Merged Discussion of femr's video data analysis

[Carll68]

Really ?

See that blue line on the graph ? That's freefall.

See the red line ? It's near the blue line for a while.

I'd suggest a +/- 5 ft/s² variance.

Yes, really sport. "Near" is vague...it is an arbitrary representation of what one thinks is "close" or "close enough".

I was not looking for the Websters definition of the word ...rather, specifically what you mean by near, and how you arrived at it, mathmatically (you don't do math and science, I know) in the context of your *analysis* without goals. In other words, what is near, defineitively, and what does "near" imply in the task you are performing?

So, why would you suggest +/- 5ft/s variance?

You're Up.

 

[rwguinn]

Really ?

See that blue line on the graph ? That's freefall.

See the red line ? It's near the blue line for a while.

I'd suggest a +/- 5 ft/s² variance.

Ok--we now have a definition of "near"
Near=+/- 15%
now we're getting somewhere.

 

[femr2]

Yes, really sport.

Shame.

"Near" is vague...it is an arbitrary representation of what one thinks is "close" or "close enough".

Ish.

I was not looking for the Websters definition fo the word ...rather, specifically what you mean by near, and how you arrived at it, mathmatically (you don't do math and science, I know) in the context of your *analysis* without goals.

Deary me. Try reading the words I posted, and looking at the pictures.

In other words, what is near, defineitively

ROFL. Close to. In the region of. Could even reach or exceed freefall, but it's a quick trace with approximate scaling metric applied.

and what does "near" imply in the task you are performing?

There are studies (and assertions) that known controlled demolitions do not get near to freefall. This data suggests such may be less than accurate (or now out of date).

So, why would you suggest +/- 5ft/s variance?

The variance of the acceleration trace during period of known static behaviour. A primitive form of error estimation.

Your Up.

You're [self censored].

 

[femr2]

Near=+/- 15%

I didn't say that.

I said +/-5ft/s^2 variance.

The data itself could easily be subject to that level of variance.

Applying -5ft/s^2 to the maximum acceleration on the graph would result in ~34ft/s^2, slightly over-g for a moment.

 

[Carll68]

I didn't say that.

I said +/-5ft/s^2 variance.

The data itself could easily be subject to that level of variance.

Applying -5ft/s^2 to the maximum acceleration on the graph would result in ~34ft/s^2, slightly over-g for a moment.

No one here is suprised that you missed the point, ...

How did you arrive, MATHMATICALLY, using what priciples, that a +/-5ft/s^2 variance is significant, and, thus as you vaguely worded it "near".

You throw out these loose terms, then when asked to show how you arrived at them, waffle and avoid.

Cincinnatti is near Kentucky. New York is near New Jersey. United States is near Cananda. This is all true, relatively.

Leave relatively at the door sport....drop *near*..talk math. Why is +/-5ft/s^2 variance sigificant, why is this the benchmark...specifically?

 

[BasqueArch]

Originally Posted by femr2
Really ?
See that blue line on the graph ? That's freefall.
See the red line ? It's near the blue line for a while.

I'd suggest a +/- 5 ft/s2 variance.

POST 2201
(My Bolding)

Ok--we now have a definition of "near"
Near=+/- 15%
now we're getting somewhere.

(This excited grateful desperation is sad to watch)
*I'm thinking ... guinn ... don't get your hopes up, he'll break your heart. *
(Later ... )

I didn't say that.

I said +/-5ft/s^2 variance.

The data itself could easily be subject to that level of variance.

Applying -5ft/s^2 to the maximum acceleration on the graph would result in ~34ft/s^2, slightly over-g for a moment.

Dang, so many beers so little time.
I'll check back at post 3201.

Call me if somebody nails this jello to the wall.

 

[femr2]

No one here is suprised that you missed the point

Just stop typing. You really do make a spectacle of yourself every time you do.

How did you arrive, MATHMATICALLY, using what priciples, that a +/-5ft/s^2 variance is significant

ROFL. It's a (fairly generous) estimate determined by simply looking at THE VARIANCE of the acceleration data during the period where the traced feature is known to be static.

In Carll68 terms...the line on the graph wobbles a bit which shows there is some inaccuracy because I already know the building wasn't moving at that time.

The *wobble* is within the +/- 5ft/s^2 grid-lines.

+/- 5ft/s^2 variance.

Kindergarten enough for you ?

and, thus as you vaguely worded it "near".

Yee gads man.

No, not thus at all. Suggesting the 1515 Flagler trace shows near freefall acceleration is due to...wait for it...the bleedin' acceleration profile reaching near freefall, and even exceeding it on the graph. (Bear in mind the scope is that it has been suggested (in several publications) that controlled demolitions do not get near freefall.)

The inclusion of the variance value is simply to highlight that the values could be 5ft/s^2 higher than they should be.

You throw out these loose terms, then when asked to show how you arrived at them, waffle and avoid.

You need a definition for near. Sooo not my problem.

Leave relatively at the door sport....drop *near*..talk math. Why is +/-5ft/s^2 variance sigificant, why is this the benchmark...specifically?

You are not even nearly funny.

Illustrating your lack of understanding of the simplest of assertions is not wise, especially after details have already been clarified for you.

 

[Carll68]

Just stop typing. You really do make a spectacle of yourself every time you do.


ROFL. It's a (fairly generous) estimate determined by simply looking at THE VARIANCE of the acceleration data during the period where the traced feature is known to be static.

In dumbed-down Carll68 terms...the line on the graph wobbles a bit which shows there is some inaccuracy because I already know the building wasn't moving at that time.

The *wobble* is within the +/- 5ft/s^2 grid-lines.

+/- 5ft/s^2 variance.

Kindergarten enough for you ?


ROFL. Yee gads man, are you really this dense ?

No, not thus at all. Suggesting the 1515 Flagler trace shows near freefall acceleration is due to...wait for it...the bleedin' acceleration profile reaching near freefall, and even exceeding it on the graph. (Bear in mind the scope is that it has been suggested that controlled demolitions do not get near freefall.)

The inclusion of the variance value is simply to highlight that the values could be 5ft/s^2 higher than they should be.


ROFL.

You need a definition for near. Sooo not my problem.


ROFL. You are not even nearly funny.

Illustrating your utter ineptitude with the simplest of assertions is not wise.

Challenger? Charger? Durango? Caliber? I am trying to name other DODGES.....

Why is +/-5ft/s^2 variance sigificant, why is this the benchmark...specifically?

 

[femr2]

Challenger? Charger? Durango? Caliber? I am trying to name other DODGES.....

Why is +/-5ft/s^2 variance sigificant, why is this the benchmark...specifically?

Try reading my posts again. It's clear you really don't understand. I don't think it can be made any clearer.

You are making yourself look rather silly still. (And I'm being very generous at that)

 

[rwguinn]

If you "Variance" gives a value above 32.2 ft/sec^2, then the data is anomalous --you either calculated it wrong, you made a measurement error (such as counting pixels in a low-res movie, as in "youtube"), the point you chose has undergone some other process (is rotating, has had a collision, resulting a new vector, etc), had a rocket motor attached, or some other nefarious event has occurred.
For whatever reason, it is certainly not representative of free-fall, or even "near free-fall"

 

[femr2]

If your "Variance" gives a value above 32.2 ft/sec^2

Why is there a problem understanding what I mean by variance of the data during the period of time where the feature being traced is known to be static ?

Each value on the trace could well be subject to +/- 5 ft/s^2 of error.

Any clearer, or shall I do it in picture form, and point at it ?

(+/- 5ft/s² variance in cyan)

then the data is anomalous --you either calculated it wrong, you made a measurement error (such as counting pixels in a low-res movie, as in "youtube")

Have you been completely oblivious of the many-page discussions within this thread relating to over-g acceleration of portions of WTC 7 ?

The raw trace data is fine. The scaling metric could be subject to some error, but not too much. The scaling value provided has been cross-checked with a couple of sources. The calculations are fine (29 point/order 4 Savitzky-Golay smoothing). I don't *count pixels* (tracing performed via SynthEyes). The video is in HD 1280*720p format. The out of date assertion that YouTube=Low Resolution is simply incorrect.

the point you chose has undergone some other process (is rotating, has had a collision, resulting a new vector, etc)

Quite possibly, with rotation being pretty high on the list.

How did you envisage the NW corner of WTC 7 (and other locations on the North facade) exceeding g ?

For whatever reason, it is certainly not representative of free-fall, or even "near free-fall"

Why on earth not ? It reaches about as "near free-fall" as WTC 7 did...

Are you suggesting that the NIST traced section of WTC 7 results were also not representative of free-fall, or even "near free-fall" ?

Swings and roundabouts again, it seems

I'll let you respond. If you're trying to set the clock back I'm simply going to ask you to re-read this thread from the beginning, as I'd rather not have to assemble all of the previous discussion and poke it at you.

 

[W.D.Clinger]

I'll let you respond. If you're trying to set the clock back I'm simply going to ask you to re-read this thread from the beginning, as I'd rather not have to assemble all of the previous discussion and poke it at you.

femr2 deserves applause for debunking Major_Tom's claim that "measured demolitions do not come close to g accelerations".


Looks like I was right to reject that unreliable source's appeal to my confirmation bias.

For more on Major_Tom's modus tollens fail, see all of this thread's page 41 as well as femr2's defense of Major_Tom's logic starting with post 1794 of this thread and continuing through post 1840.

 

[Major_Tom]

I never claimed that and if you were familiar with the material, you would know that that is not the meaning of the Framk Greening Post in 2008.

You never understood the original post. You made up a meaning and assigned the meaning to me.

You were never intelligent enough to distinguish. Shall we go back to the original Greening posts and check how well you can twist words?


Youy debunked your own dream. Sharp.

 

[Major_Tom]

Original Dr G post as before:

Did WTC 7 really fall "too fast", .... in fact, was it even faster than a typical CD?

There have been lots of great posts recently on various issues concerning the collapse of WTC 1, 2 & 7. That’s why I was not sure where to put this post, especially with all this overlap of interesting ideas, …. so I decided to simply start a new WTC 7 thread.

E. Yarimer at London University appears to be one of the few engineer/scientists who has studied real building demolitions by explosives. He has at least two papers on this subject, both written back in the 1990s, (and unfortunately hard to find on the web).

Here is a quote from the first (1994) paper:

“The current practice in controlled demolition (CD) by explosives is to pre-weaken the building on most floors, and to blast only a portion of the floors, for example one floor in two, or one floor in three. Even so, the number of charges to be placed in individual boreholes can be large: up to 6000 charges have been used depending on the size of the job. The blast floors will readily disintegrate, but the non-blast floors need the force of the impact in order to break-up. Even on the blast floors, the perimeter walls above the ground floor are usually not charged for safety reasons, and they are expected to break up by impact. The entire process is driven by gravity but the downward velocities are attenuated by the energy absorption at the point of impact, and the motion will accelerate less than a case of free fall; it may even decelerate. A spectacular case of decelerating motion was that of Northaird Point in London in 1985, which came to rest with 10 floors still intact.”

In his second, (1996) paper, Yarimer used electronic and photographic timing devices to study a number of real CDs. One of great interest to the present discussion was the 1995 demolition of a 20-story high-rise known as Sandwell East Tower. This demolition showed - as was observed for some other CDs studied by Yarimer - a latency period of ~ 1.5 seconds before significant bulk motions were detected.

I have taken Yarimer’s data to look at the accelerations for the Sandwell East Tower CD. Some time-drop data for the first 5 seconds are: 0 s, 0 m; 1 s, 0 m; 2 s, 1.8 m; 3.0 s, 10 m; 4.0 s, 22.3 m; 5.0 s, 35.9 m. These data show the collapse was well below free fall. Indeed, Yarimer states in his discussion of this data: “Near time t = 0, the calculated accelerations are influenced by the observed latency, thus lifting the estimate of the upwards reaction force.” It appears that even Yarimer had t(0) problems!

Nevertheless, I have analysed Yarimer’s data (with allowance for the t(0) problem) using the same approach many of us have applied to WTC 7 collapse data. What is most significant is that, even with a time shift of ~ 1.5 seconds, the Sandwell East building fell only about 40 meters in the first 4 seconds of bulk motion with an acceleration of no more than 5 m/s^2. And let’s remember that this was observed for a real-world CD on a 20-story building. Scaling this result to a 47-story, (WTC-7-sized building), I would predict a 50 % collapse to take at least 6 seconds and allowing for a latency period of about 1.5 seconds, a full collapse to take ~ 10 seconds or more.

D. Isobe et al. have carried out finite element calculations on a 20-story steel framed building subjected to a Kobe-wave type of seismic collapse. Isobe found that incremental collapse begins
after an initial 26-second period of vibration during which time plastic hinges are formed and column fractures occur near the ground level of the building. The modelled structure was 50 % collapsed about 10 seconds after the first bulk downward motion, and still only about 35 % collapsed after 14 seconds!

Thus we see experimental and theoretical confirmation that the global collapse of a 20-story building would take at least 10 seconds to partially collapse from deliberate man-made explosive or natural seismic trauma to lower portions of its structure.

One can only wonder what mysterious combination of forces brought down a 47 story building in less than 8 seconds.....

Can you point out any such claim?

You make some odd claim about a mistaken analysis by Dr G in [url='http://www.internationalskeptics.com/forums/showpost.php?p=7211360&postcount=1805"]this post[/url]. It makes no sense. It made so little sense there was nothing to respond to.

At this time, WDC, can you clarify your views on what is wrong with what Dr G posted? It seems pretty rude to keep posting silly things about both him and myself while your own reasoning is so poor.

Really poor.


He was probably your best JREF regular and a debunker but he was never rude to me.

Rudeness is part of the character, not an inherent part of any rational discussion.

That was the original quote and let us see what I posted as a comment...

 

[femr2]

For more on Major_Tom's modus tollens fail

Oh dear, you really shouldn't be using that term, especially given it was your own misunderstanding in the first place.

See here for additional details on where you went wrong.

(Thanks for the reminder of where it ocurred though. Should come in handy for future summaries.)

 

[W.D.Clinger]

I never claimed that and if you were familiar with the material, you would know that that is not the meaning of the Framk Greening Post in 2008.

Now you're just lying.

Here is a direct quotation, with link, from your post #1090 in this thread:

Do known demolitions attain such accelerations? Have you ever bothered to check? Obviously not. How could you not have noticed that these accelerations are outside the range of known demolitions for years? Because it is much easier to think you know than it is to verify or even think.

Without ever checking, from where does your false confidence spring? You seem to believe that you believe. Even though measured demolitions do not come close to g accelerations, little facts like that don't seem to penetrate the fog.

The claim you are denying is highlighted. I quoted it word for word.

You never understood the original post. You made up a meaning and assigned the meaning to me.

You were never intelligent enough to distinguish. Shall we go back to the original Greening posts and check how well you can twist words?

You were the author of post #1090, and you were the "source that's known to be unreliable" whose "bare assertions" I rejected.

I understand why you are trying to create the impression that I was referring to Dr Greening, but no intelligent person will fall for that.

 

[Major_Tom]

The most provocative claim repeated:

"Have any qualified experts told you near g accelerations as witnessed are expected or normal?

It is now 2011. Were you ever going to bother to check whether near g accelerations are normal or expected?

Like the big blunder on the early WTC 1 movement, this shows how serious you are as a researcher. You never intended to lift a finger to check.

It also shows how out of touch you are with physical systems in general, since if any real analysis was done on the NIST curve the greater than g or near g accelerations would have stuck out like a sore thumb.

No sane human being could tell you that type of motion is expected or normal in a collapsing building, even one being demoed intentionally.

You'd really have to be living on cloud #9 to imagine that the WTC7 early acceleration profile is normal or expected for a building.

Perhaps if someone can produce one example recorded or filmed somewhere on earth of a building undergoing this range of acceleration you'd have a better case. "

original post

Now that femr has done more totally original work, we have new information.

And it really is new, because you cannot find any other case of a person discovering what Fenr has just discovered. Before femr did that, you had nothing but speculation. Before this new revelation by femr the best we had was a crush down equation and a couple of crush calculators, but no actual examples. Crush calculators like the ones we were using at the 9/11 Forum in 2008 was placing the early accelerations very high, so posters there wouldn't be surpriosed by high accelerations. People were expecting high accelerations for a very tall building, but no sane person would call the WTC7 acceleration profile normal and expected even now.

It is something the sane would investigate, not just assume and call "normal" with no prior experience. (Like you did.)

Can't you see how well it matches the actual demo? Interesting, no?
....................................................................

The difference between femr and you is that he checks and explores. You just bitch. From the quote: " Were you ever going to bother to check whether near g accelerations are normal or expected?"

From the quote: "You never intended to lift a finger to check.".

Still true today. He checked and found something new. You bitched.

(and twisted by quote into a pretzel. Then you clung to it and dragged it around for a while.)

 

[W.D.Clinger]

Now that femr has done more totally original work, we have new information.

And it really is new, because you cannot find any other case of a person discovering what Fenr has just discovered. Before femr did that, you had nothing but speculation. Before this new revelation by femr the best we had was a crush down equation and a couple of crush calculators, but no actual examples. Crush calculators like the ones we were using at the 9/11 Forum in 2008 was placing the early accelerations very high, so posters there wouldn't be surpriosed by high accelerations. People were expecting high accelerations for a very tall building, but no sane person would call the WTC7 acceleration profile normal and expected even now.

Can't you see how well it matches the actual demo? Interesting, no?

I literally applauded femr2's debunking:

femr2 deserves applause for debunking Major_Tom's claim that "measured demolitions do not come close to g accelerations".

In my opinion, this is indeed the most interesting, original, and consequential debunking to have come out of femr2's data analysis.

I'm not sure femr2's result is important enough to justify a paper, but that's for femr2 and the engineering community to decide.

 

[NoahFence]

 

[femr2]

Now that femr has done more totally original work, we have new information.

Worth bearing in mind that I haven't spent as much time with the 1515 Flagler demolition as I have with WTC7.

I doubt that the results will change, but I suggest I perform additional traces, and perform further research into the building dimensions.

There's plenty of decent quality footage of the event (better than that available for WTC7), so it shouldn't take long.

I think it's safe to suggest at this point that the profiles are a lot closer and similar to WTC7 than previously expected, or suggested within the papers by E. Yarimer and D. Isobe et al.

I'll post details soon, but just spotted this funny...

The demolition went off five or six minutes later than expected because an intruder pretending to be with a television crew came too close to the site minutes before the scheduled detonation. Workers couldn't continue until they removed the man, who identified himself as Tom K., from the area.

My bold. You been in Palm Beach tfk ?

Some height details...
http://skyscraperpage.com/diagrams/?buildingID=17805
http://skyscraperpage.com/cities/?buildingID=17805
http://buildingdb.ctbuh.org/building.php?building_id=8943