Things that make you go "Hmmmm…"

[Uncwilly]

A small solar field could power a traffic light.
A bunch of "Botts' Dots" leading up to the stop sign would help and not be a speed hump. Or grooving the pavement. on the approach.

[rogue]

Originally Posted by Uncwilly

A small solar field could power a traffic light.
A bunch of "Botts' Dots" leading up to the stop sign would help and not be a speed hump. Or grooving the pavement. on the approach.

A solar cell could be used to put a flashing light around the stop sign. It could be combined with a motion detector. That isn't uncommon in the US. They could probably do something to prevent too much light pollution.

I suspect that a solution like that wouldn't solve the underlying problem, drivers not stopping. They know there is a sign to stop, but are ignoring it.

How about a camera taking photos of the scofflaws' vehicle plates and sending them a ticket? The fine could be large enough to replace the camera that would be broken or stolen by those caught in the act.

[xilman]

Originally Posted by rogue

A solar cell could be used to put a flashing light around the stop sign. It could be combined with a motion detector. That isn't uncommon in the US. They could probably do something to prevent too much light pollution.

I suspect that a solution like that wouldn't solve the underlying problem, drivers not stopping. They know there is a sign to stop, but are ignoring it.

How about a camera taking photos of the scofflaws' vehicle plates and sending them a ticket? The fine could be large enough to replace the camera that would be broken or stolen by those caught in the act.

You are proposing high tech solutions when a low tech solution is simple and fail-safe.

Convert the crossroads into a staggered junction. Motorists now have to stop (or, at the very least, slow down greatly) when moving in the directions which require a sideways adjustment. The NIMBY argument in the report just doesn't hold up. It's an excuse for inaction, not a reason.

There are many, many such junctions in the UK road network. The vast majority of them were created for safety reasons.

[retina]

Use this UV-C lamp to sterilise absolutely nothing.

It's just a disco light with 12 blue LEDs included. You can't expect too much for £16.

Besides, if you can see it with your eyes, then it isn't UV-anything.

[LaurV]

Originally Posted by retina

Besides, if you can see it with your eyes, then it isn't UV-anything.

Put a dollar bill in front of it. If you see the cotton strings, then it is a UV light. It may not be useful for anything, like you say (and most probably it IS unuseful for killing germs), but the fact that you see it, is not indicative of how much UV it emits. There are "bulbs" with very large spectrum, or with more then one "max", i.e. you see it green and it still shots a lot of UV or IR at you...

Swmbo used to work in a pulmonary/tuberculosis clinic for six years before we moved to Thai. Here she is teaching kindergarten kids, it is not really possible to work in a hospital here as a farang, there is a language barrier, a "union" barrier, etc., and she lost - somehow - the touching with the medical world, during 20 years of arguing with little kids , but she told me in the very beginning of the craziness that UV light does wonders (well, it was about Koch bacillus, not corona), they had huge lamps in the hospital, and used them 2-3 times per day each, in a timely sequence, when nobody was allowed to enter the area where the lamp was on (due to danger of burning, cancers, going blind, etc). And this was in the nineties... Also Trump's "clorox" ideas may be not so far fetched, except that not clorox has to be used, but something else. For example, how about methylene blue? This was used for years for disinfection, and also for some internal treatments (there are pills containing it).

(Edit: Disclaimer: by far, not a suggestion. I am by no means qualified in any medical-related field ! I just repeat things I heard here and there...)

[retina]

Let's derive GR, SR, c, QM, E=mc², ... everything, from a single rule.

Wolfram Physics Project Launch

[xilman]

Originally Posted by LaurV

There are "bulbs" with very large spectrum, or with more then one "max", i.e. you see it green and it still shots a lot of UV or IR at you...

I believe I've already recounted the tale of my experience with a xenon-arc lamp. They emit copious amount of visible and IR light, so much so that UV-stimulated fluorescence is completely drowned out unless the long wavelength radiation is removed. Without removal, the lights are dazzlingly bright white and very hot.

Isolating the UV with a quartz prism spectroscope let me see fluorescence in my cornea quite clearly. It's not an experiment I ever repeated nor do I want to do so in future.

[Uncwilly]

Originally Posted by retina

Besides, if you can see it with your eyes, then it isn't UV-anything.

I can confirm that germicidal lamps do produce in light in the visible spectrum. That is actually how they get checked often. The glow that can get emitted from a sterilization chamber lets the user know the lamp is working. The 4 lamp chamber that I used in the lab had a procedure for taking 3 lamps out, bypassing the interlock and leaving it open just a bit (a few millimeters), then plugging it in. The reflected glow emitted established that the lamp worked. Repeat for the other 3 lamps. Using a white paper to intercept the emitted light works nicely and keeps the users' eyeballs out of the blast. No need to turn off the lights or cover the windows.

[retina]

Originally Posted by Uncwilly

I can confirm that germicidal lamps do produce in light in the visible spectrum. That is actually how they get checked often. The glow that can get emitted from a sterilization chamber lets the user know the lamp is working. The 4 lamp chamber that I used in the lab had a procedure for taking 3 lamps out, bypassing the interlock and leaving it open just a bit (a few millimeters), then plugging it in. The reflected glow emitted established that the lamp worked. Repeat for the other 3 lamps. Using a white paper to intercept the emitted light works nicely and keeps the users' eyeballs out of the blast. No need to turn off the lights or cover the windows.

The review video showed a real UV-C LED and mentioned that it can't be seen. So there are often normal light emitters placed beside it to indicate that the invisible UV-C is active.

No doubt UV bulbs will operate differently and have a different output spectrum.

[kriesel]

Originally Posted by retina

No doubt UV bulbs will operate differently and have a different output spectrum.

Quite so. Lots of spectrum lines in mercury vapor lamps; UV, VIS, IR.
https://www.newport.com/f/mercury-arc-lamps
The sort of UV bulb one might buy to make partygoers' clothing fluoresce include filter coatings. Ordinary fluorescent bulbs intended for visible light production are lined with material to raise the visible output and block the UV output. As it ages it gets worse at visible light production and worse at UV blocking. UV leds I've bought down to 300nm or slightly lower nominal wavelength have enough of a longer-wavelength portion of their output spectrum that there's some visible illumination, through UV-blocking protective eyewear, which can have optical density ratings of several for UV. (OD 1 is a power of ten attenuation, OD2 is a 100fold etc.)

[Uncwilly]

PEDAL POWER ADVOCACY thread forked,
https://mersenneforum.org/showthread.php?t=25502