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My academic interests are in power plants of all types, shapes, and sizes, and how well they play with each other. My hobbyist interest are kind of all over the place. I like the maker movement, I'm most interested in the sensors and data, the "internet of things" kind of stuff. In physics, I'm probably the most curious about general relativity topics, but I'm all over the place. We once had a Nuclear Engineering proposal on Area 51, but it failed.


1d
comment How to find set point for PID controller for self balancing robot?
Perhaps hold it upside-down by the wheels and make note of the reading at this point. Then use some math to rotate 180 degrees. It sounds childishly simple but it might work for your issue.
2d
answered Is Torricelli's law “wrong” for big holes? - Tank draining problem
May
5
comment Hydrogen-boron fusion
The electron cloud does have a role, just as you described, related to penetration depth. However, I would also like to add that the nucleus' own electrostatic repulsion has a large role in poor "efficiency". The straightforward ratio of scattering to fusion events aren't enough to make a profit of energy from the first collision. This is why the DPF attempts to create a hot plasma ball that enables many successive collisions. In accelerator-target designs, you can only hit 1 or 2 nuclei before you've lost most kinetic energy.
Apr
29
awarded  Notable Question
Apr
27
comment Is the planet Mesklin as described in Hal Clement's Mission of Gravity correct?
@EmilioPisanty You are, of course, strictly correct. But for that matter, when you start walking, you'll kick in dynamic components like the Coriolis force. Thus, we can't conclusively accept your narrative from a map of the field by itself (or without other assumptions, like walking "slowly"). For Mesklin itself, it would be like a cross-continent train ride raises your head less than 60 feet. For Saturn, it would be like 2 inches.
Apr
27
revised Is the planet Mesklin as described in Hal Clement's Mission of Gravity correct?
added 361 characters in body
Apr
24
comment Is the planet Mesklin as described in Hal Clement's Mission of Gravity correct?
@TimB Ugh, I just realized one of those nasty more complicated details. The field I drew is not conservative, which means you could make energy from it. It also means that the blue line isn't truly equipotential. However, for the rotating planet, the field is conservative by some geometry tricks. We would need to imagine curved lines for the gravity vector, and that the lines are perpendicular to the blue line as well. That's not quite what I drew, and I'm sorry about that.
Apr
24
comment Is the planet Mesklin as described in Hal Clement's Mission of Gravity correct?
@TimB Potential energy is relative, so that's a little difficult to answer. Potential is constant along the ground, and it's also constant along the blue line. 1 arrow's length always represents the same change in potential (this is the relationship between fields and potential).
Apr
24
answered Is the planet Mesklin as described in Hal Clement's Mission of Gravity correct?
Apr
20
awarded  Nice Question
Apr
15
awarded  Popular Question
Apr
2
comment Why planes have propellers in front but watercraft have them behind?
@Rick My understanding is that boats remove the fluid ingress via the "flush hole". Having an exit path for ingress is almost always the better option. The pressure difference is also critically important, which clearly exists here.
Apr
2
awarded  Popular Question
Mar
30
answered Is an atom charged after undergoing beta emission?
Mar
29
awarded  Nice Answer
Mar
25
comment What would it be like “inside” a star?
@DevSolar That is exactly what I had in mind. However, I was hesitant to elaborate on one detail, and upon further research, my doubts are warranted. As you go deeper into the sun, the visible wavelengths will not decrease in intensity, because increasing temperature only adds more in shorter wavelengths, but doesn't subtract from long wavelengths. So you'll be microwaved, but you'll still be blinded in the visible spectrum.
Mar
25
answered What would it be like “inside” a star?
Mar
11
comment Could a Nuclear Reactor Run (controllably) in Prompt-Critical Mode?
@DOS4004 I had to look check, but I think I know where you get the "delayed-supercritical" wording from. This is specifically the scenario where the reactor is increasing power. In this state, you could say that it is "prompt-subcritical", because the prompt neutrons alone are insufficient to maintain criticality. You're asking if we could replace the regular ramp-up with a controled prompt-supercritical ramp-up. I don't know of any control element which is non-mechanical. Unless you can find a truly electric control method, then I think the control could be fast enough.
Mar
10
awarded  Popular Question
Mar
10
answered Could a Nuclear Reactor Run (controllably) in Prompt-Critical Mode?