"Numen", an online #Latin lexicon.
time-wasting talking-head and stock-footage #video on #graphene #materials, using tennis courts as its standard measure of area, with the occasional second or two of actually informative footage
#Veritasium #video about #entropy in #physics, explaining Carnot efficiency and thus the rudiments of #thermodynamics, but not explaining even the units of entropy; he chose to include stock footage clips instead of equations. But he does include a bargraph of how much entropy was in the early universe and how much is in stars, neutrinos, empty space, the CMB, and the Milky Way’s central black hole, so it’s still pretty informative.
another #video that doesn’t really explain #entropy, this one by #Hossenfelder, though it does at least explain S = k ln Ω
#Hossenfelder #video on #politics in #Germany resulting in infrastructural decay and trains not running on time
#TPAI #video #manufacturing a #CNC milling machine from mostly scrap metal. He’s using the crankshaft timing pulley from a VW Golf 2 1.8 8V engine to couple his head-sized NEMA 34 junkyard stepper motors to his junkyard Acme leadscrews for the Y-axis, because the pulleys cost US$5. The pulleys have a size-L toothed belt with a 14.5mm bore and four M8 threads around the outside, one offset by 5°. He drills the pulleys out larger to fit onto the leadscrew shafts, then makes an aluminum driving adapter to bolt the pulleys to so he can couple them to the shaft. For coupling the other pulleys to the 14mm stepper shafts, he also drilled them out bigger, then made a brass tube adaptor to which the pulleys are held with three setscrews. For his X axis he’s using a junkyard ballscrew. He mentions that ATX power supply #electronics have their -12V rail connected to their enclosures and to the ground wire, which I didn’t think was correct, but anyway he removed that connection in order to be able to use four of them in series to get 48V. For sheet metal bending without a brake, he clamped his sheet metal to the edge of a table and whaled on it with a 4×4 board. He demonstrates the use of his existing homemade CNC plasma cutter. Finally he mounts a 2000-watt wood router onto the large gantry he’s built and uses it to route some beech butcher block and some aluminum plate, and even 4mm-deep grooves in steel (using a tungsten carbide bit). He mentions the need to minimize the number of piercing operations for CNC plasma cutting because of how they wear out the nozzle quickly, a consideration I hadn’t realized.
#TPAI #video #toread about #manufacturing his #CNC plasma cutter
#video #documentary about the French Foreign Legion by Taylor Cavanaugh, a former Navy SEAL who went there after prison and just got out after five years. 92 minutes. #toread
old #video #documentary on #Nitinol #materials showing heat engine #mechanisms at the Lawrence Berkeley Laboratory, by Ridgeway Banks, assisted by Professor McMillan. The video credits Stewart Brand for first drawing attention to it in CoEvolution Quarterly. Looks like about 01975. They were hoping they could convert waste heat into a solution to the energy crisis.
human-interest #documentary #video by Björn Platz on energetics in old-highrise demolition, mining, #materials science, film special effects, airbags, etc., including the history with Ascanio Sobrero. Significant factual errors, including Sobrero’s first name, the health effects of nitrate, and the physical state of liners turned into jets. Shows the use of burning pollen in film special effects, which is totally hilarious, and the use of 3-D modeling software in granite quarrying, and nanodiamonds and nanosupercrystals (of carborundum?).