Supreme Court ruled today on the D.C. gun ban

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Originally Posted by trish

With questionable levity El Nino writes

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This is pretty funny too!

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…and then he posts a link to tyrannyalert’s speculative pdf on the collapse of the twin towers.

The link claims to refute the conclusions of a dozen independent engineering firms and societies. Yet it contains not a single reference to any independent engineering analysis, not a single table or chart displaying the stress analysis data or dynamics. Not a single mathematical equation. In short, it fails to rigorously and quantitatively criticize the existing models of the twin tower’s collapse and offers no rigorous model or analysis of the collapse of its own.

It’s just another piece of fluff posing as engineering science.

Here are a few slightly more serious links. The first is the final NIST report. It’s close to 300 pages long, so it may take a little while to download. The second’s only 8 pages long and demonstrates what a mathematic model of collapse should look like. The latter two are slide show presentations given at two different engineering conferences.

http://wtc.nist.gov/NISTNCSTAR1CollapseofTowers.pdf

http://ocw.mit.edu/NR/rdonlyres/Nucl...C6/0/ps2p2.pdf

http://web.mit.edu/istgroup/ist/docu...Istanbul04.pdf

http://eagar.mit.edu/EagarPresentati...C_TMS_2002.pdf

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Well yes it's true that the conspiracy crowd has no interest in actually explaining things. That automatically debunks the conspiracy usually. But I've never been fully convinced by the explanations of why the towers fell the way they did. My personal feeling, & I have absolutely no corraborating evidence nor am I an engineer, is that the towers were weakened in the '93 bombing at the base & never quite right after. A sudden shift at the bottom would explain a lot.

But be that as it may: Shortly after the incident, I stumbled on this article & have held onto the link ever since. It calls a lot of things into question. It doesn't pose a conspiracy theory though, except that maybe there was a lot of CYA happening in the engineering punditry that was all over the idiot box following 9/11. It's an old link (Oct/Nov 2001) & most of the hyperlinked graphics no longer work. Perhaps there are credible explanations for some of the questions by now. But it's still an interesting read.
http://web.archive.org/web/200210021...wot/mslp_i.htm

Hi hippiefried.

Unfortunately your linked site has a lot of broken images these days. But that’s all right, I’m not an engineer either and I don’t want to get into a discussion of the dynamics of the twin tower collapse. A physicist, or a chemist or anybody else with sufficient background to concoct a rigorous model can of course propose their own explanation for testing and review. But those best equipped to judge the model’s veracity are architectural engineers. I’m not buying any theory that doesn’t pass muster with at least one recognized society of engineers.

The discussion over the last several pages which led to El Nino’s introduction of this topic concerns the question of whether the U.S. is an oligarchy or not. Of course it isn’t. What El Nino really defends is the existence of a secret cabal within the U.S. government which conspires to manipulate the media, manipulate what we think and evidently also conspired to destroy lives and real estate in lower Manhattan (presumably to convince the American public, whose minds they already manipulate and control, that we should wage a war in Iraq).

My point is that the various factions of society manipulate the media quite openly. People watch, listen, read, talk persuade and are persuaded. The evolution and propagation of ideas within a media driven society doesn’t require gods or cabals to set it in motion nor to guide it. Now just apply Occam’s razor.

The collapse of the twin towers does require one to believe there were handful of malicious, fanatic, murderous, suicidal, Saudi born (not Iraqi) members of Al Qaeda who crashed hijacked, freshly fueled, commercial airliners into the upper stories of the towers. That part, incredible as it is, is easy to believe. It’s was witnessed first hand and recorded by hundreds of independent sources. Perhaps the buildings were previously damaged by earlier attempts to bring them down, perhaps not. The consensus of the architectural engineers who’ve made a serious study of the collapses is that the evolving consequences of the initial trauma were sufficient to eventually bring on the collapses. No further detonations of cleverly synchronized explosives were required. Indeed there is no evidence that there were such detonations. Again we are in a position to apply Occam’s razor. The explanation with the simplest ontology is the least sexy hypothesis, but the one more likely to be true.

House Keeping

House Keeping

Let’s do our own little back of the envelop calculation. The time it takes an object to free-fall from a height H to ground level

t = sqrt(2H/g).

Here g is the acceleration of the falling object due to gravity and sqrt is the abbreviation for square root (since the text here doesn’t seem to support mathematical notation).

Now imagine the pancaking collapse of a stack of floors from the top town. The collapse will not proceed at a constant rate all the way down as suggested by tyrannyalert. Rather the collapse will accelerate impulsively. The time between the failure of each successive floor increases. Hence effectively the building will acquire an effective acceleration. Notice that by varying t and g in the above equation we can approximate the dependence of the variation in fall time (usually denoted by a lower case Greek delta in front of t, but here we shall denote it by dt) on the variation in g. Namely

dt = - sqrt(H/2g^3) dg.

Here g^3 is the cube of g and dg is the variation of g. Substituting the rough height of the World Trade Center H= 1350 ft and the acceleration of gravity g = 32ft/s^2, we find that

dt = (-.14 /(ft/s^2)) dg

This means that the acceleration of the fall can be slowed by as much as 1 ft/s^2 and the time of fall will only be 0.14 seconds longer than the time of free-fall. If the acceleration of the fall were slowed by nearly 7 ft/s^2, this would only add one second to the time of fall. Hence on first glance, the pancake theory cannot be eliminated without rigorous, quantitative analysis.

House Keeping

House Keeping

[Edit: El Nino writes...]"Ummmm

Let's start with temperatures "


Let's not. I'm not an engineer and neither are you. Let's stick to the subject at hand. So I'll repeat:

A physicist, or a chemist or anybody else with sufficient background to concoct a rigorous model can of course propose their own explanation for testing and review. But those best equipped to judge the model’s veracity are architectural engineers. I’m not buying any theory that doesn’t pass muster with at least one recognized society of engineers.

The discussion over the last several pages which led to El Nino’s introduction of this topic concerns the question of whether the U.S. is an oligarchy or not. Of course it isn’t. What El Nino really defends is the existence of a secret cabal within the U.S. government which conspires to manipulate the media, manipulate what we think and evidently also conspired to destroy lives and real estate in lower Manhattan (presumably to convince the American public, whose minds they already manipulate and control, that we should wage a war in Iraq).

My point is that the various factions of society manipulate the media quite openly. People watch, listen, read, talk persuade and are persuaded. The evolution and propagation of ideas within a media driven society doesn’t require gods or cabals to set it in motion nor to guide it. Now just apply Occam’s razor.

The collapse of the twin towers does require one to believe there were handful of malicious, fanatic, murderous, suicidal, Saudi born (not Iraqi) members of Al Qaeda who crashed hijacked, freshly fueled, commercial airliners into the upper stories of the towers. That part, incredible as it is, is easy to believe. It’s was witnessed first hand and recorded by hundreds of independent sources. Perhaps the buildings were previously damaged by earlier attempts to bring them down, perhaps not. The consensus of the architectural engineers who’ve made a serious study of the collapses is that the evolving consequences of the initial trauma were sufficient to eventually bring on the collapses. No further detonations of cleverly synchronized explosives were required. Indeed there is no evidence that there were such detonations. Again we are in a position to apply Occam’s razor. The explanation with the simplest ontology is the least sexy hypothesis, but the one more likely to be true.

House Keeping

House Keeping