#video about LED #lighting lightbulb #electronics failure modes. A resistor came desoldered from the aluminum PCB on the first one. (I didn’t realize that some of them have current-limiting resistors shrinkwrapped into the leads from the E35 lamp base to the board, 10Ω in the case he shows.) In another case, a 200Ω surface-mount resistor had failed short. Interestingly he disassembles the lamp bases by running a boxcutter around under the metal base, breaking the bond to the insulator that separates the base electrode from the thread electrode. An older bulb with a cast-aluminum heatsink has a switchmode power supply in the base. Its power transistor and other major components were good, so he doesn’t find out what the problem was. #hardware
#video #toread about #Ukraine #drones #weaponry from last week
#video about #China crossbow #weaponry, funded by crossbow manufacturer (!!) Tenpoint, who is giving away a Siege 425 crossbow, which shoots 16-“inch” carbon-fiber composite arrows, mass not disclosed, at 425 “feet” per second (thus the name). One reason for China sending soldiers through two years of crossbow training might be the #India border dispute, though the armament limitations don’t seem to cover ordinary automatic rifles and no #crossbows have been observed in use in the border dispute area. Pretty worthless damn video by #TaskAndPurpose. Plonk.
#video about #bootstrapping pure #materials from fertilizers. Like calcium nitrate from the hydrated double salt with ammonia. (Boiling with slaked lime drives out the ammonia as gas.) Urea he simply recrystallizes with water. Ammonium sulfate he recrystallizes with water by evaporation, which is tedious because you can’t crystallize it by cooling. By #Apoptosis. #scouting
#video about glow powder strontium aluminate #materials fired in a microwave kiln. #toread
#video about #bootstrapping salt #materials by oxidizing urea (from #CodysLab urine) with bacteria on a charcoal packed bed supported on hardware cloth with a process tower made of a Rubbermaid trashcan and a 200ℓ drum, with water sprayed through plastic pipes connected via tee hose barbs, mounted with baling wire, using a powerline timer to run the pump a couple of hours a day. An aquarium bubbler keeps the reservoir aerated; an aluminized tarp keeps sunlight off to prevent algae. I thought this might emit a lot of ammonia, but he said, “I knew I had fed it too much when it started to smell like a truck stop bathroom,” but normally it smells like a “well-cycled fishtank”. Calcium carbonate chips in the reservoir keep the pH from dropping too low for the bacteria. He thinks he would need a machine three times bigger to process all his urine.