Why It Was Almost Impossible to Make the Blue LED
redjard @ Redjard @lemmy.dbzer0.com Posts 2Comments 443Joined 2 yr. ago

Why are you flagged as a bot?
The easy to show part was the second sentence of my comment.
This is really useful physics trivia, because the basic truth is easy to show from a simple law, but the detailed explanations go quite in-depth.
With lenses, you trade bewteen angular accuracy and light density.
For a challenge, try it with LEDs. Where do you find the source "temperature", you can get from focusing an LEDs light?
22Ah at 4.35V would be 96Wh, which iirc is just under the limit of 100Wh you can take on flights in the us, and thus the limit for basically all laptops.
There is a cool easy-to-show fact that you can never make something hotter than the light source my focusing its light.
Since otherwise you could take heat and divide it into a hotter and colder region, decreasing entropy without using energy.
In light of the current drama, could you maybe elaborate on your run in, and repeat what the deleted reply by stamets was?
1.18.0 doesn't show that for me, neither does 1.19.0
The version update notes said "removed because android doesn't do that anymore" or something like that. It might depend on the android version, which is extra stupid because many roms don't enforce that restriction, and you can mod that restriction out if you have root (which is part of many general root/lsposed modpacks).
I am running A13, but I was running A10 before and that didn't show it either
In my experience that is quite rare though. Probably less than 10% of the downgrades you'll do will actually not work.
On the other hand if the app has important data you want to preserve, the other ways of doing so are a) hunt down the apk manually, with the fdroid website not having a convenient download button for older versions, or b) use something like neo backup to make a backup, uninstall, install the older version, and revert the backup except the apk. Both are 1 minute for what could be one button press.
Edit: looking at the fdroid page the download buttons are there now, still you need to search up that page, it'll probably still take a minute using that method. Why use fdroid if you need to google apks like a caveman in the end anyway?
Then make it an option in the experimental section of the settings.
If an app cannot accept the updated data, if it has even been launched in the new version, the worst that can happen is that it doesn't work. You can still uninstall, or you can clear the data. You can also pop up a warning before downgrading, explaining the possibility of needing to clear the apps data.
It is still an essential feature for many.
Uninstalling and reinstalling is not only inconvenient, it can also change values like the apps id, that can be essential for advanced users.
For me, the app had an update that removed a feature I relied on without replacing it, making it worse as a result. This therefore makes a valid example to the point made above, that people may not enable automatic updates because updates aren't always better, sometimes they make an app worse.
Not long ago I watched the fdroid app itself enshittify.
I was testing an update of another app, saw it didn't really work yet, went to roll it back, and the downgrade button was gone. So I tracked down why and found fdroid had removed it. So I went to downgrade the fdroid app and the downgrade button was gone ...
Had to hunt the bare apk and downgrade manually.
I'm still on the old fdroid version procrastinating looking for an alternative.
Which of the two?
DroidRec works for me. I have quality on normal, codec on default, and record stereo. Selecting just mic or device audio and mic records to an m4a file.
E: smt simple voice recorder v5.12.3 works fine on default settings too for me
Simplest path is probably to use the old simple mobile tools recorder app on fdroid, which won't be getting any updates. Fossify will likely release their recorder app very shortly, which will essentially be the next update for the smt recorder app.
It is already under active development, they just haven't gotten the first release yet.
Edit:
Another interesting one is DroidRec. It is usually used and seen as a screen recorder, but it has three simple toggles for screen video, device audio, and microphone. If you turn off screen and device audio, it becomes a very nice voice recorder.
It's there for ancient compatibility reasons and recreated when steam starts, iirc. I've looked a bit into removing it last year but didn't get far
Absolutely nothing of relevance happened closer to the start of the industrial revolution than to when we figured out the greenhouse effect today
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I've just stumbled over Floorp, which to my understanding has many of Vivaldis features Firefox doesn't, like a sidebar, and is based on Firefox
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They are using repeatable builds, so the fdroid version is signed by fossify. You can update between github, izzy, and fdroid, and in the future likely also google play, if they release there.
I dug up the meta discussion on it. Mentioned there is the issue to add reproducible builds to the phone app, which is marked complete since that was released on github and izzy last week.
Further for me the app is marked installed on both entries in fdroid, which means the fdroid and izzy repos should serve bit by bit identical apks, from my understanding (the installed mark being based off of the apk hash).
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They are using repeatable builds, so the fdroid version is signed by fossify. You can update between github, izzy, and fdroid, and in the future likely also google play, if they release there.
I dug up the meta discussion on it. Mentioned there is the issue to add reproducible builds to the phone app, which is marked complete since that was released on github and izzy last week.
Further for me the app is marked installed on both entries in fdroid, which means the fdroid and izzy repos should serve bit by bit identical apks, from my understanding (the installed mark being based off of the apk hash).
I'll try to take a more nuanced and in depth look.
As a start, I'm relatively sure the main use of a large chunk of agricultural land is solely food production. A cursory search gives data like this image
from this page.
It's reasonable to assume some of the plant waste of food crops feeds some of the livestock, but if that much land is exclusively used for animals it would seem reasonable we could at least double the human plant food production with a reduced animal portion in that land use.
From a pure energy efficiency perspective animals are around 10%, so if you take half of produced plant calories and use them for animals, that will result in 10x fewer calories of animal products than the other half of the plants. This lines up with the energy spread by end human food product, which seems to be something like this:
By the raw numbers and that coarse approach we expect 75% ⸱ 10% : 25% ≈ 1:3.3, the actual data seems to be slightly worse at 1:4.
So it seems to me we are using something like 25% of the land area to produce 80% of the food, just by not passing it through animals. And if you are right then some of the animal calories are even supplemented with the plant waste of those 25%.
The raw energy approach is actually quite a good approach by now, because we can use technology to transition most things into each other. You can pass plant waste into animals and loose 90% of the energy, or convert cellulose into (digestible) sugar and get the full energy. Or use it for other things that take energy like drug production. Using the plant waste on animals still brings that opportunity cost that means more land is used in other places to get the cellulose for those alternative uses, or to produce sugar the old fashioned way from more dedicated crops.
Traditionally you had land that you could not use for agriculture but could use to graze goats, you had plant material you could not use for anything but feeding animals. Animals were our bioreactors to transform that material or land into usable products. Now we have better chains of use.
The energy approach will finally be complete when we can turn plant material straight into animal products, with methods like lab grown meat or artificial milk, but we are not there yet. When we are, the energy balance of those should be close to that of plants and this entire problem simplifies greatly.
Hm, it seems you are right. Not sure how I didn't know that.
So is my understanding correct in that there are 3 groups of substances: vitamins, minerals, essential amino acids; that you would have a bad time without? Bringing the total to calories, vitamins, minerals, essential amino acids, and water?
In that case I suppose a minimum number of Livestock products are helpful in fulfilling that, though as the increase of supplemented products probably reduces the need, the amino acids can still be chemically synthesized, right?. The main criticism is also the amount, we are consuming (way) more livestock products than needed to fulfill nutritional requirements. Especially meat would still be optional, right?
I don't actually have experience with vegan diets, I've always figured eating little meat would get me most of the way with least of the effort.
On earth we have a land shortage. If you grow animal feed, that could have also been a foodcrop. In terms of land efficiency, meat is an order of magnitude less efficient.
Why set it as a dev?