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Cake day: June 30th, 2023

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  • I love daguerrotypes, they’re such a vivid look into the past. Exposures outdoors in bright sunlight only took a few seconds, but as this one appears to be taken indoors he would have indeed needed to stand there for quite a while. That’s probably why his left hand is blurry (he’s holding the flag in his right hand - daguerrotypes were laterally mirrored).

    Also, see the faint parallel lines all over the picture? Those are faint marks made by the photographer as he was polishing the plate just prior to sensitizing it and loading it into the camera.




  • I watch long videos on my TV (45 min - 1 hr) and YouTube has the audacity to shove minute+ long ad reels in my face every 15 minuets, claiming “fewer ads for this long video.” Bullshit. I have learned however that if you go to give feedback on the ad and flag it as inappropriate, it skips all the ads in that reel and sends you right back to the video! I can get past unskippable ads in a few seconds this way.




  • There was a period where I regularly got to go inside Boeing’s Everett factory for work (I didn’t work for Boeing though). For those who don’t know, it’s one of the largest buildings in the world, built in the 60s to manufacture 747s. Now they build all kinds of aircraft there.

    “Big” is an understatement. Even “cavernous” falls short. It’s easy for your brain to forget you’re in an indoor space until you look up and see a roof over your head. It’s like a miniature city in there. It’s got its own road network, fire department, cafeterias, and I heard it can even have its own weather.

    My route to and from the job site every day took me through alleyways and around sites where workers were actively putting airplanes together. I got to watch an entire fuselage be moved from one side of the factory to the other by the overhead cranes. But my favorite part of the whole place were the underground tunnels that you could use to get around. You could still see old civil defense fallout shelter signs in the stairwells, and even though I wasn’t supposed to take pictures in the facility I did anyway:



  • In a conventional two wheel drive vehicle, the driveshaft goes from the transmission in the front to the differential in the rear. In a four wheel drive vehicle, a transfer case is mounted behind the transmission instead. This splits the power between two driveshafts, one going to the rear differential and one going to the front differential. This gives power to all four wheels, allowing the vehicle to traverse roads where the traction might rapidly change and differ between the wheels.


  • CommissarVulpin@lemmy.worldtoScience Memes@mander.xyzRadioactivity
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    2 months ago

    So there’s four types of radiation: alpha, beta, gamma, and neutron. When you’re talking about radioactive materials, it’s almost exclusively the first three. In addition to the inherent danger of the object itself, there’s also the danger of radioactive contamination: not making other things radioactive, but shedding bits of themselves as dust and then that dust getting on other things, or getting ingested/inhaled by humans.

    Active fission reactions, like what goes on in the core of a nuclear reactor (or perhaps messing around with some plutonium and a screwdriver), produce neutron radiation. Neutrons can make other things radioactive, via a process called “neutron activation”, whereby the neutrons bind to the material and change some of the atoms into radioactive isotopes.

    I hope that helps, and feel free to ask me anything else about radiation. I have some education about it thanks to my job, and I’m always happy to help other people understand it more as well.