SanderO wrote:100 firefighters hearing explosions is not evidence of explosive devices going off.
I would hesitate to draw a definitive relation between hearing explosions and knowing they were caused by explosive devices also. But I won't hand wave this evidence either. I am emphatically not saying I think this proves "controlled demolition". Did you think I was?
SanderO wrote:What would be the expected normal temperatures when 100,000 tons of concrete have been mechanically destroyed in about 10 seconds and collapses down into a "pile"?
You tell me. I've never seen the "friction" excuse peer reviewed and published, anywhere.
Or why are the temps deemed serious anomalies? And by whom with what baseline criteria?
ASTM E119.
Background information by Prof. Thomas Eagar:
The fire is the most misunderstood part of the WTC collapse. Even today, the media report (and many scientists believe) that the steel melted. It is argued that the jet fuel burns very hot, especially with so much fuel present. This is not true.
Part of the problem is that people (including engineers) often confuse temperature and heat. While they are related, they are not the same. Thermodynamically, the heat contained in a material is related to the temperature through the heat capacity and the density (or mass). Temperature is defined as an intensive property, meaning that it does not vary with the quantity of material, while the heat is an extensive property, which does vary with the amount of material. One way to distinguish the two is to note that if a second log is added to the fireplace, the temperature does not double; it stays roughly the same, but the size of the fire or the length of time the fire burns, or a combination of the two, doubles. Thus, the fact that there were 90,000 L of jet fuel on a few floors of the WTC does not mean that this was an unusually hot fire. The temperature of the fire at the WTC was not unusual, and it was most definitely not capable of melting steel.
In combustion science, there are three basic types of flames, namely, a jet burner, a pre-mixed flame, and a diffuse flame. A jet burner generally involves mixing the fuel and the oxidant in nearly stoichiometric proportions and igniting the mixture in a constant-volume chamber. Since the combustion products cannot expand in the constant-volume chamber, they exit the chamber as a very high velocity, fully combusted, jet. This is what occurs in a jet engine, and this is the flame type that generates the most intense heat.
In a pre-mixed flame, the same nearly stoichiometric mixture is ignited as it exits a nozzle, under constant pressure conditions. It does not attain the flame velocities of a jet burner. An oxyacetylene torch or a Bunsen burner is a pre-mixed flame.
In a diffuse flame, the fuel and the oxidant are not mixed before ignition, but flow together in an uncontrolled manner and combust when the fuel/oxidant ratios reach values within the flammable range. A fireplace flame is a diffuse flame burning in air, as was the WTC fire.
Diffuse flames generate the lowest heat intensities of the three flame types.
If the fuel and the oxidant start at ambient temperature, a maximum flame temperature can be defined. For carbon burning in pure oxygen, the maximum is 3,200°C; for hydrogen it is 2,750°C. Thus, for virtually any hydrocarbons, the maximum flame temperature, starting at ambient temperature and using pure oxygen, is approximately 3,000°C.
This maximum flame temperature is reduced by two-thirds if air is used rather than pure oxygen. The reason is that every molecule of oxygen releases the heat of formation of a molecule of carbon monoxide and a molecule of water. If pure oxygen is used, this heat only needs to heat two molecules (carbon monoxide and water), while with air, these two molecules must be heated plus four molecules of nitrogen. Thus, burning hydrocarbons in air produces only one-third the temperature increase as burning in pure oxygen because three times as many molecules must be heated when air is used. The maximum flame temperature increase for burning hydrocarbons (jet fuel) in air is, thus, about 1,000°C—hardly sufficient to melt steel at 1,500°C.
But it is very difficult to reach this maximum temperature with a diffuse flame. There is nothing to ensure that the fuel and air in a diffuse flame are mixed in the best ratio. Typically, diffuse flames are fuel rich, meaning that the excess fuel molecules, which are unburned, must also be heated. It is known that most diffuse fires are fuel rich because blowing on a campfire or using a blacksmith’s bellows increases the rate of combustion by adding more oxygen. This fuel-rich diffuse flame can drop the temperature by up to a factor of two again. This is why the temperatures in a residential fire are usually in the 500°C to 650°C range.2,3 It is known that the WTC fire was a fuel-rich, diffuse flame as evidenced by the copious black smoke. Soot is generated by incompletely burned fuel; hence, the WTC fire was fuel rich—hardly surprising with 90,000 L of jet fuel available. Factors such as flame volume and quantity of soot decrease the radiative heat loss in the fire, moving the temperature closer to the maximum of 1,000°C. However, it is highly unlikely that the steel at the WTC experienced temperatures above the 750–800°C range. All reports that the steel melted at 1,500°C are using imprecise terminology at best.
Some reports suggest that the aluminum from the aircraft ignited, creating very high temperatures. While it is possible to ignite aluminum under special conditions, such conditions are not commonly attained in a hydrocarbon-based diffuse flame. In addition, the flame would be white hot, like a giant sparkler. There was no evidence of such aluminum ignition, which would have been visible even through the dense soot.
http://www.tms.org/pubs/journals/jom/01 ... -0112.html
Note that this doesn't have anything to do with whether or not the fires could weaken the building supports to the point of collapse, which I believe they could. This has to do with fire temperature maxima as established by ASTM E119 and further elucidated here by Prof. Eagar.
But none of this is relevant: what was relevant was my exposition of falsification-speculation and how it relates to the topic at hand: passports and their provenance.
Which reminds me:
Ziad Jarrah's passport found at the UA 93 crash site.
Would those arguing fakery and planting now argue this passport is suspect because it's too charred?
And:
All 168 passengers and crew have died in a Caspian Airlines plane crash in northern Iran, officials say.
Wreckage was spread over a large area in a field in Jannatabad village, Qazvin province, about 75 miles (120km) north-west of Tehran, state TV said.
The Tupolev plane was flying from the Iranian capital to Yerevan in Armenia, with mostly Iranian passengers.
The cause of the crash, which happened soon after take-off, was unknown. One witness said it plummeted from the sky.
(...)
One witness said the Tu-154 circled briefly looking for an emergency landing site, while another said the plane's tail was on fire.
A man who saw the crash said the aircraft exploded on impact.
"I saw the plane crashing nose-down. It hit the ground causing a big explosion. The impact shook the ground like an earthquake. Then, plane pieces were scattered all over the fields," 23-year-old Ali Akbar Hashemi told AP news agency.
http://news.bbc.co.uk/2/hi/8151327.stm
See animation in attachment.
