Thank you...this sounds like a construction manager that has a vague understanding of HVAC

To one point though servers are more consistent with their heat output and cooling is sized appropriately and generally runs consistently. An airport has more diversity and can rapidly swing from a large load to almost none. A larger volume of air can manage that more consistently.

But yes, mostly the other things

Ahhh, I see. Thank you so much for the insight. This helped

Believe it or not they ventilated mines with fires. It likely started as a way to view what they were mining, but they noticed that the fires created an air current within their mine that drew fresh air in and the hot noxious air was pushed out. Later civilizations also had this same realization. The Greeks had ventilation shafts powered by fire heat. Romans, being engineers, figured out how to use manpower (ie slaves) and plam fronds to waft air along the ventilation shafts. Still mining was a dangerous business and many miners died from various gas poisonings.

For much of history we used simple wax candles for light in the mine. They were dim, but in pitch darkness they were more than adequate. Luckily candles really don't consume that much oxygen, much less than a human would. So there really wasn't any indications that candles were a risk.

not all life requires oxygen, for some organisms it is toxic. oxygen is an extremely corrosive chemical that gives off energy (exothermic) when you combine it with just about anything. it is very abundant on earth and in the universe, but not always in a form that can be easily accessed. interestingly, the first organisms on earth used sulphur, which is directly below oxygen on the periodic table, so a lot of similarities.

And then the power went out, the people left, the building froze, the pipes burst and all hell broke loose :)

I worked for 8 years at a software company working with reformers in the medical system trying to fix how the active learner and "resident" system works. It was pretty disturbing to learn how things work at a typical learning hospital. Especially frightening was discovering that "evidence based medicine" is (was?) still a relatively fringe idea that there was large resistance to. The system sucks. I live in Canada where the learning system is a bit better, but we have a significant brain drain problem where Canadians attend a relatively affordable medical program here and then move to the states to earn the big bucks in the private medical system.

They were heavy armored and the jousting lance were of a soft wood. They would break very easily and the one who broke his lance on the opponent was awarded the winner.

Source: I read this in a museum in germany were many armors and tournament weapons were on display.

AlphaPhoenix has an amazing video on the topic. It's also extremely closely related to Simpson's paradox in statistics. minutephysics also does a good video on that where he puts together an extremely simplified example of you you can draw from different datasets to get different results.

The overall idea is this: if you make sure that for every 10 Democrats in a district, there are 11 Republicans, then the Republicans are more likely to win that district. You repeat this for as many districts as possible. You obviously can't guarantee this for all districts, especially if there are more Democrats in the state than Republicans, but you can shove all the remaining Democrats in the few remaining districts, so even though those districts are nearly guaranteed to go Democrat, they are the minority of the results for that state.

As a simplified example, let's say there are 6 districts with 11 voters each. Districts 1 to 5 (or A to E if you prefer to avoid confusion with the numbers coming up) have 5 D voters and 6 R voters that so 5 out of 6 districts end up Republican. The last district has 9 D voters and 2 R voters. This district is a landslide D result, but it doesn't matter because R wins 5 to 6. If you actually count up the R voters, there are 32. However, there were 34 D voters in the state. So D should have won.

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Besides, the participants were literally the warrior class, practicing for war was an important part of proving your value to your liege.

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For those unaware of what this entails

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Old mining tunnels were certainly a nightmare. But they did know how to ventilate them. They would sometimes dig a vertical shaft connected to a tunnel and set a fire in it. The fire would draw air in, and send smoke up. They could configure it so that it drew air from the working face, and sent it up and out.

Mines didn't have torches, they had small lamps. It was dark and hellish. Miners had short lives.

😐

Gerrymandering is the act of drawing political boundaries that benefit one party by creating districts that are biased toward that party.

For example, say Democrats are 55% of a state. It's possible to draw districts so that only 25% of the districts are majority Democrat. So you'd end up with a state where 75% of elected representatives are Republican, but only 45% of the actual population is Republican.

Nitrogen in the air is in the form of N2 and it rather stable because it has a triple bond between the N atoms. It takes more energy to break the N2 triple bond and bacteria have been selected to do that energy requiring step. It gets broken down in the soil by bacteria in to amino-compounds which are more easily reactive and accessible for the plant. It's all governed by thermodynamic. For the plant, it is easier to take up N from the soil because it is usually broken in to molecules that are only single bonded to it and N has an extra pair of unpaired electrons that plants access much more easily and with a favorable thermodynamic.

The canning process kills bacteria with heat (the jars are “cooked” in hot water) and then vacuum seals the food so there’s no oxygen to give life to any remaining bacteria to live on.

The little pop when you open a jar for the first time is you breaking the vacuum seal and letting fresh air in for the first time since the food was put in there.

the fact it has been sealed for that long means no air not additional moisture got in. most food products are packaged in a way that it removes air/humidity and sterilized(often thru the process we call Pasteurization).

as long as the product remains sealed(before you 1st open it yourself+ the packaging is undamaged) you can generally be safe in the knowledge it will be good at least until their "best-by" date and that it hasnt been tampered with.

tho fair warning, depending on how it was stored, this doesnt mean it still "good", temperature extremes can alter the charactirstics of the product.

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You can if you live on a farm and have a fireplace or a wood-buring stove. However,

• there are more people today than in medieval times;
• they are packed into cities;
• those dwellings do not typically permit the burning of coal or wood for heat (they use modern gas-fired forced air and steam heating systems, most of which also require electricity to operate);
• the wood consumption for the population would require significant deforestation, even if everyone had a wood-buring stove (which they do not);

So, you can't use medieval heating methods (burning wood) in densly packed cities whose dwellings aren't designed to burn wood for heat.

2 of the 3 biggest advances in power in automotive engines today compared to those of the mid 20th century are efficiency changes. Fuel injection has gotten better, whether compared to earlier fuel injection or to carburetors. It can atomize fuel into smaller, more uniform particles and disperse them with more precision during the proper part of the cycle. Stronger, lighter materials and lubricants with less friction have become standard, losing less power to parasitic power loss, and the third thing is less efficiency related, but tighter tolerances, more precise control of fuel delivery and valve timing, and stronger materials have led to the compression ratio of a regular passenger vehicle today exceeding that of performance cars back in the previous century, while staying on the same grade of fuel.

The send one fellow in nonburning oiled cloth to detonate small pockets. Sometimes they died