#Video #toread about “the most powerful laser you’ve never heard of” #clickbait
#Dr-Volt #video #toread about #microscopy with a Blu-Ray laser. #hoarding #electronics
#Murray-Smith #video about making a position sensor from #hoarding a mouse. #electronics
#Language-Simp #humor #video reviewing #English, pointing out that it’s not a real language, just a bunch of other languages, since 80% of its vocabulary is loanwords. “All of the useless and irrelevant words like ‘anatomy’ and ‘democracy’ come from Greek, while all of the useful and relevant words like ‘loot’, ‘thug’, ‘bandana’, and ‘mogul’, come from Urdu.” Harshly criticizes phrasal verbs. #formina
#video on #3D-printing pneumatic logic display #mechanisms (incorrectly described as #fluidics) with FDM and silicone membrane to get 8×8 bistable pixels, which he can play Snake on. Each pixel has a single pneumatic vacuum valve (“transistor”) which permits vacuum to the display only when there is vacuum on both the column channel (providing the air current) and the row channel (opening the valve). To get airtight channels with FDM he prints slow, hot, and overextruded, which still wouldn’t give you the wall smoothness you need for fluidics. The multiplexing is rather slow because he’s driving the rather voluminous channels with solenoid-driven valves, getting speeds more like 8Hz than the 10kHz or so normally achieved with fluidics. The platinum-cured 25A silicone membrane’s smooth surface comes from the air-exposed surface of the silicone in a mold carefully leveled with a 2-dimensional bubble level; he tried using a different, commercially-made silicone membrane for the logic surface, but it had to be smooth and flat on both sides, and the commercial silicone sheet wasn’t smooth enough, so he cast his own with glass as the mold on the bottom side. To get the warped bottom surface of the 3-D print to be flat enough to seal well, he sealed it against glass in a vacuum bag and then annealed the assembly at 60° for several hours. Tiny raised concentric rings around the holes that have to make contact with the silicone membrane hopefully make the system more robust against small deviations from flatness. He 3-D prints Luer lock adapters for standard medical tubing, which connect to the logic board with O-rings. I feel like you could probably Charlieplex with this pneumatic-logic approach, and with silicone you might even get a reasonable lifespan, especially with less extreme flexions than the ones he demonstrates in the video. Amusing note: to speed up display updates, he seems to activate multiple rows simultaneously when their contents are identical, an approach which might work for other kinds of multiplexed #displays.
#Integza #video #toread with a variable #rocket nozzle for #flying.
#Thought-Emporium #video #toread on how to make dragons with science
Protocol Labs is not renewing Shipyard’s funding to maintain #IPFS.
#NileRed #video on extracting citric acid #materials from lemons. But, uh, he used lye, sulfuric acid, hydrochloric acid, and calcium chloride to do it. So I’m guessing he’s going to precipitate the citric acid with the calcium citrate, wash it, then acidulate it with the hydrochloric acid? But then you have some unknown hydrochloric and citric acid in solution, plus calcium chloride. You can simpify this to just the acids by precipitating the calcium chloride with the sulfuric acid, but then you have super annoying calcium sulfate, and you still have to separate the hydrochloric acid, which I guess you could just boil off. But then what is the lye for? Let’s see.
Oh, he says he’s not going to actually use the hydochloric acid, so I guess he’s just going to acidulate the calcium citrate with the sulfuric acid, leaving insoluble calcium sulfate and citric and sulfuric acids, but then how do you separate those?
He got 458g of lemon juice (450mℓ) with a pH of 2–3 and then started adding lye to raise the pH to 8–9, which is not at all what I expected; that’s going to give sodium citrate, which is water-soluble, not a calcium-citrate precipitate. He says to fully neutralize an acidic proton, take the pH two points above its pKa, so 8.4 to neutralize the third citric-acid proton (pKa = 6.40); at this point the lemon juice is turning orange. He found that gravity filtration with coffee filters worked better than vacuum filtration because of the lemon pulp, because it’s easier to replace the clogged filters with fresh ones. Then he added the calcium chloride (28.5g dissolved in 70mℓ of distilled water) to the slightly basic solution, which I thought would immediately precipitate calcium citrate, but which needed to be heated to boiling to do so; then it settled, and he vacuum-filtered it and washed it three times with hot water, getting 77g of calcium citrate tetrahydrate. Then he added 20.9mℓ 98% sulfuric acid dissolved in 200mℓ of water; he uses a slight excess of the citrate to ensure that the sulfuric acid is fully consumed, so that the calcium sulfate waste product is contaminated with a bit of calcium citrate, rather than the citric acid desired product being contaminated with a bit of sulfuric acid. He commented that the vacuum filtering process was “kind of slow”, which is a lot less hassle than filtering calcium sulfate usually is. So then he evaporated the water from the 350mℓ of citric acid filtrate at 70°–80° with strong stirring, where I was expecting him to boil it; on reduction to about 70mℓ, he filtered it through a coffee filter to remove a precipitate he thought was calcium citrate that had remained dissolved. On gradual evaporation at room temperature for a couple of weeks, it crystallized; some “viscous brown goop” was left as a supernatant, presumably containing some kind of impurities. Also, he thinks that some of the crystals aren’t citric acid. But he got 18.1g of a theoretical yield of 21.9g.
#public TV #video from #ACS-Reactions on extracting citric acid #materials from lemons and by fermenting with Aspergillus niger from a moldy onion, after first starting it in potato dextrose broth, then removing the metal ions from molasses with potassium ferrocyanide, and then feeding the A. niger. "ChemThug" tried using a calcium hydroxide solution to precipitate any oxalate in the mold menstruum, and didn’t find any, although I’m not clear how that would distinguish citric acid from oxalic acid.
So again he adds NaOH to the lemon juice, turning it orange, and then boils the stuff, which turns it brown. Again he precipitates calcium citrate from the slightly basic sodium citrate with calcium chloride (the heating part here is omitted), filtering it through coffee filters (using vacuum filtration) and then oven-drying the precipitate.
For the mold broth he adds calcium hydroxide directly instead of going through the sodium stage, then boils the stuff. Again, to convert calcium citrate to citric acid, he adds sulfuric acid. But his final product wasn’t citric acid, or any acid, because it didn’t make baking soda fizz. So he tried again. Interestingly, he’s using a hand pump for the vacuum filtration.
Then he tries to salt out the citric acid from water solution with acetone.
I wonder if the NileRed video product was actually citric acid after all?
#CodysLab #video converting urine to 202 grams of potassium nitrate fertilizer #materials, precipitating Ca(NO₃)₂ (having previously replaced some ammonia with CaO) with K₂CO₃. Demonstrates recrystallization in water to separate NaCl. Also uses a paper towel at one point to filter solids out of his nitrate solution.
good #electronics #introduction #tutorial #video #formina maybe
#CodysLab #video on #mining magnetite #materials efficiently. First he throws magnetite-bearing dirt with a shovel through a screen into a fan air current to remove gravel and dried grass. Then he lets it trickle out of a hole cut in the bottom of a 20-liter bucket onto a big magnet, which redirects the magnetite to the side into another bucket, while the non-magnetic sand bounces off in the other direction; it takes 8 minutes to process 20 liters. In a day and a half of work he collects 800 “pounds” of 90% thermite.
#video on #manufacturing clay #ceramics jar lids to be lapped with carborundum paste so they fit perfectly.