.
shagster put it this way: once a crushed mass of sufficient thickness exists in zone B, this protects the top block, zone A, from further damage until crush-down is complete.
All the above is only approximately correct for the actual collapses, as inspection of videos demonstrates. That is, part of each core remained standing after the progressive collapses. At least for WTC 1 this implies the surviving core must have damaged the zone A top block. In the case of WTC 2 it is possible to consider that the entire zone A top block rotated off to the southeast before the collapses reached floor 55. (Don't know that that happened, but I suspect it.)
Previously this week I posed about what B & V had to say regarding crush-up during crush-down. Under the four assumptions of their paper, other than at the beginning of crush-down, no crush-up is possible during crush-down.
shagster put it this way: once a crushed mass of sufficient thickness exists in zone B, this protects the top block, zone A, from further damage until crush-down is complete.
All the above is only approximately correct for the actual collapses, as inspection of videos demonstrates. That is, part of each core remained standing after the progressive collapses. At least for WTC 1 this implies the surviving core must have damaged the zone A top block. In the case of WTC 2 it is possible to consider that the entire zone A top block rotated off to the southeast before the collapses reached floor 55. (Don't know that that happened, but I suspect it.)
I find the discussion of Crush Up/Crush down and variations of same to be interesting (from a theoretical point of view) but still essentially pointless.
Which is why I'm glad that NIST didn't spend any of their limited time and resources on it.
These discussions simply reinforce for me why NIST's decision to not do an analysis past the point of collapse initiation was a good one.
Arthur
Which is why I'm glad that NIST didn't spend any of their limited time and resources on it.
These discussions simply reinforce for me why NIST's decision to not do an analysis past the point of collapse initiation was a good one.
Arthur
QUOTE (David B. Benson+May 2 2007, 07:26 PM)
But from this, it seems you were referring to a well done CD. If so, then you are once again simply wrong. The only well done CD for such structures would have to be an implosion.
I don't have any particular interest in a "well done CD". You added that to the discussion. One line of questioning I have has more to do with how you are deriving your confidence in the model, especially since you have such an apparent disdain for validation. I have to wonder what you think model validation is all about. It is not a classroom exercise or thought experiment. You cannot write a few equations to arrive at model validation. You cannot validate by saying people who know anything about physics are just alright with your assumptions. I have worked with good people who were led astray by models that had great agreement with test data but failed when put in the field. The failures were traced to faulty reliance on the validity of underlying assumptions. Good model validation is hard work that requires cross-referencing with data, preferably obtained from experimentation under controlled conditions. And this is just the beginning of validation, the data sets themselves have to be thoroughly questioned to determine if they are comprehensively representative of the phenomenon to be modeled. Controlled experiment to obtain data for building collapses is obviously not very feasible so where do we turn. Apparently, Bazant recognized this situation by including a discussion in BV on the use of controlled demolition data to validate his model. Frank Greening made several posts questioning the use of CD data to validate a non-CD model and I would echo that here. Metamars showed us another possible avenue with the Calladine and English paper, but rather than investigate this line you waved it off with barely a consideration. It is also possible that data from more detailed analyses, such as what could be obtained from an FEA, could help corroborate the basic assumptions of your model. But rather than welcome any data that are derived from such efforts you again waved it off as unnecessary. If you are so confident in your model, then why not welcome any work which you must feel will back it up? No experiments have been performed nor data collected to validate crush-down and crush-up, or the localization of the action to the crushing front, or the other key assumptions of the model. These notions have been created on the special occasion of the WTC 1 and 2 "collapses". This alone should open them to intense questioning. Yet you speak of them as if Newton himself passed them down to you. If you can validate the underlying assumptions of your model, then please show me the hard data that does this. If you cannot do this, then please be honest and admit it. It is possible that in the face of this you will still hold to your position, but I, and others, are not thereby compelled to share your confidence.
My other line of questioning has to do with the discriminatory nature, or lack thereof, of your model. I believe it is fruitless to carry on this area of discussion with you.
I don't have any particular interest in a "well done CD". You added that to the discussion. One line of questioning I have has more to do with how you are deriving your confidence in the model, especially since you have such an apparent disdain for validation. I have to wonder what you think model validation is all about. It is not a classroom exercise or thought experiment. You cannot write a few equations to arrive at model validation. You cannot validate by saying people who know anything about physics are just alright with your assumptions. I have worked with good people who were led astray by models that had great agreement with test data but failed when put in the field. The failures were traced to faulty reliance on the validity of underlying assumptions. Good model validation is hard work that requires cross-referencing with data, preferably obtained from experimentation under controlled conditions. And this is just the beginning of validation, the data sets themselves have to be thoroughly questioned to determine if they are comprehensively representative of the phenomenon to be modeled. Controlled experiment to obtain data for building collapses is obviously not very feasible so where do we turn. Apparently, Bazant recognized this situation by including a discussion in BV on the use of controlled demolition data to validate his model. Frank Greening made several posts questioning the use of CD data to validate a non-CD model and I would echo that here. Metamars showed us another possible avenue with the Calladine and English paper, but rather than investigate this line you waved it off with barely a consideration. It is also possible that data from more detailed analyses, such as what could be obtained from an FEA, could help corroborate the basic assumptions of your model. But rather than welcome any data that are derived from such efforts you again waved it off as unnecessary. If you are so confident in your model, then why not welcome any work which you must feel will back it up? No experiments have been performed nor data collected to validate crush-down and crush-up, or the localization of the action to the crushing front, or the other key assumptions of the model. These notions have been created on the special occasion of the WTC 1 and 2 "collapses". This alone should open them to intense questioning. Yet you speak of them as if Newton himself passed them down to you. If you can validate the underlying assumptions of your model, then please show me the hard data that does this. If you cannot do this, then please be honest and admit it. It is possible that in the face of this you will still hold to your position, but I, and others, are not thereby compelled to share your confidence.
My other line of questioning has to do with the discriminatory nature, or lack thereof, of your model. I believe it is fruitless to carry on this area of discussion with you.
Hello everyone, Just one quick question, does any one know the typical / or estimated live loads on one of the WTC towers ?
I tried to search and found :
If you search for published values of the mass of WTC 1 or 2, the number quoted is invariably close to 500,000,000 kg or 500,000 tonnes. But where does this number come from?
Greening
Is that figure right? Did you guys confirm it later on?
Sorry to bother you.
I tried to search and found :
If you search for published values of the mass of WTC 1 or 2, the number quoted is invariably close to 500,000,000 kg or 500,000 tonnes. But where does this number come from?
Greening
QUOTE
If you search for published values of the mass of WTC 1 or 2, the number quoted is invariably close to 500,000,000 kg or 500,000 tonnes. But where does this number come from?
I have certainly never seen a detailed calculation of the mass of WTC 1 or 2; but there are plenty of references on the web for the weight of the materials used in the construction of the WTC Towers. For example, the weight of structural steel used in each Tower is generally reported to be 96,000,000 kg and the weight of concrete is said to be 48,000,000 kg per Tower. I have also seen the weight of aluminum cladding reported to be 2,000,000 kg, and the weight of wallboard quoted at 8,000,000 kg per Tower, giving a total weight of structural materials of 154,000,000 kg per Tower.
Now let’s add in reasonable “guesstimates” for plumbing fixtures (5,000,000, kg), air conditioning (5,000,000 kg), electrical and telecommunication wiring (5,000,000 kg) and we have an additional 15,000,000 kg of structural mass that civil engineers always include as part of the “dead load” of a building. Thus combining all these contributions, we arrive at a weight, or dead load, of 169,000,000 kg for one WTC Tower. Surprisingly this accounts for only about 1/3rd of the oft-quoted 500,000,000 kg, so where is the missing mass?
The answer would appear to be in what civil engineers call the “live load” of the building, which in the case of one WTC Tower would have to be (500,000,000 - 169,000,000) kg or 331,000,000 kg, i.e., twice the dead load!
I have certainly never seen a detailed calculation of the mass of WTC 1 or 2; but there are plenty of references on the web for the weight of the materials used in the construction of the WTC Towers. For example, the weight of structural steel used in each Tower is generally reported to be 96,000,000 kg and the weight of concrete is said to be 48,000,000 kg per Tower. I have also seen the weight of aluminum cladding reported to be 2,000,000 kg, and the weight of wallboard quoted at 8,000,000 kg per Tower, giving a total weight of structural materials of 154,000,000 kg per Tower.
Now let’s add in reasonable “guesstimates” for plumbing fixtures (5,000,000, kg), air conditioning (5,000,000 kg), electrical and telecommunication wiring (5,000,000 kg) and we have an additional 15,000,000 kg of structural mass that civil engineers always include as part of the “dead load” of a building. Thus combining all these contributions, we arrive at a weight, or dead load, of 169,000,000 kg for one WTC Tower. Surprisingly this accounts for only about 1/3rd of the oft-quoted 500,000,000 kg, so where is the missing mass?
The answer would appear to be in what civil engineers call the “live load” of the building, which in the case of one WTC Tower would have to be (500,000,000 - 169,000,000) kg or 331,000,000 kg, i.e., twice the dead load!
Is that figure right? Did you guys confirm it later on?
Sorry to bother you.
QUOTE (medicine_freak+May 4 2007, 10:40 AM)
Hello everyone, Just one quick question, does any one know the typical / or estimated live loads on one of the WTC towers ?
I tried to search and found :
If you search for published values of the mass of WTC 1 or 2, the number quoted is invariably close to 500,000,000 kg or 500,000 tonnes. But where does this number come from?
Greening
Is that figure right? Did you guys confirm it later on?
Sorry to bother you.
YOU forgot the glass and roofing heavy water tanks, elevators heavy elevator motors standby power generators water lines and associated plumbing pumps and such.
The towers were like a city to themselves, they had a lot of mechanicals to allow them to work.
500,000 tonnes seems conservative when you add the live load of the people furniture, and other items in the buildings.
I tried to search and found :
If you search for published values of the mass of WTC 1 or 2, the number quoted is invariably close to 500,000,000 kg or 500,000 tonnes. But where does this number come from?
Greening
Is that figure right? Did you guys confirm it later on?
Sorry to bother you.
YOU forgot the glass and roofing heavy water tanks, elevators heavy elevator motors standby power generators water lines and associated plumbing pumps and such.
The towers were like a city to themselves, they had a lot of mechanicals to allow them to work.
500,000 tonnes seems conservative when you add the live load of the people furniture, and other items in the buildings.
QUOTE
If you search for published values of the mass of WTC 1 or 2, the number quoted is invariably close to 500,000,000 kg or 500,000 tonnes. But where does this number come from?
Hi,
there's a pdf here which has in the reference list some sources where the numbers have been estimated.
http://journalof911studies.com/letters/wtc..._and_energy.pdf
http://journalof911studies.com/letters.html
I have a few comments on the mass of a WTC tower:
First, take a look at NIST NCSTAR 1-5D, page 43. Here we find one of the few places where NIST gives a simple, direct, estimate of the mass of a WTC tower.
Thus on page 43 we read:
"The average load per unit area (including live and dead loads) of a typical floor was approximately 87 lb/ft^2 (4.17 kN/m^2). Based on a typical floor area of 42,200 ft^2 (3,900 m^2), each floor in the tower would have had a weight of approximately, 3,675 kip (16,400 kN), which corresponds to a mass of 114 x 10^3 slugs (1.67 x 10^6 kg.)"
The problem with this estimate is that if 1.67 x 10^6 kg is truly an "average" mass per floor, the mass of one tower is then 110 x 1.67 x 10^6 kg = 184,000 tonnes.
A similar approach to estimating the mass of a tower is used in the recent paper by G. H. Urich in the "Scholars Journal". His estimated mass of a tower is 253,000 metric tons.
However, if you look closely at the column load data given in NIST NCSTAR 1-6D, ~ pages 225 - 230, you will see why the idea of an "average mass" of a WTC floor is not very meaningful. The very massive hat truss is part of the problem.
Hope this helps.....
First, take a look at NIST NCSTAR 1-5D, page 43. Here we find one of the few places where NIST gives a simple, direct, estimate of the mass of a WTC tower.
Thus on page 43 we read:
"The average load per unit area (including live and dead loads) of a typical floor was approximately 87 lb/ft^2 (4.17 kN/m^2). Based on a typical floor area of 42,200 ft^2 (3,900 m^2), each floor in the tower would have had a weight of approximately, 3,675 kip (16,400 kN), which corresponds to a mass of 114 x 10^3 slugs (1.67 x 10^6 kg.)"
The problem with this estimate is that if 1.67 x 10^6 kg is truly an "average" mass per floor, the mass of one tower is then 110 x 1.67 x 10^6 kg = 184,000 tonnes.
A similar approach to estimating the mass of a tower is used in the recent paper by G. H. Urich in the "Scholars Journal". His estimated mass of a tower is 253,000 metric tons.
However, if you look closely at the column load data given in NIST NCSTAR 1-6D, ~ pages 225 - 230, you will see why the idea of an "average mass" of a WTC floor is not very meaningful. The very massive hat truss is part of the problem.
Hope this helps.....
QUOTE (NEU-FONZE+May 4 2007, 08:08 AM)
I have a few comments on the mass of a WTC tower:
First, take a look at NIST NCSTAR 1-5D, page 43. Here we find one of the few places where NIST gives a simple, direct, estimate of the mass of a WTC tower.
Thus on page 43 we read:
"The average load per unit area (including live and dead loads) of a typical floor was approximately 87 lb/ft^2 (4.17 kN/m^2). Based on a typical floor area of 42,200 ft^2 (3,900 m^2), each floor in the tower would have had a weight of approximately, 3,675 kip (16,400 kN), which corresponds to a mass of 114 x 10^3 slugs (1.67 x 10^6 kg.)"
Neu, it would appear that this calculation only accounts for the loads that the actual floors carried.
Since NONE of the weight of the vertical structural members, or the hat truss, was carried by the floors, this estimate appears to be low. I think it was still reasonable for the needs of the shake table experiments (estimating the mass of 9 floors above and below the impact area).
Still if the floor calculation does not account for the mass of the columns nor the hat truss, nor the significantly higher loads on the mechanical floors, it shouldn't be extrapolated by simple multiplication to the mass of the whole towers.
Arthur
First, take a look at NIST NCSTAR 1-5D, page 43. Here we find one of the few places where NIST gives a simple, direct, estimate of the mass of a WTC tower.
Thus on page 43 we read:
"The average load per unit area (including live and dead loads) of a typical floor was approximately 87 lb/ft^2 (4.17 kN/m^2). Based on a typical floor area of 42,200 ft^2 (3,900 m^2), each floor in the tower would have had a weight of approximately, 3,675 kip (16,400 kN), which corresponds to a mass of 114 x 10^3 slugs (1.67 x 10^6 kg.)"
Neu, it would appear that this calculation only accounts for the loads that the actual floors carried.
Since NONE of the weight of the vertical structural members, or the hat truss, was carried by the floors, this estimate appears to be low. I think it was still reasonable for the needs of the shake table experiments (estimating the mass of 9 floors above and below the impact area).
Still if the floor calculation does not account for the mass of the columns nor the hat truss, nor the significantly higher loads on the mechanical floors, it shouldn't be extrapolated by simple multiplication to the mass of the whole towers.
Arthur
Arthur:
I don't see how NIST's lumped mass model can legitimately ignore the mass of the vertical structural members and still be valid. It is my understanding that the whole of the upper section recoiled when the aircraft hit the tower, thereby absorbing a significant portion of the impact energy. How could the floors move off at NIST's estimated value of 12.9 m/s and leave the columns behind so to speak?
If what you are saying is correct, NIST seriously underestimated what it calls mt, "the participating mass of the tower".
I don't see how NIST's lumped mass model can legitimately ignore the mass of the vertical structural members and still be valid. It is my understanding that the whole of the upper section recoiled when the aircraft hit the tower, thereby absorbing a significant portion of the impact energy. How could the floors move off at NIST's estimated value of 12.9 m/s and leave the columns behind so to speak?
If what you are saying is correct, NIST seriously underestimated what it calls mt, "the participating mass of the tower".
Well they had to guess about so much for those tests (speed of plane, duration of impact, energy transfer vs time etc, I doubt it's that important.
The experiments were simply trying to find out how well the Ceiling tile held up but as it turns out the Shake table (designed for Earthquakes) couldn't really simulate an aircfraft impact that well anyway. The plane created motions that were too fast and then persisted for too long for the Shake table to simulate them. Their ultimate experimental solution appears to be at best a gross approximation of what the towers went through. Still, we do know from survivor responses that the plane's impacts did cause failures of the ceiling tiles (and warped doors etc), and we know that the tiles wouldn't have held up if they were in the debris path so most of them on the fire floors are fairly reasonably accounted for.
Arthur
The experiments were simply trying to find out how well the Ceiling tile held up but as it turns out the Shake table (designed for Earthquakes) couldn't really simulate an aircfraft impact that well anyway. The plane created motions that were too fast and then persisted for too long for the Shake table to simulate them. Their ultimate experimental solution appears to be at best a gross approximation of what the towers went through. Still, we do know from survivor responses that the plane's impacts did cause failures of the ceiling tiles (and warped doors etc), and we know that the tiles wouldn't have held up if they were in the debris path so most of them on the fire floors are fairly reasonably accounted for.
Arthur
Does anyone know a use for these metal spheres I keep creating?
These little hollow ones are the funnest ones.
Since I have created several, I need to find a use for them.
These little hollow ones are the funnest ones.
Since I have created several, I need to find a use for them.
QUOTE (Grumpy+May 3 2007, 07:24 PM)
3) those floors in the lower, intact section pancake into the subbasements, leaving behind the mostly intact core columns and outer frame which the top block falls into, pushing the outer frame outwards and causing the core columns to snap at their weakest points(the welds). This matches the distribution and condition of the frame members, floor rubble and the core columns. The top block does not undergo much deteriation or loss until the resistence of the GROUND becomes great enough to overcome the resistence of the top to disintegration(something pushing over outer frame members could not do). Some of the core columns were seen to still be standing after the collapses, but were not able to continue to stand unbraced horizontally.
Grumpy,
I try to visualize your point 3) but I have no idea to do that. Maybe it is really easy but I have no idea how to do that, if
anyone has an idea I'm very happy.
You said the top block funnels through the building and the welded core below breaks into pieces. I think it is a little
bit strange because that implies that the floors below are indeed not detached from the building but still one part
with the trusses and the trusses are still connected at the core which breaks stepwise. This is no pancaking.
And it probably requires more energy to break the core than detaching the trusses from the cores.
Isn't the whole pancaking idea that a core still stands and floors are detached, from video evidence we clearly see
that the whole top block falls down dramatically without any resistance, the top floors are not detached from the core columns because we then would clearly see that in the videos. But again as I said before I don't understand why a
modified Greening model isn't good enough. If I understand this paper it is not a real pancaking in which floors are detached but complete stories are compressed. Maybe a core part left at the bottom can be explained by the fact that
the E1's are higher at the bottom and the mass becomes more chaotically.
neu-fonze, i still don't see how you and NIST can ignore the accelerations observed in the lateral ejections. i think perhaps you are overestimating the work ethic of gravity.
i just watched the "WTC_trinity.mp4", and it is quite obvious that the demolition wave is:
a. - descending faster than acceleration of gravity(as evidenced by a sudden floorwide massive expulsion of debris which briefly "catches up" with freefalling debris which has been falling through air for (and most definitely out-accelerates the rate of descent of the 'cap', and is also not a steady acceleration curve, as would be expected, but one with sudden bursts of speed.)
b. - the result of controlled demolition (because the destruction on the inside of the building cannot accelerate at the rate of acceleration due to gravity, while simultaneously using gravity's acceleration as the power source for destruction)
in this particular video, you can actually see(as i've shown before from an ABC video) the wave of destruction progressing down the building FASTER than things which are falling through air on the outside. beams and cladding which has been falling for several stories ahead of the collapse wave, get enveloped by the clouds of dust and debris shooting out from inside the building.
so, it's safe to say, that although the towers did not go into freefall, the demolition wave travelled down the side of the building FASTER than freefall, which is of course, physically impossible from a gravity driven collapse.
i just watched the "WTC_trinity.mp4", and it is quite obvious that the demolition wave is:
a. - descending faster than acceleration of gravity(as evidenced by a sudden floorwide massive expulsion of debris which briefly "catches up" with freefalling debris which has been falling through air for (and most definitely out-accelerates the rate of descent of the 'cap', and is also not a steady acceleration curve, as would be expected, but one with sudden bursts of speed.)
b. - the result of controlled demolition (because the destruction on the inside of the building cannot accelerate at the rate of acceleration due to gravity, while simultaneously using gravity's acceleration as the power source for destruction)
in this particular video, you can actually see(as i've shown before from an ABC video) the wave of destruction progressing down the building FASTER than things which are falling through air on the outside. beams and cladding which has been falling for several stories ahead of the collapse wave, get enveloped by the clouds of dust and debris shooting out from inside the building.
so, it's safe to say, that although the towers did not go into freefall, the demolition wave travelled down the side of the building FASTER than freefall, which is of course, physically impossible from a gravity driven collapse.
Where can the rest of us see this video to see if we see the same things you do?
Arthur
Arthur
for arthurs
it's the one titled, "View of South Tower from Trinity Street ".
i won't be surprised when you tell me you don't see the same thing.
it's the one titled, "View of South Tower from Trinity Street ".
i won't be surprised when you tell me you don't see the same thing.
QUOTE (newton+May 4 2007, 03:50 PM)
for arthurs
it's the one titled, "View of South Tower from Trinity Street ".
i won't be surprised when you tell me you don't see the same thing.
You're right, I don't.
Clearly you can see free falling material and follow it as it reaches a point in line with the church spire, FAR AHEAD of the collapse front.
Arthur
it's the one titled, "View of South Tower from Trinity Street ".
i won't be surprised when you tell me you don't see the same thing.
You're right, I don't.
Clearly you can see free falling material and follow it as it reaches a point in line with the church spire, FAR AHEAD of the collapse front.
Arthur
QUOTE (eigenvalue+May 4 2007, 05:20 AM)
... One line of questioning I have has more to do with how you are deriving your confidence in the model, especially since you have such an apparent disdain for validation. ...
Metamars showed us another possible avenue with the Calladine and English paper, ...
... an FEA could help corroborate the basic assumptions of your model.
If you can validate the underlying assumptions of your model, then please show me the hard data that does this. ...
My other line of questioning has to do with the discriminatory nature, or lack thereof, of your model. ...
First of all, it is not my model, but rather the equations of B & V. I certainly have no disdain for validation. Would you prefer that I call what I did verification?
Metamars seems overly concerned with impact. IMO, structural stability, as in the two fine books by Simitses, is much more relevant to collapse initiation.
While I would certainly welcome anything which would provide definitive (positive or negative) information, for reasons I won't go into just now, I doubt that FEA could provide this. As I said, it is pointless.
What would satisfy you? Twice now I have asked you to state your objections to the four assumptions used by B & V. So far, no reply. (Actually, this now implicitly makes three times.
)
I fail to understand what you mean by discriminatory nature. You will have to clarify.
Metamars showed us another possible avenue with the Calladine and English paper, ...
... an FEA could help corroborate the basic assumptions of your model.
If you can validate the underlying assumptions of your model, then please show me the hard data that does this. ...
My other line of questioning has to do with the discriminatory nature, or lack thereof, of your model. ...
First of all, it is not my model, but rather the equations of B & V. I certainly have no disdain for validation. Would you prefer that I call what I did verification?
Metamars seems overly concerned with impact. IMO, structural stability, as in the two fine books by Simitses, is much more relevant to collapse initiation.
While I would certainly welcome anything which would provide definitive (positive or negative) information, for reasons I won't go into just now, I doubt that FEA could provide this. As I said, it is pointless.
What would satisfy you? Twice now I have asked you to state your objections to the four assumptions used by B & V. So far, no reply. (Actually, this now implicitly makes three times.
)I fail to understand what you mean by discriminatory nature. You will have to clarify.
I'm not sure what the point is, of course the ejected debris from the very first beginning (originating from the top block as been proven) will reach the ground first. I think Newton means the beginning in which from below you it looks like the wave accelerates faster than the rest, in other words it is not x(t)=c1 t^2 but maybe c2 t^2 + c3 t.
Did anyone measure it ? that is no academic job, of course the NIST didn't because the collapse doesn't matter.
Did anyone measure it ? that is no academic job, of course the NIST didn't because the collapse doesn't matter.
QUOTE (newton+May 4 2007, 07:55 PM)
neu-fonze, i still don't see how you and NIST can ignore the accelerations observed in the lateral ejections. i think perhaps you are overestimating the work ethic of gravity.
i just watched the "WTC_trinity.mp4", and it is quite obvious that the demolition wave is:
a. - descending faster than acceleration of gravity(as evidenced by a sudden floorwide massive expulsion of debris which briefly "catches up" with freefalling debris which has been falling through air for (and most definitely out-accelerates the rate of descent of the 'cap', and is also not a steady acceleration curve, as would be expected, but one with sudden bursts of speed.)
b. - the result of controlled demolition (because the destruction on the inside of the building cannot accelerate at the rate of acceleration due to gravity, while simultaneously using gravity's acceleration as the power source for destruction)
i just watched the "WTC_trinity.mp4", and it is quite obvious that the demolition wave is:
a. - descending faster than acceleration of gravity(as evidenced by a sudden floorwide massive expulsion of debris which briefly "catches up" with freefalling debris which has been falling through air for (and most definitely out-accelerates the rate of descent of the 'cap', and is also not a steady acceleration curve, as would be expected, but one with sudden bursts of speed.)
b. - the result of controlled demolition (because the destruction on the inside of the building cannot accelerate at the rate of acceleration due to gravity, while simultaneously using gravity's acceleration as the power source for destruction)
Gravity needs no assistance from explosives. Just the kinetic energy of one floor system mass falling one story imparts ten times the load capability of an intact floor. Now add the accumulated floor masses and you can see that resistance is negligible, with plenty of excess energy for the modest lateral ejections witnessed.
What kind of explosive demolition process is designed to do more than remove isolated structural elements? Are you suggesting that entire floors were packed with explosives in order to impart a downward thrust? Go ask einsteen how a rational demolitionist would get the job done. He at least understands that gravity is the primary force of a CD, and that explosives are just the trigger. In the case of the towers the trigger was the plane crashes and the resultant instability of the buildings.
What kind of explosive demolition process is designed to do more than remove isolated structural elements? Are you suggesting that entire floors were packed with explosives in order to impart a downward thrust? Go ask einsteen how a rational demolitionist would get the job done. He at least understands that gravity is the primary force of a CD, and that explosives are just the trigger. In the case of the towers the trigger was the plane crashes and the resultant instability of the buildings.
QUOTE (einsteen+May 4 2007, 05:09 PM)
I'm not sure what the point is, of course the ejected debris from the very first beginning (originating from the top block as been proven) will reach the ground first. I think Newton means the beginning in which from below you it looks like the wave accelerates faster than the rest, in other words it is not x(t)=c1 t^2 but maybe c2 t^2 + c3 t.
Did anyone measure it ? that is no academic job, of course the NIST didn't because the collapse doesn't matter.
NOPE,
newton states:
But looking at the video it is quite clear that the falling material is accelerating FASTER than the wave of destruction. There are in fact, numerous pieces you can track (go frame by frame) and see that their RELATIVE distances from the wave of destruction increases over time.
Arthur
Did anyone measure it ? that is no academic job, of course the NIST didn't because the collapse doesn't matter.
NOPE,
newton states:
QUOTE
the wave of destruction (is) progressing down the building FASTER than things which are falling through air
But looking at the video it is quite clear that the falling material is accelerating FASTER than the wave of destruction. There are in fact, numerous pieces you can track (go frame by frame) and see that their RELATIVE distances from the wave of destruction increases over time.
Arthur
QUOTE (einsteen+May 4 2007, 10:09 PM)
I'm not sure what the point is, of course the ejected debris from the very first beginning (originating from the top block as been proven) ...
it looks like the wave accelerates faster than the rest, in other words it is not x(t)=c1 t^2 but maybe c2 t^2 + c3 t.
Did anyone measure it ? ...
Where and what is the proof?
Nope. The power series expansion of the B & V crush-down equation has terms
(k_n)t^n
with k_n non-zero for all n > 1. However, these are cancelative terms (I think that is the name) so the sign of some are positive and others negative.
Using NEU-FONZE's data for the drop of the top, the B & V crush-down equation provides a much better fit than the best value of a in
d = (1/2)at^2.
By the way, I spent a little time looking at definitions for verification and validation. I now think that verification is the better choice for what I have done.
=================================================
It might be possible, using stop-frame videos, to measure the height of the top block (zone A) at collapse initiation and to, in later frames, estimate the height from the top of the top block down to the crushing front, this height being zone A+B. I would certainly be interested in have such (estimated) data!
it looks like the wave accelerates faster than the rest, in other words it is not x(t)=c1 t^2 but maybe c2 t^2 + c3 t.
Did anyone measure it ? ...
Where and what is the proof?
Nope. The power series expansion of the B & V crush-down equation has terms
(k_n)t^n
with k_n non-zero for all n > 1. However, these are cancelative terms (I think that is the name) so the sign of some are positive and others negative.
Using NEU-FONZE's data for the drop of the top, the B & V crush-down equation provides a much better fit than the best value of a in
d = (1/2)at^2.
By the way, I spent a little time looking at definitions for verification and validation. I now think that verification is the better choice for what I have done.
=================================================
It might be possible, using stop-frame videos, to measure the height of the top block (zone A) at collapse initiation and to, in later frames, estimate the height from the top of the top block down to the crushing front, this height being zone A+B. I would certainly be interested in have such (estimated) data!
newton
Thanks for the film.
einsteen
http://911research.com/wtc/evidence/videos...r_collapse.mpeg
http://911research.com/wtc/evidence/videos...ition_waves.mpg
and best of all
http://911research.com/wtc/evidence/videos...south_below.mpg
The "destruction wave" newton sees is the only external clue to the pancaking floors. Those relatively small ejections of dust and air from blown windows is not explosives, but is just the air ejected from the compressing floors AHEAD of the crush zone and top block.
Can you visualize it now???
Grumpy
Thanks for the film.
einsteen
QUOTE
Grumpy,
I try to visualize your point 3) but I have no idea to do that. Maybe it is really easy but I have no idea how to do that, if
anyone has an idea I'm very happy.
I try to visualize your point 3) but I have no idea to do that. Maybe it is really easy but I have no idea how to do that, if
anyone has an idea I'm very happy.
http://911research.com/wtc/evidence/videos...r_collapse.mpeg
http://911research.com/wtc/evidence/videos...ition_waves.mpg
and best of all
http://911research.com/wtc/evidence/videos...south_below.mpg
The "destruction wave" newton sees is the only external clue to the pancaking floors. Those relatively small ejections of dust and air from blown windows is not explosives, but is just the air ejected from the compressing floors AHEAD of the crush zone and top block.
Can you visualize it now???
Grumpy
QUOTE (Grumpy+May 5 2007, 12:42 AM)
Those relatively small ejections of dust and air from blown windows is not explosives, but is just the air ejected from the compressing floors AHEAD of the crush zone and top block. [emphasis added]
Since there are voids in the core floors, I suspect that the effect is due to the air in the lower block (zone C) being compressed to the point where some of the only 1/4" thick windows break.
Other evidence of this compression includes:
(i) a survivor reporting being blown down six flights of stairs;
(ii) a photograph taken by a non-survivor showing a massive gust of wind, filled with entrapped fines, being blown out the glassless windows of the lobby of one of the towers.
Since there are voids in the core floors, I suspect that the effect is due to the air in the lower block (zone C) being compressed to the point where some of the only 1/4" thick windows break.
Other evidence of this compression includes:
(i) a survivor reporting being blown down six flights of stairs;
(ii) a photograph taken by a non-survivor showing a massive gust of wind, filled with entrapped fines, being blown out the glassless windows of the lobby of one of the towers.
QUOTE (David B. Benson+May 4 2007, 03:08 PM)
First of all, it is not my model, but rather the equations of B & V.
I fail to understand what you mean by discriminatory nature. You will have to clarify.
I think it is understood that I mean the model you are working with when I say "your
model", it makes for shorter sentences.
I would prefer that you understood the terms verification and validation and how to
use them correctly (both in a sentence and in your work).
I would prefer that you understood the terms verification and validation and how to
use them correctly (both in a sentence and in your work).
Metamars seems overly concerned with impact. IMO, structural stability, as in the two fine books by Simitses, is much more relevant to collapse initiation.
I don't have much respect for the use of smilies but the perplexity these statements
cause puts me on the verge of using them. The impacts, and hence Calladine and
English, have more to do with collapse propagation. Consider this statement from
Bazant-Zhou that appears in Bazant-Verdure and which I know you are familiar with:
they are in the right ballpark and just might have something important to say. Their
applicability has not yet been established but to dismiss them out of hand is surely
inappropriate.
Of course there is NO EVIDENCE that there were ANY bombs at all.
Arthur
Of course there is NO EVIDENCE that there were ANY bombs at all.
Arthur
You mean if they were there it would be found ? Between 5 x 10 ^8 kg material ? As a lay man I would say that something that is explosive by definition vanishes away and will not be found. And what about modern chemical techniques, those dogs noises are not trained for those and aren't bomb sniffing dogs only capable to sniff unexploded bombs because afterwards they probably even cannot distinguish the mess around and the gun of a policeman.
I fail to understand what you mean by discriminatory nature. You will have to clarify.
I think it is understood that I mean the model you are working with when I say "your
model", it makes for shorter sentences.
QUOTE
I certainly have no disdain for validation. Would you prefer that I call what I did verification?
I would prefer that you understood the terms verification and validation and how to
use them correctly (both in a sentence and in your work).
QUOTE (->
| QUOTE |
| I certainly have no disdain for validation. Would you prefer that I call what I did verification? |
I would prefer that you understood the terms verification and validation and how to
use them correctly (both in a sentence and in your work).
Metamars seems overly concerned with impact. IMO, structural stability, as in the two fine books by Simitses, is much more relevant to collapse initiation.
I don't have much respect for the use of smilies but the perplexity these statements
cause puts me on the verge of using them. The impacts, and hence Calladine and
English, have more to do with collapse propagation. Consider this statement from
Bazant-Zhou that appears in Bazant-Verdure and which I know you are familiar with:
QUOTE
The kinetic energy of the top part of tower impacting the floor below was
found to be about 8.4× larger than the plastic energy absorption capability of the
underlying story, and considerably higher than that if fracturing were taken into
account (Bazant and Zhou 2002).
This sure sounds like a lot of things that C&E concerned themselves with, found to be about 8.4× larger than the plastic energy absorption capability of the
underlying story, and considerably higher than that if fracturing were taken into
account (Bazant and Zhou 2002).
they are in the right ballpark and just might have something important to say. Their
applicability has not yet been established but to dismiss them out of hand is surely
inappropriate.
QUOTE (->
| QUOTE |
| The kinetic energy of the top part of tower impacting the floor below was found to be about 8.4× larger than the plastic energy absorption capability of the underlying story, and considerably higher than that if fracturing were taken into account (Bazant and Zhou 2002). |
This sure sounds like a lot of things that C&E concerned themselves with,
they are in the right ballpark and just might have something important to say. Their
applicability has not yet been established but to dismiss them out of hand is surely
inappropriate.
While I would certainly welcome anything which would provide definitive (positive or negative) information, for reasons I won't go into just now, I doubt that FEA could provide this. As I said, it is pointless.
FEA is a major tool in the analysis of structures. On what basis do you regard it as
"pointless"? Here again, you make a proclamation without offering any substantive
support. I suspect you do not have the experience or qualifications in this area to
so make such an assertion.
My objection to the assumptions of BV are precisely as I stated in my last post, they
are unvalidated and have been created just for the cases of WTC 1 and 2. Your
inexperience with the terms verification and validation confirms to me that you lack
the experience needed in modeling and simulation to make the types of qualified
judgments you are trying to do here on this forum. I believe I have learned what I
needed to in this exchange.
they are in the right ballpark and just might have something important to say. Their
applicability has not yet been established but to dismiss them out of hand is surely
inappropriate.
While I would certainly welcome anything which would provide definitive (positive or negative) information, for reasons I won't go into just now, I doubt that FEA could provide this. As I said, it is pointless.
FEA is a major tool in the analysis of structures. On what basis do you regard it as
"pointless"? Here again, you make a proclamation without offering any substantive
support. I suspect you do not have the experience or qualifications in this area to
so make such an assertion.
QUOTE
What would satisfy you? Twice now I have asked you to state your objections to the four assumptions used by B & V. So far, no reply. (Actually, this now implicitly makes three times.)
My objection to the assumptions of BV are precisely as I stated in my last post, they
are unvalidated and have been created just for the cases of WTC 1 and 2. Your
inexperience with the terms verification and validation confirms to me that you lack
the experience needed in modeling and simulation to make the types of qualified
judgments you are trying to do here on this forum. I believe I have learned what I
needed to in this exchange.
QUOTE (eigenvalue+May 5 2007, 02:02 AM)
Consider this statement from Bazant-Zhou ...
FEA is a major tool in the analysis of structures. ...
... have been created just for the cases of WTC 1 and 2.
But it is clear that B & Z are a worse case approximation, made before NEU-FONZE made his measurements. As I have previously posted, WTC 1 offered resistance right at the beginning of collapse, before any impact of the next floor down could occur. Thus the study of structural stability, IMO, offers a better way to explain collapse initiation. As for collapse propagation, nothing depends upon a floor by floor progression other than conservation of momentum. The actual trussed floors offered at most 4% of the total resistance.
FEA probably works great for intact structures. However, the constitutive laws for connections failing in a collapse are simply unknown and probably not modelable. Therefore, without doing experiments regarding such failing connections anything but into an FEA would be guess-work. Finally, from reading NIST's NCSTAR1, I gather than FEA analysis has some difficulties correctly handling actual disconnections occurring.
Yes, the structural engineering community was shocked into action by the events at WTC. However, progressive collapse had been considered, somewhat, as early as 1974. The main focus of most of the engineers is design and construction methods which will avoid dispassionate collapse.
Now the B & V crush-down equation is a constitutive equation, one which follows from first principles. Thus what is needed to verify it is simply enough data. Unfortunately, there are only two such sequences, both rather short. However, this is enough to demonstrate that this equation provides a better match to the data than d = (1/2)at^2. If I bothered, I am positive I can show it is a better match than the B & V crush-up equation.
It is, in my experience, the phenomenological equations, and worse, discrete simulations, which require more extensive validation.
You claim the the B & V crush-down equation is unvalidated, or rather the four assumptions are. Why? B & V offer good justifications, IMO. The first three assumptions agree with the independent work of Greening. I showed that it gives a good match to the data. Quit just carping and offer some substantive criticisms.
FEA is a major tool in the analysis of structures. ...
... have been created just for the cases of WTC 1 and 2.
But it is clear that B & Z are a worse case approximation, made before NEU-FONZE made his measurements. As I have previously posted, WTC 1 offered resistance right at the beginning of collapse, before any impact of the next floor down could occur. Thus the study of structural stability, IMO, offers a better way to explain collapse initiation. As for collapse propagation, nothing depends upon a floor by floor progression other than conservation of momentum. The actual trussed floors offered at most 4% of the total resistance.
FEA probably works great for intact structures. However, the constitutive laws for connections failing in a collapse are simply unknown and probably not modelable. Therefore, without doing experiments regarding such failing connections anything but into an FEA would be guess-work. Finally, from reading NIST's NCSTAR1, I gather than FEA analysis has some difficulties correctly handling actual disconnections occurring.
Yes, the structural engineering community was shocked into action by the events at WTC. However, progressive collapse had been considered, somewhat, as early as 1974. The main focus of most of the engineers is design and construction methods which will avoid dispassionate collapse.
Now the B & V crush-down equation is a constitutive equation, one which follows from first principles. Thus what is needed to verify it is simply enough data. Unfortunately, there are only two such sequences, both rather short. However, this is enough to demonstrate that this equation provides a better match to the data than d = (1/2)at^2. If I bothered, I am positive I can show it is a better match than the B & V crush-up equation.
It is, in my experience, the phenomenological equations, and worse, discrete simulations, which require more extensive validation.
You claim the the B & V crush-down equation is unvalidated, or rather the four assumptions are. Why? B & V offer good justifications, IMO. The first three assumptions agree with the independent work of Greening. I showed that it gives a good match to the data. Quit just carping and offer some substantive criticisms.
QUOTE (eigenvalue+May 4 2007, 09:02 PM)
I believe I have learned what I needed to in this exchange.
As did the rest of us.
Arthur
As did the rest of us.
Arthur
Looks like someone managed to obtain some of the SAP2000 computer model files from NIST:
http://razor.occams.info/nist-wtc/
Anyone here with SAP2000 experience?
http://razor.occams.info/nist-wtc/
Anyone here with SAP2000 experience?
QUOTE (Grumpy+May 5 2007, 12:42 AM)
and best of all
http://911research.com/wtc/evidence/videos...south_below.mpg
I've seen those movies 1000 times. The visualization of a theoretical model is something different. When I saw that movie it was the first time in my life that I said "pancaking? my ***"
There is even some air pressed out stories and stories far below the front. The building is no bicycle pump, air also follows the way of least resistance and demolished steel and concrete is not the best way to isolate air. Ejected material due to the release of strain energy would be much more logical but that cannot explain the few isolated 'squibs' 100 meter lower. Why would the air be isolated and only go to that directory ? that single part with an area which is < 1/1000 of the area it could use to leave.
http://911research.com/wtc/evidence/videos...south_below.mpg
I've seen those movies 1000 times. The visualization of a theoretical model is something different. When I saw that movie it was the first time in my life that I said "pancaking? my ***"
There is even some air pressed out stories and stories far below the front. The building is no bicycle pump, air also follows the way of least resistance and demolished steel and concrete is not the best way to isolate air. Ejected material due to the release of strain energy would be much more logical but that cannot explain the few isolated 'squibs' 100 meter lower. Why would the air be isolated and only go to that directory ? that single part with an area which is < 1/1000 of the area it could use to leave.
QUOTE (Grumpy+May 5 2007, 12:42 AM)
newton
Thanks for the film.
and best of all
http://911research.com/wtc/evidence/videos...south_below.mpg
The "destruction wave" newton sees is the only external clue to the pancaking floors. Those relatively small ejections of dust and air from blown windows is not explosives, but is just the air ejected from the compressing floors AHEAD of the crush zone and top block.
Can you visualize it now???
Grumpy
your welcome.
in the "best of all" video, the building has not started to move, but there is the appearance of a squib about thirty storeys below the damaged floors, and about eight or ten stories(it's blurry, and impossible to count) below the skylobby and the mechanical floors. how does a plunger/syringe effect work when nothing is moving? how does it bypass the mechanical floors? why does sit puff out when nothing is moving, and then become nearly static while the (fantasy) 'syringe' actually starts to push as the top of the building starts to descend?
if it's a syringe effect, then why is there no steady stream of debris pushed out?
could be bombs accidentally triggered too early by having the wrong transponder code, or wired in the wrong sequence, if it was a hard wired job.
and, once again, you can see that the destruction is travelling down the (in)side of the building FASTER than freefalling objects on the outside. the only EASY PROOF that the destruction is not caused by gravity.
Thanks for the film.
and best of all
http://911research.com/wtc/evidence/videos...south_below.mpg
The "destruction wave" newton sees is the only external clue to the pancaking floors. Those relatively small ejections of dust and air from blown windows is not explosives, but is just the air ejected from the compressing floors AHEAD of the crush zone and top block.
Can you visualize it now???
Grumpy
your welcome.
in the "best of all" video, the building has not started to move, but there is the appearance of a squib about thirty storeys below the damaged floors, and about eight or ten stories(it's blurry, and impossible to count) below the skylobby and the mechanical floors. how does a plunger/syringe effect work when nothing is moving? how does it bypass the mechanical floors? why does sit puff out when nothing is moving, and then become nearly static while the (fantasy) 'syringe' actually starts to push as the top of the building starts to descend?
if it's a syringe effect, then why is there no steady stream of debris pushed out?
could be bombs accidentally triggered too early by having the wrong transponder code, or wired in the wrong sequence, if it was a hard wired job.
and, once again, you can see that the destruction is travelling down the (in)side of the building FASTER than freefalling objects on the outside. the only EASY PROOF that the destruction is not caused by gravity.
QUOTE
could be bombs accidentally triggered too early by having the wrong transponder code, or wired in the wrong sequence, if it was a hard wired job.
Of course there is NO EVIDENCE that there were ANY bombs at all.
Arthur
QUOTE (newton+May 5 2007, 06:50 PM)
how does a plunger/syringe effect work when nothing is moving?
It doesn't of course. But just because nothing visible was moving does not preclude internal movement. In WTC 2 there were several partial floor collapses, one of which led to the expulsion of material on floor 77, several floors down. Did your 'squib' occur at about the same time as this?
Also, the building was deteriorating internally, exponentially faster as time progressed. Greening has a paper suggesting such a tipping of the top block. If the tipping is not completely smooth (and it wouldn't be), this could cause a wave effect in the wall sufficient for your little 'squib' to appear.
Added: Another possibility is there was a transformer near that window which shorted out.
It doesn't of course. But just because nothing visible was moving does not preclude internal movement. In WTC 2 there were several partial floor collapses, one of which led to the expulsion of material on floor 77, several floors down. Did your 'squib' occur at about the same time as this?
Also, the building was deteriorating internally, exponentially faster as time progressed. Greening has a paper suggesting such a tipping of the top block. If the tipping is not completely smooth (and it wouldn't be), this could cause a wave effect in the wall sufficient for your little 'squib' to appear.
Added: Another possibility is there was a transformer near that window which shorted out.
QUOTE (adoucette+May 5 2007, 07:02 PM)
Of course there is NO EVIDENCE that there were ANY bombs at all.
Arthur
You mean if they were there it would be found ? Between 5 x 10 ^8 kg material ? As a lay man I would say that something that is explosive by definition vanishes away and will not be found. And what about modern chemical techniques, those dogs noises are not trained for those and aren't bomb sniffing dogs only capable to sniff unexploded bombs because afterwards they probably even cannot distinguish the mess around and the gun of a policeman.
QUOTE (einsteen+May 5 2007, 02:42 PM)
You mean if they were there it would be found ? Between 5 x 10 ^8 kg material ? As a lay man I would say that something that is explosive by definition vanishes away and will not be found.
NOPE,
Physical evidence of the bomb that took down the 747 over Lockerbie Scotland was easily found. Bombs, due to their hypersonic nature, create patterns of fractures, melting, pitting etc that would NOT happen to steel at mere gravitational collapse speeds.
That would have been found after the fact.
But they weren't.
More to the point, explosives, SUFFICIENT to bring down both of the WTC towers, would have been NOTICED by every friggin person around there, and the supersonic CRACKS of their detonation would have been captured on the many vidoeos.
There, in fact, would be NO DOUBT about what happened if bombs had been used.
Here's a hint, the bombs would have essentially had to do MORE DAMAGE to the towers than either plane crash.
Like I said, not something that goes unnoticed.
Which is why most CT'ers are forced to eventually gravitate to Thermate (or Beam Weapons) since ultimately they have to rely on the "noseeum" aspect of whatever lunacy they are promoting.
Arthur
NOPE,
Physical evidence of the bomb that took down the 747 over Lockerbie Scotland was easily found. Bombs, due to their hypersonic nature, create patterns of fractures, melting, pitting etc that would NOT happen to steel at mere gravitational collapse speeds.
That would have been found after the fact.
But they weren't.
More to the point, explosives, SUFFICIENT to bring down both of the WTC towers, would have been NOTICED by every friggin person around there, and the supersonic CRACKS of their detonation would have been captured on the many vidoeos.
There, in fact, would be NO DOUBT about what happened if bombs had been used.
Here's a hint, the bombs would have essentially had to do MORE DAMAGE to the towers than either plane crash.
Like I said, not something that goes unnoticed.
Which is why most CT'ers are forced to eventually gravitate to Thermate (or Beam Weapons) since ultimately they have to rely on the "noseeum" aspect of whatever lunacy they are promoting.
Arthur
einsteen
If there had been explosives the evidence of their existence would have been found(lots of it), therefore we are safe in assuming none were there until such unequivical evidence is found. So far NADA!
If there had been explosives the evidence of their existence would have been found(lots of it), therefore we are safe in assuming none were there until such unequivical evidence is found. So far NADA!
aren't bomb sniffing dogs only capable to sniff unexploded bombs
Some are specifically trained to react to the chemicals such explosives leave behind, just as there are dogs trained to find survivors and others to find corpses.
The FBI,BATF and other agencies came to the scene EXPECTING to find evidence for explosives, they declared the site explosives free three weeks later, having found absolutely NO evidence of their use.
Yet that is precisely what one would expect to see as the air is forced from between floors AHEAD OF THE VISIBLE COLLAPSE which follows along several stories behind.
Yet that is precisely what one would expect to see as the air is forced from between floors AHEAD OF THE VISIBLE COLLAPSE which follows along several stories behind.
There is even some air pressed out stories and stories far below the front.
EXACTLY!!! The pancaking, once started, proceeded faster than the visible outside collapse front, leaving only the exterior frame and core behind to be crushed and pushed aside by the top block. That is exactly my point!
newton
There is a series of puffs of air being expelled ahead of the collapse front. The only logical explanation(explosives being ruled out) is puffs of air forced from between pancaking floors and out the windows, precisely as I have been saying.
There is a series of puffs of air being expelled ahead of the collapse front. The only logical explanation(explosives being ruled out) is puffs of air forced from between pancaking floors and out the windows, precisely as I have been saying.
how does a plunger/syringe effect work when nothing is moving? how does it bypass the mechanical floors? why does sit puff out when nothing is moving, and then become nearly static while the (fantasy) 'syringe' actually starts to push as the top of the building starts to descend?
if it's a syringe effect, then why is there no steady stream of debris pushed out?
"syringe effect"??? It is not a syringe effect, it is the expulsion of air(and entrained dust, paper and other debris able to be moved fast enough not to be trapped between the floors as they collapsed) from between two flat plates(floor diaphrams) which then together fall on the next flat plate, and the next and the next....., all within the still intact external frames and ahead of the top block/collapse zone.
In the video in question the pancaking floors are at the bottom of that series of puffs, several floors ahead of the top block/collapse zone. The way the supports for the floors were stripped(vertically and rapidly) indicates this pancaking of the floors continued straight into the basement without pause. The energy of the falling mass of floors, applied to one floor at a time as it fell, was many orders of magnitude above that needed to strip those connections, and the still intact structure of the bottom section insured the vast majority of that mass was retained to be applied to the next floor.
Simply not true!!! None of this is happening any faster than the laws of physics(specifically gravity/acceleration) would allow for, that would be true whether explosives were used or not. The pancaking floors simply had a head start vs the debris falling from the visible collapse front further up the building.
Grumpy
HCl does not react much with iron or copper, but as you can see here it does react with Calcium Carbonate, creating calcium Chloride, Calcium Chloride reacts with zinc to form Zinc Chloride and hydrogen.
I mentioned that a while back. Unfortunately, it got lost in all the talk about spiked fireproofing. HCl reacts readily with Zn to form ZnCl and hydrogen. ZnCl can be produced by simply placing Zn over HCl vapor near room temperature.
QUOTE
You mean if they were there it would be found ?
If there had been explosives the evidence of their existence would have been found(lots of it), therefore we are safe in assuming none were there until such unequivical evidence is found. So far NADA!
QUOTE (->
| QUOTE |
| You mean if they were there it would be found ? |
If there had been explosives the evidence of their existence would have been found(lots of it), therefore we are safe in assuming none were there until such unequivical evidence is found. So far NADA!
aren't bomb sniffing dogs only capable to sniff unexploded bombs
Some are specifically trained to react to the chemicals such explosives leave behind, just as there are dogs trained to find survivors and others to find corpses.
The FBI,BATF and other agencies came to the scene EXPECTING to find evidence for explosives, they declared the site explosives free three weeks later, having found absolutely NO evidence of their use.
QUOTE
I've seen those movies 1000 times. The visualization of a theoretical model is something different. When I saw that movie it was the first time in my life that I said "pancaking? my ***"
Yet that is precisely what one would expect to see as the air is forced from between floors AHEAD OF THE VISIBLE COLLAPSE which follows along several stories behind.
QUOTE (->
| QUOTE |
| I've seen those movies 1000 times. The visualization of a theoretical model is something different. When I saw that movie it was the first time in my life that I said "pancaking? my ***" |
Yet that is precisely what one would expect to see as the air is forced from between floors AHEAD OF THE VISIBLE COLLAPSE which follows along several stories behind.
There is even some air pressed out stories and stories far below the front.
EXACTLY!!! The pancaking, once started, proceeded faster than the visible outside collapse front, leaving only the exterior frame and core behind to be crushed and pushed aside by the top block. That is exactly my point!
newton
QUOTE
in the "best of all" video, the building has not started to move, but there is the appearance of a squib about thirty storeys below the damaged floors, and about eight or ten stories(it's blurry, and impossible to count) below the skylobby and the mechanical floors.
There is a series of puffs of air being expelled ahead of the collapse front. The only logical explanation(explosives being ruled out) is puffs of air forced from between pancaking floors and out the windows, precisely as I have been saying.
QUOTE (->
| QUOTE |
| in the "best of all" video, the building has not started to move, but there is the appearance of a squib about thirty storeys below the damaged floors, and about eight or ten stories(it's blurry, and impossible to count) below the skylobby and the mechanical floors. |
There is a series of puffs of air being expelled ahead of the collapse front. The only logical explanation(explosives being ruled out) is puffs of air forced from between pancaking floors and out the windows, precisely as I have been saying.
how does a plunger/syringe effect work when nothing is moving? how does it bypass the mechanical floors? why does sit puff out when nothing is moving, and then become nearly static while the (fantasy) 'syringe' actually starts to push as the top of the building starts to descend?
if it's a syringe effect, then why is there no steady stream of debris pushed out?
"syringe effect"??? It is not a syringe effect, it is the expulsion of air(and entrained dust, paper and other debris able to be moved fast enough not to be trapped between the floors as they collapsed) from between two flat plates(floor diaphrams) which then together fall on the next flat plate, and the next and the next....., all within the still intact external frames and ahead of the top block/collapse zone.
In the video in question the pancaking floors are at the bottom of that series of puffs, several floors ahead of the top block/collapse zone. The way the supports for the floors were stripped(vertically and rapidly) indicates this pancaking of the floors continued straight into the basement without pause. The energy of the falling mass of floors, applied to one floor at a time as it fell, was many orders of magnitude above that needed to strip those connections, and the still intact structure of the bottom section insured the vast majority of that mass was retained to be applied to the next floor.
QUOTE
and, once again, you can see that the destruction is travelling down the (in)side of the building FASTER than freefalling objects on the outside. the only EASY PROOF that the destruction is not caused by gravity.
Simply not true!!! None of this is happening any faster than the laws of physics(specifically gravity/acceleration) would allow for, that would be true whether explosives were used or not. The pancaking floors simply had a head start vs the debris falling from the visible collapse front further up the building.
Grumpy
From my copyright 1947 desk dictionary:
verify. 1. To prove to be true; to confirm; substantiate. 2. To check or test the accuracy or exactness of. 3. To authenticate ...
valid. 1. Rare. Strong; healthy. 2. Founded on truth or fact; capable of being justified; supported, or defended; well-grounded, sound. 3. Efficient, effective. ...
validate. ... 2. To test or prove the validity of; to confirm.
=============
So the four B & V assumptions are valid in the sense of both senses 2 and 3 in that the crush-down equation has been verified in the sense of both senses 1 and 2 via using two set of measurements.
The question of the probability with which this gain of information allows the rejection of the null hypothesis (some other equation based on different assumptions) remains open. But I hope we can all agree that WTC 1 collapse and WTC 2 collapse can be considered to be two completely independent events...
verify. 1. To prove to be true; to confirm; substantiate. 2. To check or test the accuracy or exactness of. 3. To authenticate ...
valid. 1. Rare. Strong; healthy. 2. Founded on truth or fact; capable of being justified; supported, or defended; well-grounded, sound. 3. Efficient, effective. ...
validate. ... 2. To test or prove the validity of; to confirm.
=============
So the four B & V assumptions are valid in the sense of both senses 2 and 3 in that the crush-down equation has been verified in the sense of both senses 1 and 2 via using two set of measurements.
The question of the probability with which this gain of information allows the rejection of the null hypothesis (some other equation based on different assumptions) remains open. But I hope we can all agree that WTC 1 collapse and WTC 2 collapse can be considered to be two completely independent events...
One approach to comparing two hypotheses is via inductive logic for which there is an especially good page on the Stanford Dictionary of Philosophy web site. We want to compare the probability of hypothesis H (the B & V crush-down equation) versus the probability of hypothesis K (free-fall) given the evidence E (the measurements for WTC 1 provided by NEU-FONZE). This makes sense to do probabilistically since there is a certain random error in collecting the data. (NEU-FONZE estimated +/- 0.2 meters.)
Likelyhoodists state that the only objective measure is the ratio of the probabilities of the evidence E given the competing hypotheses, that is, the ratio
R(E,H,K) = P[E|K] / P[E|H].
Since the evidence fits free-fall very poorly, let us state that P[E|K] = 0.00001 since it is possible that the measurements error is quite large. However, the evidence fits the crush-down equation quite well. Here I will use P[E|H] = 0.8. So the ratio against H and for K is 0.0000125, higher, but not much. A likelyhoodist will strongly choose hypothesis H over K.
A Bayesian uses the ratio of the posteriori probabilities. Here is Bayses's Theorem in ratio form:
P[K|E] / P[H|E] = R(E,H,K)(P[K] / P[H])
where P[K] and P[H] are the prior probabilities subjectively assigned the each of the competing hypotheses.
Suppose, by way of example, you find K more appealing than H, assigning P[K] = 0.9 and P[H] = 0.2. In this case P[K|E]/P[H|E] = 0.0000125(0.9/0.2) = 0.00005625 which is much larger than just R(E,H,K), but not enough to confirm K. It is still rejected in favor of hypothesis H.
In this sense, H is probabilistically valid and K is not.
Likelyhoodists state that the only objective measure is the ratio of the probabilities of the evidence E given the competing hypotheses, that is, the ratio
R(E,H,K) = P[E|K] / P[E|H].
Since the evidence fits free-fall very poorly, let us state that P[E|K] = 0.00001 since it is possible that the measurements error is quite large. However, the evidence fits the crush-down equation quite well. Here I will use P[E|H] = 0.8. So the ratio against H and for K is 0.0000125, higher, but not much. A likelyhoodist will strongly choose hypothesis H over K.
A Bayesian uses the ratio of the posteriori probabilities. Here is Bayses's Theorem in ratio form:
P[K|E] / P[H|E] = R(E,H,K)(P[K] / P[H])
where P[K] and P[H] are the prior probabilities subjectively assigned the each of the competing hypotheses.
Suppose, by way of example, you find K more appealing than H, assigning P[K] = 0.9 and P[H] = 0.2. In this case P[K|E]/P[H|E] = 0.0000125(0.9/0.2) = 0.00005625 which is much larger than just R(E,H,K), but not enough to confirm K. It is still rejected in favor of hypothesis H.
In this sense, H is probabilistically valid and K is not.
you OCTs are tiring me out.
what i see in those videos is definitive proof of explosives.
the destruction wave(for the first ten or twenty floors) is faster than freefall acceleration. period.
the "puff" i'm talking about is inexplicable. it is not the one you see once the collapse is under way. it is the tiny one at the lower left of the view. it puffs out at the same time the collapse begins, and then just SITS there as the collapse begins in ernest.
if it was the result of things falling inside the building, than debris should CONTINUE to come out of it, as the collapse front approaches, because it is the path of least resistance for grumpy and arthurs overpressures.
this does not happen.
it is also highly unlikely that a transformer would be placed right next to a window. that's what mechanical floors are for.
david's explanations are at least technically possible(although i don't know what colour smoke from transformer explosions is), but they are highly unlikely, and require ridiculously complex conditions.
i'm gonna eat my wheaties. i'm starting to take a sick pleasure in teaching the voluntarily blind to see involuntarily.
what i see in those videos is definitive proof of explosives.
the destruction wave(for the first ten or twenty floors) is faster than freefall acceleration. period.
the "puff" i'm talking about is inexplicable. it is not the one you see once the collapse is under way. it is the tiny one at the lower left of the view. it puffs out at the same time the collapse begins, and then just SITS there as the collapse begins in ernest.
if it was the result of things falling inside the building, than debris should CONTINUE to come out of it, as the collapse front approaches, because it is the path of least resistance for grumpy and arthurs overpressures.
this does not happen.
it is also highly unlikely that a transformer would be placed right next to a window. that's what mechanical floors are for.
david's explanations are at least technically possible(although i don't know what colour smoke from transformer explosions is), but they are highly unlikely, and require ridiculously complex conditions.
i'm gonna eat my wheaties. i'm starting to take a sick pleasure in teaching the voluntarily blind to see involuntarily.
QUOTE (newton+May 6 2007, 12:35 AM)
what i see in those videos is definitive proof of explosives.
...
the "puff" i'm talking about is inexplicable.
newton, you need a lesson on what constitutes DEFINITIVE PROOF.
That video, as is, certainly doesn't.
YOU think it shows that the blast is faster than free fall, but OTHERS seeing the same video disagree.
Hence its by definition NOT definitive.
Now if you want to do some frame by frame analysis of that video, counting floors and timing the advance so you can PROVE that the it progresses FASTER than free fall, by ALL MEANS, have at it.
I just have to caution you, that video's been out there a LONG time and NO ONE has taken the time to do that and publish the results in over 6 years.
Considering how much the CT'ers DESPERATELY want just ONE piece of DEFINITIVE PROOF, doesn't that suggest that other CT'ers have probably timed it and found that NO, its NOT faster than free fall?
As to the "puff".
The towers were a COMPLEX structure undergoing progressive collapse. There are a great deal of mechanical, electrical, plumbing connections etc that run the length of the tower, not to mention the continuous welded columns that make up the core. So given these solid connections, forces would clearly be propagated faster than the collapse front through the tower.
So no, it doesn't surprise me that you will see SOME damage ahead of the collapse front whose cause is INEXPLICABLE.
And though we don't know what caused that puff, it CLEARLY is not a SQUIB.
A SQUIB is a blasting cap, which is like a big firecracker and if explosives were used would be found embedded in a hunk of High Explosive, which would be somewhere near a core column.
See: http://www.oregon.gov/OSP/AES/Blasting_Caps.shtml
Arthur
...
the "puff" i'm talking about is inexplicable.
newton, you need a lesson on what constitutes DEFINITIVE PROOF.
That video, as is, certainly doesn't.
YOU think it shows that the blast is faster than free fall, but OTHERS seeing the same video disagree.
Hence its by definition NOT definitive.
Now if you want to do some frame by frame analysis of that video, counting floors and timing the advance so you can PROVE that the it progresses FASTER than free fall, by ALL MEANS, have at it.
I just have to caution you, that video's been out there a LONG time and NO ONE has taken the time to do that and publish the results in over 6 years.
Considering how much the CT'ers DESPERATELY want just ONE piece of DEFINITIVE PROOF, doesn't that suggest that other CT'ers have probably timed it and found that NO, its NOT faster than free fall?
As to the "puff".
The towers were a COMPLEX structure undergoing progressive collapse. There are a great deal of mechanical, electrical, plumbing connections etc that run the length of the tower, not to mention the continuous welded columns that make up the core. So given these solid connections, forces would clearly be propagated faster than the collapse front through the tower.
So no, it doesn't surprise me that you will see SOME damage ahead of the collapse front whose cause is INEXPLICABLE.
And though we don't know what caused that puff, it CLEARLY is not a SQUIB.
A SQUIB is a blasting cap, which is like a big firecracker and if explosives were used would be found embedded in a hunk of High Explosive, which would be somewhere near a core column.
See: http://www.oregon.gov/OSP/AES/Blasting_Caps.shtml
Arthur
well, your explanation for the 'puff' i'm thinking of doesn't work, because the building has not begun to collapse, and the 'puff' is coming from far, far below the damaged area of the building.
you know, i've never been to eager to PROVE myself right, and paint a big target on my head, LOL!
you know, when i made this .gif, i was kinda nervous about proving what the picture proves, but since then, i've learned that the beast doesn't care about small fry, only big fry.
i'll wait until we have a swarm of small fry, and then it will be the beast that gets nervous.
you know, i've never been to eager to PROVE myself right, and paint a big target on my head, LOL!
you know, when i made this .gif, i was kinda nervous about proving what the picture proves, but since then, i've learned that the beast doesn't care about small fry, only big fry.
i'll wait until we have a swarm of small fry, and then it will be the beast that gets nervous.
Newton, if you have time (I don't have because my mother-in-law is here on vacation ) then you could try to synchronize all vids you have and find
x(t), estimate a function, take the double time derivative and try to check if it satisfies x''(t)<g
DBB is the pancaking indeed takes places before any visual features outside then that implies it is even faster than the wave, not what you want I guess.
) then you could try to synchronize all vids you have and findx(t), estimate a function, take the double time derivative and try to check if it satisfies x''(t)<g
DBB is the pancaking indeed takes places before any visual features outside then that implies it is even faster than the wave, not what you want I guess.
QUOTE (einsteen+May 6 2007, 08:34 AM)
Newton, if you have time (I don't have because my mother-in-law is here on vacation ) then you could try to synchronize all vids you have and find
x(t), estimate a function, take the double time derivative and try to check if it satisfies x''(t)<g
DBB is the pancaking indeed takes places before any visual features outside then that implies it is even faster than the wave, not what you want I guess.
i might do something similiar to what i did with the 'faster than freefall' gif.
i prefer working with the actual evidence, rather than pure math(mostly because i haven't had to do pure math for over twenty years), but, happily, also because, it is direct evidence and admissible in a court of law.
i don't think i have the facility to synch up a bunch of videos, but i will do what i can with what i have.
however, you seem a good fellow. how about your opinion on the .gif i made?
those are two consecutive frames from a universally accessible video. frame rates are not so important, because it is the relative change in position of the circled objects/features in two frames.
the object is the falling chunk of either cladding or steel(or other, but it's probably cladding). of course, cladding will not fall as quickly as steel because of the mass to surface area ratio, but it is not falling much slower than freefall in a vacuum, because it is still a honking big chunk of metal.
because this object is spinning i roughly used the centre of it to draw the lines to. the horizontal line illustrates the initial position(1st video frame), and the termination of the vertical line illustrates the next position(2nd video frame).
the feature(s) is the clouds of dust being expelled from inside the building. a dust cloud begins to PUFF(damn i hate that word, now) out the side of the building in the second frame, and it puffs out below the freefalling chunk of metal. the chunk of metal has been falling for several stories, and is really booting it. this proves(to me, at least), that what was happening inside the building, was progressing towards earth at a faster rate than debris which is freefalling through air.
because this feature is nebulous, i used the lowermost point observable on the dust clouds. the first frame, the horizontal line is drawn to the bottom of the visible ejections from inside. the second frame, the vertical line terminates at the bottommost visible dust cloud expulsion.
i observe this phenomena in that 'trinity' video, too. you see large metal chunks falling for a few storeys, and then they are caught up to, and swallowed by dust clouds shooting out from inside the building.
i don't want to bogged down in arguments about foreshortening, frame rates, and whatnot. i think the truth is pretty clear, without determining the actual velocity/acceleration. all's i need to know, is that it was 'easier' for the debris to fall through the building, than it was for it to fall through air.
of course, it wasn't 'falling' through, and what i observe is demolition sequences which are trying to approximate gravity's acceleration. smarter demolishers would have slowed it down a bit, but i guess they would have needed more bombs, then.
) then you could try to synchronize all vids you have and findx(t), estimate a function, take the double time derivative and try to check if it satisfies x''(t)<g
DBB is the pancaking indeed takes places before any visual features outside then that implies it is even faster than the wave, not what you want I guess.
i might do something similiar to what i did with the 'faster than freefall' gif.
i prefer working with the actual evidence, rather than pure math(mostly because i haven't had to do pure math for over twenty years), but, happily, also because, it is direct evidence and admissible in a court of law.
i don't think i have the facility to synch up a bunch of videos, but i will do what i can with what i have.
however, you seem a good fellow. how about your opinion on the .gif i made?
those are two consecutive frames from a universally accessible video. frame rates are not so important, because it is the relative change in position of the circled objects/features in two frames.
the object is the falling chunk of either cladding or steel(or other, but it's probably cladding). of course, cladding will not fall as quickly as steel because of the mass to surface area ratio, but it is not falling much slower than freefall in a vacuum, because it is still a honking big chunk of metal.
because this object is spinning i roughly used the centre of it to draw the lines to. the horizontal line illustrates the initial position(1st video frame), and the termination of the vertical line illustrates the next position(2nd video frame).
the feature(s) is the clouds of dust being expelled from inside the building. a dust cloud begins to PUFF(damn i hate that word, now) out the side of the building in the second frame, and it puffs out below the freefalling chunk of metal. the chunk of metal has been falling for several stories, and is really booting it. this proves(to me, at least), that what was happening inside the building, was progressing towards earth at a faster rate than debris which is freefalling through air.
because this feature is nebulous, i used the lowermost point observable on the dust clouds. the first frame, the horizontal line is drawn to the bottom of the visible ejections from inside. the second frame, the vertical line terminates at the bottommost visible dust cloud expulsion.
i observe this phenomena in that 'trinity' video, too. you see large metal chunks falling for a few storeys, and then they are caught up to, and swallowed by dust clouds shooting out from inside the building.
i don't want to bogged down in arguments about foreshortening, frame rates, and whatnot. i think the truth is pretty clear, without determining the actual velocity/acceleration. all's i need to know, is that it was 'easier' for the debris to fall through the building, than it was for it to fall through air.
of course, it wasn't 'falling' through, and what i observe is demolition sequences which are trying to approximate gravity's acceleration. smarter demolishers would have slowed it down a bit, but i guess they would have needed more bombs, then.
newton
The pancaking floors do indeed fall faster than a piece of Aluminum cladding would due to the difference between densities and the air resistence. The aluminum cladding reaches it's terminal velocity very quickly, the steel and concrete inside the building would have a higher density, thus a higher terminal velocity and quicker acceleration which would soon catch up to and pass the slower falling cladding.
It is really amazing to me how ANYONE could work so hard as you do NOT to understand what they see.
Grumpy
The pancaking floors do indeed fall faster than a piece of Aluminum cladding would due to the difference between densities and the air resistence. The aluminum cladding reaches it's terminal velocity very quickly, the steel and concrete inside the building would have a higher density, thus a higher terminal velocity and quicker acceleration which would soon catch up to and pass the slower falling cladding.
It is really amazing to me how ANYONE could work so hard as you do NOT to understand what they see.
Grumpy
QUOTE (newton+May 6 2007, 09:09 AM)
i might do something similiar to what i did with the 'faster than freefall' gif.
i prefer working with the actual evidence, rather than pure math(mostly because i haven't had to do pure math for over twenty years), but, happily, also because, it is direct evidence and admissible in a court of law.
i don't think i have the facility to synch up a bunch of videos, but i will do what i can with what i have.
however, you seem a good fellow. how about your opinion on the .gif i made?
those are two consecutive frames from a universally accessible video. frame rates are not so important, because it is the relative change in position of the circled objects/features in two frames.
the object is the falling chunk of either cladding or steel(or other, but it's probably cladding). of course, cladding will not fall as quickly as steel because of the mass to surface area ratio, but it is not falling much slower than freefall in a vacuum, because it is still a honking big chunk of metal.
because this object is spinning i roughly used the centre of it to draw the lines to. the horizontal line illustrates the initial position(1st video frame), and the termination of the vertical line illustrates the next position(2nd video frame).
the feature(s) is the clouds of dust being expelled from inside the building. a dust cloud begins to PUFF(damn i hate that word, now) out the side of the building in the second frame, and it puffs out below the freefalling chunk of metal. the chunk of metal has been falling for several stories, and is really booting it. this proves(to me, at least), that what was happening inside the building, was progressing towards earth at a faster rate than debris which is freefalling through air.
because this feature is nebulous, i used the lowermost point observable on the dust clouds. the first frame, the horizontal line is drawn to the bottom of the visible ejections from inside. the second frame, the vertical line terminates at the bottommost visible dust cloud expulsion.
i observe this phenomena in that 'trinity' video, too. you see large metal chunks falling for a few storeys, and then they are caught up to, and swallowed by dust clouds shooting out from inside the building.
i don't want to bogged down in arguments about foreshortening, frame rates, and whatnot. i think the truth is pretty clear, without determining the actual velocity/acceleration. all's i need to know, is that it was 'easier' for the debris to fall through the building, than it was for it to fall through air.
of course, it wasn't 'falling' through, and what i observe is demolition sequences which are trying to approximate gravity's acceleration. smarter demolishers would have slowed it down a bit, but i guess they would have needed more bombs, then.
Da explosions happen in burning buildings usually form explosive gasses, created by fires.
i prefer working with the actual evidence, rather than pure math(mostly because i haven't had to do pure math for over twenty years), but, happily, also because, it is direct evidence and admissible in a court of law.
i don't think i have the facility to synch up a bunch of videos, but i will do what i can with what i have.
however, you seem a good fellow. how about your opinion on the .gif i made?
those are two consecutive frames from a universally accessible video. frame rates are not so important, because it is the relative change in position of the circled objects/features in two frames.
the object is the falling chunk of either cladding or steel(or other, but it's probably cladding). of course, cladding will not fall as quickly as steel because of the mass to surface area ratio, but it is not falling much slower than freefall in a vacuum, because it is still a honking big chunk of metal.
because this object is spinning i roughly used the centre of it to draw the lines to. the horizontal line illustrates the initial position(1st video frame), and the termination of the vertical line illustrates the next position(2nd video frame).
the feature(s) is the clouds of dust being expelled from inside the building. a dust cloud begins to PUFF(damn i hate that word, now) out the side of the building in the second frame, and it puffs out below the freefalling chunk of metal. the chunk of metal has been falling for several stories, and is really booting it. this proves(to me, at least), that what was happening inside the building, was progressing towards earth at a faster rate than debris which is freefalling through air.
because this feature is nebulous, i used the lowermost point observable on the dust clouds. the first frame, the horizontal line is drawn to the bottom of the visible ejections from inside. the second frame, the vertical line terminates at the bottommost visible dust cloud expulsion.
i observe this phenomena in that 'trinity' video, too. you see large metal chunks falling for a few storeys, and then they are caught up to, and swallowed by dust clouds shooting out from inside the building.
i don't want to bogged down in arguments about foreshortening, frame rates, and whatnot. i think the truth is pretty clear, without determining the actual velocity/acceleration. all's i need to know, is that it was 'easier' for the debris to fall through the building, than it was for it to fall through air.
of course, it wasn't 'falling' through, and what i observe is demolition sequences which are trying to approximate gravity's acceleration. smarter demolishers would have slowed it down a bit, but i guess they would have needed more bombs, then.
Da explosions happen in burning buildings usually form explosive gasses, created by fires.
QUOTE (newton+May 6 2007, 08:17 AM)
well, your explanation for the 'puff' i'm thinking of doesn't work, because the building has not begun to collapse, and the 'puff' is coming from far, far below the damaged area of the building.
you know, i've never been to eager to PROVE myself right, and paint a big target on my head, LOL!
you know, when i made this .gif, i was kinda nervous about proving what the picture proves, but since then, i've learned that the beast doesn't care about small fry, only big fry.
i'll wait until we have a swarm of small fry, and then it will be the beast that gets nervous.
Here are a couple of explanations for your puffs. Before the collapse is visible externally, an avalanche of debris falls through an elevator shaft and is expelled out through a lower level shaft opening into a partitioned corridor and then out through a window. The avalanche could also be assisted by the compression of an internal volume of air, or as Chainsaw pointed out, by explosive byproducts of the fires. This same process could occur at multiple locations and intervals during the entire collapse. Once large areas of falling floor sections compressed large volumes of debris ladened air into the restricted areas of the elevator shafts, the velocities of the air currents would increase and could easily out pace the collapse fronts. Your comment about how debris should continue to flow out these vents might have merit if the buildings were in a static state, but as you may have noticed, they weren't. Circuits for debris and airflow were constantly changing.
you know, i've never been to eager to PROVE myself right, and paint a big target on my head, LOL!
you know, when i made this .gif, i was kinda nervous about proving what the picture proves, but since then, i've learned that the beast doesn't care about small fry, only big fry.
i'll wait until we have a swarm of small fry, and then it will be the beast that gets nervous.
Here are a couple of explanations for your puffs. Before the collapse is visible externally, an avalanche of debris falls through an elevator shaft and is expelled out through a lower level shaft opening into a partitioned corridor and then out through a window. The avalanche could also be assisted by the compression of an internal volume of air, or as Chainsaw pointed out, by explosive byproducts of the fires. This same process could occur at multiple locations and intervals during the entire collapse. Once large areas of falling floor sections compressed large volumes of debris ladened air into the restricted areas of the elevator shafts, the velocities of the air currents would increase and could easily out pace the collapse fronts. Your comment about how debris should continue to flow out these vents might have merit if the buildings were in a static state, but as you may have noticed, they weren't. Circuits for debris and airflow were constantly changing.
QUOTE (Chainsaw+,May 6 2007, 12:02 PM)
Da explosions happen in burning buildings usually form explosive gasses, created by fires.
Chainsaw, what kinds of explosive dust or chemical reactions were being created during the turbulence of the collapses? I know of the reactive mix left in the debris pile, but how much reaction was occurring in the collapses themselves. I think people tend to concentrate on explosive situations at the beginning and end of the collapses, and only think of the collapses as the process that creates the reactive materials, but not the environment where the reactions take place.
I have a feeling that this is what you have been driving at in a lot of your posts, but I failed to see the light until you stated the obvious to newton. Now I feel like a DA.
Chainsaw, what kinds of explosive dust or chemical reactions were being created during the turbulence of the collapses? I know of the reactive mix left in the debris pile, but how much reaction was occurring in the collapses themselves. I think people tend to concentrate on explosive situations at the beginning and end of the collapses, and only think of the collapses as the process that creates the reactive materials, but not the environment where the reactions take place.
I have a feeling that this is what you have been driving at in a lot of your posts, but I failed to see the light until you stated the obvious to newton. Now I feel like a DA.
A lot of the reactive elements that fueled the thermal processes in the debris piles for many months were also present in the collapse fronts. If these elements were reacting during the collapses, you could argue that the buildings were manufacturing and detonating their own explosives, thereby assisting in their own destruction. The towers in a sense performed CDs on themselves, which would make the CTs correct in their assertion that it was an inside job. We would have theory unification.
QUOTE (newton+May 6 2007, 03:17 AM)
well, your explanation for the 'puff' i'm thinking of doesn't work, because the building has not begun to collapse, and the 'puff' is coming from far, far below the damaged area of the building.
you know, i've never been to eager to PROVE myself right, and paint a big target on my head, LOL!
The towers have OBVIOUSLY begun to collapse when the "puff" first appears.
The video is shot at 30 frames per second.
That's why:
Frame 28: the fireman started turning his head towards the towers (which is about 1 second after the sound that attracted his attention was created)
Frame 34: The camera starts to pan towards the sound
Frame 72: The camera is turned to the tower, and the camera has adjusted to the higher light levels, but the camera view does not capture the top of the towers.
Frame 80: While the camera is still below the top of the towers, increasing darkness of shadows at the top of the frame from the dust clouds show that the collapse is underway
Frame 88: We are now 2 seconds since everyone started looking at the tower, ~ 3 seconds into the event.
Frame 103: Puff emerges ~15 ft in the span of one frame. (this is 75 frames AFTER people on the ground knew that the towers were collapsing)
Frame 104-108: Puff increases in size
Frame 109: Puff density increases such that it casts a distinct shadow
Frame 116: Puff appears to be near maximum size/density. At this point the cloud at the end of the puff is ~ 15 ft across and extends ~ 30 ft from the tower. The puff has taken ~ 1/2 second for this transformation, CLEARLY not the hypersonic movements associated with EXPLOSIVES, The "puff" will remain for well over 100 more frames but will be slowly dissapating over that time)
Frame 123: The Pressure Pulse from the collapsing towers reaches the ~93rd floor of WTC 1 causing a MASSIVE increase in the fire rate which is clearly visible until obscured by smoke from the collapsing WTC 2 tower.
As to "paint a target on your head"
What a joke.
Maybe you didn't notice but people put out movies, hold "truther" conventions, go on TV and Radio Talk shows, publish books, post on internet forums for YEARS etc etc.
and NOTHING happens to them.
Well, that is, if you ignore brain rot.
Arthur
you know, i've never been to eager to PROVE myself right, and paint a big target on my head, LOL!
The towers have OBVIOUSLY begun to collapse when the "puff" first appears.
The video is shot at 30 frames per second.
That's why:
Frame 28: the fireman started turning his head towards the towers (which is about 1 second after the sound that attracted his attention was created)
Frame 34: The camera starts to pan towards the sound
Frame 72: The camera is turned to the tower, and the camera has adjusted to the higher light levels, but the camera view does not capture the top of the towers.
Frame 80: While the camera is still below the top of the towers, increasing darkness of shadows at the top of the frame from the dust clouds show that the collapse is underway
Frame 88: We are now 2 seconds since everyone started looking at the tower, ~ 3 seconds into the event.
Frame 103: Puff emerges ~15 ft in the span of one frame. (this is 75 frames AFTER people on the ground knew that the towers were collapsing)
Frame 104-108: Puff increases in size
Frame 109: Puff density increases such that it casts a distinct shadow
Frame 116: Puff appears to be near maximum size/density. At this point the cloud at the end of the puff is ~ 15 ft across and extends ~ 30 ft from the tower. The puff has taken ~ 1/2 second for this transformation, CLEARLY not the hypersonic movements associated with EXPLOSIVES, The "puff" will remain for well over 100 more frames but will be slowly dissapating over that time)
Frame 123: The Pressure Pulse from the collapsing towers reaches the ~93rd floor of WTC 1 causing a MASSIVE increase in the fire rate which is clearly visible until obscured by smoke from the collapsing WTC 2 tower.
As to "paint a target on your head"
What a joke.
Maybe you didn't notice but people put out movies, hold "truther" conventions, go on TV and Radio Talk shows, publish books, post on internet forums for YEARS etc etc.
and NOTHING happens to them.
Well, that is, if you ignore brain rot.
Arthur
QUOTE (Capracus+May 6 2007, 01:49 PM)
A lot of the reactive elements that fueled the thermal processes in the debris piles for many months were also present in the collapse fronts. If these elements were reacting during the collapses, you could argue that the buildings were manufacturing and detonating their own explosives, thereby assisting in their own destruction. The towers in a sense performed CDs on themselves, which would make the CTs correct in their assertion that it was an inside job. We would have theory unification.
Actually the reactions are caused by the rapid release of chemicals because of the conflagration on multi stories by the jet fuel in the early fireball.
PVC Has chemicals that retard its combustion because PVC gives off HCl which can be corrosive to metals, a combination of HCl and other compounds can make galvanized metals burn like tissue paper.
I do not want to say more about this because the work is continuing all it takes is getting enough PVC reacting to over come the combustion retardation compounds that were added to PVC to stop the reaction.
Just think what a buoyant hydrogen flame would to to steel as it burn in air heating the steel and transforming into super heated steam. Steel dust in hot steam is explosive, Hydrogen can come from reactive metals as well as steam reacting with steel well below the fire temperatures. Free chlorides are given off by Aluminum Chloride at 700c. Also carbon dust can be explosive especially when hydrogen is present.
You do not need Controlled Demolitions to bring these buildings down all of them, all you need is intense chemical reactions, sparked by quick acceleration of the combustion of jet full.
Get the reactions started, give them about an hour to work and the building is gone from natural causes, you just should not crash planes into buildings.
Also it kind of destorys the Cters Ideas by destroying the Idea that Jet fuel fires would not cause the buildings collapses, because, the fires are just the accelerating compounds the Bunsen burner that speeds the reactants.
You should watch what happens when A 325 bolts,
are exposed to steam and hydrogen they litterally bubble the carbon out of them.
Forming weird hollow iron spheres,
I have sent Dr. Steven Jones a sample of Iron spheres that I made from Chemical reactions of metals, with compounds that would have been present, in the buildings. Like these.
I must confess there are others though that know more about this than I do.
All I know is if I start a huge hydrocarbon combustion reaction in the right enviroment it can acclerate other chemical reactions provided the chemicals are released fast enough in the right enviroment.
I think I read some where that there were 6000 pounds of PVC, per floor in the World Trade Center towers.
I just nearly blew myself up with PVC pipe, 22 Gage corrugated galvanized steel, some aluminum, some steam, and 40 gallon of Low sulfur diesel fuel trying an experiment to see if ignition of the floor pans could cause the metals spheres, and yes it could, however I was not prepared for how violent and energetic the reaction was. I forgot that hydrogen produces a super hot buoyant flame of super hot water molecules that littlery can burn-Oxidize steel.
Anyone want to come help me clean up the mess?
Idiots should not fly large planes into buildings, it causes fires and reactions in those fires that kill people.
Only people who no nothing about fires think that Hydrocarbons were the only fuel in the buildings.
PS. all the reactions I witness release heat, or happen below 900c.
Actually the reactions are caused by the rapid release of chemicals because of the conflagration on multi stories by the jet fuel in the early fireball.
PVC Has chemicals that retard its combustion because PVC gives off HCl which can be corrosive to metals, a combination of HCl and other compounds can make galvanized metals burn like tissue paper.
I do not want to say more about this because the work is continuing all it takes is getting enough PVC reacting to over come the combustion retardation compounds that were added to PVC to stop the reaction.
Just think what a buoyant hydrogen flame would to to steel as it burn in air heating the steel and transforming into super heated steam. Steel dust in hot steam is explosive, Hydrogen can come from reactive metals as well as steam reacting with steel well below the fire temperatures. Free chlorides are given off by Aluminum Chloride at 700c. Also carbon dust can be explosive especially when hydrogen is present.
You do not need Controlled Demolitions to bring these buildings down all of them, all you need is intense chemical reactions, sparked by quick acceleration of the combustion of jet full.
Get the reactions started, give them about an hour to work and the building is gone from natural causes, you just should not crash planes into buildings.
Also it kind of destorys the Cters Ideas by destroying the Idea that Jet fuel fires would not cause the buildings collapses, because, the fires are just the accelerating compounds the Bunsen burner that speeds the reactants.
You should watch what happens when A 325 bolts,
are exposed to steam and hydrogen they litterally bubble the carbon out of them.
Forming weird hollow iron spheres,
I have sent Dr. Steven Jones a sample of Iron spheres that I made from Chemical reactions of metals, with compounds that would have been present, in the buildings. Like these.
I must confess there are others though that know more about this than I do.
All I know is if I start a huge hydrocarbon combustion reaction in the right enviroment it can acclerate other chemical reactions provided the chemicals are released fast enough in the right enviroment.
I think I read some where that there were 6000 pounds of PVC, per floor in the World Trade Center towers.
I just nearly blew myself up with PVC pipe, 22 Gage corrugated galvanized steel, some aluminum, some steam, and 40 gallon of Low sulfur diesel fuel trying an experiment to see if ignition of the floor pans could cause the metals spheres, and yes it could, however I was not prepared for how violent and energetic the reaction was. I forgot that hydrogen produces a super hot buoyant flame of super hot water molecules that littlery can burn-Oxidize steel.
Anyone want to come help me clean up the mess?
Idiots should not fly large planes into buildings, it causes fires and reactions in those fires that kill people.
Only people who no nothing about fires think that Hydrocarbons were the only fuel in the buildings.
PS. all the reactions I witness release heat, or happen below 900c.
Chainsaw, what percentages of those spheres have the holes in them? It looks like gases may have dissolved in the steel when it was molten above the melting point and then were released at a lower temperature near the melting point where the gas solubility was lower. The gases would form a bubble in the melt that would rise to the surface. If that happens just as the melt is solidifying, it would leave a hollow feature the steel. I'm not sure if that's what happening but it's one explanation.
It would help greatly if you would include a ruler in your pics so we know the dimensions of these features.
It would help greatly if you would include a ruler in your pics so we know the dimensions of these features.
well, arthur, tell it to michael zebhur, and i don't buy that it was random street violence.
chainsaw, it seems you and NF are onto the very good idea that there were things exploding, and that this helps explain the collapse. good on ya.
the plunger explanation is lame, and i already explained two reasons that it is.
elevator shafts?
if there was such a passageway, then the debris would increase in volume as the collapse progresses. it does not.
the firemen and people turned because they heard cutter charges going off. the same ones that every media channel repeatedly reported.
chainsaw, it seems you and NF are onto the very good idea that there were things exploding, and that this helps explain the collapse. good on ya.
the plunger explanation is lame, and i already explained two reasons that it is.
elevator shafts?
if there was such a passageway, then the debris would increase in volume as the collapse progresses. it does not.
the firemen and people turned because they heard cutter charges going off. the same ones that every media channel repeatedly reported.
QUOTE (shagster+May 6 2007, 05:42 PM)
Chainsaw, what percentages of those spheres have the holes in them? It looks like gases may have dissolved in the steel when it was molten above the melting point and then were released at a lower temperature near the melting point where the gas solubility was lower. The gases would form a bubble in the melt that would rise to the surface. If that happens just as the melt is solidifying, it would leave a hollow feature the steel. I'm not sure if that's what happening but it's one explanation.
It would help greatly if you would include a ruler in your pics so we know the dimensions of these features.
NO it is from a hydrogen and carbon reaction caused by steam on steel above 900c, it is similar to what happens in a gun barrel from free radical attack.
Hydrogen
Steam is very reactive on steel, it is just simple chemistry just never occurred to me before.
steel and steam
HCl does not react much with iron or copper, but as you can see here it does react with Calcium Carbonate, creating calcium Chloride, Calcium Chloride reacts with zinc to form Zinc Chloride and hydrogen.
HCl
The weird thing is the static electrical charge caused by the Calciums Chlorides reaction with the zinc, that is like a zinc acid battery.
I can tell you there is more going on in these buildings than simple hydrocarbon fires.
However I still have not figured out the true extent of the reactions it is just over whelming once you start them they build, and it might be impossible to figure out the true existent of the reactions.
I wanted to contact MR. Mark Ferran on this but he seem to be unavailable, now.
The combustion of hydrocarbons can actually create super heated steam.
If any one has any good articles on this please post them, I want to learn all that I can on this the work is on going.
I believe that reactive metals were the most likely source of fuel in the rubble pile as such they could have continued slowly heating the rubble pile for months, maybe even years.
It would help greatly if you would include a ruler in your pics so we know the dimensions of these features.
NO it is from a hydrogen and carbon reaction caused by steam on steel above 900c, it is similar to what happens in a gun barrel from free radical attack.
Hydrogen
QUOTE
Hydrogen: Hydrogen gas is a reducing agent and in contact with steel at high temperatures can result in decarburization and the subsequent formation of hydrogen carbons; C(Fe) + 2H2 <==> CH4
Hydrogen 2Steam is very reactive on steel, it is just simple chemistry just never occurred to me before.
steel and steam
HCl does not react much with iron or copper, but as you can see here it does react with Calcium Carbonate, creating calcium Chloride, Calcium Chloride reacts with zinc to form Zinc Chloride and hydrogen.
HCl
The weird thing is the static electrical charge caused by the Calciums Chlorides reaction with the zinc, that is like a zinc acid battery.
I can tell you there is more going on in these buildings than simple hydrocarbon fires.
However I still have not figured out the true extent of the reactions it is just over whelming once you start them they build, and it might be impossible to figure out the true existent of the reactions.
I wanted to contact MR. Mark Ferran on this but he seem to be unavailable, now.
The combustion of hydrocarbons can actually create super heated steam.
If any one has any good articles on this please post them, I want to learn all that I can on this the work is on going.
I believe that reactive metals were the most likely source of fuel in the rubble pile as such they could have continued slowly heating the rubble pile for months, maybe even years.
Talk about lame, a totally unknown 9/11 troother gets killed and you claim its because of 9/11, but there is absolutely nothing done to the BIG NAMES.
Pretty backwards.
Re: Michael Zebhur, there was plenty of crime in the area.
http://mplscrimewatch.blogspot.com/2006_11_01_archive.html
Cutter charges, that could cut sufficient columns to bring down the towers, would make SHARP CRACKS on that video, there are none.
Face it newton, your "evidence" is just plain silly.
But JUST TO BE SAFE, If I was you, I'd MOVE, have PLASTIC SURGERY done (preferably change your sex), CHANGE YOUR NAME and then, I'd only go out in LARGE CROWDS.
Arthur
Pretty backwards.
Re: Michael Zebhur, there was plenty of crime in the area.
http://mplscrimewatch.blogspot.com/2006_11_01_archive.html
Cutter charges, that could cut sufficient columns to bring down the towers, would make SHARP CRACKS on that video, there are none.
Face it newton, your "evidence" is just plain silly.
But JUST TO BE SAFE, If I was you, I'd MOVE, have PLASTIC SURGERY done (preferably change your sex), CHANGE YOUR NAME and then, I'd only go out in LARGE CROWDS.
Arthur
Do most of the spheres have the hollow feature or just a few?
QUOTE (Chainsaw+,May 6 2007, 06:36 PM)
HCl does not react much with iron or copper, but as you can see here it does react with Calcium Carbonate, creating calcium Chloride, Calcium Chloride reacts with zinc to form Zinc Chloride and hydrogen.
I mentioned that a while back. Unfortunately, it got lost in all the talk about spiked fireproofing. HCl reacts readily with Zn to form ZnCl and hydrogen. ZnCl can be produced by simply placing Zn over HCl vapor near room temperature.
QUOTE (shagster+May 6 2007, 06:43 PM)
Do most of the spheres have the hollow feature or just a few?
If they are formed from hydrogen and steam on steel they tend to be mostly hollow and of assorted sizes, I have formed other spheres though other reactions that are solid Iron oxide, and some that are pure solid iron by reactions of iron oxide and iron chloride with aluminum Chloride and aluminum and water or air.
My problem is not that I could not find reactions I found to many reactions and it is a struggle to understand them all.
I have done tension test with Hydrogen and steam attack on the A 325 bolts that I got from the state road department and the bolts can actually be seen to bubble out the sphere right before they break.
They last about 3.5 minutes before breakage. The temperature simply has to be hot enough were the metal crystals oscillate and let the hydrogen though to react with the carbon in the steel.
MY problem is in such and energetic environment I find too many possible reactions to choose from and I do not know which one to study first.
If they are formed from hydrogen and steam on steel they tend to be mostly hollow and of assorted sizes, I have formed other spheres though other reactions that are solid Iron oxide, and some that are pure solid iron by reactions of iron oxide and iron chloride with aluminum Chloride and aluminum and water or air.
My problem is not that I could not find reactions I found to many reactions and it is a struggle to understand them all.
I have done tension test with Hydrogen and steam attack on the A 325 bolts that I got from the state road department and the bolts can actually be seen to bubble out the sphere right before they break.
They last about 3.5 minutes before breakage. The temperature simply has to be hot enough were the metal crystals oscillate and let the hydrogen though to react with the carbon in the steel.
MY problem is in such and energetic environment I find too many possible reactions to choose from and I do not know which one to study first.
Chainsaw, so it's possible some of this type of reaction may have been occurring where concrete had been cracked and the reactants found their way to the floor pans. The heat from such reactions could heat up the top chords of the floor trusses, which would flow into the diagonals and could cause them to fail. It's something that wouldn't be expected in an ordinary office fire. The heat would be coming in from the back door, so to speak, instead of through the insulation that would normally be on the lower chord and diagonals. It's possible for the situation to be even worse if the insulation was still on the trusses, as heat could come in from the top but not leave from the bottom chord and diagonals. I don't know if that really happened, but it's another possible scenario.
newton
Mar 15, 2007 5:30 pm US/Central
Minneapolis Man Gets 30 Years In Death Of Student
(AP) Minneapolis The man convicted of killing a 25-year-old graduate student in Uptown Minneapolis is sentenced to 30 years in prison.
Billy Ray Deshawn Johnson pleaded guilty in February to shooting and killing Michael Zebhur in March 2006.
Zebhur, a doctoral student in bioengineering at Clemson University in South Carolina, was visiting family in the Twin Cities.
According to a criminal complaint, Zebhur, his mother, sister and another woman were walking to their car when Johnson and another man approached them and asked for Zebhur's mother's purse. Police said no one resisted but Johnson shot Zebhur anyway.
Johnson's family packed the courtroom to hear his sentence and before Johnson entered the courtroom they prayer.
Zebhur's mother, Dr. Suzanne Strong spoke in court as part of the sentencing. She said, "The tragedy has caused inconceivable suffering for me, for our family and friends. My life changed forever after I was robbed and my son murdered."
She also told the court that she has nightmares about the shooting and that her son received a death sentence, executed unjustly by a criminal.
"I thought she had amazing strength and grace to be able to make that statement in court. I don't know of a lot of people having that could have done that having gone through what she's gone through," Assistant Hennepin County Attorney Marlene Senechal.
Johnson's grandmother, Gloria Johnson was also moved by Strong's statement.
"I listened to her hurt, I prayed for that lady, for God to hold her hand and mine too," said Johnson.
When Johnson, 18, was given the chance to speak in court he looked at Zebhur's mother and said, "I apologize and I hope you forgive me for what happened to your son."
Another person Donte Jacobs, 18, will go on trial in April for allegedly participating in the robbery and driving the get-away car.
Lasonya D. Miles, 19, is serving a year in the workhouse and will be on probation for being an accomplice after the fact for giving false testimony about the case to a grand jury.
http://wcco.com/topstories/local_story_074183546.html
Are tinhatters exempt from or immune to the crime the rest of us face??? Let's be generous and say that 1/3 of the American population is retarded and buys the CTer delusion, then one would expect that very close to 1/3 of ALL murders, rapes, assaults, etc. would be one of those retarded people. If that one third behave like killtown and others, calling normal people murderers, then I would actually expect they would represent even more than a third. I know if one of you idiots accused me of murder to my face...well, let's just say you would have a permanent impression of the head of my cane on the side of your head and I'm sure that, once he heard the whole story, the judge would understand.
Grumpy
PS I'm sure this Johnson character was a paid gov't assasin.
Mar 15, 2007 5:30 pm US/Central
Minneapolis Man Gets 30 Years In Death Of Student
(AP) Minneapolis The man convicted of killing a 25-year-old graduate student in Uptown Minneapolis is sentenced to 30 years in prison.
Billy Ray Deshawn Johnson pleaded guilty in February to shooting and killing Michael Zebhur in March 2006.
Zebhur, a doctoral student in bioengineering at Clemson University in South Carolina, was visiting family in the Twin Cities.
According to a criminal complaint, Zebhur, his mother, sister and another woman were walking to their car when Johnson and another man approached them and asked for Zebhur's mother's purse. Police said no one resisted but Johnson shot Zebhur anyway.
Johnson's family packed the courtroom to hear his sentence and before Johnson entered the courtroom they prayer.
Zebhur's mother, Dr. Suzanne Strong spoke in court as part of the sentencing. She said, "The tragedy has caused inconceivable suffering for me, for our family and friends. My life changed forever after I was robbed and my son murdered."
She also told the court that she has nightmares about the shooting and that her son received a death sentence, executed unjustly by a criminal.
"I thought she had amazing strength and grace to be able to make that statement in court. I don't know of a lot of people having that could have done that having gone through what she's gone through," Assistant Hennepin County Attorney Marlene Senechal.
Johnson's grandmother, Gloria Johnson was also moved by Strong's statement.
"I listened to her hurt, I prayed for that lady, for God to hold her hand and mine too," said Johnson.
When Johnson, 18, was given the chance to speak in court he looked at Zebhur's mother and said, "I apologize and I hope you forgive me for what happened to your son."
Another person Donte Jacobs, 18, will go on trial in April for allegedly participating in the robbery and driving the get-away car.
Lasonya D. Miles, 19, is serving a year in the workhouse and will be on probation for being an accomplice after the fact for giving false testimony about the case to a grand jury.
http://wcco.com/topstories/local_story_074183546.html
Are tinhatters exempt from or immune to the crime the rest of us face??? Let's be generous and say that 1/3 of the American population is retarded and buys the CTer delusion, then one would expect that very close to 1/3 of ALL murders, rapes, assaults, etc. would be one of those retarded people. If that one third behave like killtown and others, calling normal people murderers, then I would actually expect they would represent even more than a third. I know if one of you idiots accused me of murder to my face...well, let's just say you would have a permanent impression of the head of my cane on the side of your head and I'm sure that, once he heard the whole story, the judge would understand.
Grumpy
PS I'm sure this Johnson character was a paid gov't assasin.
QUOTE (shagster+May 6 2007, 06:49 PM)
I mentioned that a while back. Unfortunately, it got lost in all the talk about spiked fireproofing. HCl reacts readily with Zn to form ZnCl and hydrogen. ZnCl can be produced by simply placing Zn over HCl vapor near room temperature.
ZnCl reacts with aluminum to form aluminum Chloride, aluminum Chloride Oxidizes at 700c, and releases free Chlorides, free Chlorides oxidize hydrogen producing HCl and a White flame.
Hydrogen+Chloride combustion
My problem is I was looking for one clear process and I found and endless circle of processes.
I thinking of just giving up while I am behind! I have a constant head ache and I am loosing a lot of sleep on this.
ZnCl reacts with aluminum to form aluminum Chloride, aluminum Chloride Oxidizes at 700c, and releases free Chlorides, free Chlorides oxidize hydrogen producing HCl and a White flame.
Hydrogen+Chloride combustion
My problem is I was looking for one clear process and I found and endless circle of processes.
I thinking of just giving up while I am behind! I have a constant head ache and I am loosing a lot of sleep on this.
QUOTE (shagster+May 6 2007, 06:58 PM)
Chainsaw, so it's possible some of this type of reaction may have been occurring where concrete had been cracked and the reactants found their way to the floor pans. The heat from such reactions could heat up the top chords of the floor trusses, which would flow into the diagonals and could cause them to fail. It's something that wouldn't be expected in an ordinary office fire. The heat would be coming in from the back door, so to speak, instead of through the insulation that would normally be on the lower chord and diagonals. It's possible for the situation to be even worse if the insulation was still on the trusses, as heat could come in from the top but not leave from the bottom chord and diagonals. I don't know if that really happened, but it's another possible scenario.
Your forgetting the towers have live decking, that is what I modeled, that is the perfect place for the reactions. Hydrogen would also tend to be buoyant and rise to the floor pans there it could ignite.
Once it is ignited the hydrogen burn hot and melts that zinc chloride that falls and the steam actually rises into the steel oxidizing the steel with the protective zinc removed.
I also have to take into account the hydrogen produce from SO2 attack on the concrete over time.
This problems is so complicated it is incredible I am constantly wondering why I got myself into this mess, now that I know about the reactions I am to curious to stop investigating them.
The aluminum releasing free Chlorides does in minutes what would take hours in building 7, and I even solved the pentagon plane problem do to PVC and water many parts of the plane could actually form Aluminum Hydroxide.
This is driving me up the wall, I think I am going nuts, it just fits so perfectly.
Your forgetting the towers have live decking, that is what I modeled, that is the perfect place for the reactions. Hydrogen would also tend to be buoyant and rise to the floor pans there it could ignite.
Once it is ignited the hydrogen burn hot and melts that zinc chloride that falls and the steam actually rises into the steel oxidizing the steel with the protective zinc removed.
I also have to take into account the hydrogen produce from SO2 attack on the concrete over time.
This problems is so complicated it is incredible I am constantly wondering why I got myself into this mess, now that I know about the reactions I am to curious to stop investigating them.
The aluminum releasing free Chlorides does in minutes what would take hours in building 7, and I even solved the pentagon plane problem do to PVC and water many parts of the plane could actually form Aluminum Hydroxide.
This is driving me up the wall, I think I am going nuts, it just fits so perfectly.
QUOTE (einsteen+May 6 2007, 08:34 AM)
DBB is the pancaking indeed takes places before any visual features outside ...
Each story contained almost twelve acre-feet of air. All this air has to go somewhere else before one trussed floor can bagel onto another. I estimate that about 7% of this air goes down through the voids in the core. All the rest has to go out through the broken windows. This is visible because the escaping air is filled with paper and fines (finely ground materials).
So, no invisible bageling...
Each story contained almost twelve acre-feet of air. All this air has to go somewhere else before one trussed floor can bagel onto another. I estimate that about 7% of this air goes down through the voids in the core. All the rest has to go out through the broken windows. This is visible because the escaping air is filled with paper and fines (finely ground materials).
So, no invisible bageling...
http://www.saunalahti.fi/wtc2001/sor11.jpg
Supposed CT debunkers:
Do you have a mechanism for why in this picture steel beams are shown suspended in air hundreds of feet above the collapse zone?
Do you know of a mechanism for why such steel beams not only were ejected straight up vertically, but thrown hundreds of feet horizontally with enough force to implant into nearby buildings?
This has already been covered, but no mechanism has been postulated, and these facts simply ignored or denied.
Supposed CT debunkers:
Do you have a mechanism for why in this picture steel beams are shown suspended in air hundreds of feet above the collapse zone?
Do you know of a mechanism for why such steel beams not only were ejected straight up vertically, but thrown hundreds of feet horizontally with enough force to implant into nearby buildings?
This has already been covered, but no mechanism has been postulated, and these facts simply ignored or denied.
memeticverb
What steel beams...OH, you mean the thin aluminum cladding from the exterior of the buildings??? Besides, I have seen NO video in which ANY pieces are expelled vertically, everything is falling toward the ground, sometimes as whole sections that reach pretty far out(>300 ft).
Any other PRATTs(Points Refuted A Thousand Times) you need explained in terms even CTers can understand???
Grumpy
What steel beams...OH, you mean the thin aluminum cladding from the exterior of the buildings??? Besides, I have seen NO video in which ANY pieces are expelled vertically, everything is falling toward the ground, sometimes as whole sections that reach pretty far out(>300 ft).
Any other PRATTs(Points Refuted A Thousand Times) you need explained in terms even CTers can understand???
Grumpy
QUOTE (memeticverb+May 6 2007, 04:38 PM)
Do you have a mechanism for why in this picture steel beams are shown suspended in air hundreds of feet above the collapse zone?
No.
Why don't YOU tell us?
(this oughta be good)
Arthur
No.
Why don't YOU tell us?
(this oughta be good)Arthur
QUOTE (memeticverb+May 6 2007, 09:38 PM)
Do you have a mechanism for why in this picture steel beams are shown suspended in air hundreds of feet above the collapse zone?
Do you know of a mechanism for why such steel beams not only were ejected straight up vertically, but thrown hundreds of feet horizontally with enough force to implant into nearby buildings?
I see the aluminum cladding above the main collapse zone.
The steel exterior wall sections were only ejected laterally, not up, IMO. The are two possible sources of the force needed to do this: air resistance of the air being ejected and more important, the pressure of the mass of crushed materials trapped inside the exterior walls. These then finally not only destroy the connections, but eject the wall sections.
The main point is that there is ample available energy to do all this and still propagate the collapse front.
Do you know of a mechanism for why such steel beams not only were ejected straight up vertically, but thrown hundreds of feet horizontally with enough force to implant into nearby buildings?
I see the aluminum cladding above the main collapse zone.
The steel exterior wall sections were only ejected laterally, not up, IMO. The are two possible sources of the force needed to do this: air resistance of the air being ejected and more important, the pressure of the mass of crushed materials trapped inside the exterior walls. These then finally not only destroy the connections, but eject the wall sections.
The main point is that there is ample available energy to do all this and still propagate the collapse front.
QUOTE (David B. Benson+May 4 2007, 07:35 PM)
But it is clear that B & Z are a worse case approximation, made before NEU-FONZE made his measurements.
Now the B & V crush-down equation is a constitutive equation, one which follows from first principles. Thus what is needed to verify it is simply enough data. Unfortunately, there are only two such sequences, both rather short. However, this is enough to demonstrate that this equation provides a better match to the data than d = (1/2)at^2. If I bothered, I am positive I can show it is a better match than the B & V crush-up equation.
It is, in my experience, the phenomenological equations, and worse, discrete simulations, which require more extensive validation.
You claim the the B & V crush-down equation is unvalidated, or rather the four assumptions are. Why? B & V offer good justifications, IMO. The first three assumptions agree with the independent work of Greening. I showed that it gives a good match to the data. Quit just carping and offer some substantive criticisms.
Yes, exactly. If this "worse" case approximation is invalidated by considering the effects of Calladine and English or related work then the less than "worse" cases don't have much ground to stand on.
You have demonstrated that you have little or no experience with verification and validation. For instance, we do not validate discrete simulations. We verify that they are returning good results. We do, or should, validate the underlying model upon which the discrete simulation is based. I state that the BV assumptions have not been validated. You may regard them as having "good" justifications, but that does not validate them. That one of the assumptions agrees with Greening does not validate it. They merely make an assumption they agree on. Forgive me for asking for higher standards. If you cannot validate the assumptions, quit dancing around and say so. That they are not validated does not mean they are invalid. I have not said they are invalid, only that I doubt their validity since they were created specifically for the 9/11/01 collapses of WTC 1 and 2 and have not been used before or since. It is apparently no interesting feat to match the timing data, it is intuitively clear (at least to me) that a demolition model can do this as well.
Here is a statement from a recently published book on using FEA for modeling collapse:
Here is a statement from a recently published book on using FEA for modeling collapse:
The development of new finite element methodologies and formulations, to model highly non-linear behavior such as buckling and collapse, continues to advance at a rapid pace. The majority of the methodologies and modeling strategies presented in this book may be found in current commercial finite element packages. To give this book relevance beyond the immediate time, recent developments which are still at the research stage are also discussed. While these may not be available commercially at the time of writing, there is enough information given for the interested reader to implement these schemes in non-commercial (research) codes or, if possible, as user subroutines in commercial finite element packages.
There are also related techniques, such as the applied element method (AEM) and the modified or extended distinct element method (MDEM, EDEM) that are yielding excellent results in collapse modeling. Here is a statement on AEM:
Now the B & V crush-down equation is a constitutive equation, one which follows from first principles. Thus what is needed to verify it is simply enough data. Unfortunately, there are only two such sequences, both rather short. However, this is enough to demonstrate that this equation provides a better match to the data than d = (1/2)at^2. If I bothered, I am positive I can show it is a better match than the B & V crush-up equation.
It is, in my experience, the phenomenological equations, and worse, discrete simulations, which require more extensive validation.
You claim the the B & V crush-down equation is unvalidated, or rather the four assumptions are. Why? B & V offer good justifications, IMO. The first three assumptions agree with the independent work of Greening. I showed that it gives a good match to the data. Quit just carping and offer some substantive criticisms.
Yes, exactly. If this "worse" case approximation is invalidated by considering the effects of Calladine and English or related work then the less than "worse" cases don't have much ground to stand on.
You have demonstrated that you have little or no experience with verification and validation. For instance, we do not validate discrete simulations. We verify that they are returning good results. We do, or should, validate the underlying model upon which the discrete simulation is based. I state that the BV assumptions have not been validated. You may regard them as having "good" justifications, but that does not validate them. That one of the assumptions agrees with Greening does not validate it. They merely make an assumption they agree on. Forgive me for asking for higher standards. If you cannot validate the assumptions, quit dancing around and say so. That they are not validated does not mean they are invalid. I have not said they are invalid, only that I doubt their validity since they were created specifically for the 9/11/01 collapses of WTC 1 and 2 and have not been used before or since. It is apparently no interesting feat to match the timing data, it is intuitively clear (at least to me) that a demolition model can do this as well.
QUOTE
FEA probably works great for intact structures.
Here is a statement from a recently published book on using FEA for modeling collapse:
QUOTE (->
| QUOTE |
| FEA probably works great for intact structures. |
Here is a statement from a recently published book on using FEA for modeling collapse:
The development of new finite element methodologies and formulations, to model highly non-linear behavior such as buckling and collapse, continues to advance at a rapid pace. The majority of the methodologies and modeling strategies presented in this book may be found in current commercial finite element packages. To give this book relevance beyond the immediate time, recent developments which are still at the research stage are also discussed. While these may not be available commercially at the time of writing, there is enough information given for the interested reader to implement these schemes in non-commercial (research) codes or, if possible, as user subroutines in commercial finite element packages.
There are also related techniques, such as the applied element method (AEM) and the modified or extended distinct element method (MDEM, EDEM) that are yielding excellent results in collapse modeling. Here is a statement on AEM:
QUOTE
Through nine years of continuous development and testing, the AEM has consistently proven itself to be the method that can best track the structural collapse behavior passing through the stages of the application of loads, crack initiation and propagation, element separation, element collision (contact), and collision with the ground and with adjacent structures. The method's degree of accuracy has been compared with more than 20 experimental and theoretical results to date. Literature surve ys also indicate that no other simulation technology has a rate of performance comparable to that of AEM. The AEM solver can accommodate the following aspects during analysis:
* Nonlinear material models for steel and concrete can be accommodated.
* All reinforcement details, including stirrups diameter, and concrete cover are easily considered.
* Analysis can include non-structural elements as well as structural elements such as glass windows or brick bearing walls.
* Separation, contact, and collision between elements are taken into consideration.
* Special performance elements, such as interface or gap elements that are required in FEM, are not needed at separation or contact locations.
* The separation of structural elements and the collisions between elements are arbitrary at any location of the structure.
* Collapse simulation involves the use of advanced optimization techniques to solve large-scale problems using less memory size and shorter time.
* Nonlinear material models for steel and concrete can be accommodated.
* All reinforcement details, including stirrups diameter, and concrete cover are easily considered.
* Analysis can include non-structural elements as well as structural elements such as glass windows or brick bearing walls.
* Separation, contact, and collision between elements are taken into consideration.
* Special performance elements, such as interface or gap elements that are required in FEM, are not needed at separation or contact locations.
* The separation of structural elements and the collisions between elements are arbitrary at any location of the structure.
* Collapse simulation involves the use of advanced optimization techniques to solve large-scale problems using less memory size and shorter time.
QUOTE (eigenvalue+May 6 2007, 10:22 PM)
I state that the BV assumptions have not been validated. ...
it is intuitively clear (at least to me) that a demolition model can do this as well.
... the applied element method (AEM) ...
There are two separate issues: collapse initiation and collapse progression. I don't find B&Z appropriate, in light of what has since been learned, for collapse initiation.
I have no idea what you are expecting regarding validating these assumptions. (And Greening uses three of the four B&V assumptions.) When a constitutive equation gives a good fit to data, most take that as sufficient, provided there is enough data. When data is lacking Bayesian techniques provide the sharpest means to choose one constitutive equation over another. (By the way, reading the Wikipedia page on constitutive equation would certainly enhance the quality of our exchanges.[which is actually reasonably good anyway])
Since you have proposed no demolition model for the collapse itself, I have nothing to compare. But if you happen to mean 'in nearly free-fall, as an implosion demolition', then I can already assure you that this hypothesis provides a very bad match to the data. (I'll have some actual numbers in a few days.)
By all means acquire a copy of AEM and go to work modeling the collapses. It might actually say something useful regarding the behavior of traditional connections in a progressive collapse. The structural engineering community would welcome this, although doubt has been expressed that traditional steel connection designs can ever be modified to withstand progressive collapse.
it is intuitively clear (at least to me) that a demolition model can do this as well.
... the applied element method (AEM) ...
There are two separate issues: collapse initiation and collapse progression. I don't find B&Z appropriate, in light of what has since been learned, for collapse initiation.
I have no idea what you are expecting regarding validating these assumptions. (And Greening uses three of the four B&V assumptions.) When a constitutive equation gives a good fit to data, most take that as sufficient, provided there is enough data. When data is lacking Bayesian techniques provide the sharpest means to choose one constitutive equation over another. (By the way, reading the Wikipedia page on constitutive equation would certainly enhance the quality of our exchanges.[which is actually reasonably good anyway])
Since you have proposed no demolition model for the collapse itself, I have nothing to compare. But if you happen to mean 'in nearly free-fall, as an implosion demolition', then I can already assure you that this hypothesis provides a very bad match to the data. (I'll have some actual numbers in a few days.)
By all means acquire a copy of AEM and go to work modeling the collapses. It might actually say something useful regarding the behavior of traditional connections in a progressive collapse. The structural engineering community would welcome this, although doubt has been expressed that traditional steel connection designs can ever be modified to withstand progressive collapse.
According to the site that quote comes from:
But it appears that this software was not available until late 2004, so too late for NISTs work on the WTC towers.
Course that doesn't prevent someone from doing it NOW.
Of course, one thing is quite interesting, here's a company that sells a package that was designed to specifically allow one to model PROGRESSIVE COLLAPSE.
Guess that should shut up the people who claim its not possible.
http://www.gostructural.com/article.asp?id=177
http://www.appliedscienceint.com/Home.shtml
http://www.appliedscienceint.com/ProgressiveCollapse.shtml
and
http://www.extremeloading.com/AEM_tech.asp...ive&type=common
Arthur
QUOTE
Methods used for structural analysis are mainly based upon rules of continuum mechanics, such as the finite element method (FEM), an approach that cannot be applied to discrete elements. Therefore, continuum mechanics-based methods cannot be extended to simulate a collapse. Conversely, analysis methods based on rules of discrete material cannot be used to predict the behavior of continuum elements.
During a collapse situation, structures pass first through a continuum stage, and then through a discrete stage. Because of these factors, the computer simulation must follow both of these behavior stages in order to answer the following questions:
During a collapse situation, structures pass first through a continuum stage, and then through a discrete stage. Because of these factors, the computer simulation must follow both of these behavior stages in order to answer the following questions:
But it appears that this software was not available until late 2004, so too late for NISTs work on the WTC towers.
Course that doesn't prevent someone from doing it NOW.
Of course, one thing is quite interesting, here's a company that sells a package that was designed to specifically allow one to model PROGRESSIVE COLLAPSE.
Guess that should shut up the people who claim its not possible.
http://www.gostructural.com/article.asp?id=177
http://www.appliedscienceint.com/Home.shtml
http://www.appliedscienceint.com/ProgressiveCollapse.shtml
and
http://www.extremeloading.com/AEM_tech.asp...ive&type=common
Arthur
From Answers.com thesaurus:
Validation (noun)
That which confirms:
attestation
authentication
confirmation
corroboration
demonstrate
evidence
proof
substantiation
testament
testimonial
testimony
verification
warrant
Validation (noun)
That which confirms:
attestation
authentication
confirmation
corroboration
demonstrate
evidence
proof
substantiation
testament
testimonial
testimony
verification
warrant
QUOTE (David B. Benson+May 6 2007, 04:29 PM)
From Answers.com thesaurus:
Validation (noun)
That which confirms:
attestation
authentication
confirmation
corroboration
demonstrate
evidence
proof
substantiation
testament
testimonial
testimony
verification
warrant
Verification and validation (V&V) have very important meanings in the context of modeling and simulation. You are very well aware that everyday terms have sometimes more specific uses in the sciences. Try to focus on those.
Validation (noun)
That which confirms:
attestation
authentication
confirmation
corroboration
demonstrate
evidence
proof
substantiation
testament
testimonial
testimony
verification
warrant
Verification and validation (V&V) have very important meanings in the context of modeling and simulation. You are very well aware that everyday terms have sometimes more specific uses in the sciences. Try to focus on those.
QUOTE (eigenvalue+May 7 2007, 12:03 AM)
You are very well aware that everyday terms have sometimes more specific uses in the sciences.
Yes. Which science?
These refer to process in pharmaceutical manufacture.
There are other uses in IT.
But I have never seen V&V applied to confirming a constitutive equation. What I have seen is comparing equations (more generally, so-called hypotheses) via Fischer/Pearson style statistics (lots) and Bayesian reasoning (a little).
Yes. Which science?
These refer to process in pharmaceutical manufacture.
There are other uses in IT.
But I have never seen V&V applied to confirming a constitutive equation. What I have seen is comparing equations (more generally, so-called hypotheses) via Fischer/Pearson style statistics (lots) and Bayesian reasoning (a little).
Try this (from the NNSA's Advanced Simulation and Computing program):
Note that this distinguishes between code accuracy and model accuracy. Two distinctly different areas that each need to be addressed (in those cases where a computational simulation is performed using a given model).
QUOTE
Verification & Validation
Based on the functional and operational requirements established by designers, analysts and code developers for greater fidelity of codes and models, this subprogram establishes a technically rigorous foundation for the credibility of code results. This sub-program interfaces with the Integrated Codes Sub-program to obtain regular, official code releases from the code projects. Verification activities assess code precision in implementing numerical approximations and assess the accuracy of these numerical approximations. Validation activities aid in the understanding and assessment of a model’s accuracy by comparing model predictions with experimental data. Quantification methodologies provide measures of the uncertainties associated with the simulations. Sound software quality engineering practices are used to ensure robust, efficient, and well documented software releases of the ASC codes. This sub-program collaborates with the Science and Engineering Campaigns and DSW to obtain experimental data for validation purposes. Final V&V assessment reports contain the standard deliverables of this subprogram.
Based on the functional and operational requirements established by designers, analysts and code developers for greater fidelity of codes and models, this subprogram establishes a technically rigorous foundation for the credibility of code results. This sub-program interfaces with the Integrated Codes Sub-program to obtain regular, official code releases from the code projects. Verification activities assess code precision in implementing numerical approximations and assess the accuracy of these numerical approximations. Validation activities aid in the understanding and assessment of a model’s accuracy by comparing model predictions with experimental data. Quantification methodologies provide measures of the uncertainties associated with the simulations. Sound software quality engineering practices are used to ensure robust, efficient, and well documented software releases of the ASC codes. This sub-program collaborates with the Science and Engineering Campaigns and DSW to obtain experimental data for validation purposes. Final V&V assessment reports contain the standard deliverables of this subprogram.
Note that this distinguishes between code accuracy and model accuracy. Two distinctly different areas that each need to be addressed (in those cases where a computational simulation is performed using a given model).
eigenvalue,
Do you have a POINT to all this?
Arthur
Do you have a POINT to all this?
Arthur
QUOTE (David B. Benson+May 6 2007, 09:51 PM)
I see the aluminum cladding above the main collapse zone.
The steel exterior wall sections were only ejected laterally, not up, IMO. The are two possible sources of the force needed to do this: air resistance of the air being ejected and more important, the pressure of the mass of crushed materials trapped inside the exterior walls. These then finally not only destroy the connections, but eject the wall sections.
The main point is that there is ample available energy to do all this and still propagate the collapse front.
Thanks for at least admitting that you see a problem in that the perimeter columns appear to be flying at angles they should not, had the energy they were being extracted and propelled with been only gravity.
You may also have noticed that each of the beams in that picture and many others all appear to be the same size.
They may not in fact be steel beams that we see in the above picture, but the exterior columns. However, I do not see any available energy, neither air as you claim, nor crushed materials, as possibly providing enough energy to propel even aluminum beams hundreds of feet, even horizontally into neighboring buildings.
The steel exterior wall sections were only ejected laterally, not up, IMO. The are two possible sources of the force needed to do this: air resistance of the air being ejected and more important, the pressure of the mass of crushed materials trapped inside the exterior walls. These then finally not only destroy the connections, but eject the wall sections.
The main point is that there is ample available energy to do all this and still propagate the collapse front.
Thanks for at least admitting that you see a problem in that the perimeter columns appear to be flying at angles they should not, had the energy they were being extracted and propelled with been only gravity.
You may also have noticed that each of the beams in that picture and many others all appear to be the same size.
They may not in fact be steel beams that we see in the above picture, but the exterior columns. However, I do not see any available energy, neither air as you claim, nor crushed materials, as possibly providing enough energy to propel even aluminum beams hundreds of feet, even horizontally into neighboring buildings.
memeticverb, you're a meme after me me meme do.
I know you two will get along, he sees motion in a still picture. You need to teach him how to fold bills to see the Pentagon and the Towers.
Arthur
Arthur
QUOTE (adoucette+May 7 2007, 02:45 AM)
eigenvalue,
Do you have a POINT to all this?
Arthur
I think he wants a thesaurus for his birthday.
Do you have a POINT to all this?
Arthur
I think he wants a thesaurus for his birthday.
QUOTE (Capracus+May 7 2007, 06:14 AM)
I think he wants a thesaurus for his birthday.
i don't think he's the one who needs one.
i don't think he's the one who needs one.
QUOTE (newton+May 7 2007, 07:22 AM)
i don't think he's the one who needs one.
He and David seem to get a kick out of of parsing words, so let's send them each a copy.
He and David seem to get a kick out of of parsing words, so let's send them each a copy.
A debate between Leslie Robertson and Steven Jones:
http://www.911podcasts.com/files/audio/Ste...on_20061026.mp3
Here is the transcript:
http://www.journalof911studies.com/volume/...nTranscript.pdf
Here's what the actual engineer of the towers thinks of the collapses:
Steven Jones defends his position with peer reviewed papers of some notable engineers:
Steven Jones defends his position with peer reviewed papers of some notable engineers:
JONES: Thank you. I would like to say something about that. There are two papers, published peer-reviewed papers, on this topic. It's actually not clear that these tests had fully protected floor trusses, but these were actual tests that were conducted and they did not fail. That’s discussed in a paper by Kevin Ryan in the Journal of 911studies.com.29 The other paper I'd like to refer to regarding the Towers is a paper by Gordon Ross,30 a mechanical engineer out of the United Kingdom. His point is that even if we allow that the towers could begin to collapse, that is the upper floors – for instance in the North Tower, that would be the upper 15 floors – if they begin to collapse, that does not mean that they would continue a complete collapse in ten seconds. Instead, the remaining structure below the upper block would halt or significantly slow down the collapse and the motion of the upper floors.
They may not in fact be steel beams that we see in the above picture, but the exterior columns. However, I do not see any available energy, neither air as you claim, nor crushed materials, as possibly providing enough energy to propel even aluminum beams hundreds of feet, even horizontally into neighboring buildings.
wow. you said the same thing i did, except you prefaced it with the word, "no". LOL!
"relatively weak"
LOL!
i can't believe how many physics fans can forget one of the three golden rules...
"equal and opposite"
whatever you claim is "weak" is being hit by identical material, and so it's like smashing two eggs together.
you know at easter, there's a game we play with hard boiled eggs. one player holds his egg with the tip pointed upwards, and the other player smashes his egg tip down onto it. the winner is the one who's egg doesn't break. now the force equations for two two hundred pound humans swinging an egg with destructive intent at another egg are way off the ratio scale of tower cap "INSTANTLY FALLING"(impossible to begin with) and smashing into the lower floors.
and so, with my analogy in place, which egg usually breaks? it's 50/50. the stronger egg wins, not the faster egg with the most momentum and force.
in the case of the tower, which egg was stronger? why the bottom one, of course, because it is moored into the ground, whereas the top is free to bounce around.
here's a link to the demolition of a thirty-odd storey building.
very nicely demoed
the first explosion(seismic trace) is at the 10 or 11 second mark. the building then sits there for another 6 seconds, and at the 17 second mark, the main flash goes off at the base. the building's top hits the ground about 10 seconds later.
total demo time of about 16 seconds.
now, why again was WTC7 not a controlled demolition? it took those 47 storeys less time to hit the ground than it took these 30-odd.
http://www.911podcasts.com/files/audio/Ste...on_20061026.mp3
Here is the transcript:
http://www.journalof911studies.com/volume/...nTranscript.pdf
Here's what the actual engineer of the towers thinks of the collapses:
QUOTE
ROBERTSON: But the collapse mechanism of the Trade Center is as we had anticipated it would be when we first designed it. It was not – please don't misunderstand me – it was not designed to collapse. But any prudent engineer looking at the future has to think about, what are the mechanisms that cause collapse, and how to go about strengthening the building so as to minimize that circumstance. So sure, we spent time looking at that kind of event, and that which was observable from the photographs and so forth is reasonably consistent with that which we thought would be the case.
Steven Jones defends his position with peer reviewed papers of some notable engineers:
QUOTE (->
| QUOTE |
| ROBERTSON: But the collapse mechanism of the Trade Center is as we had anticipated it would be when we first designed it. It was not – please don't misunderstand me – it was not designed to collapse. But any prudent engineer looking at the future has to think about, what are the mechanisms that cause collapse, and how to go about strengthening the building so as to minimize that circumstance. So sure, we spent time looking at that kind of event, and that which was observable from the photographs and so forth is reasonably consistent with that which we thought would be the case. |
Steven Jones defends his position with peer reviewed papers of some notable engineers:
JONES: Thank you. I would like to say something about that. There are two papers, published peer-reviewed papers, on this topic. It's actually not clear that these tests had fully protected floor trusses, but these were actual tests that were conducted and they did not fail. That’s discussed in a paper by Kevin Ryan in the Journal of 911studies.com.29 The other paper I'd like to refer to regarding the Towers is a paper by Gordon Ross,30 a mechanical engineer out of the United Kingdom. His point is that even if we allow that the towers could begin to collapse, that is the upper floors – for instance in the North Tower, that would be the upper 15 floors – if they begin to collapse, that does not mean that they would continue a complete collapse in ten seconds. Instead, the remaining structure below the upper block would halt or significantly slow down the collapse and the motion of the upper floors.
QUOTE (memeticverb+May 7 2007, 04:48 AM)
They may not in fact be steel beams that we see in the above picture, but the exterior columns. However, I do not see any available energy, neither air as you claim, nor crushed materials, as possibly providing enough energy to propel even aluminum beams hundreds of feet, even horizontally into neighboring buildings.
Every time a floor was overloaded during the collapses, the exterior columns were subject to tension from the floor system. This built up strain energy in the columns, and when the truss connections failed, the columns recoiled and ejected loose or fractured cladding and column sections laterally away from the buildings.
QUOTE (Capracus+May 7 2007, 10:19 AM)
Every time a floor was overloaded during the collapses, the exterior columns were subject to tension from the floor system. This built up strain energy in the columns, and when the truss connections failed, the columns recoiled and ejected loose or fractured cladding and column sections laterally away from the buildings.
That implies that if you implode the whole building from the bottom that also horizontal ejections would occur.
That implies that if you implode the whole building from the bottom that also horizontal ejections would occur.
memeticverb
There were NO aluminum "beams". The cladding was decorative covers having more in common with aluminum foil than with the beams of steel that held up the buildings. Such lightweight, low density sheets fall much slower than would a solid steel beam due to air resistance.
Being surprised that the outer steel framework reached over 300 feet from the buildings is akin to being surprised that the top of a one hundred foot tree ended up one hundred feet away from the stump, and for the same reasons. The outer frame fell over after the top block pushed them outward.
Grumpy
QUOTE
They may not in fact be steel beams that we see in the above picture, but the exterior columns. However, I do not see any available energy, neither air as you claim, nor crushed materials, as possibly providing enough energy to propel even aluminum beams hundreds of feet, even horizontally into neighboring buildings.
There were NO aluminum "beams". The cladding was decorative covers having more in common with aluminum foil than with the beams of steel that held up the buildings. Such lightweight, low density sheets fall much slower than would a solid steel beam due to air resistance.
Being surprised that the outer steel framework reached over 300 feet from the buildings is akin to being surprised that the top of a one hundred foot tree ended up one hundred feet away from the stump, and for the same reasons. The outer frame fell over after the top block pushed them outward.
Grumpy
QUOTE (Grumpy+May 7 2007, 02:23 PM)
memeticverb
There were NO aluminum "beams". The cladding was decorative covers having more in common with aluminum foil than with the beams of steel that held up the buildings. Such lightweight, low density sheets fall much slower than would a solid steel beam due to air resistance.
Being surprised that the outer steel framework reached over 300 feet from the buildings is akin to being surprised that the top of a one hundred foot tree ended up one hundred feet away from the stump, and for the same reasons. The outer frame fell over after the top block pushed them outward.
Grumpy
grumpy you are stating that an aluminum beam(cladding) meets more resistance from AIR than a steel beam meets from A STEEL BUILDING.
nice science.
There were NO aluminum "beams". The cladding was decorative covers having more in common with aluminum foil than with the beams of steel that held up the buildings. Such lightweight, low density sheets fall much slower than would a solid steel beam due to air resistance.
Being surprised that the outer steel framework reached over 300 feet from the buildings is akin to being surprised that the top of a one hundred foot tree ended up one hundred feet away from the stump, and for the same reasons. The outer frame fell over after the top block pushed them outward.
Grumpy
grumpy you are stating that an aluminum beam(cladding) meets more resistance from AIR than a steel beam meets from A STEEL BUILDING.
nice science.
newton
No, I am pointing out that the rate of fall through air of a piece of thin aluminum sheeting in no way represents the speed of fall of a steel beam, nor does it match the speed steel and concrete debris can fall through the relatively weak floors of that building(the steel frame structure of those buildings offered very little resistance, being bypassed and pushed over). In fact the aluminum sheeting could fall very slowly indeed if it's orientation is right, like a falling leaf or Frisbee.
Grumpy
QUOTE
grumpy you are stating that an aluminum beam(cladding) meets more resistance from AIR than a steel beam meets from A STEEL BUILDING.
No, I am pointing out that the rate of fall through air of a piece of thin aluminum sheeting in no way represents the speed of fall of a steel beam, nor does it match the speed steel and concrete debris can fall through the relatively weak floors of that building(the steel frame structure of those buildings offered very little resistance, being bypassed and pushed over). In fact the aluminum sheeting could fall very slowly indeed if it's orientation is right, like a falling leaf or Frisbee.
Grumpy
See NIST NCSTAR 1-6A - fig 3-4 - The aluminum cladding was actually a U shape and as such (and based on its actual final shape when detached) probably could generate signifiant air resistance as it fell.
Arthur
Arthur
QUOTE
newton
QUOTE
grumpy you are stating that an aluminum beam(cladding) meets more resistance from AIR than a steel beam meets from A STEEL BUILDING.
No, I am pointing out that the rate of fall through air of a piece of thin aluminum sheeting in no way represents the speed of fall of a steel beam, nor does it match the speed steel and concrete debris can fall through the relatively weak floors of that building(the steel frame structure of those buildings offered very little resistance, being bypassed and pushed over). In fact the aluminum sheeting could fall very slowly indeed if it's orientation is right, like a falling leaf or Frisbee.
Grumpy cool.gif
QUOTE
grumpy you are stating that an aluminum beam(cladding) meets more resistance from AIR than a steel beam meets from A STEEL BUILDING.
No, I am pointing out that the rate of fall through air of a piece of thin aluminum sheeting in no way represents the speed of fall of a steel beam, nor does it match the speed steel and concrete debris can fall through the relatively weak floors of that building(the steel frame structure of those buildings offered very little resistance, being bypassed and pushed over). In fact the aluminum sheeting could fall very slowly indeed if it's orientation is right, like a falling leaf or Frisbee.
Grumpy cool.gif
wow. you said the same thing i did, except you prefaced it with the word, "no". LOL!
"relatively weak"
LOL!
i can't believe how many physics fans can forget one of the three golden rules...
"equal and opposite"
whatever you claim is "weak" is being hit by identical material, and so it's like smashing two eggs together.
you know at easter, there's a game we play with hard boiled eggs. one player holds his egg with the tip pointed upwards, and the other player smashes his egg tip down onto it. the winner is the one who's egg doesn't break. now the force equations for two two hundred pound humans swinging an egg with destructive intent at another egg are way off the ratio scale of tower cap "INSTANTLY FALLING"(impossible to begin with) and smashing into the lower floors.
and so, with my analogy in place, which egg usually breaks? it's 50/50. the stronger egg wins, not the faster egg with the most momentum and force.
in the case of the tower, which egg was stronger? why the bottom one, of course, because it is moored into the ground, whereas the top is free to bounce around.
here's a link to the demolition of a thirty-odd storey building.
very nicely demoed
the first explosion(seismic trace) is at the 10 or 11 second mark. the building then sits there for another 6 seconds, and at the 17 second mark, the main flash goes off at the base. the building's top hits the ground about 10 seconds later.
total demo time of about 16 seconds.
now, why again was WTC7 not a controlled demolition? it took those 47 storeys less time to hit the ground than it took these 30-odd.
QUOTE (eigenvalue+May 7 2007, 01:05 AM)
Try this (from the NNSA's Advanced Simulation and Computing program):
Note that this distinguishes between code accuracy and model accuracy. Two distinctly different areas that each need to be addressed (in those cases where a computational simulation is performed using a given model).
Read what your quotation says about validation. By the definition used there, that is exactly what I have done: confirm that the equation (model) agrees well with the data.
Next, while every computer program needs to be carefully designed and checked, this one is basically the most vanilla application of Runge-Kutta one could hope for. Bread-n-butter stuff, really.
This has been an interesting exchange. I now regret using the heavily overloaded (ambiguous) word validated. I should have used simply confirmed.
Note that this distinguishes between code accuracy and model accuracy. Two distinctly different areas that each need to be addressed (in those cases where a computational simulation is performed using a given model).
Read what your quotation says about validation. By the definition used there, that is exactly what I have done: confirm that the equation (model) agrees well with the data.
Next, while every computer program needs to be carefully designed and checked, this one is basically the most vanilla application of Runge-Kutta one could hope for. Bread-n-butter stuff, really.
This has been an interesting exchange. I now regret using the heavily overloaded (ambiguous) word validated. I should have used simply confirmed.
QUOTE (newton+May 7 2007, 01:12 PM)
here's a link to the demolition of a thirty-odd storey building.
very nicely demoed
the first explosion(seismic trace) is at the 10 or 11 second mark. the building then sits there for another 6 seconds, and at the 17 second mark, the main flash goes off at the base. the building's top hits the ground about 10 seconds later.
total demo time of about 16 seconds.
now, why again was WTC7 not a controlled demolition? it took those 47 storeys less time to hit the ground than it took these 30-odd.
The main blast is at 18 seconds, though no movement is seen in the video till 19 seconds.
The top hits at the 25 second mark.
So collapse time is between 6 and 7 seconds.
Arthur
very nicely demoed
the first explosion(seismic trace) is at the 10 or 11 second mark. the building then sits there for another 6 seconds, and at the 17 second mark, the main flash goes off at the base. the building's top hits the ground about 10 seconds later.
total demo time of about 16 seconds.
now, why again was WTC7 not a controlled demolition? it took those 47 storeys less time to hit the ground than it took these 30-odd.
The main blast is at 18 seconds, though no movement is seen in the video till 19 seconds.
The top hits at the 25 second mark.
So collapse time is between 6 and 7 seconds.
Arthur
As I continue to lurk and learn about all things 9/11, I occasionally come across items that keep me from finally and fully accepting the official version. This site may be old news here, but it is new to me. I see the video of the presentation is from 4/20/07, so I'm thinking all their information is post NIST.
Anyway, FYI/FWIW:
http://www.brightpathweb.net/ae911/index.html
Anyway, FYI/FWIW:
http://www.brightpathweb.net/ae911/index.html
QUOTE
Why are Architects and Engineers Re-examining the WTC Collapses?
Architects and Engineers are trained to create buildings that function well and withstand potentially destructive forces. However, the 3 high-rise buildings at the World Trade Center which "collapsed" on 9/11 presented us with a body evidence (i.e. controlled demolition) that was largely outside the scope of our training and experience.
In addition, the shock that hit us on that date from the repeated attacks and staggering loss of life has limited our ability to rationally evaluate what really happened. We therefore find ourselves relying solely upon the judgment of outside experts and, quite willingly, "go along" with the collective myth that has unfolded: that the buildings failed structurally due to the aircraft impacts and resulting fires. After all, we saw the aircraft slam into the building, the resulting huge fireball, and the ensuing "collapses".
There is however a growing body of solid evidence regarding these "collapses" that has emerged in the last couple of years - gaining ground even in the mainstream media. This new evidence casts grave doubt upon the theories of the 9/11 experts as well as the official reports by the 9/11 Commission, FEMA, and NIST.
It lays out a solid convincing case which architects & engineers will readily see: that the 3 WTC high-rise buildings were destroyed by both classic and novel forms of controlled demolition. You will find the evidence here in our website as well as at the linked websites. We hope you will find the courage and take the necessary time to review each section thoroughly.
Architects and Engineers are trained to create buildings that function well and withstand potentially destructive forces. However, the 3 high-rise buildings at the World Trade Center which "collapsed" on 9/11 presented us with a body evidence (i.e. controlled demolition) that was largely outside the scope of our training and experience.
In addition, the shock that hit us on that date from the repeated attacks and staggering loss of life has limited our ability to rationally evaluate what really happened. We therefore find ourselves relying solely upon the judgment of outside experts and, quite willingly, "go along" with the collective myth that has unfolded: that the buildings failed structurally due to the aircraft impacts and resulting fires. After all, we saw the aircraft slam into the building, the resulting huge fireball, and the ensuing "collapses".
There is however a growing body of solid evidence regarding these "collapses" that has emerged in the last couple of years - gaining ground even in the mainstream media. This new evidence casts grave doubt upon the theories of the 9/11 experts as well as the official reports by the 9/11 Commission, FEMA, and NIST.
It lays out a solid convincing case which architects & engineers will readily see: that the 3 WTC high-rise buildings were destroyed by both classic and novel forms of controlled demolition. You will find the evidence here in our website as well as at the linked websites. We hope you will find the courage and take the necessary time to review each section thoroughly.
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