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Cake day: June 11th, 2023

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  • Summary:

    But then, in the geologically abrupt space of only a few decades, this great river of ice all but halted. In the two centuries since, it has moved less than 35 feet a year. According to the leading theory, the layer of water underneath it thinned, perhaps by draining into the underside of another glacier. Having lost its lubrication, the glacier slowed down and sank toward the bedrock below.

    /…/

    “The beauty of this idea is that you can start small,” Tulaczyk told me. “You can pick a puny glacier somewhere that doesn’t matter to global sea level.” This summer, Martin Truffer, a glaciologist at the University of Alaska at Fairbanks, will travel to the Juneau Icefield in Alaska to look for a small slab of ice that could be used in a pilot test. If it stops moving, Tulaczyk told me he wants to try to secure permission from Greenland’s Inuit political leaders to drain a larger glacier; he has his eye on one at the country’s northeastern edge, which discharges five gigatons of ice into the Arctic Ocean every year. Only if that worked would he move on to pilots in Antarctica.

    It’s not wild at all. :) The plan makes sense from a physical perspective, but should not be implemented lightly because:

    • it’s extremely hard work and extremely expensive to drain water from beneath an extremely large glacier
    • it doesn’t stop warming, it just puts a brake on ice loss / sea level rise

  • Interestingly, warfare also has the effect of:

    • causing houses to be abandoned, necessitating houses elsewhere while the abandoned ones likely get bombed

    • decreasing the number of future consumers, whose future footprint would depend on future behaviour patterns (hard to predict)

    • changing future land use patterns, either due to unexploded ordnance or straight out chemical contamination (there are places in France that are still off limits to economic activity, because World War I contaminated the soil with toxic chemicals), here in Estonia there are still forests from which you don’t want trees in your sawmill because they contain shrapnel and bullets from World War II

    I have the feeling that calculating the climate impact of actual war is a difficult job.

    But they could calculate the tonnage of spent fuel and energy, that would be easier.







  • I think the EU Commission has done a fairly good job of listing the pros and contras of small modular reactors:

    https://energy.ec.europa.eu/topics/nuclear-energy/small-modular-reactors/small-modular-reactors-explained_en

    They have some advantages over conventional (large) reactors in the following areas:

    • if they are serially manufactured without design chances, manufacturing is more efficient than big unique projects
    • you can choose a site with less cooling water
    • you can choose a site where a fossil-burning plant used to be (grid elements for a power plant are present) but a renewable power plant may not be feasible
    • some of them can be safer, due to a higher ratio of coolant per fuel, and a lower need for active cooling*

    Explanation: even a shut down NPP needs cooling, but bigger ones need non-trivial amounts of energy, for example the 5700 MW plant in Zaporizhya in the middle of a war zone needs about 50 MW of power just to safely stay offline, which is why people have been fairly concerned about it. For comparison, a 300 MW micro-reactor brought to its lowest possible power level might be safe without external energy, or a minimal amount of external energy (which could be supplied by an off-the-shelf diesel generator available to every rescue department).

    The overview of the Commission mentions:

    SMRs have passive (inherent) safety systems, with a simpler design, a reactor core with lower core power and larger fractions of coolant. These altogether increase significantly the time allowed for operators to react in case of incidents or accidents.

    I don’t think they will offer economical advantages over renewable power. Some amont of SMRs might however be called for to have a long-term steerable component in the power grid.


  • I noticed a journalist mention (hopefully based on good sources) that this months’s storm was estimated to be 4-5 times weaker than the 1859 storm.

    NASA, in their article mentions the recent storm as a G5 level geomagnetic storm caused by an X8.7 level solar flare.

    X is the strongest class of solar flares and G is the strongest class of geomagnetic storms, but this was definitely not a record - an X20 flare has been observed once, but as I understand, the ejected particles didn’t hit Earth.

    Where I live (latitude 59), a short electrical grid event occurred during the display of auroras. Something tripped and something immediately switched over to replace it, most people didn’t notice anything, but some had to restart various heat pumps and similar devices. Then again, in Europe, the power grid has relatively short lines and many transformers between them, which makes it comparatively less vulnerable.


  • Regarding transformers: it’s easier to let a power grid trip offline (and transformers are designed to behave so instead of being overpowered) rather than to keep operating despite a Carrington level solar storm and suffer failure on all longer east-west connections.

    Also, I don’t think they used capacitors to protect their high voltage lines back in 1921, because the article Overvoltage Protection of Series Capacitor Banks notes:

    “Their first application dates back to 1928 when GE installed such a bank – rated 1.2 MVar – at the Ballston Spa Substation on the 33 kV grid of New York Power and Light. Since then, series capacitor banks have been installed on systems across the globe.”

    Also, failure on north-south connections isn’t nearly as likely, so a considerable part of the transformer “population” would be spared from impact.

    Thus, while a single strong solar storm within the limit charted out in 1859 would be an extreme inconvenience and strong economic setback, it seems unlikely to end civilization.

    A long period of severe solar storms could also result in ozone depletion in the atmosphere and become another extreme inconvenience - through increased UV exposure. However, most forms of life have seen such things in their evolutionary past, and humans have the ability to wear glasses, clothes and apply sun screen.



  • I’ve been hearing about ZFS and its beneficial features for years now, but mainstream Linux installers don’t seem to support it, and I can’t be bothered to switch filesystems after installing.

    Out of curiosity - can anyone tell, what might be blocking them?

    Edit: answering my own question: legal issues. Licenses “potentially aren’t compatible”.

    Due to potential legal incompatibilities between the CDDL and GPL, despite both being OSI-approved free software licenses which comply with DFSG, ZFS development is not supported by the Linux kernel. ZoL is a project funded by the Lawrence Livermore National Laboratory to develop a native Linux kernel module for its massive storage requirements and super computers.

    Source: https://wiki.debian.org/ZFS



  • From a person who builds robots, three notes:

    1. Camera

    Raspberry Pi has two CSI (camera serial interface) connectors on board, which is a considerable advantage over having to deal with USB webcams. This matters if your industrial robot must see the work area faster, your competition robot must run circles around opposing robots, or more sadly - if your drone must fly to war. :( On Raspberry Pi, in laboratory conditions (extreme lighting intensity), you can use the camera (with big ifs and buts) at 500+ frames per second, not fast enough to photograph a bullet, but fast enough to see a mouse trap gradually closing. That’s impossible over USB and unheard of to most USB camera makers.

    1. Optimized libraries

    I know that Raspberry Pi has “WiringPi” (a fast C library for low level comms, helping abstract away difficult problems like hardware timing, DMA and interrupts) and Orange Pi recently got “WiringOP” (I haven’t tried it, don’t know if it works well). I don’t know of anything similar on a PC platform, so I believe that on NUC, you’d have to roll your own (a massive pain) or be limited to kilohertz GPIO frequencies instead of megahertz (because you’d be wading through some fairly deep Linux API calls).

    1. Antenna socket

    Sadly, neither of them has a WiFi antenna socket. But the built-in WiFi cards are generally crappy too, so if you needed a considerable working area, you’d connect an external card with an external antenna anyway. Notably, some models of Orange Pi have an external antenna, and the Raspberry Pi Compute Module has one too.


  • It might interest people that the soon-to-be previous biggest thermal energy store is also located in Finland, under the island of Mustikkamaa in the capital city of Helsinki. The city heating company Helsingin Energia “charges” the store by pumping heat out of sewage in summer. I think it was about 10 gigawatt-hours and it’s not pressurized, so water can only reach 90 C over there.

    (A side note: if you allow water at 140 C to boil in a controlled manner, you get steam, which can also produce electrical power, although probably in a suboptimal manner.)

    Finnish bedrock seems more suitable than average rock for such ventures (which I would call “artificial geothermal energy”) - granite is a poor thermal conductor and a reliable rock for making caverns.

    I hope it goes well. :)


  • Copying out the noteworthy bits.

    Claim:

    the UAE’s National Center for Meteorology told CNBC it had not seeded any clouds before the storm struck on Tuesday

    Verifiable with a bit of FlightRadar searching:

    seeding operations tend to take place in the east of the country, far from more populated areas like Dubai. This is largely because of restrictions on air traffic, and means it was unlikely that any seeding particles were still active by the time the storms reached Dubai.

    Verifiable with a weather map:

    perhaps the best evidence that cloud seeding wasn’t involved in these floods is the fact that it rained all over the region. Oman didn’t do any cloud seeding, but it was even more badly affected by flooding, with a number of casualties.

    Now, if I was running a cloud seeding programme and saw a mega-rainstorm coming, I would quickly consult with a person who knows about drainage and call off the flight, saying “we’ve got enough coming”. It doesn’t take superintelligence to make that decision, just a functioning meteorological office and a bit of sense.

    …and the final conclusion:

    Dubai is comically ill-equipped to deal with rainfall

    (because they typically don’t get any)


  • perestroika@slrpnk.nettosolarpunk memes@slrpnk.netHow is the hydrogen made?
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    3 months ago

    They 100% know that electrolysis methods won’t be economically viable.

    I would argue against that any day. Electrolysers are viable, they are just not the current state of the industry because dirt cheap solar and wind weren’t around in previous decades.

    It’s the storage that might not be viable in most countries (because only some have geology that allows for underground gas storage). Producing hydrogen from water at 95% efficiency is doable with today’s tools, if you have somewhere to put it.