Repost from Adriana Guatame
(@adriguatame.bsky.social):
With #kyanite I always remember this video created by Stacey Phillips via the Mineralogical Society (the LEGO stop motion science videos)

https://www.youtube.com/watch?v=4tm5DrTU0W8

#MinCup24 #Aluminosilicate #LEGO #PhaseDiagram #Tectonics

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.130.166701

"We find that the melting of the magnetic long-range order into an isotropic gaslike paramagnet proceeds via an intermediate stage where the classical spins remain anisotropically correlated."

#PhaseDiagram #liquidPhase #liquidMagnet #magnetism #liquid #magnetofluid #phaseTransition

#SoftMatter have just published the results of a project that Renato Assante, Davide Marenduzzo, Alexander Morozov, and I recently worked on together! What did we do and what’s new? Briefly…

#Microswimmer suspensions behave in a similar way to fluids containing kinesin and microtubules. Both systems can be described by the same system of three coupled nonlinear #PDEs.

A #LinearStabilityAnalysis of these equations suggests that variations in concentration across the system don’t significantly affect emergent #phaseBehaviour. How then can we explain #experiments that show visible inhomogeneities in #microtubule–#kinesin mixtures, for instance?

With increasing activity, we move away from the quiescent regime, past the onset of #SpontaneousFlow, and deeper into the active phase, where #nonlinearities become more important. What role do concentration inhomogeneities play here?

We investigated these questions, taking advantage of the #openSource #Dedalus #spectral framework to simulate the full nonlinear time evolution. This led us to predict a #novel regime of #spontaneous #microphaseSeparation into active (nematically ordered) and passive domains.

Active flow arrests macrophase separation in this regime, counteracting domain coarsening due to thermodynamic coupling between active matter concentration and #nematic order. As a result, domains reach a characteristic size that decreases with increasing activity.

This regime is one part of the #PhaseDiagram we mapped out. Along with our other findings, you can read all about it here!

low #ReynoldsNumber #turbulence #ActiveTurbulence #CahnHilliard #ActiveMatter #NavierStokes #BerisEdwards #CondensedMatter #PhaseTransitions #TheoreticalPhysics #BioPhysics #StatisticalPhysics #FluidDynamics #ComputationalPhysics #Simulation #FieldTheory #paperthread #NewPaper #science #research #ActiveGel #activeNematic #analytic #cytoskeleton #hydrodynamics #MPI #theory

#SoftMatter have just published the results of a project that Renato Assante, Davide Marenduzzo, Alexander Morozov, and I recently worked on together! What did we do and what’s new? Briefly…

The #hydrodynamic behaviour of inhomogeneous #activeNematic gels (such as extensile bundles of #cytoskeletal filaments or suspensions of low #ReynoldsNumber swimmers) can be described by the time evolution of three coupled #PDEs.

Standard #ActiveGel #theory concludes, from a #LinearStabilityAnalysis of these equations, that fluctuations in concentration don’t significantly affect emergent #phaseBehaviour. However, this leaves #experimental #observations of visible inhomogeneities in #microtubule–#kinesin mixtures unexplained. As we move away from the passive (quiescent) regime, past the onset of #SpontaneousFlow, and deeper into the active phase, #nonlinearities become more important. What role do concentration inhomogeneities play here?

Alongside #analytic techniques, we used an in-house #MPI-parallel code developed within the #Dedalus #spectral framework to investigate. We predict a #novel regime of #spontaneous #microphaseSeparation into active (nematically ordered) and passive domains. In this regime, active flow arrests macrophase separation, which is itself driven by the thermodynamic coupling between active matter concentration and #nematic order. As a result, domains do not #coarsen past a typical size, which decreases with increasing activity. This regime is one part of the #PhaseDiagram we mapped out.

Along with our other findings, you can read all about it here!

#CahnHilliard #ActiveMatter #NavierStokes #BerisEdwards #CondensedMatter #PhaseTransitions #TheoreticalPhysics #BioPhysics #StatisticalPhysics #FluidDynamics #ComputationalPhysics #Simulation #FieldTheory #paperthread #NewPaper #science #research

Make Your Desoldering Easier by Minding Your Own Bismuth

Any video that starts with a phase diagram has instantly earned our attention. Admittedly, we have a pretty low bar for that kind of stuff, but eye candy aside, [Robin Debreuil]'s quick outline of his technique for desoldering with the help of bismuth is worth watching.

Aside from its use in those pink gloopy solutions one takes for an upset stomach, bismuth has a lot of commercial applications. For the purposes of desoldering, though, its tendency to lower the melting point of tin and tin alloys like solder is what makes it a valuable addition to the toolkit. [Robin] starts with a demonstration of just how far a little bismuth depresses the melting point of tin solder -- to about 135°. That allows plenty of time to work, and freeing leads from pads becomes a snap. He demonstrates this with some large QFP chips, which practically jump off the board. He also demonstrates a neat technique for cleaning the bismuth-tin mix off the leads, using a length of desoldering braid clamped at an angle to the vertical with some helping-hands clips. The braid wicks the bismuth-tin mix away from the leads along one side of the chip, while gravity pulls it down the braid to pool safely on the bench. Pretty slick.

Lest leaded solder fans fret, [Robin] ensures us this works well for lead-tin solder too. You won't have to worry about breaking the bank, either; bismuth is pretty cheap and easily sourced. And as a bonus, it's pretty non-toxic, at least as far as heavy metals go. But alas -- it apparently doesn't machine very well.

#toolhacks #bismuth #braid #desolder #eutectic #lead #phasediagram #solder #tin