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I know at least one painter with a permanently scarred and disfigured hand from an injection injury with an airless paint sprayer. Guys think they can wash it out, bandage it up, and call it a day, and nope that's not going to cut it
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# ? Jun 14, 2024 06:18 |
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Jesus loving Custer. I knew it was bad and have taken the utmost care to avoid hydraulic leaks (including power steering and brakes and diesel past the injection pump) but that is nightmare inducing.
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I used to work with a guy who, in his younger days, had axle grease injected into his hand via a pinhole in a hose from some oldschool pressurized greasing apparatus. The doctors had to flay open his hand and clean it all out. His hand swelled up to twice it's size and he was on all sorts of drugs for months.
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This is a dumb question on my part but I never studied fluids. If I've got a pipe containing fluid at 1000 psi, and I put a small hole in that pipe, like .001 square inches, what's the force of the fluid coming out? Naively I'd expect 1 pound, but that doesn't explain the horrificness of hydraulic injection injuries.
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Phanatic posted:This is a dumb question on my part but I never studied fluids. Try the reciprocal? e; but that doesn't seem quite right either? joat mon fucked around with this message at 15:44 on Apr 18, 2023 |
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It's 1 pound overall, but it's still 1000 PSI, and pressure is what matters for puncturing your skin, not overall force. That 1 lb is focused on a teeny tiny area. Hold a sewing needle against your skin and balance a 1 lb weight on top and see how that feels. Same concept. Also part of the thing about hydraulic injection injuries is that they often aren't that horrific at first. Someone up thread said he saw one that just looked like a pimple. This makes sense if you think of it as basically like a needle made of oil stabbing deep into your body. The horrifying part happens later when the injected oil starts to rot your flesh from the inside out. Sagebrush fucked around with this message at 15:47 on Apr 18, 2023 |
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You should check out the psi on my sharts
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Phanatic posted:This is a dumb question on my part but I never studied fluids. Its the pressure and the velocity of the fluid combined if I had to guess.
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Pressure isn't often useful as a measurement of something that's in motion, so what you have is 1000psi of potential energy changing to velocity when the fluid leaves the hole, then back into pressure when your skin tries to stop it. My experience is primarily with compressible fluids which are governed by Bernoulli's principle, but I think this explanation is correct enough. If you're close enough to the hole you're effectively getting almost the entire 1000psi because the biggest losses are to air friction and fluid changing directions in the cylinder, so 1000psi times a .001in spray of psi is putting a pound of force into a tiny enough area that the fluid can break through the skin and continue to force more fluid in under the skin, as HPC's video illustrates.
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EvenWorseOpinions posted:Pressure isn't often useful as a measurement of something that's in motion *Aerodynamicists start shaking violently*
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Hi, I'm an aircraft mechanic! I have education specifically in aerodynamics as part of my certification process. I didn't word that very well, my point is that it's difficult to measure the pressure of a moving fluid. There are ways to do it, as in pitot static systems, but it's easiest to accurately measure pressure in a system that's not in motion as pressure is inversely correlated to velocity for a given amount of energy in a system, non-compressible fluids behave similarly, but not identically. In aerodynamics specifically, the only way to measure airspeed is as a function of pressure, which also means you have to do special things to measure air pressure separately from airspeed (as with pitot static systems).
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Unreal_One posted:*Aerodynamicists start shaking violently* Get that ærolastic fluttering checked out, buddy.
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You've got to think of things like surface tension and friction with pinholes too, I've seen holes and cracks on high pressure hydraulic systems that just ooze instead of spraying, even pinhole leaks in high pressure steam systems just produce a lazy little wisp of visible steam. Got to watch a hairline crack in a weld get smashed into a 1/8" seem by several thousand pound air once, that was really cool to watch.
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EvenWorseOpinions posted:In aerodynamics specifically, the only way to measure airspeed is as a function of pressure, We can do it with lasers now.
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Phanatic posted:We can do it with lasers now. Today I learned that laser anemometers were a thing. They use diffraction! And maybe can’t replace a pitot tube because dynamic pressure is the thing that makes aero surfaces effective so that’s the actual information the pilot wants.
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Phanatic posted:We can do it with lasers now. and ultrasound i believe. maybe that only works for water
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Sagebrush posted:and ultrasound i believe. maybe that only works for water Ultrasound works for wind speed and direction.
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Jonny Nox posted:Today I learned that laser anemometers were a thing. When you’re doing airspeed calibrations you need another calibrated source of airspeed data to compare the aircraft’s pitot/static system against. Historically this has been done with an instrumented boom that sticks out into non-turbulent air. Since the stuff I work on is rotary-wing what we use is called a YAPS head, and it also has vanes that turn potentiometers to measure yaw and pitch as well, so we get pitot, static, alpha, and beta. But now we just do all that with a LIDAR system mounted in the cabin with an array of lasers mounted outside. Supposedly it can give us 1/rev as well but we haven’t tried yet.
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Sagebrush posted:and ultrasound i believe. maybe that only works for water Ultrasound definitely works with gasses, I think it's even capable of density compensating without a pressure input, which is neat.
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I know just enough about some of this stuff to have just learned a little more. Cool!
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Phanatic posted:We can do it with lasers now. I've worked with windshear detection before, but it's a bit different mechanism, didn't realize we we had this capability, cool!
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oh haha yeah it's funny when your panorama camera screws up like that
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Please spoiler that, I'm not fully caught up on cursedshitbox's saga.
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We all know CSB wouldn't keep an abortion like that on the road.
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Is that a frieghtliner flatbed that someone put two cut up truck beds on in a mindbogglying display
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UCS Hellmaker posted:Is that a frieghtliner flatbed that someone put two cut up truck beds on in a mindbogglying display That is an International XT with a pair of cut up Aluminaduty beds on it. I have nothing to do with this mess.
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Safety Dance posted:I don't understand it, but I like it! The color is perfection. Is it some kind of updated Nomad concept? The tailgate definitely gives me those vibes
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BOOTY-ADE posted:Is it some kind of updated Nomad concept? The tailgate definitely gives me those vibes Perhaps an update of the "Corvette wagon" concept from back in the 50s.
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![]() ![]() ![]() it tells a story
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That's a novelty plate hoonigan sells in their store. https://www.hoonigan.com/products/hoonigan-license-plate I wonder if it was even insured.
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I hope not
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What in the world? Kit car evaporated?
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Fifty Three posted:What in the world? Kit car evaporated? Warranty expired.
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Fifty Three posted:What in the world? Kit car evaporated? Got cut in half by drifting in a pole by the look of it.
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also when you have a "bit of rust". Fifty Three posted:What in the world? Kit car evaporated? C5 Corvette, power-on oversteered into a pole at high speed. edit: just noticed that it clipped a... Forester? as well. Probably why it started drifting - swerved to avoid.
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I pieced together the light pole split, I'm just trying to figure out why there's nothing below the headlights like it got sent down a cheese grater
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I'm going to guess it slid sideways against the curb which gutted out the suspension on the half that was left (you can see a still standing wheel further up the road). I'm assuming the door was cut off by rescue personnel. The opening looks pretty intact and the door is laying intact in the grass a bit further up. Doesn't look like crash forces tore it off.
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# ? Jun 14, 2024 06:18 |
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Darchangel posted:edit: just noticed that it clipped a... Forester? as well. Probably why it started drifting - swerved to avoid. First gen Lexus RX.
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