fullsquare

joined 11 months ago
[–] fullsquare@awful.systems 2 points 1 day ago

it's not regulation, it's a metric that looks nice to investors. but also lower energy use means lower cost

[–] fullsquare@awful.systems 4 points 2 days ago (2 children)

the thing you're missing is scale. what you're describing is overgrown car radiator type scheme, and it works up to some couple MW if need be. when you have access to sea, or large river, you can just use that water as a coolant and dissipate some couple GW this way. this is the reason why so many nuclear powerplants are on seashore. because sea is generally very big [citation needed] temperature increase is slight and mostly harmless in usual cases

inland, in absence of large river, the other way to provide cooling is by evaporation of water. one form is to take that oversized car radiator and spray water on it, water evaporates taking away some heat. this arrangement allows for no-added-water operation in low load conditions. in principle this means that lowest possible temperature is not air temperature, but instead it's wet bulb temperature, which is always lower, and difference is greatest when air humidity is low. in practice this doesn't allow to reach this lower temperature, but the other approach does. for bigger scale still, instead of using heat exchanger, water is dripped in a tower of some shape and air is moved in some way against it. small part of water evaporates, and the rest, now cooled down, is collected at the bottom. this is how these large cooling towers near coal or nuclear powerplants work, but so do smaller towers that rely on fans instead of chimney effect. extra water is always needed, and temperature closer to wet bulb temperature is achieved in all load conditions. rarely used alternative is to make an artificial lake, and allow for evaporation from water surface

notice that if water is evaporated, it'll leave whatever is dissolved in evaporator part, which means it has to demineralized at all times. in practice it means that some part of evaporated water is treated continuously by reverse osmosis, and the less saline input water is, the easier and more energy efficient it is to do it

the thing with heat exchangers is, without water evaporation, that they have some constant thermal resistance. if you want to dissipate more heat, you need more of heat exchanger, or alternatively have to allow for higher temperature. the former means more metal needed, the latter means limits to other parts of coolant loop, or using heat pump to cool down silicon, while increasing temperature of coolant. both of these mean extra capex and/or energy use, but evaporating water is cheap, so it's done instead. it doesn't help that one of dc ratings is ratio of how much energy gets into dc to how much energy powers actual silicon. evaporating water does not add to energy use, so designs chasing this rating are likely to use that solution

[–] fullsquare@awful.systems 9 points 1 week ago

all profit is based on deception - lao zidong

[–] fullsquare@awful.systems 11 points 1 week ago (5 children)

as a side effect, it's a phenomenal accountability sink. people almost forget that usaf can make entirely human-made fuckups https://en.wikipedia.org/wiki/Amiriyah_shelter_bombing

[–] fullsquare@awful.systems 1 points 1 week ago

i think you can say that at least some people of iran already turned against their government, except those with guns. historically the parts of strategic bombing that worked were targeting of military leadership (in progress), communications (?), weapons storage and manufacture (in progress), energy production (no signs so far). not sure if there is any plan beyond strikes, leave it to them to turn operational success into diplomatic failure

[–] fullsquare@awful.systems 1 points 1 week ago (1 children)

i had no idea that you can buy anti-ship missiles in any corner store. not sure how do you make sense of how both of these militias mentioned decided to do nothing after the guy signing their checks and sent them weapons was killed

[–] fullsquare@awful.systems 1 points 1 week ago

last time i've checked, wandel durch handel style approach was determined to not work as intended, not that it matters in this case anymore

[–] fullsquare@awful.systems 1 points 1 week ago

i also think that americans are currently allergic to boots on the ground involvement* so it's not likely. my best guess is airstrikes only, then ??? then i guess they expect regime change to materialize out of thin air. only time will tell

* unless it's not theirs, but for example kurds, this way they don't care

[–] fullsquare@awful.systems 1 points 2 weeks ago (12 children)

i don't give a shit about sam harris. if iranians were broadly fine with theocracy, there wouldn't be 30k+ dead protesters last month, or major protests every year for a decade. like every other country on earth, you can expect that iran secularizes, except that apostasy or conversion is capital offense, or any significant dissent for that matter, so any survey unaffected by self-censorship would be hard to conduct

[–] fullsquare@awful.systems -2 points 2 weeks ago (19 children)

there is some reason to think this way. also keep in mind that a segment of that anti-americanism was funded by sales of iranian oil. not all of course, but houthis wouldn't be a thing without it, or large parts of hezbollah, for example. of course what people want and how it shakes down after the bombs drop is different thing entirely, i guess we'll see, eventually (i assume that decision to strike was already made)

 

I'm picking up an idea left by Dick KK4OBI, that you can lower impedance of dipole by arbitrary ratio if said dipole is zigzagged or otherwise uniformly contorted in some meandering shape. Side effect is that dipole becomes shorter and needs more wire. While there's data about impedance for fundamental, there's nothing about harmonics which is something that OCFD might be expected to handle well, so guessing that the really important part is aspect ratio of meander, i've made a couple of VHF-scale models with different meander aspect ratios (and many more much smaller sections), and some of data i've been able to collect roughly matches. The thing I'm trying to figure is what aspect ratio should be to cover multiple bands while using OCFD, say 40-20-15m bands, and whether impedances at different frequencies fall at the same rate. Eventually, when i figure this out, i'll try to make a full size 40m fundamental antenna, as I think that i've figured it out in mechanical terms

However during testing it turned out that I have severe common mode current problems, as two 10mm dia split ferrite beads were evidently not enough, so what little i've been able to collect is mostly useless. When I packed up everything I've found 4 Laird 28B beads that should together give 1100 ohms of impedance or so at 100MHz which also happens to be close to lowest frequency in my setup. Is this enough? Feedline is currently about as long as shorter arm of straight dipole at 22,5:77,5 split ratio, should I change it?

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