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Joined 11 months ago
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Cake day: July 25th, 2023

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  • I agree with all of this. At the same time, I think that, in most cases, people should allow their body to adapt to heat, if they are healthy enough to do so. Most people can learn to be comfortable in higher heat than they believe, although some people have medical conditions that will make them more susceptible to heat exhaustion and heat stroke. If you can get by without it, you should. If you’re at risk by not using it, don’t feel guilty.

    (FWIW, my office only has a/c because I have a very, very large printer in here, and it tends to have head strikes and scrap prints out if there’s no climate control. But since I’m not printing at the moment, the current temp in here is 82F.)


  • On top of that, as we experience higher temperatures, many people also crank up their air conditioners—which emit more heat-trapping greenhouse gases into the atmosphere.

    This is not correct. Air conditioning units do not ‘emit more […] greenhouse gases’. Air conditioners use a refrigerant–usually R134a–which does have a high global warming potential (GWP) compared to methane or CO2, but that refrigerant is in a closed loop; it’s not going anywhere unless the system is damaged. Most a/c failures aren’t from refrigerant leaking out of the system, and the system no longer being able to effectively transfer heat, but from the compressor motor failing. When the compressor fails, in most cases you can evacuate the refrigerant, replace the broken part, and then recharge the system. (The fact that they can be repaired doesn’t mean that they usually are repaired. Which is shitty.)

    What is true is that a/c units emit heat themselves. An air conditioner moves heat from inside a space to outside of that space; in the process of doing so, the a/c unit itself is creating an additional small amount of heat from the function of the compressor motor, electronics, etc.

    Beyond that, most electricity that’s used to run a/c systems–and every other electrical device–is produced from burning fossil fuels. So if there’s more demand for electricity–such as from a heat dome that has everyone running their a/c full-time–then yes, more CO2 is going to get pumped out into the atmosphere. But if your electricity is coming from sources that are largely emissions-free, like solar, wind, or hydro, then air conditioning is a negligible source of heat.

    tl;dr - don’t feel bad about using your a/c when heat rises to dangerous levels; agitate at a local, state, and national level for renewable, carbon-neutral ways of generating electricity, and for more efficient use of electricity.








  • It’s not free; it’s included in the price. Those are entirely different things.

    As for why someone would want to haul things themselves, well, there are a lot of things that you can not reasonably expect delivery on, or paying another person to haul would be unreasonably expensive for. Does that necessarily make up for the cost of a truck? Probably not by itself, in most cases.





  • I’m pretty sure you’re correct, although I believe that the part that’s capturing photons also needs to be heavily protected from the environment, and you also need something to prevent to many photons from getting to it and burning it out (e.g., almost all gen 3 NODs are autogated so that someone shining a flashlight at you won’t wreck your image intensifier tubes.)

    It’s one of those things that can get pretty overwhelming to try and research as a consumer, because it gets really technical really fast.


  • Okay, so you’re talking about the IR that most people would refer to as thermal, rather than the IR that’s technically NIR, and is used in most image intensification. My mistake; as you say, these things get slippery because most of the time people aren’t talking about specific wavelengths and frequencies.

    Yes, IR-as-in-thermal is going to be stopped by most glass. IR-as-in-NIR-for-NODs is not. The IR lasers and weapon lights that show up very well with NODs are definitely not visible to the naked human eye, so they’re outside of the visible light spectrum, and get generally labeled as IR, even if they’re outside of the spectrum of IR that’s used by most thermal optics. (It would be interesting to see if a Steiner DBAL could illuminate an area that had low IR for a FLIR camera.) And yes, for that, a red dot sight will work, because it will be set to very, very dim; too dim to be seen by the naked eye.




  • because regular glass is usually opaque to IR.

    I’m almost 100% positive that this is not correct, because I’ve been driven around by someone wearing PVS-14 NODs with no headlights, on dirt roads, in a commercial van. (Edit - most red dot sights also work very well with NODs, and those have one or two layers of glass, depending on which type of system it is. The sights that don’t work well usually can’t dim the dot enough to avoid massive bloom.) Glass is mostly opaque to thermal though, and a lot of glass significantly reduces UV.




  • In your previous comment, you were equating “Danger” to “Death Rates.” How often do you hear of a cyclist dying in an incident that doesn’t involve a car?

    First: you said, and I quote, “Riding a bicycle itself isn’t all that dangerous, even without a helmet.”. That is blatantly, proveably false, especially when you say that it’s not dangerous even without a helmet. I’ve broken multiple helmet in multiple single-bicycle accidents over the 20-odd years that I was commuting regularly by bicycle; at least one of those would have very likely have been fatal without a helmet.

    How many cyclists die outside of interactions with cars? In 2001, 44% of fatal bicycle accidents–377 out of 853–did not involve being hit by, or hitting, a car. So, there ya go. Damn near half of cycling fatalities aren’t involving motor vehicles. (The site mentions them as being bicycle transportation fatalities, which seems to exclude bicycle recreation fatalities, but I can’t guarantee that they aren’t including deaths from mountain biking. Per the same source, helmets appear to reduce the risk of brain trauma by about 60%.)

    And if that was a car, do you think she would have survived?

    If she had been in a car, and hit by another car? Yes, I think she would have been fine. Cars have airbags, set belts, and crumple zones. If she’d been hit by a car, while on a bicycle? Can’t say. Statistically? Yes.