At 85 dB you’ll have hearing damage from long term exposure without hearing protection. Normally considered 8 hours a day 5 days a week. So 2000 hours in a year. Higher sound levels have a lower threshold so shorter times. 120 dB is the threshold of pain, so immediate hearing damage. Also, dB are a 10x log scale. So every 10 dB is an order of magnitude increase. So the siren is actually about 3000x louder than when you should start wearing earpro.
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ultracritical@lemmy.worldto Technology@lemmy.world•Google to build first subsea fiber-optic cable connecting Africa with AustraliaEnglish1·1 year agoProbably not. Too much alliteration. There is one from Angola to Brazil though!
ultracritical@lemmy.worldto Technology@lemmy.world•Finland detects more GPS jammers as drivers increasingly try to hide their tracks | Yle News | YleEnglish73·1 year agoNot really. Radio power decreases with the square of the distance. So at if “blackout” is at 10 feet then at 100 feet your at 1% of your original power. So realisticly your blocking your GPS signal and partially obstructing signals for 2-3 cars adjacent to you and likely less than that. You wouldn’t be reaching any planes without a lot of power and a big transmitter.
Planes avionics are more then sufficient to navigate and fly the plane without GPS. And planes will most definitely land without GPS as a.) GPS isn’t the predominant tool for altimetry and b.) a plane has to land or it will crash. GPS is primarily used for navigation of routes and most critically for planning approaches and landings. It enables the tower to send an approach plan directly to a plane. So, really important for packing the skies with planes, but a malfunctioning gps unit isn’t going to stop a plane from landing at its designated airport. May stop one from taking off though. This really only applies to big planes. Small planes don’t always have gps and don’t always land at airports using gps. Still really nice to have so you don’t get lost, though.
Accurate GPS is a fairly recent luxury as until the 90s it was made inaccurate by design as only the military could access the full radio spectrum, and only recently has the full constellation of current gen sats been fully deployed. Also interestingly commercial gps receivers won’t function beyond 600 mph and/or 60 000 ft to prevent people from using them for missiles. Military ones (in missiles) or if you home brewed it won’t have this restriction though.
You are right though. Running a jammer is illegal as hell and you can really fuck other people’s day. Especially do not try bring a jammer on a plane. They monitor radio very closely at and around airports. You will be caught and you will be sent to federal “pound me in the ass” prison.
ultracritical@lemmy.worldto You Should Know@lemmy.world•YSK: it's not just Tesla, 1/3 of cars in built in the last ten years have passenger/rear windows that are almost impossible to break in an emergency.2·1 year agoIt have suicide doors? God I miss those. Terrible for passenger safety, but I could fit so much stuff into my ion with those. Made moving with a sedan so much easier.
ultracritical@lemmy.worldto World News@lemmy.world•Young climate activist tells Greenpeace to drop ‘old-fashioned’ anti-nuclear stanceEnglish2·2 years agoIt’s not unfair, nor is it misleading. Coal contains a few parts per million of uranium. Sometimes more depending on source. So when burned this uranium is released into the atmosphere. When used for fission uranium has about 200 million times the energy density then burning the carbon carbon bonds in coal. So kilo for kilo a coal power plant dumps about as much uranium and other nasty trace elements into the atmosphere then a nuclear plant has in it’s core.
The situation is even more unfavorable for coal as nuke plants don’t typically dump any of their primary radioactive elements to atmosphere. Increasing scale of nuclear doesn’t change this either as it would require every nuclear plant on the planet to go full Chernobyl just to match what coal outputs.
Only really counts for feet and inches. But yes, having your base unit be divisible by halves, thirds, quarters, sixths, and twelths with whole numbers of sub units is highly useful when fabricating objects when you don’t have access to modern tooling and supplies. In fact I would argue base 12 is the superior numerical system that was abandoned for metric and we have lost something in the meantime. Though Jan Misali might disagree with his love for sexinal.
Imperial units do have another advantage to this day, though. When talking about machining bolts and threads Imperial use threads per inch or threads per unit length while metric uses the pitch of the thread, so mm in-between threads. This decision means that when machining imperial nuts and bolts we by default pick whole numbers of threads per inch which due to the circular nature of lathes means that a simple clock dial can keep the lead screw synchronised with the head. Since metric uses pitch we pick numbers like 1.25mm pitch which does not always synchronous well with the lead screw and head and requires some odd gear ratios to cut specific threads.