tubing-lined full-body #cooling garment from "CompCooler", US$199. “Tubing-lined full body garment for use with COMPCOOLER personal cooling systems. Compatible with self-contained backpack and waistpack cooling systems. Compatible with stationary ice chest and vehicle-mounted cooling systems.”
TUI color picking tool. #formina
#video #toread of building a secrete workshop in a 500-year-old Spanish farmhouse.
Joel Spolsky’s original “Guerrilla Guide to Interviewing”. “Good programmers plan before they write code, especially when there are pointers involved. For example, if you ask them to reverse a linked list, good candidates will always make a little drawing on the side and draw all the pointers and where they go. They have to. It is humanly impossible to write code to reverse a linked list without drawing little boxes with arrows between them. Bad programmers will start writing code right away.”
Joel seems to have memory-holed the original “Guerrilla Guide to Interviewing”.
Thermal #energy-storage in a gigantic cavern in Finland by a company called "Helen". #energy
So-called “thermal batteries” using molten-salt electrolytes for high power output. “The high power is due to the high ionic conductivity of the molten salt (resulting in a low internal resistance), which is three orders of magnitude (or more) greater than that of the sulfuric acid in a lead–acid car battery. (...) In the 1980s lithium-alloy anodes replaced calcium or magnesium anodes, with cathodes of calcium chromate, vanadium or tungsten oxides. Lithium–silicon alloys are favored over the earlier lithium–aluminium alloys. The corresponding cathode for use with the lithium-alloy anodes is mainly iron disulfide (pyrite) replaced by cobalt disulfide for high-power applications. The electrolyte is normally a eutectic mixture of lithium chloride and potassium chloride. (...) In these batteries the electrolyte is immobilized when molten by a special grade of magnesium oxide that holds it in place by capillary action.”
#energy-storage in “earth tubes” that heat or cool air. #energy
The "Barra system" is an interesting #passive-solar #energy-storage #building system using #thermosiphon air flow. #energy
very nice overview of #passive-solar #energy-storage in #building. #energy
hot water tanks for thermal #energy-storage, including stratified types, safety issues, etc. #energy
overview of thermal #energy-storage. #energy
huh, salinity gradients let you insulate your hot water with cold water! So you get a passive solar thermal collector for just the price of the pond liner. #energy
household sand batteries, more or less, which have been mainstream in Europe for quite a while. #energy-storage #energy
Korean "ondol" heating stoves provide thermal #energy-storage. #energy
Chinese "dikang" also provides thermal #energy-storage, and you sleep on it. #energy
"Russian stoves" also provided thermal #energy-storage and sleeping space. #energy
overall article on thermal #energy-storage stoves like #Russian-stoves, #ondol, #dikang, etc. #energy #archaeology
the modern masonry heater based on #rocket-stoves. #energy-storage #energy
#video on video driver regression #testing in #videogames and #latency (“microstuttering” and “hitching”) on Linux. No, on Windows (10? 11?) due to mtkwecx, the MediaTek integrated Wi-Fi/Bluetooth hardware driver, which also causes replugging the keyboard and mouse to not work. Disabling the hardware in the BIOS solves the problem. So does downloading an updated driver from ASRock, but only for the keyboard/mouse problem.
“Who Invented the Reverse Mode of #Automatic-Differentiation?” #PDF #paper by Andreas Griewank from 02012
In #Lotus 1-2-3 3.1 in 01991, #goal-seek was an “enhancement add-in” called “The Backsolver Add-in”. #ebook #history #spreadsheets
#taviso ported #Lotus 1-2-3 3.0 to Linux. #retrocomputing
#video on #Jupyter #simulation of #electronics with #LTSpice. He’s using a library called spice_invoker and using some canned functions that invoke maybe matplotlib to plot the characteristics curves of various hypothetical transistors. #hardware
#video #toread on ball-joint-based open-source XYZ sub-micron #precision translation #mechanisms using NEMA17 stepper motors and some homebrew magnetic encoders, with 5-arcsecond microstepping in open-loop operation, but using an MT6835 21-bit magnetic angle encoder IC to overcome the hysteresis in the steppers’ laminations and friction. The magnetic encoder uses “magnetic gearing” in the sense that it has 17 permanent magnets with alternating orientations moving past the IC in about a quarter turn, so you get about 68× higher precision (but no absolute readout).
#video explaining oscilloscope probe compensation for #electronics with the Laplace transform. #hardware
#video #toread by #Bitluni on how he built a miniature data cassette tape drive #electronics
#video #toread about folding #robotics actuator mechanisms using an endless cable around two pulleys (with multiple turns of the cable around the smaller pulley) into a very compact package with four idlers.
#Technology-Connections #video dissecting an “Aeocky” rotary desiccant dehumidifier, which uses red-hot heating elements, a shaded-pole fan motor for the regeneration air, and a plastic cross-current heat exchanger to regenerate the desiccant and recondense the water. The main desiccant wheel has air forced through it by a large (300mm?) BLDC-like fan. He reports that it’s much smaller than vapor-compression types, the fans only consume about 12W, but the regeneration heating element is 300W, very similar to a vapor-compression device, condensing some 100g of water per hour (11kJ/g water), about ⅕ as much as the refrigerant-based unit. A Peltier-based dehumidifier was about as efficient as the desiccant-based unit in his moist bathroom, but the desiccant-based unit was able to remove water even from the 40%-RH air of his office. Most the ones he found on amazon.co.uk in the US$170–300 range were 580–735W, 7.5–11ℓ/day, and 6–7.5kg, most being almost twice as efficient as the one he tested (≈5kJ/g water). Recommends an adsorption dehumidifier brochure from Technofrigo Tuscany (“TFT dry air solutions”). #desiccants #mechanisms #HVAC
#video on #NASA’s EAST, Something Air Shock Tunnel, where they dump 1.25MJ into an exploding bridgewire to rupture a rupture disc and produce a 48km/s shockwave in a tunnel.
#video on #Amish people, an #interview with an ex-Amish woman Naomi Swartzentruber, who says that Amish people do swear, even though it’s prohibited.
#video #interview with woman Naomi Swartzentruber who left the #Amish 27 years ago at 17 and later worked as a stripper in Vegas. “I was speechless, because I thought that strippers were bad people because of how I grew up.” Then she explains how she got hooked on crack and went into #prostitution to survive, then moved to Vegas and LA and got her phlebotomist license, etc. Now she visits her Amish family once a year.
#video #toread of British RP #phonology, analyzing Queen Elizabeth II’s changes in pronunciation between 01957 and 02021.
#Microsoft has open-sourced Microsoft #BASIC for the #6502. #retrocomputing