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| bio | website | |
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| location | ||
| age | 29 | |
| visits | member for | 2 years, 4 months |
| seen | 1 hour ago | |
| stats | profile views | 1,086 |
We once had a Nuclear Engineering proposal on Area 51, but it failed. The space technology proposal might be interesting.
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 my curiosities wind up all over the place.
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2d |
comment |
what is the density of natural gas at 293K and 700 kPa? @thewheelz no, that can't be right because when you put in 100 kPa it puts you at STP. I think it's absolute. John's method is probably the better one for natural gas, these are probably correct numbers for just methane. |
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2d |
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what is the density of natural gas at 293K and 700 kPa? @thewheelz I get 3.995 kg/m^3 when I put in 600 kPa. I don't see any indication that this would be the relative pressure. Maybe post what input you used and I'll retry it? |
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May 15 |
answered | what is the density of natural gas at 293K and 700 kPa? |
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May 14 |
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How reliant is the Solar System on being exactly the way it is? Good question, but it goes deep into orbital resonances. The familiar rules of gravitation start to look extremely different when played out over millions of years. I could confidently say it wouldn't cause planets to plummet to their death in the very next orbit, but after that the system is quite chaotic. |
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May 13 |
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Thermodynamics, PV diagrams? @Anuar Here $T$ matters, but you don't integrate over $T$. You're somewhat confusing those two concepts. You could set $T$ equal to a constant for a particular type of process, or you could plug in some $T(V)$ function. In the latter case, the $V$ in the argument will affect the anti-derivative, so it has to be arithmetically included before the integration. |
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May 13 |
revised |
Curiosity Rover (MSL): current coordinates bottom right |
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May 13 |
answered | Thermodynamics, PV diagrams? |
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May 13 |
answered | Curiosity Rover (MSL): current coordinates |
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May 13 |
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Our Universe Can't be Looped? I've wondered the same thing as this question. The conclusion looks half correct. I think it demonstrates that the universe can't be a loop, but not that it must have an end point. Basically, this disproves a special relativity version of wormholes. I think the harder question is if you can formulate a general relativity metric that loops and doesn't violate causality. My current belief is that answer is "no", in spite of the fact that people like Michio Kaku publicly argue otherwise. I do not understand how a space loop can avoid violating causality. |
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May 9 |
awarded | Popular Question |
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May 3 |
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Uniqueness and existence of polygonal orbits through a spherical shell I have to confess to stealing your stuff now, but I give credit. gravitationalballoon.blogspot.com/2013/05/… |
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May 1 |
accepted | Uniqueness and existence of polygonal orbits through a spherical shell |
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May 1 |
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Uniqueness and existence of polygonal orbits through a spherical shell @JJFleck yep, and that will even work for any given speed. For some reason, I had never even considered a non-trivial 2-gon (pardon the abuse of terminology) until I made that image. As two conjoined ellipses it's probably the most simple periodic path (that's neither a line nor a circle). So questions about degrees of freedom are probably best answered looking at that shape. |
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May 1 |
asked | Uniqueness and existence of polygonal orbits through a spherical shell |
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Apr 30 |
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Coulomb barrier and proton evaporation @BenCrowell I think that's too specific of a definition for that word, there are simple anthropic observations, which are entirely different than the anthropic principle. But maybe I'm the one over extending the scope of the word. What would you call the observation? |
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Apr 30 |
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Coulomb barrier and proton evaporation @BenCrowell There are 3 relevant parts to the picture I see here. There's the Q value, there's the more-or-less the Coulomb quantum tunneling barrier which favors lower charges (which I missed above), and there's a sort of anthropic principle. If a nucleus found it energetically favorable to decay by neutron emission then it likely would have already done so. Because we're interested in nuclei that actually exist, we want to know about decays that have half-lives on the order of 10 billion years or so. To explain that final point probably requires more research than I've done. |
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Apr 30 |
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Coulomb barrier and proton evaporation Isn't the binding energy of an alpha particle less than for a proton? I mean, this is how fusion in stars work. So given the choice, a nucleus would rather throw off an alpha particle, and that does happen more often than neutrons so in a fully circumspect view I think the nuclei emissions make complete sense. |
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Apr 30 |
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Is it possible for a charged, fast-moving object to slow down and enter geo-stationary orbit? What you need is a good ratio of capacitance to mass. You need to avoid discharge at the same time, limiting the mass you have to move. Practically, this would be a large spherical wire mesh surrounding a micro satellite, large and light to the extent of what could withstand the acceleration. Even then, the movement due to the magnetic field is nothing like you've imagined because the field lines are not oriented in a helpful way and they are probably useless anywhere near GEO. |
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Apr 29 |
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Orbits within a $-\vec{r}$ field @JJFleck is correct. I had meant to use a sin/cos parametric representation but was sloppy when typing it. Changing cosine to sin introduces the phase shift alluded to. |
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Apr 29 |
accepted | Orbits within a $-\vec{r}$ field |
