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Cake day: June 16th, 2023

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  • With refresh rates like that, you must be talking about LED billboards.

    These are different from consumer monitors, which mostly use constant LED backlights and a liquid crystal layer to determine color.

    An LED bilboard is going to have a fuckton of singular LEDs - each of which can emit exactly one color - arranged in groups to form full pixels capable of displaying many colors. There is no extra LCD layer between your eyes and the billboard LEDs.

    The reason for the high refresh rates is because each led must be extinguished and and relit to redraw the image, and the eye is very good at picking up this strobe effect.

    The difference vs. a consumer display is that the backlight in a typical monitor is constant. Refreshes the screen involves sending updated instructions to the LCD layer, twisting the crystals and possibly changing the color they allow through.

    To make a crude concrete example:

    Imagine I am shining a white flashlight in your face. In front of the flashlight I put a colored piece of plastic so the light hitting you is colored. Then I change the plastic to one with a (slightly) different color. I do this 120 times per second. That is a typical consumer display.

    Now imagine I am shining a colored flashlight directly in your face. Then I turn it off and grab a flashlight of a different color and shine it in your face. Imagine I do that 120 times per second. That is an LED billboard.

    Which do you think is more likely to give you a headache?

    One final complication - the brightness of the LEDs is variable over time, they received a modulated signal rather than a steady voltage, so at lower refresh rates there will be a noticeable ripple across the image, similar to how early CRT screens could look.

    Increasing the refresh rate hides a lot of these problems.




  • TheChurn@kbin.socialtoMemes@sopuli.xyzWATER
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    10 months ago

    There are plenty of things that can cause fires that are not oxygen, and don’t contain oxygen.

    The halogens, Fluorine and Chlorine in particular, are powerful oxidizing agents on their own and can produce flames in the same manner as common flames.

    Here’s a report on the spectra of flames produced by combustion in a Fluorine atmosphere (PDF warning).


  • Not quite. First, the vast majority of Iraqi equipment was Soviet, and the vast majority of the stuff that wasn’t Soviet was French.

    French contractors even built the air defense network and control center.

    Certainly there are tensions in Iraq as a result of it coming in to being as a constructed nation - nowhere did I say otherwise. However that doesn’t justify a war of aggression against a neighboring country.

    Further, Iraq’s casus belli had nothing to do with having a potential ‘claim’ to Kuwait’s land. Kuwait sovereignty pre-dates by centuries. The real reason was Kuwait’s refusal to write off Iraqi debt and refusal to lower its oil product (it was producing above its OPEC quota - depressing prices and hurting Iraq’s exports).

    It is true that Saddam thought the West was using OPEC and Kuwait to undermine Iraq. That may be true. Putin thinks the West is using Ukraine to undermine him - so should we stop supporting Ukraine and let Russia annex it?










  • Most of the combustion products from gas are ‘clean’ - water and CO2. They don’t contribute to particulate air pollution.

    CO and NOx are output in much smaller quantities, and are contributors to air pollution, but not to particulate air pollution.

    From the tailpipe, the only real particulate matter is a very small amount of soot, and this is a small fraction of the overall combusted mass - engines are designed to minimize soot in order to increase performance and fuel efficiency.

    Tires and break pads, in contrast, simply abrade into the air essentially in their entirety.