#video of M. Oskar van Deventer’s “Extreme Reduction” gear #mechanical #hardware, which gears the input motion down by about 11.3 million to 1 by way of a differential between two sets of what he calls “grinder gears”, which are themselves differential #cycloidal drives made of about three moving parts. The mechanism is quite compact. Later he made a billion-to-one version.
#video of how to repair a #mechanical #cycloidal drive, unfortunately with horrible elevator music
#mechanical #video playlist showing lots of renders, including many of thang010146’s.
Michal Zalewski’s page about #mechanical #cycloidal drives, including one he resin-cast, and his Grasshopper scripts
“practical #deep-learning for coders” MOOC
65 pounds of excelsior costs US$183 at retail, US$6.20/kg #materials
discussion of how #solar #photovoltaic EROEI just crossed oil #energy at about 14:1 or 15:1
#solar #photovoltaic EROEI just crossed oil #energy at about 14:1 or 15:1
standard-issue infantry #weaponry in #Finland is a locally-manufactured version of the #AK-47, because they decided to switch to automatic rifles a decade before the USA did
shooting range dude says the #AK-47 (or rather the AKM, with the stamped receiver) usually suffers a catastrophic failure at “80,000–100,000 rounds”, but then can be repaired by welding.
#solar #photovoltaic #energy is now cheaper than wind at US$1.65 million capex per megawatt (nameplate I guess). And the latest auctioned solar contracts (US$29.10/MWh in Chile) are half the price of coal energy.
reporter spies on how beggars spend money by giving them gift cards
efficient skip list #algorithms, with nice diagrams made with Dia and TikZ
discussion of #energy; mentions capacity factors of 32.2% for wind and 25.8% for utility-scale #solar #photovoltaic in the US in 2015. Includes the rather terrifying report from Japan, “They are clear cutting forest to put up installations everywhere.”
National Geographic documentary #video about Adani’s new #solar #photovoltaic #energy plant that was built in 8 months in #India. Seems like they graded the site but didn’t concrete it, and use a dry robotic brushing system to clean the panels.
a 2016 #paper on #solar #energy payback times and EROEI (“EROI”) and life-cycle analysis (LCA) and net energy analysis (NEA). In particular fixed ground-mounted “multicrystalline” silicon #photovoltaic cells have EPBT of 0.9 to 2.1 years depending on irradiation (insolation), and an EROEI of 15 to 35. This is surprising because that’s pretty much what it was when NREL published an EPBT analysis around 2001 or so.
8 MWh of vanadium flow battery (#VRFB) #energy storage is scheduled to come online in January 2017 at Snohomish County Public Utility District (SnoPUD)’s Everett Substation in Washington State, built by UniEnergy Technologies; they claim the cost of storage is 5¢/kWh; the photo makes it appear to occupy ten TEUs (it’s containerized) but maybe the battery in the photo is only 4MWh. An 800MWh system is planned for Dalian by “UET’s sister company Rongke”. The electrodes are solutions of vanadium salts at different oxidation states separated by an ion-selective membrane. #hardware
this article claims SnoPUD’s UET vanadium redox flow battery (#VRFB) is scheduled to come online before Q3 2017, not in January. The cost for that project and a couple of others is US$15M. #energy
the horrifying baseband processor operating system in every #phone, typically AMSS on REX on a separate ARMv5
how Norbert #Wiener was manipulated into unfriending McCulloch and Pitts, resulting in Pitts setting fire to his dissertation and drinking himself to death via esophageal bleeding, the same way Phil Katz died. #history
#humor nonfiction about catproofing an automatic cat-feeding machine by, ultimately, encasing it in thick steel plate
How to escape from a nightmarish merge conflict in #Git
How wood’s equilibrium moisture content depends on relative humidity. #materials