That's true, but those uses of the word are pretty obscure. I would say the most common meaning of "toot" in the UK is the noise a horn makes, especially a bicycle/car/train horn.
Some of us who have been on Mastodon for a few years now insist on calling them toots, despite the official renaming in the original Mastodon repo. A toot is the sound elephant friend (our mascot) makes with their trunk.
Also it's silly and all of the other silly associations you have with it are a plus. "Twitter", "tweet", "google", "facebook", "amazon", "apple", "mac", "tumblr", "kindle" are all also pretty stupid names we've just gotten used to, but "toot" is OUR stupid name, and we made it ours, and if its silliness delays the corporate takeover of Mastodon, that's a huge plus.
I don't like the idea of Twitter-like quoting. Linking to the original toot is fine, it's clear that there's a link.
The Twitter-like quoting was used way too much for abuse. It had legitimate uses, but the abuse it generates does not warrant the legitimate uses.
Plus, it always made things so weird to read.
2. The reply
1. The original
3. The replies to the reply
You say you find linking confusing right now, but it's just a matter of getting used again to the idea that links exist and can be followed, without always having a link preview. I find Twitter-quoting confusing because it messes up the order of the conversation.
This has been discussed to death on mastodon already. However recently the mastodon devs added this feature to their short list of what they are working on. (I think they said they are “exploring” it.)
Quote toots offer a functionality not offered by other functions, which is the ability to show two toots at once as well as notify the original toot owner of this activity. Linking another toot has a pretty horrible UX in comparison. Last time I clicked on a linked toot, it opened a new tab to view it, and then in order to click like on that toot I was instructed by the UI to copy the toot address to yet another mastodon window in to the search bar. An absolute mess.
Quote toots allow side discussions while allowing everyone to see what is being discussed. And they’re great when someone has a long thread and you want to pull out one piece to share with your followers and add context like “this piece of the puzzle is particularly important.”
The fact that it changes the order of the conversation is the point. Conversations fork in ways not always conducive to a reply-only view.
I primarily want quote toots so I can quote myself to start fresh threads that build on old ones. I did this all the time on Twitter where I posted a thread of updates for every evening that I worked on a project, with a new thread quoting the last one for each new evening. Since replies and links don’t show the other posts, it’s not as clear what I’m talking about when I link to an old toot and say “I made progress on this project tonight” given the awful UX on link toots.
The recent wave of Twitter immigration has reignited the quote-toot discussion. People mostly want a silly copy of a half-baked Twitter feature. If we get something like it in Mastodon, I hope it's better thought-out. For example, editing toots was done in an entirely sane way: it's just plain possible to edit toots, and if someone edits a toot you boosted, you get notified, so people can't fool you initially and then insert a completely different idea in your timeline.
Don’t want to start a side discussion here, but what I like about quote tweets is that I can see the quoted content without having to click out to another tab and go back and forth. Could probably handled with some auto-expanding by clients though.
Looking at this Safecast map, do you know how these values are collected? From the path it looks like it's some kind of mobile collection where user submit data? Are there people walking around with Geiger counters every day?
Can you tell me how to find other stations with the Safecast map?
Rosenthaler Platz station is just blue all-around on that map - maybe I'm doing something wrong?
I don't think I'd worry about that from a radiation standpoint. Natural uranium is only around 1000 times more radioactive than natural potassium, it's really not very bad in that sense and it wouldn't have survived from the birth of the solar system to the present day if it was.
On the other hand, it is a toxic heavy metal so please, please don't eat it.
And you'll get a lot more of that potassium into your body than uranium. So long as you don't eat such low-level things they're not a threat. (And, personally, I'm not convinced there's any threat. All of our estimates of the threat of radioactivity are based on high level exposures. IIRC it's about 100 Sieverts = 1 death. We project that linearly into the lose dose realms that are effectively impossible to test, but we have some data points that suggest the linear projection is not accurate and low level exposure is of much lower or possibly even negative threat--that the body's reaction to the low level radioactivity actually is protective. There is no relationship between cancer and background radioactivity. The threat of radon noted in uranium miners only shows up if they're also smokers--huh??)
Yes, Fiestaware. Where the most popular color was red, which originally used natural uranium oxide as the pigment in the glaze. It was actually WWII that saw the US government confiscate their stock of uranium in 1943. They used depleted uranium from 1959 to 1973 when the finally discontinued the red color. And an estimated 2 million pieces sold between 1959 and 1969. [1]
And people collect them. I remember being a kid and looking at my grandmother's display of plates and being told they were radioactive. But only a little. You can also still find them on eBay easy enough.
A family I knew in Montgomery County, Maryland, dumped the pepper out of its Fiestaware shaker and took it to a fire station's test-your-stuff day. My recollection is that the pepper was not hazardous.
I don't know why. Perhaps because I never heard of hazardous substance days at firehouses elsewhere. Perhaps because it sounds less as if I made up the story.
Interesting. I have heard about this famous speech many times but I have never made the connection to the pastry "Berliner" (or heard anyone mention this association).
Also, as a native German speaker, saying "Ich bin ein Berliner" is not unusual if you are talking about being a citizen of Berlin.
I don't think that was a common association at the time as well. Especially since (pastry) "Berliners" are not called "Berliners" in Berlin but "Pfannkuchen" instead.
I suppose that raises the question, if people from Berlin do indeed call themselves Berliners - do people from Hamburg call themselves Hamburgers? (genuine question)
I don't see why not. Hamburger means "of Hamburg". If you're thinking about the food item, it isn't a funny coincidence or anything, its name is derived from Hamburg.
Berliner and Pfannkuchen are very different pastries (at least in the Northwest of Germany). Pfannkuchen literally implies it is made in a pan, whereas a Berliner is typically deep fried. It often has a fruit jelly filling, but you will also find those without a filling.
I agree that no native speaker would think of the pastry when hearing "Ich bin ein Berliner." Just like I wouldn't think of a sausage if someone were to say "Ich bin ein Frankfurter."
> There is a widespread misconception that Kennedy accidentally said a malapropism that he was a Berliner, a German doughnut specialty. This is an urban legend which emerged several decades after the speech, and it is not true that residents of Berlin in 1963 would have mainly understood the word "Berliner" to refer to a jelly doughnut or that the audience laughed at Kennedy's use of this expression.[2]
Buying a Berliner in Germany can be very challenging if you travel a lot. There are so many words for it depending on the region. At least: "Berliner", "Krapfen", "Pfannkuchen", "Kräppel", "Küchli" and probably others I don't know..
I have seen Heroes that are much more like hoagies and I am seeing Heroes like the Greek rap depending on where you are in the countrymy point overall is there doesn't seem to be definitive things or just a lot of regional uses and spellings of these differentfood types by region so if you're cleaning that there's only one it probably means you haven't traveled enough
The terms are unrelated [a sandwich named hero predates the appearance of the Greek item]; though they may sound the same depending on how they are pronounced. A hero is just a submarine sandwich by another name. A gyro is a pita-wrap --mostly pronounced like the 'gyro' in gyroscope but also like /yirou/ or /hirou/
I've never heard anyone use it myself, but then I've never tried to order the sandwich otherwise known as a sub in the parts of the country where that name is used.
That's what someone who grew up in Berlin would probably say, but the city being what it is it genuinely depends on which shop you're standing in. I've seen it every which way.
I've seen them sold here in Berlin under the names "Pfannkuchen" (not to be confused with pancakes), "Krapfen" (not as rude as it sounds in English), "Amerikaner" (not to be confused with an oversized iced soft cookie), and "Berliner" (not to be confused with the alcohol).
This isn't true.[0] The difference between "Ich bin Berliner" and "Ich bin ein Berliner" is that the former says that you literally are from/living in Berlin, and the latter means you are figuratively speaking as like a Berliner. "Ich bin Clown" means that your job is to entertain people with face-paint on, whereas "Ich bin ein Clown" means that you sometimes behave clownishly.[1]
The source [1] is misleading to the point of being wrong. It is perfectly valid German to say "Ich bin ein Student" meaning that one is indeed a student. "Ich bin Clown" is not grammatical at all.
Actually, the traditional stuffed donut-shaped fried pastry without hole is called pancake (Pfannkuchen) in Berlin whereas at other places of Germany a Pfannkuchen is the sweet soufflé-like thing you make yourself in the pan called Eierkuchen in Berlin and elsewhere. Just saying, as native Berliners won't understand or take orders for "Berliners".
FWIW, I'm not a native speaker but I did study German in high school and college, and used my moderate proficiency extensively while traveling in Germany (including Berlin in 1990), and Austria, and living in Prague.
I've laughed with native Germans about the JFK speech (which story was first related to me by my hs German teacher), and regardless of its provenance / veracity, it makes for an interesting discussion. :)
There's also a European liquor, bright blue in color, aptly named "Blau" (which word, "blau", is slang for drunk or intoxicated).
As for varieties of sausage, "wieners" (Wien/Vienna), and Frankfurters (Frankfurt) were referred to as "hot dogs" by Parisian college students jokingly(?) describing their mysterious ingredients... (citation needed, but I did read that in a seemingly-reputable magazine.)
It's strange that the count increase too much near the wall.
If you have a 1/r^2 decreasement from a point source, the if you have an infinite wall it becomes a constant value that does not decrease with the distance.
Clearly the wall is not infinite, but when the distance from the wall is much smaller (1/5?) than the distance to the border of the wall, the approximation is good enough. The wall is like 8 tiles tall , so I expect the radioactivity at 1/2 tile (15cm, 5in) to be almost equal to the radioactivity when the counter is touching the wall.
Good question. Another intuitive way to view (no pun intended) 1/r^2 law is that the solid angle visible from an isotropic emitter (like supposedly this wall) gives the exact decay coefficient. So near the surface the solid angle is like 1/2 sphere (1/2 4pi), and doesn't change much with distance. Only when you get a bit further away it starts to decrease.
Eventually at large distances, any finite object will have the apparent radius decay as 1/r and solid angle as 1/r^2.
I think in this case it could be atmospheric absorption or just getting near a peak point of emission.
Does that apply if the emitter is neither coherent nor opaque? If we were interested in gamma radiation, is the sum from each part of an infinite wall infinite (if we pretend the wall and the air are perfectly transparent to gamma rays)?
Note that in this case radiation is definitely incoherent. This rule applies to incoherent isotropic emission.
The coherent case is similar I believe, but because for an antenna (emitter) the field is usually tangent to the surface, you get some additional trigonometric factors (not purely solid angle). But by my calculations it's still 1/r^2.
Am I doing a calculation wrong then? For e.g. gravity towards an infinite plane, then the force is finite because components in opposite directions cancel out, but for radiation, then if you're 1m away from the wall, you could consider an infinite set of disjoint squares on the wall, each 2^n meters by 2^n meters and with the furthest point 2^(n+1) meters away from you. Since 2^2n / ((2^(n+1))^2) is 1/4 and an underestimate for the radiation you would receive from each section of wall, then the total radiation should be infinite.
Oh you might be right! I think what I wrote is incorrect in this case.
For gravity, it's clear the orientation of a small surface doesn't influence its gravitational force. In fact the source can be replaced by a point of equivalent mass.
For radiation, it seems the angle of a surface matters? For example, lambertian surfaces (everyday diffuse surfaces) do depend on their angle for total incoming radiation? Does only reflection exhibit lambertian behavior? There's something funny at work here.
In the lambertian case, there's a cosine term making your terms go to zero and sum converge.
When observing a small oblique (lambertian) surface, you get less radiation by a factor of cos(angle). I believe this is true for black body radiators as well (think a small glowing plate emitting red light). I'm not completely sure it would be true for x-ray and high energy radiation, and intuitively I suspect it indeed isn't. It seems like for high energy emissions, or generally isolated emissions (discounting opaqueness), only the total power is relevant like in gravity. I think self-absorption might be the culprit here.
If we say self-absorption (material absorption) in the high energy case is roughly negligible, then it becomes more strongly non-lambertian and the received power is simply a 1/r^2 integral (which would also explain why radiation gets stronger as it approaches the surface).
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Here's a simple proof of the solid angle formula I've found I believe is correct for lambertian surfaces: chop your object into infinitesimal pieces (limit goes to 0). For each piece, it tends to behave like a point, so we expect the radiation scaling with distance to be 1/r^2. But solid angle also scales as 1/r^2 for small enough pieces. (it's probably missing many technicalities to make the proof work, but I think it works). Note that for oblique surfaces their solid angle is a function of cos(angle), which follows Lambert's cosine law exactly as well.
> If you have a 1/r^2 decreasement from a point source, the if you have an infinite wall it becomes a constant value that does not decrease with the distance.
It will still decrease with distance. If you represent the wall as a collection of point sources distributed over a plane, as the distance to the plane diminishes, the distance to individual points do not diminish to and from the same distance as each other, and do not diminish at the same rate. However they still all diminish, and thus the sum intensity must diminish. Though the appropriate function describing the sum of the contributions from each point is no longer 1/d^2.
There will be some continuous equation to describe this... someone more familiar with radiance feel free to chime in!
They’re referencing a classic Electricity & Magnetism proof. Given an infinite sheet of uniform charge density, the electric field is constant at all distances from the sheet, which is deeply unintuitive.
That is unintuitive, but then is my mistake only in representing the wall as an infinite plane? Would my parent comment still be true for a finite plane, or is that merely technically true but missing the point of the function shape being almost constant up to some threshold (depending on the limits of the finite plane).
I feel like I want to plot this now to build an intuition.
If you're looking down at an infinite plane, then the plane occupies half your field of view (assuming you have a 360 degree field of view) no matter how far you are from it. Given a 2d object of uniform density, the component of the gravitational force towards that object in the direction perpendicular to the plane it lies in is proportional to the solid angle of your field of view it occupies. For an infinite plane, the components in other directions cancel out. I think this is related to how a sphere acts equivalently to a point at its center - an infinite plane is just a sphere of infinite radius.
The situation is similar for an opaque light source (apart from the lack of atmosphere in the way, I don't think the sun would be much brighter if you were much closer to it and looking through a pinhole), but I'm not sure it applies to gamma radiation which is emitted uniformly in all directions from each point and treats most stuff as pretty transparent - unless there's some weird interference you don't get to cancel out the parts coming from different directions.
Yes, I actually kind of get the infinite part, but thanks for the explanation it's interesting. I was wondering what the intensity looks like for a distance field around a finite plane and how that relates. This might be harder to describe.
What I'm suspecting is that under a certain distance for a given finite plane it's almost constant similar to the infinite version, but outside of that distance there must be some non uniform falloff function.
You are correct. For a short distance it's a almost a constant 1 like an infinite wall with the same charge density. For a long distance is almost 1/r^2 like punctual source. For an intermediate distance, it's a mess and you hope nobody ask for an exact solution.
A rectangle is a mess. It's easier with a circle. The approximations at short and long distance are the same, but a circle has an "easy" formula in between. http://hyperphysics.phy-astr.gsu.edu/hbase/electric/elelin.h... 1-x/sqrt(x^2+R^2) where R is the radio of the circle. Let's use R=10 to keep it simple.
There are some trick to add more term to the approximations to reduce the middle part where both approximations are bad, like using A+Bx or A+Bx+Cx^3 for short distance and D/x^2+E/x^4 or D/x^2+E/x^4+F/x^4 for long distance. It depends on how much you care about the precision and how many calculations you want to do.
In some particular cases like a circle or the shell of a sphere there are closed formulas for the intermediate distances. In other cases there is no nice formula.
For a finite circle, where you're on a line perpendicular to it going through its center, the gravitational force you experience towards it is exactly proportional to the amount of your field of view it occupies - if I'm right, that should be proportional to `1-cos(atan(r/d))` where r is the radius of the circle and d is the distance between you and the center of the circle.
Yes, I understand that. I'm wondering separately (in a vacuum if you will), what the falloff looks like with a finite plane, and how that relates to the infinite version. Obviously we cannot actually represent the wall as an infinite plane, from my current location it's accurate enough to represent it as a point source... so there is some threshold for a particular finite plane after which the "constant" nature is clearly not true.
> Auch an einem eher ungewöhnlichen Ort haben die Mitarbeiter der Behörde schon Messungen durchgeführt. Der U-Bahnhof Rosenthaler Platz rückte wegen seiner vielen orangefarbenen Kacheln ins Visier der Behörde. „Die Farbe wird mit dem Schwermetall Uran hergestellt, weil es beim Brennvorgang sehr hitzebeständig ist“, sagt Leps. Die Strahlung ist laut dem Experten jedoch belanglos. Auch für Menschen, die sich länger auf dem U-Bahnhof aufhalten, besteht keine Gefahr.
In short: "According to experts the radiation is trivial."
If I'm not mistaken that's 0.1137 milisievert / hour. Meaning you have to stand glued to the tiles for about 4 years to get the LD50 lethal dose of about 4000 Sievert. Also, the lethality of the dose only really applies when the exposure is short.
Or, alternatively, the average yearly background radiation of about 2 milisievert takes about 18 hours of being glued to those tiles.
The real danger is the tiles, it's that throws something hard, shatters one of the tiles, releases dust, and someone breathes the dust in.
I'm actually astounded this is allowed to be there in a public place, because at home you can reasonably expect protect against someone shattering a tile, but in public? One drunk guy is all you need.
That's most likely the reason they are still there, because of how much more hazardous it would be to attempt to remove them.
Then again there are well practiced methods for removing sources of similarly hazardous air-bourn particulates such as asbestos, i'm not sure how much difference there is between the two beyond the low risk of pure exposure (inhalation being the serious risk here).
> Then again there are well practiced methods for removing sources of similarly hazardous air-bourn particulates such as asbestos, i'm not sure how much difference there is between the two beyond the low risk of pure exposure (inhalation being the serious risk here).
There's also the difference that this is a U-Bahn station in use, in the rough middle of a line. Closing it down for a prolonged period of time, and fully sealing it from the rest of the line to avoid the spread of dust through the metro tunnels would be a significant and disruptive undertaking.
Even if it happens from time to time, the amount of dusk is going to be ridiculously small (you don't release that much dust from damaging a rock, let alone glazing, unless you grind it).
And keep in mind that this is a subway station, places where the pm2.5 levels are routinely extremely high because of the dust released by train breaks, so a microscopic amount of uranium dust is really negligible in such an environment.
I imagine some drilling would create quite a nasty cloud. Of course this would require being oblivious of composition by magistrate and allowing it, which I don't think is the case here. Still, at least put on it some hard transparent protective paint, I am sure there are things for that.
The average, of course, is just that, an average. There are some places that are naturally around 100 mSv dose annually, or some 50x higher, and places that are much lower than average. Under truly non-ideal conditions, like having a poorly-ventilated basement made out of uranium-rich limestone, it could probably get even higher than 100 mSv a year just from the radon.
Speaking of which, radon gas is the main way in which uranium affects the health of people. Depending where you live and the construction methods, it may be worth getting your basement checked, and ventilated properly if necessary.
Even the extreme scenario there is still far short of causing acute radiation sickness. People who live in such regions are sometimes exposed to such levels their whole lives, which can still be long and healthy. But not quite as long and healthy as those without such exposure, on average.
EDIT: Someone linked to the Wikipedia article for uranium tiles, which says that the majority of the radiation comes from the decay products and is beta radiation[1]. Beta radiation has a weighing factor of 1, which makes your calculation pretty much correct!
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EDIT 2: Looking more closely it appears that the dosimeter in the video is switched to µSv/h, so it's reading 0.1 mSv/h anyway and the whole discussion below can be skipped if you're not interested in the difference between Gy and Sv.
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If I remember my lectures correctly (Wikipedia did help me here), the conversion is 1 Roentgen ~ 00.1 Gray (Gy), which is a slightly different unit from Sievert (Sv).
1 Gy is 1 J/kg of absorbed energy, however the biological effects change depending on the type of radiation. Sv is Gy adjusted by a weighing factor. It's 1 for gamma rays, where 1 Gy = 1 Sv, but for alpha particles it's 20 [0].
Uranium-238 emits alpha particles, which get stopped by a few cm of air or even dead skin. So the effective dose you are receiving from the decay of U-238 is probably closer to 0 mSv/h.
Or, if you eat it and it's inside you, 2 mSv/h, at which point you should probably be quite worried.
The decay products of U-238 however are beta emitters, which changes the calculation again. The beta particles can penetrate the skin, but the weighing factor for beta radiation is 1, so it can reach you but is also less dangerous.
So what's the actual final value? I honestly don't know, radiation can be complicated, and I just wanted to share the difference between Gy and Sv!
An idea for Berlin police looking to move on those pesky loitering youths in the station, charge them with triggering an INES incident. (Giving themselves a dose of radiation exceeding annual limits by leaning against the wall.)
They are using different and not directly convertible units.
Roentgen (R) used by the instrument only measures exposure, but this is not the same as absorption which depends on the type of radiation, the type of biological tissue exposed, the duration of exposure etc. The parent is using Sv which measures absorption for the purpose of more usefully assessing biological risk. I'm not sure how the parent is converting them, there are probably some good rules of thumb.
Here's a screenshot of the highest reading I saw (11.37) and an english overlay of possible units it can display. It's hard to see the button positions.
They're switches, and it looks like it's set to mSv/h based on your English overlay. So 11.37 mSv/h, or .01137 Sv/h - about 4 1/2 times the level of the typical background radiation.
The overlay gets that position wrong -- it's µSv/h (microsieverts, the transliterated legend is "mkZv/ch".) 11.37 mSv/h would be a radiological incident. The Australian lost density gauge capsule from a couple of days ago was 2-5 mSv/h.
Hmm, 3 mSv is supposed to be the average annual background radiation absorption for humans [0], that's roughly 0.000342 mSv/h. Which would make 11.37 mSv/h 33245 times greater.
At the other end of the scale the minimum annual dose with a clear link to increased risk of cancer is supposedly 100 mSv [1]. But the risk is different depending on the distribution over time, so if we make it hourly for comparison that is 0.0114 mSv/h making this reading about 1000 times higher than that risk threshold (but the risk is over a year is effectively assuming continuous exposure).
Seconds or minutes isn't going to be terrible, but in only 9 hours leaning against it you would get a years worth of high risk cancer dose!... I'd stay away from the wall. happy to be corrected, this stuff is hard to interpret if you are not an expert. The falloff is really fast though, so it's basically harmless if you are just walking through... maybe the original intent was to stop people touching the walls :D like an electric fence without the need for power.
Background radiation is less than 3.5 mSv/year, or less than 0.0004 mSv/hour. So if these tiles radiate 11.37 mSv/hour that would be 28 000 times more than background radiation !
The LD50 would apply to effects of acute radiation sickness. However, given the long duration exposure, it would increase your relative risk of stochastic effects, like cancer.
Hm.... I've spent a lot of waiting time in this station (Rosenthaler Platz) over the years.
And these tiles (in different colors though) are in a considerable amount of Berlin subway stations. Are they all radioactive like these here? Or is it only caused by the orange pigment?
There are around half a dozen or so homeless people sleeping in this particular station every night, way more now during winter. I'm worried about them. Not like they didn't have enough issues besides the walls they sleep next to being radioactive.
Ah that's actually my local ubahn station. I assume the risk is pretty minimal. Unless you spend a lot of time in close proximity to those tiles. Like some homeless people seem to be doing.
Quite a few homeless people stay around for the entire day in this station, leaning against these tiles all the time. Would anyone be able to tell if this is a health risk?
If they are always sitting in front of the tiles, leaning on them with their back, they might have higher skin cancer rates on their back.
But generally, the effect of frequent low doses isn't very well understood, and you could even find specific circumstances where it might be beneficial.
This is great, nice find. I grew up with Uranium-based Fiestaware in the house, and I am looking at a radioactive red vase right now. My dad was a ceramics engineer and researcher. He wrote the book on red ceramic glazes (The Defiant Red), and there is a whole chapter on Uranium.
I was at an antique store where they had numerous pieces of Uranium glass glowing under a UV light last weekend.
I think it's funny that Uranium has this connotation of "glowing in the dark" which has nothing to do with the nuclear properties at all but rather very interesting optical phenomena that happen when you have an atom with a huge number of electrons like the way Thorium Oxide is good for gas lamps because it emits thermally in the visible range but not so much in the infrared.
That Pu238 pellet is surrounded by ash, I think they buried it in ash to hold the heat in and then uncovered it so you could see the glow. In this case it is driven by heat transport so the bigger of a mass you have the more the ratio of volume to area and the more it heats up.
That's very different scaling from this kind of thing
A person running around Berlin with a Geiger counter (not on official business) is a CCC kind of hacker.
Of course this comes to us via Jonty Wareing (@jonty@chaos.social ), who is involved with the related EMF ( https://www.emfcamp.org/ ) event in the UK.
The Suffix "social" means "this is the social media (mastodon) host".
In fact it says here https://chaos.social
"chaos.social – a Fediverse instance for & by the Chaos community"
EDIT: Someone linked to the Wikipedia article for uranium tiles, which says that the majority of the radiation comes from the decay products and is beta radiation[1]. Beta radiation has a weighing factor of 1, which means it's about 0.1 mSv/h. For comparison Wikipedia says:
"90 μSv/h: Natural radiation on a monazite beach near Guarapari, Brazil."
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EDIT 2: Looking more closely it appears that the dosimeter in the video is switched to µSv/h, so it's reading 0.1 mSv/h anyway and the whole discussion below can be skipped if you're not interested in the difference between Gy and Sv.
==========
Seems to be milliroentgen/h according to another commenter, which is an older unit. Today you'd use Gray (Gy), which is 1 J/kg of energy deposited in material, and Sievert (Sv), which is Gy adjusted by a factor to account for different radiation types and body parts to get comparable biological effects.
For soft tissue (~= humans) 1 R = 0.01 Gy, so the dose would be ~0.1 mGy/h.
Converting that to Sievert is more complicated. Uranium is an alpha emitter, for which you'd use a weighing factor of 20 [0], getting 2mSv/h.
1 mSv/h = "NRC definition of a high radiation area in a nuclear power plant, warranting a chain-link fence." [0]
However alpha radiation also gets blocked by very flimsy barriers, such as a few cm of air, or the layer of dead skin cells on your skin. So the effective dose might be closer to 0!
You also have to consider that the decay products or Uranium are beta emitters. Beta rays have a weighing factor of 1, but they do penetrate deeper (stopped by a few feet of air, can penetrate the skin).
The real effective dose in Sv depends on the exact ratio of decay products to U-238, and how deeply the beta rays of those products penetrate your body (there's different weighing factors for different body parts!).
In conclusion: probably not too much, but radiation and radiation shielding is a complicated subject we managed to spend a whole semester on.
I'm very surprised that radiation workers are allowed half the dose which is directly linked to cancer. Especially because you get that dose in two years, imagine how much you get over a 40 year career.
Generally kept lower than that. Exceeding the human exposure threshold for a worker amounts to an international nuclear incident. Literally. Must be reported and the IAEA will do a full investigation and eventually assign it an International Nuclear Event Scale number. (7 = Chernobyl. 2 = Worker dropped a small vial of tritium gas and breathed it in.)
The "banana equivalent dose" is an error that refuses to die. Based on tables that estimate the effect of various radioactive isotopes acting for 50 years, people ignoring physiology decided that the average K40 in a banana will produce 0.078 microsievert of damage (rounded to 0.1 because it's close enough for jazz and comics).
The reality is that, due to homoeostasis, the excess potassium you ingest is eliminated the next time you piss, so there's no accumulation inside the organism. Those 50 years become something like 12 hours and the radiation exposure is more in the ballpark of 0.00000213 microsievert.
But that value is now too small to use it in science fanboyism, isn't it?
"For radioisotopes of elements that are under tight homeostatic control by the human body, the inhalation or ingestion risk coefficients given in this document may not be appropriate for application to some exposure scenarios. For example, the ingestion risk coefficient for ^(40)K would not be appropriate for application to ingestion of ^(40)K in conjunction with an elevated intake of natural potassium. This is because the biokinetic model for potassium used in this document represents the relatively slow removal of potassium (biological half-time of 30 d) that is estimated to occur for typical intakes of potassium, whereas an elevated intake of potassium would result in excretion of a nearly equal mass of natural potassium, and hence of ^(40)K, over a short period." - ["Federal Guidance Report No. 13: Cancer Risk Coefficients for Environmental Exposure to Radionuclides"](https://www.epa.gov/sites/default/files/2015-05/documents/40...) - page 16
So, if you accept that the duration of exposure from eating a banana is 12 hours instead of 50 years, a dental x-ray is the equivalent of eating 2,347,417 bananas.
Kraftwerk famously sing about above ground trains, with "Trans-Europe Express," the freeway, with "Autobahn," and radioactivity, with "Radioactivity," but nothing I know of about the subway.
There is a guy on youtube called "Radioactive Drew". He has some interesting episodes exploring former/current uranium mines and other things related to radioactive substances. He has a video about a postoffice in Burbank California with similar radioactive tiles on the walls. https://www.youtube.com/watch?v=tuZzOVxreK4
I would say a truckload, because bananas radiations are making just a bit more crack noises than the background, here the Geiger counter go crazy. But without the background reading and units it's hard to tell
Serious answer would be, it depends on the underlying soil. Granite is particularly radioactive, to the point that yearly exposure to background radiation in Scandinavia (a granite penninsula) would be considered as crossing threshold of general population exposure to artificial sources (i.e. over background) in my country.
Also, famously, the dose of radiation in one of the long term storage facilities nearby (measured on the floor, outside containers) is lower than in the main church in that town, which, you've guessed it, is built from granite blocks.
A major rock-forming mineral is Potassium Feldspar (K-spar to geologists). The weathering products of K-spar include many varieties of clay. Those, in turn, wind up incorporated in sedimentary rocks
When logging a well for permeability -- an activity that occurs for both hydrocarbon and geothermal projects -- detection of radio-emissions due to K is an indicator of sedimentary strata that are unlikely to have much permeability because the clays clog up the fluid-flow pathways.
Many (or most) of the natural marble kitchen countertops are radioactive, especially the dark spots. Perhaps not hazardous, if epoxy glazed.
If I were to build a house, I would walk all materials with a geiger counter, especially alpha particles. Sometimes difficult to replace material, if it is already worked into the structure.
Many antique pendants, earrings, etc., used Uranium Oxide orange paint.
Orange is actually a difficult color to make. Another dangerous orange is Cadmium Orange (I used to be an artist, and probably breathed in the paint, as I used it in an airbrush).
There are other stations on the U-Bahn with uranium tiles too, you can find them with the crowdsourced Safecast radiation map: https://map.safecast.org/?y=52.5002&x=13.4852&z=13&l=0&m=9