perestroika

joined 1 year ago
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[–] perestroika 3 points 1 month ago* (last edited 1 month ago)

On individual scale, precisely that - a split type AC with one half indoors (or in a water tank) and the other half in an outdoor environement (air, water or ground).

If you're extracting heat from the environment, the machine lets the working fluid evaporate into the outdoor heat exchanger and compresses it back into the indoor heat exchanger. If you're cooling your premises - reverse that.

However, on a city scale, it's like "you've got a lot of sewage at 30 C" -> "your heat pump is a large building" -> "your sewage outflow is now at 10 C, but your underground heat reservoir gets charged to 140 C (stays liquid because of water column pressure), and you spend much less energy pumping the heat than you would spend heating the water directly".

[–] perestroika 8 points 1 month ago* (last edited 1 month ago)

I have had many encounters with cops, and I decide about the extent of cooperating with them on a case-by-case basis.

  • landlord is illegally evicting my mother's neighbour --> I call cops and they prove how useless they are at prevention, but the matter goes to court and the landlord gets convicted later, and it was my only time to testify in court
  • cops accuse me of ignoring their lawful order --> sorry, I was listening to music, didn't hear nothing, no comment, no comment, I admit nothing (nothing came of it)
  • cops intrude into the squat yard without knowing it's a squat --> "the ~~droids~~ drunken people you look for are elsewhere" --> the cops go elsewhere
  • cops raid the squat --> refuse to provide documents until threatened, require cops to provide their own ID, contest every statement and discuss the matter publicly in media
  • cops try to steal equipment during a demonstration --> pull the equipment back and yell to them a description of what it is (I assume they thought I was planting a bomb instead of packing up)
  • cops want to interview me about illegal demonstrations --> I politely tell them to fuck off, then call back and volunteer for the interview to convey the opinion of other anarchists :D
  • a new squat is being established --> establish a security perimeter that is watched with attention and never let cops close
  • an attempted squat gets burglarized and set on fire -> inform the fire brigade that a bottle of propane could be present (fortunately it was stolen), the fire brigade had better things to do than involve cops
  • a new squat gets burglarized --> pepper spray the burglar and take their tools, without involving cops
  • a new squat gets burglarized, episode N --> threaten the burglars and take their tools, without involving cops
  • cops try to fall into a hole in ground during a stupid training excercise --> tell the cops not to go there, as they might fall in (leave untold: it would be a major embarrasment for squatters to rescue them)
  • the squat is suddenly in the security perimeter of a NATO summit --> find some military lurking in the yard and invite them into the squat so they could be reasonably certain we don't have anything that shoots down planes :P (runway was about 250 m away)
  • a drunken person tries to SWAT me at a street party --> fully explain the situation to the SWAT team and later participate in amateur theatre with cops to get the drunken person safely removed from the police station :o
  • one drunken neighbour hits their spouse and when I forbid, hits me --> seeing that the neigbour has already paid for his deed since pepper was 100% effective and he'll feel extremely bad for many hours, I did not file a complaint to cops, although they were called and showed up
  • after two geniuses tried to steal my car, but fled after a warning shot --> I did not involve cops
  • after some person attacked his partner and hit her on street --> I pepper sprayed him, and since he took out a knife and attempted to come at me (I evaded, no harm occurred to me), I did call cops and make a complaint, as did the woman he had hit
  • cops call me about one neigbour's car --> I don't remember anything (I did actually remember, but wasn't in a mood for helping them repress a neighbour)
  • my car gets burglarized --> I ask the cops for info, they have none, I don't involve them beyond that

...etc.

[–] perestroika 4 points 1 month ago

P.S. I have once used DC to power a pump "directly". I use quotation marks because the pump (a water pump) was a brushless DC motor with an integrated controller. I used it on a field for removing water after a spring flood. Its controller accepted 24..48 V input, and it was powered from a 40 V solar panel brought on a wheelbarrow. :)

[–] perestroika 6 points 1 month ago* (last edited 1 month ago) (1 children)

instead of powering the heat pump from the wall, the heat pump can be connected directly to a PV

I have no experience with this exact combination. I know that "batteryless" inverters exist, but most of them are on-grid inverters. In that scenario, all that matters is monitoring your production: if you don't want grid energy, you only run your system when your PV produces enough.

Another type of batteryless inverters are "pump inverters". Farmers seem to like them for pumping water from wells into water towers. A pump inverter can be configured to run at 50 Hz (or 60 Hz for North Americans) and 230..240 V (or 110 V for North Americans) alright, but it is not designed to power electronic devices, but dumb agricultural motors. There is considerable risk involved with powering a heat pump from a pump inverter, unless you find an exceptionally simple and dumb heat pump with very limited or resilient steering electronics.

Efficiency losses are small anyway, but mostly happen during battery storage or when voltage needs to rise or drop considerably (e.g. a transition of 700 -> 24 V or 24 -> 240 V would cause a small efficiency loss).

I’ve heard that a PV can directly power a compressor

This seems unlikely as the compressor would have to be a brushed DC motor. That kind of motors don't last long, they wear out their brushes. Long-lasting motors are brushless, and those generally cannot be run on DC power. For example, a "brushless DC" motor is essentially a three-phased AC motor, just its controller (full of smartness and MOSFET transistors) accepts DC input.

If you have a good technical overview of your heat pump system, maybe you can locate a point where regulated DC can be fed into the system, but that would be hacking. Alternatively, maybe a niche market already exists for DC-powered heat pumps, e.g. for caravans, trucks or ships? But on niche markets, prices typically aren't good for you. :(

[–] perestroika 1 points 1 month ago

Mulje: arutelu oli huvitav, kuid aega oli selleks liiga vähe. Kohal oli mitukümmend inimest, kellest osad kirjutavad ministeeriumile enne kooskõlastusringi tähtaja lõppu.

Kohal oli siseminister Läänemetsa nõunik, kes veidi ümarat juttu ajas, kuid ilmselt ka kõrvad lahti hoidis.

Eks vaatame, mida sealt tuleb. Kui tuleb mingi halva maiguga eelnõu, siis peab lipud ja loosungid kolikambrist välja otsima.

[–] perestroika 4 points 1 month ago (1 children)

Relays: my use for truck relays is switching on heaters in my thermal storage water tank. Not big ones, though - I use relays rated for 24V and 40A of current. Since they are old, I have applied a safety margin and only let 25 A flow through them, so each of them handles 24 x 25 = 600 W.

As for using DC appliances: benefits do exist. If a household has a low voltage DC battery bank (some do, some don't) then dropping the battery voltage a few times to power car parts comes with a smaller efficiency loss. In my household, DC appliances are used for lighting, communications, computing, cooling food, pumping water and soldering electronics. The rest goes via AC. I think a car air conditioner could cool some small storage room decently. With big living rooms, it would have difficulty since it's a small device.

[–] perestroika 2 points 1 month ago* (last edited 1 month ago)

it would (as far as i understand with high school chemistry) be strictly more efficient to electrolyse rust directly

I'm not a chemist either, but I do know a bit of chemistry.

Typically, you need a solution of NaOH (sodium hydroxide) to directly reduce iron oxide in an electrolysis cell. If your iron oxide contains impurities, those may react with NaOH and ruin the fun. Also, if you have exposure to CO2, your NaOH will gradually degrade, producing NaHCO3 and losing potency.

My impression: wet electrolysis is great for making high purity iron, but it would be hard to make it work for energy storage.

[–] perestroika 8 points 1 month ago* (last edited 1 month ago) (5 children)

Relays can be used for anything, and a car contains a fair number.

You can make a pulse jet engine from a muffler parts, but a solarpunk society would probably not do that. :)

Copper brake pipe and cooling radiators can be used as heat exchangers for other stuff.

Air conditioner parts can be reverse-used for Stirling engines or to pump heat in other contexts.

[–] perestroika 2 points 1 month ago* (last edited 1 month ago)

Wow, really interesting tools. :)

But sadly not for me - I left biology behind at some point and have fallen off the sleigh so badly that I'd probably need a year of study before I could use this tool for something less than practical (e.g. make a bacterium glow in the dark).

[–] perestroika 5 points 2 months ago* (last edited 2 months ago)

This one didn't have rocket boosters, but was also nice: :)

( it traveled 180 km on one charge, back in 2009 :D )

[–] perestroika 2 points 2 months ago* (last edited 2 months ago)

Apparently, the Caspian Sea Monster is back, and it's electric now. :) If I had a need for watercraft (I live on land and I don't need more than a SUP board), this would be something that I'd try building (naturally with seatbelts and airbags to survive a crash). :)

[–] perestroika 3 points 2 months ago* (last edited 2 months ago) (1 children)

Wow. :)

I was expecting something with rotor sails, but I click, and it's a fancy new derivative of schooners. :)

As a result, I guess that rotating masts aren't optimal after all - too much moving mass, impossible to take down during a hurricane, etc.

I also guess that this sailboat has a fairly good motor, for use during total lack of wind (rare) or storms that would damage sails or masts.

 

The inverse vaccine, described in Nature Biomedical Engineering, takes advantage of how the liver naturally marks molecules from broken-down cells with “do not attack” flags to prevent autoimmune reactions to cells that die by natural processes.

PME researchers coupled an antigen — a molecule being attacked by the immune system— with a molecule resembling a fragment of an aged cell that the liver would recognize as friend, rather than foe. The team showed how the vaccine could successfully stop the autoimmune reaction associated with a multiple-sclerosis-like disease.

 

Alustaks kommentaari tsitaadiga tüübilt nimega Aristoteles: "Peetakse demokraatlikuks, et avalikud ametid antakse liisku heites ning oligarhiliseks, kui neid täidetakse valimiste abil."

Lugesin enda jaoks põnevat uudist, kuna olen sortitsiooni kui meetodi pooldaja. Tundub, et see demokraatia meetod on kohalike poliitikute jaoks horisondil nähtavale tulnud. Nad on käinud asju lugemas, lasknud omale kärbseid pähe ajada ning nüüd tegelevad mingi uutmisega. Minu arust täitsa positiivne. :)

Valdkond on esialgu lahja - ainult haljastus. Kui läheb kapitaalselt nässu, siis haljastusega ühiskonda tuksi ei keera. Luuakse rahvakogu. Tundub, et see püütakse luua juhuvalimi abil, aga mitte kompromissitu juhuvalimiga, kus valituks osutunule pakutakse kõva palka ja eeldatakse kobisemata otsustama tulemist, vaid kaalutud valimiga. Kaalumine on ilmselt vajalik, kuna palka ei saa.

Rahvakogu liikmetelt oodatakse 5 päeva tööd. Kuna see on vabatahtlik, võib karta, et saadikute osas toimub kõigile märkamatult selektsioon jõukuse järgi. Turu nähtamatu käsi eemaldab otsustajate ringist need, kes ei saa lubada omale viit vaba päeva. Sellest on kahju. Õnneks on need siiski nädalavahetuse päevad, mistõttu võib loota, et varaline selektsioon ei tule väga karm. Haljastuse küsimuses ei tarvitse see protsessi nurjata, küll aga võiks valimi kaldu lüüa raha-asjade arutamisel.

Rahvakogu kahjuks ei ole volitatud tegema siduvat otsust, üksnes võimalikult häid ettepanekuid. Kõige lihtsam seletus on Kohaliku Omavalitsuse Korralduse Seadus: riik on sätestanud nii, et tema osad peavad töötama nagu väikesed riigid. Õigust volitada otsused juhuvalimile pole riik omavalitsusele andnud.

Kõigist vajaka jäämistest hoolimata: kui osutute loosituks, olge tubli ja tehke head soovitused. :) Oletan, et linn võtab neid arvesse, kuna protsessi on investeeritud palju tööd ning vaeva. Siiski, garantiid ei anta.

Rahvakogu koostamiseks saadab või on juba saatnud Tallinn 30 000 kutset juhuslikult valitud pealinlasele. Lõplik rahvakogu liikmete arv on märksa väiksem – 60 – ning need valitakse välja inimeste hulgast, kes kutsele on vastanud nõusolekuga. Nii kutse saajad kui 60 rahvakogu liiget valib arvuti algoritm, ütles ERR-ile Tallinna strateegiakeskus rohepöörde büroo analüütik Tuuli Veersalu.

Tallinna abilinnapea Vladimir Svet ütles eelmisel nädalal, et kokku soovitakse panna väga kirjut seltskonda. "Tahame Tallinna elanikkonna läbilõiget, tahame saada väga erinevaid inimesi," lausus ta.

Veersalu ütles, et koosseis peab juba metoodikast tulenevalt olema läbilõige elanikkonnast ja et juhuvalimiga luuakse nii-öelda mini-Tallinn.

"Igal Tallinna elanikul on võrdne võimalus sattuda rahvakogusse valituks. Rahvakogu koosseisust välistatakse mõned erandid, näiteks linnavalitsuses ja linnavolikogus töötavad inimesed, et säilitada protsessi usaldusväärsus ja apoliitilisus," lausus ta.

Rahvakogu projektijuht, Maiu Lauring DD Demokraatiakeskusest, ütles, et rahvakogus osalemine peab olema inimese teadlik otsus, kuna rahvakogus osalemiseks annab inimene ära viis nädalavahetuse päeva.

 

Rubriigist "anarhist annab aru"

Hiljuti sai ette võetud üks strateegiline hagi, eesmärgiga et kohus:

  • tuvastaks ABIS põhimääruse ja ITD andmekogu põhimääruse teatud punktide (mis sätestavad andmete, muuseas nüüd kohustuslikult kogutavate sõrmejälgede, hoiu aastakümneteks) vastuolu EL parlamendi ja nõukogu määrusega "(EL) 2019/1157" (mis sätestab andmete kustutamise koheselt, igal juhul hiljemalt 90 päeva jooksul)

  • tuvastaks ITDS-i vastuolu põhiseadusega (kuna see volitab valitsusele otsused, mida Riigikogu on suuteline reguleerima ja on ka reguleerinud)

Kahjuks tagastas kohus kaebuse, selgitades, et pole võimalust asja enne käsitlema asuda, kui kaebaja õigusi rikutud on. Kuna kaebaja oli ettenägelik ja uuendas oma ID-kaardi ilma sõrmejälgi esitamata viieks aastaks aastal 2021, tekib kaebuse esitamiseks võimalus alles aastal 2026.

Senikaua - kui ei leidu teist kaebajat, kes oleks pidanud riigile äsja sõrmejäljed loovutama, ning kelle andmed PPA oleks euromääruse järgse kustutamise asemel Eesti määruste järgi andmebaasi lükanud - ei saa midagi ette võtta.

Kodanik ei sa kohtusse pöörduda õigusaktide vastu, ainult haldusaktide või haldustoimingute vastu. Meie õiguskord on kurvastuseks natuke tobe, aga see pole uudis.

Anonüümne anarhist plaanib vahepealsed 3 aastat aega veeta molutades. Molutamise vahelt kirjutab ta ühe korra veel õiguskantslerile ja ühe korra EL andmekaitse volinikule.

Kui keegi soovib anarhistilt kaebuse blanketti (ca. 8 lk), et ise võidelda - küsige ja saab. Eesmärk pole ise see olla, kes lolluse ära lõpetab, vaid et lollus lõppeks.

4
submitted 1 year ago* (last edited 1 year ago) by perestroika to c/science
 

Most people would typically think than smelling a scent (unless it's a powerful poison or medicament) won't change much in a person's health... but apparently, a variation in the scent environment has effect on the human brain, especially if the person is already old and their senses are degrading. It has also been observed that viral infections damaging a person's olfactory nerves result in changes to the brain - with less input, the neural networks involved with scent tend to atrophy. Coinidentally, some neural networks involved with scent recognition are also involved with memory.

Prios studies already support the idea that training one's sense of smell helps older people avoid cognitive deterioration. This study brings highly significant statistical results and adds one bit - wakefulness is not required to benefit. Apparently, the stimulation a person receives from feeling different scents bypasses sleep (or maybe, even improves the quality of sleep).

 

Long story made short: apparently, the previous administration didn't really try (since it was Bolsonaro's, I am not surprised). EU import controls and financial interventions have also helped:

He believes the slowdown is due to a combination of factors: the resumption of embargoes and other protection activities by the government, improved technical analysis that reveal where problems are occurring more quickly and in more detail, greater involvement by banks to deny credit to landowners involved in clearing trees, and also wariness among farmers generated by the European Union’s new laws on deforestation-free trade. It may be no coincidence that deforestation has not fallen as impressively in the cerrado savanna, which is not yet covered by the EU’s controls.

6
submitted 1 year ago* (last edited 1 year ago) by perestroika to c/science
 

Superconductivity is a condition of matter where resistance to electrical current disappears.

The first superconductors needed cooling to near the absolute zero. The next generation worked at temperatures of liquid nitrogen. A room-temperature atmospheric-pressure superconductor is a highly sought after material (e.g. it would expand possibilities to hande plasma for fusion research and make MRI machines easier to build).

A substance named LK-99 has recently caused interest in the research community. Its a copper-enriched lead apatite, typically made by reacting lead sulphate with copper phosphide. It is speculated to be superconductive at room temperature.

It is also thought that interesting properties are not inherent to the substance, but a particular kind of crystal lattice which this subtance obtains - if produced in certain ways.

The name LK-99 refers to Sukbae Lee and Ji-Hoon Kim, and the number refers to 1999, when these Korean researchers first stumbled upon it.

Studies back then were interrupted. They weren't certain of its properties and it was hard to make repeatably. When a researcher named Tong-Shik Choi died in 2017, he requested in his will that research into LK-99 be continued. The resources were found and his request was granted.

Then, other factors intervened, among them COVID. The first article was rejected by Nature because an extraordinary claim requires extraordinary proof. An article in Arxiv (not peer reviewed) at the end of July 2023 drew international attention, however.

Many persons and teams started attempting to replicate the experimental results. The process is still half way through, but considerable progress has been made.

  • Beijing University, school of material science + Beihang university: the experiment was made, but the effect could not be reproduced (they obtained a paramagnetic semiconductor of little interest)

  • Huazhong University, center for crystalline materials and micro/nanodevices: they obtained a diamagnetic crystal with interesting properties (repelled by a ferromagnet regardless of orientation, a property which a superconductor must have, but which is also shared by non-superconductive diamagnets)

  • National Physics Laboratory of India: failed to replicate the effect

  • Professor Sun Yue, South-Eastern University of China: got a weak diamagnetic crystal

  • Iris Alexandra (from Russia, plant physiologist): with an alternative production method, obtained a tiny but strongly diamagnetic crystal

  • Sinéad Griffin (Lawrence Berkley National Laboratory, from the US): published an article, attempting to theoretically explain how superconductivity might arise in the substance, explanatory tweet here

  • Junwen Lai (Shenyang National Material Science Laboratory, China): published an article about the electron structure of the substance, without opinion regarding superconductivity, with the opinion that gold doping would be better than copper doping

So, strong evidence is absent until now - we may have much merriness about nothing. There is a bunch of hypothesis and enough material to fit on a fingertip. :)

Background:

https://en.wikipedia.org/wiki/LK-99

7
submitted 1 year ago* (last edited 1 year ago) by perestroika to c/science
 

I noticed that we have a community for talking about applied science and engineering in the form of c/technology, about climate science in the form of c/climate, but there didn't seem to be a field-neutral place to discuss any sort of science.

To fill the absence and introduce a few articles which caught my interest, I created it. I think I should make this thread stick to the top of the community, so meta-discussion could be easily located here.

 

People at MIT made a capacitor of cement and carbon black (not to be confused with soot). It worked and they are planning to test bigger samples. The construction of such capacitors is easy and they can be structural elements in architecture.

 

Siseministeerium saadab peagi kooskõlastusringile eelnõu, millega keelataks isikustamata kõnekaartide kasutamine.

Jälle üritavad sama hiilivat autoritaarsust, põhiliselt et saaks kanepimüüjaid kiusata, kuna need sõltuvad klientidega suhtlemisest.

Ega muud, tuleb jälle hakata poliitikaga tegelema. Tüütu, nürimeelne töö - aga vältimatu, kui riik õue peale ülbama tuleb.

 

Lühikokkuvõte: retsilt kuum, Sardiinias kuni 48 kraadi. Sellise kuumusega on nõrga tervisega inimese elu ohus, ning ka tugeva tervisega inimene peab end hoidma ja kaitsma. Kardetakse, et Lõuna-Euroopa tulevikus suvel turismi ei ole.

Kas järgneb ka hullemat sorti metsapõlengute hooaeg, veel ei tea.

 

YLE raporteerib maikuus Vahemerel uppunud kalalaeva kohta, mille ümberminekul sattus Vahemerre kuni 750 inimest (täpset arvu ei teata). Pääsesid 104.

Mõned asjad on kindlad: inimkaubitsejad koormasid laeva üle. Mootor tõrkus. Lõppes joogivesi. Saadeti abikutse. Edasine on segane. See, et laev uppus ja sajad hukkusid on kindel.

Frontexi lennuk avastas laeva 13. mail lõuna paiku. Märgati, et alusel on selgelt liiga palju rahvast. Pärastlõunal avastas laeva Kreeka rannavalve kopter, mis raporteeris et "laev on teel Itaalia poole". Ometigi palus rannavalve kahte lähedal olevat suuremat laeva, et nad annaksid hädas olijatele kütust ja joogivett. Logiraamatud näitavad, et nad kutsuti kohale mitmeid tunde hiljem.

Päästeoperatsiooni mitte käivitamise põhjenduseks ongi saanud lause "laev on teel Itaalia poole". Ööseks saabus pagulaste laeva juurde Kreeka patrull-laev, kuid ei alustanud päästeoperatsiooni, vaid asus laeva pukseerima.

Päästeoperatsioon käivitati, kui pukseeritav Adriana stabiilsuse kaotas, kummuli läks ja uppus. Mõned pääsednud on öeldnud, et "nad vedasid meid liiga kiiresti".

Süüdistuse on saanud 9 inimkaubitsemises kahtlustatavat meest. Usun, et nad ka väärivad süüdistust. Kreeka rannavalve käitumises on aga täheldada tõsiseid kinnimätsimise märke. Võib arvata, et ka seal on keegi, kes väärib süüdistust, kuna ignoreeris sadade inimeste elu ohusviibimist kuni nende surmatunnini. Kas ta saab süüdistuse või sumbub asi ringkaitsesse - ei tea.

 

To summarize: people have known that cows' methane production can be reduced with an appropriate diet for quite some years. There has been a fair bit of searching for what that diet could be - tropical algae from high seas may produce the right outcome but aren't readily available where the cows graze.

It is nice to learn that daffodils also do the trick, and reduce methane production by "at least 30%" (a cautious estimate, some results using artificial cow stomachs have given a reduction of 96%).

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