For Questions That Don't Merit Their Own Thread

[kerbiloid]

Georgia (country) is going to grow vine on Mars.

https://translate.google.com.tr/translate?hl=ru&sl=ru&tl=en&u=http%3A%2F%2Fwww.interfax.ru%2Fworld%2F617848&sandbox=1

Spoiler

If melt some ice and solve the Martian ground, they can also make Borjomi

HCO3-	3500—5000
SO4-	<10
Cl-	250—500
Ca2+	20—150
Mg2+	20—150
Na+	1000—2000
K+	15—45

 

Edited June 21, 2018 by kerbiloid

[K^2]

^ Grapevine, specifically, since Georgia is known for their wines and brandy.

[TheDestroyer111]

If a nuclear reactor gets rid of primary loop water (the water in contact with the core), how are radioactive elements typically removed from it?

Edited July 1, 2018 by TheDestroyer111

[ARS]

2 hours ago, TheDestroyer111 said:

If a nuclear reactor gets rid of primary loop water (the water in contact with the core), how are radioactive elements typically removed from it?

The water in direct contact with the core is used to generate steam for turning the turbine as well as for cooling the core. Some reactor employ liquid cooling system that's separated from core liquid, but some has a system where core liquid is used directly as a steam before being cooled and put back into the core. Not all nuclear reactor use water as a cooling medium, there's also gas-cooled reactor, which uses carbon dioxide gas. It is common for medium active wastes in the nuclear industry to be treated with ion exchange or other means to concentrate the radioactivity into a small volume. The much less radioactive bulk (after treatment) is often then discharged. For instance, it is possible to use a ferric hydroxide floc to remove radioactive metals from aqueous mixtures. After the radioisotopes are absorbed onto the ferric hydroxide, the resulting sludge can be placed in a metal drum before being mixed with cement to form a solid waste form. This solid waste can then be stored in nuclear disposal facility and handled like any other solid radioactive waste such as depleted fuel rods

[Xd the great]

23 hours ago, TheDestroyer111 said:

If a nuclear reactor gets rid of primary loop water (the water in contact with the core), how are radioactive elements typically removed from it?

@ARS the elements need to be decayed into less harmful stuff. So it takes thousands if not millions of years.

[ARS]

47 minutes ago, Xd the great said:

@ARS the elements need to be decayed into less harmful stuff. So it takes thousands if not millions of years.

That's why it's concentrated into radioactive sludge first and solidified to make it easier to store. Most radioactive waste storage bunker is designed to keep radioactive waste safe and store them for decaying, which does take thousands or millions of years. In fact, one of the problem in storing nuclear waste is finding a way how to make the storage site still obviously dangerous for millions of years, since a warning sign of "Danger, nuclear waste disposal area" won't last very long compared to the time required for complete decay. Those radioactive waste could outlast human civilization, and due to the length of time involved, liquid isn't the best form for storing radioactive stuff for that long

[kerbiloid]

13 minutes ago, ARS said:

a way how to make the storage site still obviously dangerous for millions of years, since a warning sign of "Danger, nuclear waste disposal area" won't last very long compared to the time required for complete decay

Why do that?

Wise people always do this way.

Spoiler

Complete morons will fail any caution.

Spoiler

A tribal elite will get superpowers.

Spoiler

Horns are natural.

And there is always a good way to turn wastes into goods.

Spoiler

 

[ARS]

2 minutes ago, kerbiloid said:

And there is always a good way to turn wastes into goods.

Back then during the atomic-happy era... When you can sell radioactive material as a child's toy and no one bats an eye

[magnemoe]

On 7/2/2018 at 1:56 PM, ARS said:

That's why it's concentrated into radioactive sludge first and solidified to make it easier to store. Most radioactive waste storage bunker is designed to keep radioactive waste safe and store them for decaying, which does take thousands or millions of years. In fact, one of the problem in storing nuclear waste is finding a way how to make the storage site still obviously dangerous for millions of years, since a warning sign of "Danger, nuclear waste disposal area" won't last very long compared to the time required for complete decay. Those radioactive waste could outlast human civilization, and due to the length of time involved, liquid isn't the best form for storing radioactive stuff for that long

Two reasons for reprocessing, you get an faction of the waste and you can reuse most of the fuel. 

High level nuclear waste is just an cost issue and less so than the reactors. 
irrelevant as an long term concern as long as you monitor them, yes make them fail safe so they don't leak for decades if stuff like civil wars or other breakdowns happens. 
Its just an hypothetical event from the anti nuclear crowd. Reactors and short term storage is way more dangerous. 

[kerbiloid]

Spoiler

The storage entrance should be deadly radioactive to stop any villain trying to steal the wastes.
Barrels of wastes can be rolled or poured from top.

If launch radioactive wastes to space with a cheap reusable superrocket, and gather them in a frozen ball, we can get a Minmus glowing blue in the sky.
Isn't that amusing?

Edited July 4, 2018 by kerbiloid

[Wjolcz]

Can somebody explain the Bell's theorem to me like I'm an idiot?

What I don't get is why people assume that the particles' spins are unknown until they are measured. Their spins (I'm aware there are other properties) are always opposite no matter what so what's the problem? If you measure for 'up' then one will be up and the other down. If you rotate the measuring device 90° then one will rotate 90° to one side and the other to the other. So, if you do the same but with 60° angle then one will rotate 60° and the other >60° to match the opposite spin and that's the problem?

And yes, I've seen the Veritasium and minutephysics videos and I still don't get it. Maybe I'm just dumb.

Edited July 5, 2018 by Wjolcz

[Terwin]

1 hour ago, Wjolcz said:

Can somebody explain the Bell's theorem to me like I'm an idiot?

What I don't get is why people assume that the particles' spins are unknown until they are measured. Their spins (I'm aware there are other properties) are always opposite no matter what so what's the problem? If you measure for 'up' then one will be up and the other down. If you rotate the measuring device 90° then one will rotate 90° to one side and the other to the other. So, if you do the same but with 60° angle then one will rotate 60° and the other >60° to match the opposite spin and that's the problem?

And yes, I've seen the Veritasium and minutephysics videos and I still don't get it. Maybe I'm just dumb.

To start with, a diffraction grating will polarize the light going through it, and absorb any light that is polarized perpendicular to the direction it polarizes.  This means if you have two of them you can rotate them so that either most of the light passes through, or none of the light passes through.  And if you put them at the 'nothing passes through' orientation, adding a third in the middle that is 45 degrees  between them, will mean light gets through again.

As far as I understand Bells theorem, they basically entangled some particles and sent them through diffraction gratings.  On one side they would have them turned to block all light, and on the other side they would have the one at 45%, letting some light through.

If the 45% grating was present in beam B, then beam A would get through the 'block all light' gratings, but if it was not in beam B, all of beam A would get blocked.

This proved that it could not be a hidden variable, because they were both still interacting in some way.

(I think I have the exact details of the experiment wrong because this approach would allow communicating at faster than light speeds if it worked, but something like that)

 

Edited July 5, 2018 by Terwin

[K^2]

14 hours ago, Wjolcz said:

Can somebody explain the Bell's theorem to me like I'm an idiot?

No. But I can explain it like you don't know any Quantum Mechanics.

Particles are complicated and unintuitive. Lets work with marbles instead. Imagine that I designed some nifty "smart" marbles that can change colors. The surface is covered with e-ink that can turn red or green depending on electrical signal from internal circuitry. Each marble comes in a box. It detects when the box is opened for the first time, and picks a color at that point. Once chose, the color stays. Inside, there is also a tilt sensor that measures direction of gravity, and we'll use it to make a decision on the color.

Now, I have two types of these marbles. First is the "deterministic" marbles. It has very simple circuitry. If it detects that sensor is pointing mostly down, it will make the marble red. Otherwise, it will be green. Since the marble is spherical, the sensor can be oriented any which way, but before you even open the box, the outcome is predetermined. Of course, you can influence the outcome by tilting the box before opening it, but for any given orientation, the result will always be the same. Still, you don't know the initial orientation of the sensor, so from your perspective it's a random 50/50 chance of finding a red or green marble.

Second type of marbles is "quantum". They are slightly more complicated. The circuitry inside will take a measurement of the angle of the sensor, and will use that to randomly assign the color. The closer the sensor is oriented to pointing straight down, the more likely it is to pick red, getting to 100% red when sensor is pointing directly down. The outcome still depends on how you tilt the box, but in an impossible to predict way, so you still observe these coming out 50/50 red and green.

Evidently, there is no simple way to distinguish between these two mechanisms. Any way you try it, it's 50/50 from either batch. So now, lets consider special pairs of these marbles.

 

Lets say I hand you boxes with marbles in pairs. For each pair, I guarantee that the sensors point in exact opposite direction. You still don't know what the direction is, so any box will still produce red or green marble at 50/50 odds, but you can make some conclusions. Specifically, if you open a box with "deterministic" marble, and it's red, you KNOW, the other one is green. Since sensor points in opposite direction, if first was mostly pointing down, the second mostly points up. Opposite color guaranteed. So you start opening these up, and you notice that ALL marbles behave this way. So are all of them deterministic?

Well, there is one more thing "quantum" marbles do. They use radio to talk to each other. So if one marble picked red, the other will re-calibrate the initial zero position of its sensor to guarantee that it will turn green. And vice versa. So when you open them up in pairs, they still produce one red and one green. Annoying!

 

Enter Bell and his inequalities. I won't get into too much detail, because the actual theorems are quite general. But we can talk about specific case that applies to our marbles.

Lets take a single pair of boxes. We'll keep one box as it is, and we'll tilt the other box by some angle before opening it. If the tilt angle is zero, boxes behave exactly as before - one red one green. If you flip one box by 180°, then both marbles will be red or both will be green. And the exciting stuff happens in the middle. For the two "deterministic" marbles, as you change the tilt angle of one of the boxes from 0° to 180°, the correlation between colors changes LINEARLY from -1 to 1 (from always opposite to always same). If I stop at 45°, I expect the two marbles to have the opposite color 75% of the time, and same color 25% of the time.

But not for "quantum" marbles. If you tilt one of these boxes to 45°, and you follow all of the above rules, you'll find that the odds of two marbles ending up with different colors will still be higher than 75%. And this is guaranteed to be the case, pretty much regardless of the rules used to chose the colors, so long as it's a smooth dependence on orientation of the sensor.

 

The more general statement of the Bell's Theorem is that any kind of hidden variable, which pre-determines outcome of experiment, can be distinguished from a random outcome by considering these types of correlation experiments. And that gave us a way to confirm some of the most important assumptions of Quantum Mechanics about how the outcome of the experiment is determined.

[Vanamonde]

Please keep in mind that the cartoonish aspects of KSP draw many younger people to the game and the forum, and for that reason, we ask folks to avoid discussions of things such as sex in space. For that reason, some posts have been trimmed from this thread. 

[KG3]

How is mass measured on the ISS?  I mean when they are doing experiments and they need so many grams of this or that.  I'm guessing a triple beam balance is useless up there.  Maybe experimental stuff is premeasured and packaged on earth before being sent up and then examined after being brought back down?     

[StrandedonEarth]

I would guess by using a device that can impart a known impulse. How fast the object to be weighed moves will determine its weight in accordance to FT=mV (impulse equals momentum)

[ARS]

If we bring Maus tank, the heaviest tank ever built (weight 188 tons, maximum speed 20 km/h) into the moon (which has 1/6 earth's gravity), how much it's speed and performance increased?

[kerbiloid]

18 hours ago, KG3 said:

How is mass measured on the ISS?

For bodies they use a mass-meter.
It measrues an oscillation period of a spring.
https://translate.google.com.tr/translate?hl=ru&sl=ru&tl=en&u=https%3A%2F%2Fru.wikipedia.org%2Fwiki%2FИзмеритель_массы_тела_в_невесомости&sandbox=1

Probably, something like that for smaller things, too.

10 hours ago, ARS said:

If we bring Maus tank, the heaviest tank ever built (weight 188 tons, maximum speed 20 km/h) into the moon (which has 1/6 earth's gravity), how much it's speed and performance increased?

Its travel capability would drastically increase because there are no rivers on the Moon. No rivers - no bridges.

[p1t1o]

 

1 hour ago, kerbiloid said:

Its travel capability would drastically increase because there are no rivers on the Moon. No rivers - no bridges.

It does have seas though...

[kerbiloid]

They can cross a sea by ship. 

[p1t1o]

Lunar submarines.

[Racescort666]

Also, there would be no atmosphere for the engine to run on.

[kerbiloid]

Friction should be 6 times weaker.
On another hand, regolith is more sticky.
Maybe, it's like a wet snow on ice.

So,  an instrumental speed probably would differ from a true speed.

Edited July 18, 2018 by kerbiloid

[magnemoe]

19 hours ago, ARS said:

If we bring Maus tank, the heaviest tank ever built (weight 188 tons, maximum speed 20 km/h) into the moon (which has 1/6 earth's gravity), how much it's speed and performance increased?

You got less ground pressure while you would still get decent ground pressure as in 20 ton.
Would it be less bumpy? you have lower gravity but you would jump higher and then crash down at the same force, note that getting airtime is not good as you probably rotate. 
Now add that you would need to change the gearing probably add more gears as you mass is the same. 
Most heavy stuff outside of tanks and oversize long haul trucks are slow as you don't have an major need for high speed.

[ARS]

1 hour ago, magnemoe said:

lower gravity but you would jump higher and then crash down at the same force

Wait, if it jump higher with only 1/6 gravity, should it fall slower than on earth? Meaning less force when crashing when compared if it jumps on earth?