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I'm a post-doctoral researcher with a wide range of interests. My career is in complex systems science (or maybe cybernetics) and the origins of life, but I also have research interests in

  • the foundations of statistical mechanics and its relationship to information theory
  • Earth systems science
  • non-equilibrium thermodynamics in general

I'm also generally interested in the foundations of quantum mechanics and in black holes, though I wouldn't say I'm an expert on those things.

It's probably worth noting that despite the fact that my research is in physics-related areas, all my degrees are in other subjects. If I occasionally seem to start talking in an alien language, this is probably why.


Mar
18
comment If I bury a cylinder (top end sealed) in sand, how much force do I need to pull it out?
It's a deeper question than I thought. You might get more responses if you change the question to be more about the phyisics - e.g. ask if there is an equation for the force depending on the geometry of the tube, rather than giving your specific figures. Personally I think it's unlikely there will be an easily derived formula - if it's well and truly stuck to the ground then it isn't going anywhere, so it's just a case of experimenting in shallow water until you find a design that works well. But others with more experience might have a better idea than me.
Mar
18
comment If I bury a cylinder (top end sealed) in sand, how much force do I need to pull it out?
Just thinking... perhaps easier than an inverted bucket might be a rigid flat surface, like a sheet of plywood weighed down with weights. As long as it's flat against the sand (e.g. if you bury it under a small amount of sand), it should behave like the sole of the stuck shoe, sticking to the sand below it. (Of course it would move around horizontally, but I'm sure you could solve that.) That's just an idea - I don't have the practical experience to tell if it would work - but it sounds more plausible than the bucket to my naïve imagination, because of its greater surface area.
Mar
18
comment If I bury a cylinder (top end sealed) in sand, how much force do I need to pull it out?
It's still gravity that's holding it down ultimately. It's just that you you want to take advantage of the sand below the device, which is heavier than any lead weight would be.
Mar
18
comment If I bury a cylinder (top end sealed) in sand, how much force do I need to pull it out?
Well, the stuck shoe thing is ultimately for the same reason: when you try to lift it, the sand tries to come up as well (because the air/water can't get in, as you say), and so you're actually trying to lift a whole load of mud as well as your shoe. That example does suggest that the weight you're lifting can be a lot more than the sand inside the bucket, which means my answer's probably a massive underestimate.
Mar
18
revised If I bury a cylinder (top end sealed) in sand, how much force do I need to pull it out?
added 198 characters in body
Mar
18
revised If I bury a cylinder (top end sealed) in sand, how much force do I need to pull it out?
added 205 characters in body
Mar
18
answered If I bury a cylinder (top end sealed) in sand, how much force do I need to pull it out?
Mar
18
asked Are the Hamiltonian and Lagrangian always convex functions?
Mar
17
comment How to calculate tortuosity of a signal?
I think it will be impossible to answer this without knowing what your signal is and where it comes from, and what your objective is in measuring it's tortuosity.
Mar
17
comment Should theory be the appropriate term?
I'm not criticising, just adding to your point. An example from mathematics is "set theory": that theory isn't the kind that can be falsified. Arguably, the "theory" in "quantum field theory" refers to it being a mathematical theory in this sense, rather than a scientific theory. (But as dmckee says, the terminology is very subjective anyway.)
Mar
17
comment Should theory be the appropriate term?
It's worth mentioning that the world "theory" can also be used in the sense of "mathematical theory", which is just a bunch of deductions from axioms, with no particular notion of testability implied.
Mar
16
revised What is the exact relation between $\mathrm{SU(3)}$ flavour symmetry and the Gell-Mann–Nishijima relation
Please don't use < and > to represent angle brackets, it's the wrong symbol and the spacing comes out all wrong.
Mar
16
comment Do black holes exist?
Possible duplicates: physics.stackexchange.com/questions/95555/… physics.stackexchange.com/questions/47669/… physics.stackexchange.com/questions/21319/… (It's a good insight, and I'd go so far as to say it's a correct one, but we've covered it before.)
Mar
15
comment Why does ice melts, waits for 100 degrees and THEN vaporises? Why is not the process of expansion of things continuous?
"Why can't a body be solid, then solid-ish, then solid-like, then liquid-like, then liquid-ish, then liquid, then vapor-like and then vapor?" Actually it can --- this is often the case for mixtures, at least regarding the solid-liquid transition. But the question of why water and other pure substances don't behave this way is an interesting one, and actually quite difficult to answer.
Mar
14
comment Function for curved line in log-log-plot
But then it is from a physics measurement (of biological tissue), so on that basis I'm not sure. I actually think we should allow questions like this, so I'll remove my close vote.
Mar
14
comment Function for curved line in log-log-plot
This question appears to be off-topic according to current policy because it is about data analysis. I think it belongs in Math.SE or Cross Validated instead.
Mar
13
comment If we hear a noise long enough, is it going to settle as tinnitus?
This question appears to be off-topic because it is about human perception. (Maybe try Biology stack exchange instead?)
Mar
13
answered Work done by isothermal expansion from two different viewpoints
Mar
13
comment Does putting color filters make the sources incoherent?
It will have a small effect on the photons in practice, due to having a different refractive index than air. (But that's a minor technical issue that's easily mitigated, e.g. by putting a transparent piece of the same material over the other slit.)
Mar
13
comment Explanation request for flashes of light
My first guess would be that you have some electronic device in the room, which briefly flashed an LED. For example, an incoming message on a phone that's set to silent. Because LEDs are quite directional, if it was aimed at the ceiling it might look like light coming from the ceiling rather than the device.