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Order of magnitude estimate of Beirut explosion at 3 kilotons of TNT

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Re: Order of magnitude estimate of Beirut explosion at 3 kilotons of TNT

#81

Post by jabl »

grogenaut wrote: post #69
aaomidi wrote: post #37

Earlier quoted context omitted.

Longer fire = less energy for explosion?

High explosives burn too fast for regular flames and suck the oxygen out for subsequent burning. Though you can definitely see fire in the first few frames. https://en.m.wikipedia.org/wiki/Red_Adair got famous for putting out oil well fires with high explosives. Explosives on burn that fast due to their chemical structure not because of free oxygen in the atmosphere. So if you see a fireball, the explosion has slowed…

> In those videos when the white large cloud comes out (likely some form of the air being hyper compressed by the shockwave and forced faster than the speed of sound)

The white cloud is due to the shockwave causing moisture in the atmosphere to condense. Or rather immediately after the shockwave in the low pressure region.

You can see the same effect sometimes due to supersonic aircraft.

Re: Order of magnitude estimate of Beirut explosion at 3 kilotons of TNT

#82

Post by burfog »

compscistd wrote: post #77
burfog wrote: post #68

Earlier quoted context omitted.

The news is way worse than that. A couple notable things they mostly buried just this past week: The George Floyd bodycam video leaked out, destroying the BLM narrative (see https://news.ycombinator.com/item?id=24046940 for DailyMail). ABC doesn't cover it. CBS and NBC edit out "Stop resisting". Youtube suppresses it from trending. NBC even had privately seen the bodycam video a month prior, leaving them no excuse fo…

This is less an issue of biased narrative vs the truth than _your_ values vs BLM values. To BLM, nothing excuses someone who is supposed to protect and serve putting their weight onto someone's neck for nearly ten minutes. Is a stained toxicology report and non-compliance permission to kill? The BLM "narrative" assumes the answer is no. The right-wing "narrative" assumes the answer is yes. This is less a question of…

There were no neck injuries (see the autopsy report) and thus the "putting their weight" concept is clearly an exaggeration. Nothing involving the neck was involved in the death.

It is a gross mischaracterization of the right that "the answer is yes".

There doesn't exist any way to arrest a non-compliant criminal without somebody getting all upset about it. Ultimately, some degree of violence will be required. Leaving criminals to run free is how you get a failed state, and then gangs create their own not-so-nice justice system.

Hiding the video in order to create needless racial strife was just plain evil. Numerous additional people have died as a result.

Re: Order of magnitude estimate of Beirut explosion at 3 kilotons of TNT

#83

Post by chmod775 »

sillysaurusx wrote: post #76

@quantian1 correctly determined that this was an ammonium nitrate blast by analyzing the footage: https://twitter.com/quantian1/status/1290695231910875136 CHEMISTRY FACT: Explosives have characteristic "detonation velocities" at which shockwaves expand. Smartphone video records at 30 FPS, so the adjacent frames here suggest the front expands at ~100 m/(1/30 sec), or 3,000 m/sec. Consistent with ammonium nitrate, not…

Some chemist acquaintances of mine suggested the same from just looking at the footage immediately after. Along with some scary explanations of what fast shockwaves like that do to human blood vessels.

I was convinced this stuff should be outlawed for most uses pretty fast.

https://en.wikipedia.org/wiki/Ammonium_nitrate_disasters

Though on the other hand, the number of incidents and deaths aren't that high considering how prevalent it is. It's just that a critical failure of handling that stuff is quite spectacularly bad.

Re: Order of magnitude estimate of Beirut explosion at 3 kilotons of TNT

#84

Post by look_lookatme »

tzs wrote: post #56

This video [1] from The Guardian include the same video in that tweet, but also has a few other angles which gives a better appreciation of how big that thing was. [1] https://www.youtube.com/watch?v=93tV6-0Ugwk

This video is the one that made me gasp the hardest: https://twitter.com/FadyRoumieh/status/1290670721488900096

Something about the distance and the fact that it's on water puts everything into stark relief.

Re: Order of magnitude estimate of Beirut explosion at 3 kilotons of TNT

#85

Post by jandrewrogers »

IAmGraydon wrote: post #59
KMag wrote: post #57

Note that the distinctive orange color is probably a large volume of nitrogen dioxide at pretty high concentration. If it was an ammonium nitrate explosion, the orange cloud supports the idea it was accidental. The explosion would have been easier to set off and more powerful had there been a fuel (or more fuel) mixed with the ammonium nitrate.

Why do you think that the release of NO2 makes it an accident? Nitrate based high explosives only release NO2 during an actual high-order detonation. Ammonium nitrate does this with or without sensitizers such as fuel oil.

This is definitely not the case. NO2 release is characteristic of spontaneous decomposition of nitrates, which can happen under a wide variety of conditions that have nothing to do with detonation. I’ve had the misfortune of seeing this happen once in a lab, due to a rookie mistake. It usually is the harbinger of a runaway exothermic reaction. There is nothing surprising here if ammonium nitrate is the primary suspect.

In the specific case of bulk ammonium nitrate, it has a low melting point (relative to a fire) and it starts to become quite unstable in that phase. The low risk of AN is premised on it being stored in a relatively clean, non-reactive environment.

Fuel oil generally isn’t considered a sensitizer for AN, you still need a booster, it compensates for the oxygen richness which improves efficiency. There are a bunch of nitrogen organics and metals, which I won’t list here, that will sensitize AN quite effectively but those aren’t implicated here.

Most fires with AN are caused by its reactivity. It will readily combine with other chemicals in the environment to produce compounds that are far more unstable than AN. These byproducts often act as the ignition point that ultimately causes the AN to detonate.

Re: Order of magnitude estimate of Beirut explosion at 3 kilotons of TNT

#86

Post by qserasera »

hn_throwaway_99 wrote: post #23
nodesocket wrote: post #17

Earlier quoted context omitted.

It's hard to imagine, but that would mean this explosion was nearly 3.5x larger than 2015 Tianjin[1] which was 800 tonnes of ammonium nitrate (336 tons TNT equivalent). The video[2] from Tianjin looked way bigger and apocalyptic, but perhaps just because of the the fireball. [1] https://en.wikipedia.org/wiki/2015_Tianjin_explosions [2] https://www.youtube.com/watch?v=ONsmJAyFAAw

Yeah, honestly, the Beirut explosion looked bigger/scarier to me, like how they show nuclear explosions in the movies. The Tianjin explosion was an enormous fireball but didn't seem to have the same magnitude of shockwave from the videos I've seen of it.

I don't think it was over a kiloton

Re: Order of magnitude estimate of Beirut explosion at 3 kilotons of TNT

#87

Post by 082349872349872 »

chmod775 wrote: post #83
sillysaurusx wrote: post #76

@quantian1 correctly determined that this was an ammonium nitrate blast by analyzing the footage: https://twitter.com/quantian1/status/1290695231910875136 CHEMISTRY FACT: Explosives have characteristic "detonation velocities" at which shockwaves expand. Smartphone video records at 30 FPS, so the adjacent frames here suggest the front expands at ~100 m/(1/30 sec), or 3,000 m/sec. Consistent with ammonium nitrate, not…

Some chemist acquaintances of mine suggested the same from just looking at the footage immediately after. Along with some scary explanations of what fast shockwaves like that do to human blood vessels. I was convinced this stuff should be outlawed for most uses pretty fast. https://en.wikipedia.org/wiki/Ammonium_nitrate_disasters Though on the other hand, the number of incidents and deaths aren't that high considerin…

What do you recommend using for fertiliser in its place?

(I'm sure someone's thought about this idea before. Timothy McVeigh did his mad bombing with typical rural materiel. Not so fun fact: the VBIED predates the internal combustion engine.)

Re: Order of magnitude estimate of Beirut explosion at 3 kilotons of TNT

#88

Post by nradov »

chmod775 wrote: post #83
sillysaurusx wrote: post #76

@quantian1 correctly determined that this was an ammonium nitrate blast by analyzing the footage: https://twitter.com/quantian1/status/1290695231910875136 CHEMISTRY FACT: Explosives have characteristic "detonation velocities" at which shockwaves expand. Smartphone video records at 30 FPS, so the adjacent frames here suggest the front expands at ~100 m/(1/30 sec), or 3,000 m/sec. Consistent with ammonium nitrate, not…

Some chemist acquaintances of mine suggested the same from just looking at the footage immediately after. Along with some scary explanations of what fast shockwaves like that do to human blood vessels. I was convinced this stuff should be outlawed for most uses pretty fast. https://en.wikipedia.org/wiki/Ammonium_nitrate_disasters Though on the other hand, the number of incidents and deaths aren't that high considerin…

Ammonium nitrate is essential as a fertilizer. There are no cost effective alternatives so we'll have to just accept the risk.

Re: Order of magnitude estimate of Beirut explosion at 3 kilotons of TNT

#89

Post by pstrateman »

chmod775 wrote: post #83
sillysaurusx wrote: post #76

@quantian1 correctly determined that this was an ammonium nitrate blast by analyzing the footage: https://twitter.com/quantian1/status/1290695231910875136 CHEMISTRY FACT: Explosives have characteristic "detonation velocities" at which shockwaves expand. Smartphone video records at 30 FPS, so the adjacent frames here suggest the front expands at ~100 m/(1/30 sec), or 3,000 m/sec. Consistent with ammonium nitrate, not…

Some chemist acquaintances of mine suggested the same from just looking at the footage immediately after. Along with some scary explanations of what fast shockwaves like that do to human blood vessels. I was convinced this stuff should be outlawed for most uses pretty fast. https://en.wikipedia.org/wiki/Ammonium_nitrate_disasters Though on the other hand, the number of incidents and deaths aren't that high considerin…

There's no real economical alternative fertilizer.

Re: Order of magnitude estimate of Beirut explosion at 3 kilotons of TNT

#90

Post by rtx »

chmod775 wrote: post #83
sillysaurusx wrote: post #76

@quantian1 correctly determined that this was an ammonium nitrate blast by analyzing the footage: https://twitter.com/quantian1/status/1290695231910875136 CHEMISTRY FACT: Explosives have characteristic "detonation velocities" at which shockwaves expand. Smartphone video records at 30 FPS, so the adjacent frames here suggest the front expands at ~100 m/(1/30 sec), or 3,000 m/sec. Consistent with ammonium nitrate, not…

Some chemist acquaintances of mine suggested the same from just looking at the footage immediately after. Along with some scary explanations of what fast shockwaves like that do to human blood vessels. I was convinced this stuff should be outlawed for most uses pretty fast. https://en.wikipedia.org/wiki/Ammonium_nitrate_disasters Though on the other hand, the number of incidents and deaths aren't that high considerin…

Yup, you can see water vapourize.
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