lenbrazil
Saturn
Now there's a man with an open mind - you can feel the breeze from here!
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Post by lenbrazil on Oct 18, 2005 17:19:01 GMT -4
The link for the original article is: www.garlicandgrass.org/issue6/Dave_Heller.cfmIn it Heller says "Jim Hoffman, a professional scientist published in several peer-reviewed scientific journals, took a long look at all of this. He calculated that even if the structure itself offered no resistance — that is to say, even if the 110 floors of each tower were hovering in mid-air — the "pancake" theory would still have taken a minimum of 15.5 seconds to reach the ground." Unfortunately he gives us no clue as to how Hoffman reached his conclusion. Also since he doesn't refer to him as Dr. Jim Hoffman he probably has a master's degree at best. And since he didn't even tell us what kind of scientist he was I imagined his specialty was in some embarrassingly unrelated field. I googled his name unfortunately there are a lot of Jim Hoffmans out there. One is a computer scientist another is linguist another is a psychologist etc After I Googled "jim hoffman" +9/11 I started doubting if he really is a scientist. There was no mention of this in any of the PCT sites that cited him. Even when I did a site search of his site site:911research.wtc7.net "jim hoffman"and only saw him referenced as being a webmaster. If he is the comp. scientist his degree is a "B.S. in Marketing with a Minor in Psychology: Eastern Illinois University • December 1990 • GPA: 3.16 of 4.0 " www.ryumaou.com/hoffman/resume.html
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lenbrazil
Saturn
Now there's a man with an open mind - you can feel the breeze from here!
Posts: 1,045
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Post by lenbrazil on Oct 18, 2005 18:21:00 GMT -4
I took a look at the school Heller got his masters from. I asked Turbonium in the main 9/11 thread if any architects or civil engineers doubted the official explanation. I asked Jack White the same question on the Ed. Forum. Heller was the only person with any sort or relevant degree they could cite who examined the WTC more than a few days after the fact. A civil or structural engineer would be more qualified because most architectural courses teach sociology, art [especially architectural] history, psychology etc as much or more so than the engineering aspect. The main thrust of the "San Francisco Architectural Institutes's program is "natural architecture". "The school is open to all" you don't even need to have gone to college to get into it's masters degree program. Most of the class are taught by it director and most of the others by a SFIA graduate. Only a handful of classes are tought per period. Payment is by credit card on a course by course basis. It sounds like a PC eco-friendly diploma mill to me. I looked through it's course catalogue an saw no evidence that any classes teaching the science end of architecture are taught there. Heller the CTists only expert it seems has no academic training that would qualify him as an expert. For example in Summer 2005 the classes offered were VECTORWORKS COMPUTER-AIDED DESIGN AND DRAFTING E-95 INTERN STUDY FOR AN ECO DESIGN CASE STUDY . E-85 BECOMING AN ECOLOGICAL DESIGN PROFESSIONAL E-100 "EVERYTHING ECO" WORKSHOPS E-100-1 Materials & Methods E-100-2 Energy & Environment C-10 SKETCHUP: 3-D MODELING THE EASY WAY SELF-PACED STUDY D-14 COMMUNICATING YOUR DESIGNS: PERSPECTIVE DRAWING & MEDIA __ C-11 Winter 2005 • Ancient Egypt • Buddhist Architecture • Green Walls -- Hands-On Workshop • Sketch Perspective Drawing and Rendering -- Hands-On Studio • Understanding Working Drawings www.sfia.net/Courses.asp
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Post by JayUtah on Oct 18, 2005 19:13:59 GMT -4
I took a look at the school Heller got his masters from.As did I. It's unaccredited, meaning its graduates cannot apply for professional licensing. Architecture is considered a professional program and as such is ruthlessly examined for accreditation purposes. A civil or structural engineer would be more qualified because most architectural courses teach sociology, art [especially architectural] history, psychology etc as much or more so than the engineering aspect.A civil or structural engineering would indeed be much more qualified. But as an engineer who has nevertheless descended from a long line of architects, I have to defend that profession somewhat. Architects learn the same principles of mechanics and structural analysis as engineers. They just don't delve as deeply into the whys and wherefores as structural engineers do. But a graduate of an accredited architectural program would be expected to understand the behavior of structural systems such as those in the WTC. I looked through it's course catalogue an saw no evidence that any classes teaching the science end of architecture are taught there.Correct. There is none of the rigor that is found in accredited programs. Here is the curriculum of an accredited program with which I am intimately familiar, having served as this college's assistant librarian (ca. 30,000 titles) for a few years. capd.ksu.edu/pdfs/architecture-curriculum.pdfNote that the graduate will have completed four semesters of study in structural systems. Heller the CTists only expert it seems has no academic training that would qualify him as an expert.I concur.
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lenbrazil
Saturn
Now there's a man with an open mind - you can feel the breeze from here!
Posts: 1,045
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Post by lenbrazil on Oct 18, 2005 21:58:16 GMT -4
I took a look at the school Heller got his masters from.As did I. It's unaccredited, meaning its graduates cannot apply for professional licensing. Architecture is considered a professional program and as such is ruthlessly examined for accreditation purposes Jay how did you determine the school is unaccredited?
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lenbrazil
Saturn
Now there's a man with an open mind - you can feel the breeze from here!
Posts: 1,045
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Post by lenbrazil on Oct 18, 2005 22:00:00 GMT -4
Has anybody know who this Jim Hoffman is, and what it any science background he has?
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Post by turbonium on Oct 18, 2005 22:57:54 GMT -4
In your first reply on this thread you said "The temperatures cited of 1832F are not substantiated by any investigations, even the NIST report itself! "
So are you now admitting you were wrong???
No - I meant exactly what I said....
substantiated (Definition from dictionary). ... supported or established by evidence or proof
I noted the 1000C temperature cited in the NIST report , which is why I specifically mentioned that they did not prove (substantiate) their claim.
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Post by turbonium on Oct 18, 2005 23:13:33 GMT -4
I know it seems lawyerly, but where do you stop timing? Do you stop when the last bit of wreckage stops moving? Do you extrapolate the last bit of each collapse that's hidden in a dust cloud? Do you stop when the first girder hits the pavement? These are important considerations. You have to consider also, for example, seismic data that can "see" through the dust and register when the bulk of the material stopped falling.
This is a point I too am unsure about. I would assume you would want to visually try and calculate (through the debris/dust cloud) the time for the top of the towers to collapse to ground level. Seismic data would possibly indicate a longer time span as the material would "pile up", while at the same time be driven into the very deep basement levels, tunnels and access areas underground. But, the seismic data indicates a time of about 10 seconds, so that seems unlikely to be too [/i]long[/i] a collapse time.
Upon further thought, would the top floor(s) of the towers even reach ground level? It is difficult at best to come to a conclusive measurement of the time for complete collapse. The estimates to date have ranged from 10 to 15 seconds. WTC 7, however, is much easier to calculate, as there is little to impede the view of the building as it collapsed. Estimates range mostly from 6 to 8 seconds.
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Post by turbonium on Oct 18, 2005 23:21:36 GMT -4
Jay how did you determine the school is unaccredited?
It says so in the FAQ section of their website, though I can't say if that's how Jay knew.
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Post by jaydeehess on Oct 18, 2005 23:55:38 GMT -4
At a time of collapse , 10 seconds would be 8.6% slower than free-fall
At a time of collapse of 14 seconds would be 52% slower than free-fall.
As said above Heller and Russell before him, say nothing about the time of collapse they would say it should be. In such they simply beg the question.
Seismic readings would give as good a reading for time of collapse as any other method. Turbonium's complaint that the debris would pile up would actually serve to substantiate the idea that it was less than free-fall rate. The last items to hit packed earth and debris would have less distance to fall since they are hitting the top of the pile and not the level of the ground about the towers. If the pile was 100 feet high then the distance those last pieces from the top of the towers would have had approx 10% less distance to fall.
Fall time from 1300 feet is 9.01 seconds for instance and fall time through 1200 feet is 8.66 seconds.
So this entire complaint about the time it took to collapse is a very thin arguement. Given the uncertainties involved in attempting to get a time period for the actual collapse that is usable, and the fact that no CT site even attempts to show calculations on the time they believe it should have taken.
I have not seen Heller's claim that he did the calcs for an unsupported 110 floors. I am not even sure what that means.
This is speculation but I suppose he is thinking along the lines that all the floors have the same mass m. The first floor falls X number of meters and thus has momentum mv when it inelastically hits the next mass m, that would mean that the total momentum is not 2mv' but 2mv'=mv and therefore the inertia of the second mass results in it moving at 1/2 v as the two floor masses start their inelastic fall. When they hit the third floor they will be moving at v/2 + v (giventhe equal spacing of the floors) and the momentum of the three inelastically colliding masses is now (v/2 + v)2m = 3mv'' etc..
The problems with this would be a) it is not an inelastic collision b) the original moving mass is that of the upper section of a dozen floors, not just one.
the momentum of that enormous moving mass would dwarf the inertial resistance just as it would dwarf the ability of the structure to remain intact.
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Post by turbonium on Oct 19, 2005 1:07:59 GMT -4
the original moving mass is that of the upper section of a dozen floors, not just one.
the momentum of that enormous moving mass would dwarf the inertial resistance just as it would dwarf the ability of the structure to remain intact.
The initial direction of movement for the upper section of the South Tower was not directly vertical downward. It tilted by approximately 22 degrees, but despite its momentum, the 'center of gravity' of the upper section suddenly changed into a vertical path to the ground, in line with the lower section as it collapsed.
The tilt of the upper section should have relieved much of the uniform distribution of vertical stress from above onto the lower section of the tower. The lower section continued its uniform collapse while the dynamic load from above was not distributed uniformly, but only along one side of the building.
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Post by JayUtah on Oct 19, 2005 10:01:27 GMT -4
It says so in the FAQ section of their website, though I can't say if that's how Jay knew.
No, I checked the National Architecture Accrediting Board web site, the only authoritative source in the United States for architecture accreditation.
I subsequently noticed on their web site that they do not claim to be accredited. They do, however, claim to be undergoing the accreditation process, which the webmaster says is "lengthy". It is, but it lasts at most an academic year. Other sources I consulted substantiate that they have been seeking accreditation for several years. The conclusion I draw is that they've been seeking it and missing it.
I bring up accreditation because it is important for a licensed profession such as architecture. All the state licensing boards I know of require one to have graduated from an accredited professional program before they are even eligible to take the licensing exam.
Since the school from which Heller claims credentials does not offer training in structural mechanics, then I cannot consider him an expert in structures.
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Post by JayUtah on Oct 19, 2005 10:06:48 GMT -4
The initial direction of movement for the upper section of the South Tower was not directly vertical downward. It tilted by approximately 22 degrees, but despite its momentum, the 'center of gravity' of the upper section suddenly changed into a vertical path to the ground, in line with the lower section as it collapsed.
That's exactly the way it should happen. It pivots until the pivot is destroyed, whereafter it falls downward.
The tilt of the upper section should have relieved much of the uniform distribution of vertical stress from above onto the lower section of the tower.
There is no such "uniform distribution".
The lower section continued its uniform collapse while the dynamic load from above was not distributed uniformly, but only along one side of the building.
That's a gross oversimplification of the dynamics of the collapse.
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Post by JayUtah on Oct 19, 2005 10:43:45 GMT -4
I noted the 1000C temperature cited in the NIST report , which is why I specifically mentioned that they did not prove (substantiate) their claim.
The section of the report says that this kind of data was obtained from "validated computer models." They have not changed the story of where they got these figures, nor have they kept it a secret.
The draft final report does not contain all the science that was used to arrive at NIST's findings. The report's first sections list the subcommittees who investigated the various detailed aspects of the incident and the more detailed reports they wrote. The reader is supposed to refer to those reports for additional information such as the science behind the models.
I think the confusion here derives from the fracas over the PM article. You first said it was intentionally misleading -- an allegation of fact -- but then later backpedalled and said you only found it yourself to be misleading -- an expression of opinion. We notice when you soften your claims. It's okay to soften them; that's what debate is often meant to elicit. However, don't be sneaky about it. You'll find you have more credibility if you explicitly withdraw a claim that you realize isn't well supported.
You then went on to contrast the claim of 1,000 C in the PM article (for air) with the 250-600 C in the NIST report (for steel). You quoted from the report only regarding the lower steel temperatures. This led me -- and perhaps others -- to conclude that you were unable to find the higher temperature claimed in the report. I wasn't able to either, because I was looking for Farenheit tempertures.
I was all set to agree partially with you over the 1,832 F claim in the PM article with no substantially similar claim in the NIST report -- that this would constitude misleading information. However I see that the PM and NIST reports substantially agree. I don't agree that the PM report is misleading in any alarming way; perhaps only in the sense that all journalism, by its requirement to summarize and reconcile, is misleading.
I find the Cardington data remarkably helpful too. Not only do they validate NIST's fire model for Class B combustibles at that load factor (ca. 1,700 F air layer temperatures), they validate the failure modes of some specific structural elements in the NIST structural model. The building didn't collapse, you say. And that's true; and it's because the flat-slab (i.e., post-and-beam) construction method is the easiest and cheapest to build and also the easiest to engineer. You can get a lot wrong with the flat slab method and still have a building with a very healthy structural margin. I would expect such a building to withstand quite a battering. It is indeed highly redundant.
The WTC structure was also redundant, but not to the same extent or in the same way. A flat-slab building can demonstrably withstand an enormous amount of slab hogging without failure, but the WTC structural system placed greater emphasis on the floor system; it was responsible for more of the overall structural integrity of the building. You can essentially remove the floor system altogether from a flat-slab building without affecting the strucure. The notion that Cardington "proves" the WTC collapse model is false because that building didn't fall down, is as naive as it can possibly be.
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Post by jaydeehess on Oct 19, 2005 13:51:37 GMT -4
the original moving mass is that of the upper section of a dozen floors, not just one.
the momentum of that enormous moving mass would dwarf the inertial resistance just as it would dwarf the ability of the structure to remain intact.The initial direction of movement for the upper section of the South Tower was not directly vertical downward. It tilted by approximately 22 degrees, but despite its momentum, the 'center of gravity' of the upper section suddenly changed into a vertical path to the ground, in line with the lower section as it collapsed. The tilt of the upper section should have relieved much of the uniform distribution of vertical stress from above onto the lower section of the tower. The lower section continued its uniform collapse while the dynamic load from above was not distributed uniformly, but only along one side of the building. You can do an experiment yourself for this. Place a 4 foot long 2X4 vertically on the ground. Balance another 2X4(two foor section will do) on the top of the first one, holding onto the top one to keep it upright. Now let go the upper board and allow it to start to tip over. When it reachs 20 degrees over quickly remove the lower board on which the upper one was pivoting. Note that the center of mass of the upper board falls straight downwards and that the board now transfers that rotational momentum to pivoting about the center of mass NOT the lower end of the board. (This means it wil slow down in its pivoting). In fact the upper board's lower end will hit the point at which the lower board was previously sitting on. BTW IIRC "center of gravity" is not a term that is normally used by anyone other than non-scientists. It is a term that would imply that the object in question actually be in a gravity well.
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Post by jaydeehess on Oct 19, 2005 13:57:34 GMT -4
RE: Cardington tests
One CT complaint is that the fires were dieing down when the building collapsed. The Cardington tests showed clearly that many restrained columns and beams failed not when the temps were at their highest but actually during the cooling stages. They had softened, expanded, and buckled during the heating. Then, when cooling and becoming less plastic and contracting they could not be stretched out (essentially) to their previous shapes due to the new forces on them due to sagging and therefore broke, ie:failed!
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