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@sga013@lemmy.world

(Earlier also had @sga@lemmy.world for a year before I switched to @sga@lemmings.world, now trying piefed)

  • 38 Posts
  • 236 Comments
Joined 1 year ago
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Cake day: March 14th, 2025

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  • fun fact, days have actually been getting longer pretty much since formation of earth (well moon to be correct). reason iirc is that moon is slowly moving away from earth, and this results in some dynamics changing and as a result earth spins slower. like billions of years ago, it was closer to 23 hours.

    ps - very rusty memory right now, should have skipped writing instead of half borked fact



  • From the reports that i have read (am indian), 20+ generics are expected, within roughly 2 months or so, with previous price being something along 10k INR (roughly 100USD) a month to about 3-4k INR (30-40 USD) a month. Drugs have always been kinda cheap here (as an example, a simple paracetamol (tylenol) tablet costs 1 INR (~1cent US)), so it is still expensive (for vast majority, it is more than 2-3 days of work), but much better. hope people use this cautiously though with reasonable expectations.






  • I have 2 lines of though to explain this, both going totally different ways.

    I am not a chemist, and polymeric science is arguably my worst. so take everything with lots of salt

    I do not know your sex (yes), but for the first one it maybe matters.

    Humans basiccaly have best perception of greens. we have 3 kinds of cones (color detecting cells) and it is basically blue and green and a little redder green (it effectively works as red detector), and we percieve much better granularity in green color spectrum. also those who are female at birth are better at this (some source that i remeber said something in line of 10x more colors observable by females than males). so it is possible all kinds of dyes degrade, and wwith greens you are better able to percieve it. this is in theory testable by perfectly caliberated camera and lighting and displays, and measuring the pl response (doable in a lab setup).

    more likely reason is dyes degrade. dyes are often organic (organic in sense of carbon containing) aromatic or more generally resonant structures designed to have absorption in specific ranges. the wavelengths they absorb the most, or reflect or transmit (as in allow it to pass) determines their colors. for example, our sun has peak emmision around green wavelengths, and life on earth evolved too roughly reject that (they absorb lower and higher wavelengths, if they absorb the most common, they probably die faster). if i remember correctly, organic dyes in paint often absorb the wavelength and then emit (resonance, the color being the resonant frequency) the light, so green dyes get the most common light (assuming the paint is applied on a surface recieving sunlight, if not, with leds for example, it is a bit bluer), and hence has a higher degradation rate. dyes degrade by general oxidation or any other chemical reaction, and that could also be possibly more likely on certain pigments as compared to others, and thegreen one just might be more reactive one. If pigment is inorganic, then it is whole different can of worms - whatstarting compound - lets say FeO (II), which may oxidise further (green -> brown) or something else.

    Without much to go by, there are just so many possibilities.













  • not my domain, so i looked the title online (the original article is in nature, and not open access, and currently not in uni, so can not access through uni wifi)

    here is a theoretical version establishing physics for this effect - https://arxiv.org/pdf/2505.23083v1

    I am also not reading the linked article, as it is too flowery for me.

    so here is a tl;dr - if you know seebeck effect, this should be somewhat easy. seebeck effect is a effect where if there is a temperature gradient in a material, electricity can be generated. i will not go on about why that happens, but as a statistical argument, just keep in mind that as things are heated, they jiggle (very specific physics term, definitely not me stupidifying oscillations). if it is a “bond” between two atoms (aptly named atomic bonds), we consider a quantisation (fancy way to put number to how strong the vibration is, there is more to it, but not for now) of these oscillations as phonons. another thing is that in materials, these bond are often arranged in some special manners. for most materials, these arrangements are periodic lattices, (think junglee gym bars or rubik cube or some other periodic arrangement). in these materials, phonons can often transfer in different modes, always trapped by the ends. in some materials, these bonds can form helices, where phonons instead of going in straight line, will travel across the helix. if you know what angular momentum is then great, if not, think something with some “speed” going in circles. in that case it will have some angular momentum along the axis of that circle. coming back to main topic, here we have some phonon going across helix, having some angular momentum. now essentially this motion of phonon can create spin current. this requires us to go into separate tangent, abou what spin is, which is well hard to explain. in most materials, there are 2 types of electrons, and we just name these 2 spins up and down (and it has practically nothing to do with up or down directions). as to why there are only 2, is a really big topic we are not going into. but roughly, it is because of nature of material. in non magnetic materials, they behave same, but in magnetic materials, they do not. in some other words, you can say magnetic materials are magnetic because these 2 spins behave differently in these materials. in normal current, we have electrons going from 1 direction to another (kinda, but that is tangent to tangent, not going there). in spin current, these 2 electrons flow in opposite directions. since both are electrons, there is no charge difference created, a spin potential is created. this tudy showed that in non magnetic materials (tungsten and titanium), you could generate spin currents by “injecting” a angular momentum from quartz crystal phonon. if yo have ever heard of angular momentum conservation, this is a consequence of that, as spin current is a kind of angular momentum.

    as to why this could be special, spintronics (the name for using electron spin instead of charge for generating currents and making devices) requires lower power than electronics. one of the problems was that you required special magnetic materials, this is a demonstration without magnetic materials.

    in my physics world, this is big (in a scale of 1 to 10, 10 being theory of everything done, 1 being boring desk work - this is 5-7 - very big in spintronics, and reasonably big electronics), but to someone outside -not that big, like for decade(s). we made first transistors in 50s and 60s, an reasnable electronic devices (the semiconductor chips) by 70s and 80s. we made first spin transistors in 00-10s so i guess another 10 or so years before we see some industry level production.