#vanlife #argentina #video #Al-Mundo-con-el-Mate #clickbait pretending to give up again, but it turns out they just had to go back to their hometown to renew a driver’s license and the verificación técnica of the van. They say the Axion stations are better than the YPF stations for spending the night, and often have picnic areas; in the south, near El Bolsón, there are more places where you can’t spend the night because they’re overloaded with motor homes. Lots of footage of driving down the highway
two-minute #video about #card-catalogs
#video with a three-minute segment about #card-catalogs
“Expando” brand #expanding-grout generates heat that can result in steam explosions (“Do not look directly into the filled holes for the next 2 – 6 hours”!), should be poured into holes of 28mm to 40mm diameter, takes 24–76 hours to expand mostly and 5 days to expand fully, has a 10-minute working time, comes in five different formulations for different temperature ranges, and produces 14000 “psi” of compressive stress (100MPa). #materials
“Expando” brand #expanding-grout costs AU$305 for 20kg. #materials #pricing
#MSDS for “Dexpan” brand #expanding-grout #materials “for controlled demolition, reinforced concrete cutting, rock breaking”, etc. Causes serious eye damage because it’s 75–90% slaked lime, also containing vitreous silica, hematite (Fe₂O₃), and alumina. But that can’t be all Expando is or it wouldn’t cost AU$15 a kilo. Specific gravity 3.2.
#CodysLab #video on #expanding-grout. He uses quicklime (not slaked lime like “Dexpan”!) and, to delay the reaction, washing soda (200mg or 600mg per 10g of quicklime). Features a quicklime steam explosion in the kitchen. He sinters the quicklime to try to reduce its porosity, which I didn’t think will do much because his kiln was only set for 1200°, but apparently it did. The mix was successful in breaking a rock in a couple of hours and a test tube in a bit more. The higher-soda mix expanded more (possibly because it stayed wet longer) but more slowly.
“The use of expansive chemical agents for concrete demolition: Example of practical design and application” says #expanding-grout is CaO, SiO₂, Al₂O₃, MgO, and SO₃, which last is obviously an error; it says, “They expand due to the exothermic reaction between CaO and H₂O. … Additional pressure can also be created by ettringite formation.” Ettringite (Ca₆Al₂(SO₄)₃(OH)₁₂·26H₂O) can form in portland cement from the reaction of alabaster with tricalcium aluminate, and a thin layer of ettringite is what makes portland cement have a usably long pot life #paper
#PDF #paper on #expanding-grout from 02009: “Expansive Cements and Soundless Chemical Demolition Agents: State-of-Technology Review” by Huynh and Laefer, using the term “soundless chemical demolition agents”, or “SCDAs”, which says ettringite formation is the main mechanism. Lists brands including Prostar, CrackAG, Chemshine, Buster, and Dexpan.
#CC #paper describes various excavation methods (plasma, foam injection, etc.) including #expanding-grout, which it says works by hydrating lime under confinement and also producing ettringite, but lists four different types: type K (4CaO·3Al₂O₃·SO₃ + 8CaSO₄⋅H₂O + 6Ca(OH)₂ + 74H₂0 → 3(3CaO⋅Al₂O₃⋅3 CaSO₄⋅32H₂O, can be enhanced with silica fume and plasticizer), type M (CaO⋅Al₂O₃ + 3CaSO₄⋅H₂O + 2Ca(OH)₂ + 24H₂O → 3CaO⋅Al₂O₃⋅3CaSO₄⋅32H₂O), type S (3CaO⋅Al₂O₃ + 3CaSO₄⋅H₂O + 26H₂O → 3CaO⋅Al₂O₃⋅3CaSO₄⋅32H₂O), and class [sic] G (CaO + H₂O → Ca(OH)₂). Calls it “SCDA” and mentions ASTM C 845 “Standard Specification for Expansive Hydraulic Cement”. It says they work too slowly (12h) to replace explosives in the usual mining cycle, but I suspect that’s not true of class G, where the main problem is keeping it from reacting to completion before you can pour it into the hole.
#CC #paper #PDF “An Alternative to Conventional Rock Fragmentation Methods Using SCDA: A Review” on #expanding-grout, describing many different products from different manufacturers, DOI 10.3390/en9110958. Also contains the absurd error mentioned in an earlier paper that the cement contains SO₃.
#Nighthawk #video about waterproofing fabric #materials making oilcloth by ironing cubes of paraffin wax plasticized with mineral oil (paraffin oil, vaseline, ideally about 500mℓ per 2kg of wax) into the fabric. This seems dramatically inferior to the naphtha-thinned silicone recipe he showed previously. Contains some of the usual backwards science of Nighthawk videos; here he claims that the thermal coefficient of expansion of steel is greater than that of paraffin wax, for example, and that naphtha and gasoline are carcinogenic. For his jacket he ended up applying it as a paste wax, like to floors, but melting it with a heat gun instead of kerosene. Unrelatedly, he also demonstrates tying a slipknot (a taut-line hitch) around an acorn wrapped in the corner of his tarp in place of a tiedown grommet. Commenters advise that the wax needs to be reapplied every year; that you can filter lubricating oil out of camp fuel with nonwoven polypropylene to get naphtha; that the Hartford Circus Fire was caused by waxed fabric; and that adding about 6% by mass wood ash to the wax improves durability.
#video on a nice #vanlife conversion for about US$900: 12-volt chest fridge (US$250), furniture from scrap wood or modified thrift-shop goods, metal bed frame off Craigslist, mattress (US$300), blackout curtains for #stealth-camping, custom insulation panels fit to (“ceramic” tinted) windows, 4 100W “Renogy” #photovoltaic #solar panels for #energy feeding two 100Ah LiFePO₄ batteries under the bed, no inverter, “shore power”, dc-to-dc charger for when driving, one-burner camping stove, 12-volt electric blanket, fuse panel under bed, smoke detector and carbon monoxide detector, “Renogy Rover” 40A charge controller. I think he’s maybe forgetting a lot of the costs and the real cost is a lot higher. USB fans for ventilation. Diesel space heater hooked up to a gas can screwed to the back door. Indiana plate C843CA. Two fire extinguishers. No toilet, uses public restrooms, bucket for emergencies. Showers at Planet Fitness, friends’, and truck stops.
#video on modern reconstruction of 01930s hobo “everyday carry” pack: gum blanket/rubber poncho, shelter half, wool blanket, wool socks, etc. Probably not worth summarizing.
Chris Date oral #history interview with the #CHM, focusing on relational #databases, 51 pages, talks about how he founded a company with Codd and about the “Required Technology” “Transrelational” model. “While I’m pleased that these #SQL systems are now ubiquitous, I wish they were relational systems.”
Don Chamberlin oral #history interview with the #CHM, focusing on relational #databases, 39 pages, #toread
Codd’s 01970 paper defining relational #databases. It’s a bit hard going because of the terminology disconnect.