It looks like you are using this one: ArctiClean 1
Which seems to be specifically made for this application and supposedly consists of “citrus and soy based solvents”. Aluminium is solved by highly acidic (like sulphuric acid) and highly basic (like sodium hydroxide) solutions. Which it really doesn’t sound like until it somehow broke down in a way it got more potent.
Was it maybe a specific thermal paste with a metal like mercury or gallium inside? Supposedly they can quickly dissolve aluminium. Of course, I don’t know what happened but maybe it was dissolved by the cleaning solution and then rapidly reacted with the Aluminium of the heat sink. If so, that would still make me wonder about the bubbling and foaming when the cleaning solution comes in contact with the left overs.
I would assume that nobody makes thermal paste out of anything terribly reactive, but… That .gif looks like something out of a NileRed video.
IIRC, gallium makes aluminum get super brittle, which might cause it to crumble like that; but the foaming makes me think that the heat sink might have managed to oxidize all the way through, and it’s aluminum oxide reacting with the cleaner.
I can’t get your images to load, but to me, a materials chemist, it definitely sounds like you’ve managed to dissolve the aluminium and copper by using an acidic solution. Presumably, the cleaning solution contains some electrolyte that should help dissolve oxides, but if the solution is corrosive enough to oxidise the aluminium and/or copper the electrolyte will make the reaction more aggressive by rapidly dissolving the protective oxide layer as it is formed, such that the aluminium/copper is further corroded.
To be fair, this is just speculation based on what I’ve read here. I could maybe give a better analysis if you let me know what solution you’ve used, and what the heat sink/paste were made of, and if I can get the pictures of the resulting product (“ash”) to load.
This seems brilliant, I wonder what will be the efficiency of such system, it seems like it could almost power itself as long as you supply it with salt water (and have the Fresh water column outlet lower than the inlet). What am I missing?
Hi, could you expand on your question (or questions) in the main post? The more clear your questions are, the easier it’ll be for someone to address them. Thanks!
you’re seeing elecrochemical corrosion. if you scratch aluminum in such a way that:
oxide layer is removed, and
finely divided copper is deposited, and
oxide layer can’t reform
you’ll see rapid corrosion of aluminum. normally, alumnium doesn’t corrode because of very tight oxide layer. here, oxide layer is removed first by scratching and this also deposits copper in electrical contact with aluminum. then, citrate can bind aluminum removing some of oxide layer, making aluminum more exposed and so more reactive. if you used gallium as heat transfer compound (sp?) then gallium will also disturb oxide layer and make corrosion of aluminum faster. copper elements are in this case actually protected from corrosion (by dissolving aluminum)
I don’t know if anecdotal stories are allowed here, but I grew up in Florida before the rise of A/C (no air conditioner in school until 7th year, no house with central air until I was 25. Didn’t really ever sweat until I was 20, though I can now quite normally.
My ex and husband are both from “up north” and both suffer so much more in the heat and the humidity. I suffer so much more in dry and/or cold environments.
Not completely convinced it’s biology - there is a trick to being really still in the shade that seems to sort of cool off/slow down the body. It could be behavior differences. But does seem like they are built differently, thicker and warmer, I am built more spare and cooler.
It is worth dehumidifying a building always though! It’s not good for the materials. Always fighting mildew in the houses before the central air. Everything is so much easier to maintain with the A/C.
Ignaz Semmelweis tried to convince the medical establishment that washing hand stop’the spread of disease in hospitals. His colleagues responded that doctors are gentlemen and gentlempdo not have dirty hands. Semmelweis was committed to a mental institution soon after and died from an infection as a result of a beoti’he received from institution workers. A few decades later the four humors school of medicine was replaced with diseases caused by microorganisms.
Imagine living at a time when the germ theory of disease wasn’t widely accepted. You might even need to convince people that microbes exist. If they already know about microbes, they might believe that microbes spawn out of thin air through abiogenesis. Previously that word was used when talking about microbes spoiling food whereas nowadays it’s applied to the early stages of the earth.
This isn’t exactly a ‘science debate’ but I’ve met several people that still think the ‘Great Wall is the only man made object visible from orbit.’ I read somewhere that may come from a dream some Chinese king had like 1000 years ago.
Almost crazier than flat-Earth in terms of being easily disprovable just by thinking about it for 20 seconds, but people have stated that to me as a fact and were kind of incensed when I explain it’s obvious nonsense.
Personal favorite is probably Lamarckian Inheritance. Feels like super buff people having wimpy ass babies would key people in that acquired traits weren’t being passed on.
But it’s also the textbook example of how science progresses even when the underlying model being used is incorrect. Darwin credited Lamarck for suggesting a potential mechanism for evolution. Works prior to Mendel were direct tests to Lamarckism. Mendel responded to those, and on and on it goes. Lamarck helped push the field along and that’s great.
Side note, people like to say epigenetics is a continuation of Lamarckism but I’d disagree completely. Heritability of traits is what is important here, and epigenetic marks don’t necessarily tag the genes that contribute to the traits themselves.
The funny thing about heliocentrism is, that isn’t really the modern view either. The modern view is that there are no privileged reference frames, and heliocentrism and geocentrisms are just questions of reference frame. You can construct consistent physical models from either, and for example, you’ll probably use a geocentric model if you’re gonna launch a satellite.
But another fun one is the so-called discovery of oxygen, which is really about what’s going on with fire. Before Lavoisier, the dominant belief was that fire is the release of phlogiston. What discredited this was the discovery of materials that get heavier when burned.
Not any kind of expert, but this seems wrong to me. My understanding is that heliocentrism vs geocentrism is about the whole solar system, ie: the same frame of reference.
So if you were launching a satellite, yes, you would use earth as your reference point but that is NOT geocentrism. You would never use a geocentric model. Ever. Not these days anyway.
Again though, I'm not an expert so maybe don't take this as law
You're absolutely right. Heliocentrism and geocentrism aren't "questions of reference frame", they're cosmological models.
Nobody is using a geocentric model when they launch satellites, as any geocentric model that works with our existing observations of the universe ultimately does not have a functional understanding of gravity. And it will be remarkably difficult to keep a satellite in orbit if you disagree with the universe about how gravity works.
“‘There was some wonderful stuff about [railway trains] too in the U.S., that women’s bodies were not designed to go at 50 miles an hour. Our uteruses would fly out of our bodies as they were accelerated to that speed.’” From: www.wsj.com/articles/BL-TEB-2814
There were (and are) a ton of utterly ridiculous beliefs about what can cause harm to women, but I find this one particularly amusing in an age where millions of women fly on planes. Imagine the plane takes off, leaving all those wayward uteri spinning in the dust at the gate…
Like... they did realize any acceleration strong enough to cause your uterus to go flying out would also be strong enough to make all your other internal organs fly out too? And that men, in fact, have internal organs?
Some beliefs along these lines have been used more recently in extremely religious places like Saudi Arabia.
"If a woman drives a car, not out of pure necessity, that could have negative physiological impacts as functional and physiological medical studies show that it automatically affects the ovaries and pushes the pelvis upwards,” ...
“That is why we find those who regularly drive have children with clinical problems of varying degrees,”
Not exactly a scientific debate, but among the general public there was strong opposition to the idea that rocket engines would work in space, where there’s “nothing to push against.” Famously, the New York Times editorial board mocked Robert Goddard (the rocket scientist that now has a NASA space flight center named after him) in a 1920 article:
“That Professor Goddard, with his ‘chair’ in Clark College and the countenancing of the Smithsonian Institution, does not know the relation of action to reaction, and of the need to have something better than a vacuum against which to react — to say that would be absurd. Of course he only seems to lack the knowledge ladled out daily in high schools.”
The New York Times eventually formally retracted that op ed, on July 17th, 1969 - while the Apollo 11 crew was already en route to the moon. The retraction is pretty funny:
Further investigation and experimentation have confirmed the findings of Isaac Newton in the 17th century and it is now definitely established that a rocket can function in a vacuum as well as in an atmosphere. The Times regrets the error.
Goddard wasn't just another rocket scientist, he was the inventor of the liquid fuel rocket! And he also made a ton of other key discoveries about rocket design that formed the groundwork for rocketry as we know it today.
A) Brain. You can train yourself to use more of your whole field, but you’ll lose that attentional “spotlight” that you normally aim at things and picks out all the detail.
If you’re ever scanning something like a thick tree, looking for something, hold your arms out and form your fingers into a square frame. Use this to further focus your attention, and scan the tree in a more methodical way by moving the finger frame. You are more likely to find the thing you are looking for this way.
I kind of feel the opposite. There are literally invisible spores that float around the air that can spring to life in the right conditions. Until you discover the means of transport, spontaneous generation is a hypothesis that matches the facts.
I’m sure there’s a physical answer as to why a spherical lens can’t focus the entire image (or maybe it can, physics is not my area and I think it shows haha).
But the biological explanation is that your retina isn’t uniform, instead you have a very small region called fovea where the vast majority of your cone cells are concentrated. If you could take an instantaneous snapshot of your vision, like a picture, you’d be scared to see that everything is grossly blurry and distorted save for a very small circle where the image is very clear - that’s the fovea. Your brain takes multiple images where different parts of a scene are focused on the fovea to create a composite end result that looks better. The rest of your eye still captures light, but with less detail, and therefore it’s mostly dedicated to getting broad positioning of objects, noticing fast changes in movement, tracking peripheral motion, and so on - not on focusing on text or small details.
Curiously, you also have a circle that would be completely black if your brain didn’t fill it in - it’s the blind spot left by the insertion of the optical nerve, where your retina can’t capture anything.
you’d be scared to see that everything is grossly blurry and distorted save for a very small circle where the image is very clear
This is what interests and distresses me about the mysteries of the human body. I once saw a video about capturing a person’s recollection of his memory of a video clip by scanning his brain activity. The result was really obscured and blurry, but it actually did resemble the clip, which was deeply disturbing. I would have never known my actual vision is vastly different from what my brain makes me perceive to be.
What you perceive is vastly different than a continuous filmstrip. Have you ever tried to watch unstabilized footage from a person jogging? Totally unwatchable! But your brain smooths it out better than the best steadicam. Tilt your head from side-to-side: what you perceive stays upright. And of course you know hat your eyes don’t smoothly pan from subject to subject but are constantly “saccading” around, but your brain processes that all away.
Visual processing is amazingly complex. Its also interesting that our other senses have different levels of processing. Our sense of smell is nothing compared to a dog’s, our sense of hearing is nothing compared to a whale’s, etc. A metaphor I heard once (don’t know how accurate it is) is that when a human walks into a kitchen they might smell that a stew is cooking. A dog would smell both the overall smell but would also smell the individual carrots, peas, chunks of meat, etc.
I think a useful way to think about it is that your perceptual brain isn’t in the business of making you see, or hear, or anything like that - it’s in the business of giving you an accurate-enough-to-be-useful idea of what’s around you. You see the world as being sharp and stable and consistent even though the literal visual signals going from your eyes to your brain aren’t… because the world is sharp and stable and consistent. Or at least it’s enough those things that it was useful for the brain to evolve to generate that specific perceptual experience. The signals coming from your eye are just (some of) the information the brain uses to generate that experience.
Your eyes have a central area of the retina called the fovea which is more densely packed and has much higher acuity than the rest of your retina. That’s the area you use to pay close attention such as for reading or hunting for food. The rest of the wide field of view is more useful for detecting movement than anything else.
It’s not a flaw—it’s just the best solution for the problem of survival.
askscience
Oldest
This magazine is from a federated server and may be incomplete. Browse more on the original instance.