Recent comments in /f/askscience
Old_comfy_shoes t1_j640w89 wrote
Reply to comment by Seraph062 in How hot is the steam coming out of nuclear power plants? by ivy-claw
How do you make sure your steam gets to 500C?
tdmonkeypoop t1_j63v923 wrote
Reply to comment by gandraw in Why do sample return missions such as OSIRIS-REx use their own reentry vehicles instead of just going to the space station for pickup and return with ISS equipment? by PromptCritical725
Ok.. Socrates!! Dudes over here playing 4D chess like he's dust in the wind or something
Seraph062 t1_j63qqh0 wrote
Reply to comment by Old_comfy_shoes in How hot is the steam coming out of nuclear power plants? by ivy-claw
> But usually it would only be a little bit hotter in conventional use. 300C seems like a lot though. Idk anything about reactors, but I think they plunge massive insanely hot rods into water?
You generally want steam for turbines to be pretty hot, the ones I'm familiar with usually run about 500°C. There are a few reasons for this, hotter steam is generally easier (and more efficient) to extract energy from, it's also better for the turbines because droplets can cause damage and higher steam temperatures help avoid droplet formation.
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appame t1_j62rl03 wrote
Reply to comment by Taalnazi in Biologically speaking, what makes men typically stronger than women? by Erratic_Noman
Yes. Every hormone in everyone varies. Natural hormone levels change over time (minutes, hours, days, months, years). The relative amounts do sit in particular ranges, and those ranges vary between men and women.
HRT I don't know much about, but I assume so. I believe one issue is that it lacks the variations of natural hormone secretion. But that's way out of my wheelhouse.
Top_Shelf_Jizz t1_j62pwd5 wrote
Reply to comment by SerinaL in Ask Anything Wednesday - Economics, Political Science, Linguistics, Anthropology by AutoModerator
Mama and papa are the two most universal words. The theory is that those sounds are the easiest for a new mouth to create and that we have given them immediate meaning in our environment.
Top_Shelf_Jizz t1_j62prnv wrote
Reply to comment by ElonBlows in Ask Anything Wednesday - Economics, Political Science, Linguistics, Anthropology by AutoModerator
Sure it is! Just look at post pandemic. High inflation globally can lead to recession when people with flat earnings decide that they can’t afford to spend that money and decide to save. Families decide that they can’t afford to buy a new car or move into a larger house because their collective salaries are 9% less valuable in the US or 40% less valuable in Turkey. The unemployment rate can actually decrease with people getting jobs who were previously retired because now their retirement or social security isn’t providing them with enough to live on and we could still enter a recession if collectively we feel like we need to save instead of spend.
Flannelot t1_j62nuux wrote
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AndChewBubblegum t1_j623zs4 wrote
In short, yes, it's most likely true that nonhuman brains can be lateralized in function.
For a very simple example, damaging the visual cortex of animals unilaterally (only on one hemisphere) will result in unilateral blindness. This indicates that visual information is processed on a hemispherical basis.
lmxbftw t1_j623uu9 wrote
Reply to comment by Krail in How do we know that the biggest known stars are actually so big and not just regular sized ones at the end of their "life"? by realzanji
It's about 6-7 times further out than the heliopause. (The heliopause is far from spherical, since the Sun is moving relative to the ISM, but from the close part of it.)
Krail t1_j61z616 wrote
Reply to comment by Flannelot in How hot is the steam coming out of nuclear power plants? by ivy-claw
So, to make sure I'm understanding this correctly - One form of reactor has superheated water kept under pressure so it won't boil, and that superheated water heats another body of water that does boil, and then a different type of reactor directly boils the water without that intermediary step?
Krail t1_j61yhi4 wrote
Reply to comment by lmxbftw in How do we know that the biggest known stars are actually so big and not just regular sized ones at the end of their "life"? by realzanji
How does that compare to the further most reaches of the solar system? (Like, to the Heliopause? Is that the considered the edge of the solar system?)
Lindseydanger007 t1_j61rsk4 wrote
Reply to comment by LittleCreepy_ in What determines whether we can create a vaccine for an illness or not? by ShelfordPrefect
>irus. You can actually get bit and then go get the vaccine and be saved. That’s part of the reason we can be vaccinated for it. A primed immune system can still have time to react and clear
your explanation was very clear - you did great.
could we kill HIV with radiation in the same way we kill cancer cells? Why isn't that on option - other than obviously radiation isn't ideal in any situation. But would it hypothetically be an option?
neffs t1_j61r4m8 wrote
Reply to [Electricity and magnetism] For a half-wavelength dipole antenna, why is the voltage distribution a quarter wavelength out of phase with the current? by VainVeinyVane
Read the last part of the description of the gif;
Dipoles have relatively high Q factor so the amount of energy stored in the standing waves is large compared to the energy added each cycle by the feedline, the feed voltage just represents a small perturbation to the standing waves. This is why the voltage standing wave is much larger than the voltage step at the feedline. Since the standing waves are storing energy, not transporting power, the current in them is not in phase with the voltage but 90° out of phase.
"Q Factor"
VainVeinyVane OP t1_j641t7v wrote
Reply to [Electricity and magnetism] For a half-wavelength dipole antenna, why is the voltage distribution a quarter wavelength out of phase with the current? by VainVeinyVane
OK. Got the answer. For anybody who stumbles upon this question and has the same question: Current is proportional to direction and concentration of charge, whereas Voltage is only proportional to concentration of charge.
So when the electrons "bounce" off the end of the end of the antenna (the wave is reflected), the NEGATIVE of the wave is reflected for current (since the direction reverses!), while the POSITIVE of the wave is reflected for the voltage.
For example:
if the wave is cos(wt-kx), the reflected traveling wave is -cos(wt+kx) for current, while the reflected wave for voltage is +cos(wt+kx).) The resulting standing waves formed are one with peaks at the ends for voltage, while the current's resulting standing wave has its peak at the center and nodes at the ends.
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The graph for current, cos(wt-kx) - cos(wt+kx) will be 2sin(wt)sin(t). This is a standing wave with nodes at the ends of the antenna.
However, the graph for voltage, cos(wt-kx)+cos(wt+kx) will be 2cos(wt)cos(kx). This is a standing wave with the node at the center of the antenna and peaks at the ends (90 degrees shifted from the current standing wave).
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Hope this helps!