mostlygray posted:

An uncle of a friend of mine blew himself up trying to weld a fitting to an old gas tank to make a pressure tank for an air compressor. He was killed instantly.

I don't understand how it's possible, but no amount of rinsing will make a fuel tank safe to weld. I was always told that, if you were going to weld or braze a fuel tank, to fill it to the brim with water first. I'd never risk it myself.

zedprime posted:

e. If you look at it like a piston problem, you have 14 psi pushing on your body's surface area. That's about 183 kN, but all spread out over some 2 square meters of body. If you try to stick all 2 square meters of body into a quarter inch hole with 183 kN of force, the itty bit of your head that hits the hole first is seeing something like 210000 psi.

zedprime posted:

I don't follow the perpetual motion? The whole example's point is being a static balance. Most of all I don't understand the focus on the neck being a bigger opportunity to exert force. A plug missing from a hydraulic oil system is a mess you clean up with oildri. A pinhole in a hydraulic system is a mess you clean up with amputation.

How about this way. Your body's surface area is N. In pressure equilibrium, all of N is pushed on by all pressure, and you are in the case you describe.

You lose air pressure or whatever and now there's not pressure equilibrium. Your dive suit turns into a positive displacement pump, or other words a toothpaste tube. N-x% of your body you are getting that 41klbf for suitably small x, pressure differential times actual area in a strict case. Since I am looking at it as a static problem (ie the diver goes nowhere, just pulped in his suit) all that's left to counteract that force is some pressure exerted on x% of your body. So x is the percent of your body that is impinging on the suit, at the top, at the neckhole, whatever plugs. In actuality the situation is dynamic, the force is balanced by the work of forcing junk through the "clog" (yuck) until X-n has fallen low enough to reach equilibrium with what must become a column of blood inside the hose, as well as a hundred other factors like incomprehensible bits, spring response etc. The piston problem follows as a naive static case where you have a pressure differential acting on area N-x, that can be balanced by a force acting on remainder x. There is no relative hydraulic force on x, we are necessarily in an unbalanced regime, but it must balance with the hydraulic force on N-x.

The pressure of toothpaste at the nozzle follows from that analogy. Peristaltic pumps follow from the principle, where small force enacted on a flexible membrane magnifies into a big pressure at pump outlet.

So a diver would be a big tube of toothpaste. Yuck.

Improbable Lobster posted:

Elendil004 posted:

Tom Scott (well, a guy named Grady, really) did a video on the Hyatt Regency Collapse:
https://www.youtube.com/watch?v=VnvGwFegbC8

The Walrus posted:

wouldn't a 6 foot stake driven into the ground at a 45 degree angle to the house be pretty good?

Cool Bear posted:

My hands are beautiful and perfect.

Sometimes I wonder if I should smash and cut my hands to make them look grizzled and badass in order to make girls like me.

edit- to make anyone respect me

GnarlyCharlie4u posted:

HOLY gently caress that cable bounced off the bucket a couple of times it looks like! Possibly not, but it sure got freakin close. It's tough to tell because of the angle.
That could have really sucked if it managed to catch him.

Wasabi the J posted:

All this poo poo has been done before.

https://www.youtube.com/watch?v=E7w_v9J7iOc

Memento posted:

Everyone should read Command and Control: Nuclear Weapons, the Damascus Accident, and the Illusion of Safety.

The most important part of that title is at the end. The number of times that poo poo nearly kicked off due to rank incompetence and fevered egos was staggering. This is my all-time favourite passage, from an incident that happend on October 5th, 1969.

Kith posted:

Humphreys posted:

Thats proper hosed up.

Also, having only touched snow once, why are they riding backwards and down? Isn't the point of skiing to actually ski down the hill?

boner confessor posted:

pedestrian deaths increased in the united states by 11% between 2015 and 2016, the largest increase on record

data is too spotty or limited to prove it but everyone assumes it's because of people playing with their phones while walking which includes wandering into traffic and getting hit

Devor posted:

For a car traveling 65 mph, the standard braking distance used in the AASHTO Policy on Geometric Design of Highways, using deceleration of 11.2 ft/s2 (again what AASHTO uses for humans), it would take 405 feet to come to a stop.

Flash Gordon Ramsay posted:

There's no way that truck was loaded, right? That stopping distance was incredibly short. I don't know how even an empty truck could do it.

Phanatic posted:

I also think it's crazy that in Normal Law if you try to stall the aircraft, the stall alarms/stick shaker/etc still go off. Even though you're not stalling the aircraft. In other words, the stall alarms are themselves *modal*, they mean two different things based upon which mode you're in:

Phanatic posted:

In normal law you can get an airspeed warning, but you won’t get a stall warning unless the aircraft has failed into alternate.