Group items tagged

Apparently the core does not only produce a magnetic field - it is also an electric motor!

Heat and a magnetic field cause the liquid lithium to swirl rapidly, an effect that could be useful in fusion reactors. With a nice video http://physics.aps.org/assets/eab7d11d-20cd-4c37-ab2c-313729ad8422/video-v1.mp4

Using the angular momentum transmitted by an internal flywheel as an impulse, these cubes can move, jump, roll across the ground and climb over and around one another. They stick together using a set of small magnets, smart !

That is indeed a great way of using modular robots to build larger structures. I think we did bump into this some time back, but never really considered it much. Considering now the working group on structure assembling, I think we should add it to the list of building strategies and seriously consider it.

Useful for space exploration, e.g. subsurface water reservoirs such as Europa or Enceladus? Nanoengineers at the University of California, San Diego used an innovative 3-D printing technology they developed to manufacture multipurpose fish-shaped microrobots -- called microfish -- that swim around efficiently in liquids, are chemically powered by hydrogen peroxide and magnetically controlled.

A 60-year-old theory about the structure of the magnetic fields that surround Earth has been confirmed directly for the first time. The lead author of the paper is an undergraduate student who invented a way to view the Earth's magnetosphere in three dimensions.

antihydrogen propulsion...?

didn't roger write an assessment of antimatter propulsion when he was in the ACT?

yeah the problem is the amount of antimatter you can get and more specifically how to trap it. I found that you would need around one gram to go to the outer Solar System. So we are far from that, but finding an efficient way to trap it, with an electromagnetic trap rather than solid walls is a first step !

While my attitude to articles about interstellar travel is generally sceptical, this one seems to raise quite an interesting point... Physicists?

Also, remember never to dereference null pointers.

True, it's almost like installing accelerometers upside down...

Remember this theory that made a fuzz because a surfer posted something on arxiv...?

and all this without magic metamaterials ...

It's funny to see how people get more and more humble in the desperate attempt to save their stupid ideas... At the beginning was the brave and bold aim to cloak something in free space (in a sphere or a cylinder). This requires inhomogeneous, anisotropic, magnetic materials; hopeless!! So one reduces to one polarization, now we have inhomogenous, anisotropic materials; still hopeless! At this point one downgraded the pretension: instead of cloaking in free space, we make a "carpet cloak" and hide an object behind an invisible dent in a mirror. But if that shall be continuous, we still need inhomogeneity and this is very hard. So now instead of a dent we take a cone and then it is claimed to work ... for ONE polarization. But of course the cloak can't work at all incident angles... irony of fate: everything is now made from birefringent media, the antithesis of what the metamaterials dogma was at the beginning!

Hi Luzi, can you please send me the paper. We are writing a project based on sulfates and carbonates, and all this BS sounds great for the introduction (The authors used Calcite as birefringent material)

very nice paper ... 

very interesting. Quasi-particles acting as magnetic monopoles.

"We pursue an alternative strategy, namely that of realizing monopoles not as elementary but rather as emergent particles-that is, as manifestations of the correlations present in a strongly interacting many-body system."

The biophysics guy with the good paper.