• 14 Posts
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Joined 2 years ago
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Cake day: June 11th, 2023

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  • Indeed, vertical solar panels are fully compatible with farming. :) And it’s also smart to position them north-south, to get on the market on morning and evening hours - because midday is already “crowded” by conventional solar parks.

    Also, vertical panels are more resistant to hail - giant hail can smash a big investment in a few minutes if it’s horizontal. With a vertical solar park (and only a little of extra reinforcement on the upper beams), risk would be many times lower.





  • perestroika@slrpnk.nettoDIY@slrpnk.netHomebrew battery
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    21 days ago

    Nice to know. :)

    Reading tip: a comment from a reader John Beech (an old radio amateur) at the bottom is probably of greater practical value: he describes how he developed DIY cells to the point of running a 2 W radio.

    Another way to build DIY batteries is using the iron-air chemical combination. A decent collection of recipes can be found here, using filter cartridges of activated carbon as cathodes and rebar wrapped in steel wool as anodes:

    https://www.instructables.com/Create-large-refuelable-metal-air-battery/

    These cells convert iron into rust at an accelerated pace, producing power while doing that. However, they have really low cell voltages. Aluminum gives high cell voltages, but on the downside, produces annoying waste chemicals.


  • Pigs are intelligent and curious creatures, so it’s possible that they would learn this.

    However, they might come looking at a ground ambush FPV for other reasons too - most FPV controllers slowly spin their motors when armed, or beep (resonate their motors) to indicate that they’re armed. This could draw attention - pigs might think that a piglet is in trouble and come looking. Hopefully not touching, because on that screenshot, the warhead is also waiting to be touched.

    But the killed-to-wounded ratio (as well as the overall loss ratio) is probably very bad for Russians:

    • if a front moves slowly, leaving devastated land behind it, those who come across that land, they won’t have infrastructure supporting them
    • Ukrainians do not seem hell bent on crawling slowly across devastated land, they either defend or do maneuver warfare… Russians seem to have different priorities, they attack even when the attack is very costly
    • these days, any vehicle is a target for FPV drones and must be equipped with powerful electronic countermeasures (which also announce its presence) to survive
    • but some FPV drones lock onto targets with machine vision and others are piloted over optical cable, and there’s not much hope against these even with jammers
    • so, approximately within 7 km of the front, vehicles are a risky thing to have
    • evacuating a wounded person to a distance of 7 km to get him on a vehicle requires non-trivial effort
    • if the official tactic is making “meat attacks”, it’s hard to imagine where that effort comes from

    So, that effort probably doesn’t happen.

    I know of a company in Ukraine making remote operated ground vehicles (“stretcher on tracks”) that can be used to evacuate a person even if they cannot steer the vehicle, but even Ukrainians have few such tools. Russians probably aren’t bothering.



  • Some guesses, in declining order of probability. :)

    • Vanity and spite. After all, he’s not emotionally mature.

    • With some probability, rational attention-seeking to keep his supporters entertained and lobbyists (who bought and propagandized his way to power) satisfied. He has to deliver them goods. This is how he shows that he intends to deliver the goods… that he actually cannot deliver without changing the constitutional order very much. You can mark my words: lots of wind parks will be opened under the Trump administration, despite anything he does.

    • Maybe he wants to test the mettle of the terrible Renewable Industries Complex - an industry very prone to organizing coups and hiring assassins. If I were him, I’d consider twice, all the people in the solar business that I know have been extremely menacing. ;P


  • Hydrogen is a nuisance of a gas, though - it has a very wide combustible range of mixtures.

    But an airship envelope containing multiple lifting units of hydrogen could be passivated by filling the envelope with a non-combustible gas like helium.

    So, there’s a big sausage providing structure and that’s full of helium (or nitrogen, or CO2, or anything else which doesn’t react with hydrogen in normal conditions)… and it contains balloons full of hydrogen. If one of them springs a leak, the leak won’t be going into an environment that supports fire. And if the leak then proceeds into surrounding air, the hydrogen is hopefully diluted beyond its combustible range.

    Considerably less expensive than using helium only. But considerably safer than using hydrogen among air.


  • Part of the safety focus is from sticking so many people in the same fuselage - which, being big, has no individual rescue equipment and cannot be brought down by parachute either - so nothing critical is allowed to fail.

    Side note: that’s not the only possible model, however - one can also design heavier than air craft that are smaller, almost passively safe (falling controllably without power, at somewhat above parachute speed), and design small aircraft that have rescue systems (parachutes which can land the whole aircraft).

    Size itself is then a function of economic realities (air travel has undergone explosive growth).

    Blimps would have to somehow fit in. Having considerable air resistance, blimps cannot travel as fast. Being unable to travel as fast, they would fall behind at moving X people per hour - while a blimp makes one roundtrip, a jet aircraft would make multiple roundtrips.

    If however a jet aircraft is deemed environmentally unsustainable on account of fuel use - then the milestone to compare a blimp against will be a propeller-electric aircraft. Which is more limited in speed, requires charging time, is more limited in range - and therefore makes less roundtrips in an unit of time.

    From one viewpoint then, the success of airships thus depends on whether fast aircraft can reduce their environmental footprint. If they can, blimps will not be widespread. If they cannot, blimps might become widespread.

    Overall, a fast airplane is effective at getting results (transporting people) but not necessarily efficient at doing that. There is perhaps only one aspect where a high-powered aircraft is more efficient… use of space. But space is not a scarce resource in the atmosphere. Only on the runway.

    Out of the previous considerations, I come to the conclusion: blimps probably won’t replace airplanes. Especially for longer trips, having to wait less is what makes people prefer speedier travel. Blimps cannot provide that. However, airships might carve out a niche for servicing shorter routes and local traffic.



  • …and for those who prefer their information as text anyway, here’s an article on a very overlapping topic, which likely gives the same information as the video:

    Geothermal Energy with Millimeter Wave or Direct Energy Drilling

    The problem:

    Multiple countries, over decades, have tried to drill into the Earth’s crust to reach the mantle without success due to exceedingly hot temperatures in deep bore holes and extremely hard rock formations located under pressure deep underground. From 1961 to 1966, the United States’ Project Mohole tried to drill through the crust out in the Pacific Ocean off of the coast of Mexico. They were only able to reach a depth of 601 ft (183 m) in 11,700 ft (3,600 m) of water. Between 1970 and 1992, Russia’s Kola Superdeep Borehole Project (see Figure 3) reached a record depth of 40, 230 ft (12.2 km) but were only able to drill about a third of the way through the Earth’s crust. In 1990, Germany initiated the German Continental Deep Drilling Program in Bavaria to try to break Russia’s record but were only able to drill to a depth of 5.6 miles (9 km).

    Today, boreholes of 7 km are probably reliably attainable with state-of-the-art equipment. This can be very expensive and in most places, ground temperature at 7 km is not sufficient to warrant going there for energy.

    The proposed solution: drilling boreholes with a maser (radio frequency laser in the millimeter wave spectrum). The gyrotron would likely sit on surface while the waveguide (antenna) is lowered into ground. Meanwhile, vapours would be blown out with compressed air (or maybe nitrogen, if things keep catching fire).

    If the company developing it gets the system to work, boreholes deep enough to reach good quality heat would be possible everywhere on Earth, not just handful of places.

    It makes good sense in theory, and I hope they get it working. But its benefits won’t reach many people for at least a decade or two, so while the folks at Quaise Energy do their thing, I suggest that everyone else continue installing renewables and storage. :)





  • Sadly, Rojava is incredibly land-locked. It is possible to deliver assistance in various forms (from woolen socks and SDR cards to items one won’t mention on the net) to folks who defend Ukraine… but I don’t know a single organization except Heyva Sor (Red Crescent, humanitarian and medical assistance) that reaches North-Eastern Syria (even Heyva Sor is better than nothing, for all I know they depend on imported antibiotics).

    If anyone knows of channels that can get assistance to those people, clues would be welcome.

    I hope the HTS and SNA don’t have overlapping interests and listen to different people. They might hold each other in check, at least for a while, and thus prevent restarting of the civil war.

    I hope the folks in North-Eastern Syria get a tolerable (or even favourable) political solution - some kind of extended autonomy within Syria.

    But the wider context is Erdogan waiting for Trump to make deals with him (and also Israel seems to be trying to ruin its relations with any new government of Syria pre-emptively) - so if I were them, I’d keep drone batteries charged. They have a snowball’s chance in hell.