Episode 17 – Life, The Universe, and Frogs

LASER: Materials Science Podcast

This week on LASER we discuss a realistic computer simulation of a universe, a proposed mechanism for why tin whiskers are destroying our most sensitive computers, and GaInSn liquid metal used to reconnect severed nerves in frogs.

5:00 Our first story is about the story “Astronomers create first realistic virtual universe” from the Illustris Project.
15:40 By “first realistic simulation” they probably mean that this is the first simulation that results in a realistic distribution of galaxy types.

16:40 One of the most important thing about this simulation is being able to “see” how galaxies evolve and form and interact with each other, and since it is a computer simulation we are able to look into the past and future.

22:05 maybe eventually we’ll be able to look for distribution of M-class planets.

25:00 after talking about videogames, reddit, minority report, and cutting a five minute discussion on the history of neckbeards (https://en.wikipedia.org/wiki/Neckbeard#Neckbeard) we finally move onto the second topic…

25:30 Whiskers!!! ( http://news.sciencemag.org/physics/2014/05/scienceshot-how-shave-metal-whiskers)

26:45 Whiskers are when a thin single-crystal piece of metal grows (very quickly) out of a metal (most often something used in solder or semiconductor packaging). This causes problems for electronic devices, where it can short out devices, and has been attributed to taking offline three satellites and one nuclear power plant (specifically places where you can’t go in and fix a part. This also has taken out many computers that just stopped working for seemingly no reason).

28:15 Lead-free solders are especially prone to this problem, because they often contain Tin. We would prefer to use lead-free because of the environmental and health effects, but it is–so far–the most reliable available solder, based on whiskers and microcracking.

34:50 The paper is V. G. Karpov, “Electrostatic Theory of Metal Whiskers” Phys. Rev. Applied 1, 044001 – Published 15 May 2014. doi:10.1103/PhysRevApplied.1.044001

37:00 the proposed mechanism for whisker buildup is charge differences on the surface, that are centered around defects. This extra energy might give the metal the energy it needs to grow directly out.

44:40 Now we’re talking about Liquid Metal nerve grafts in frogs! http://www.newscientist.com/article/dn25510-terminatorstyle-liquid-metal-connects-severed-nerves.html#.U5DWzzk2pHT
and the paper freely available on the arXiv: http://arxiv.org/abs/1404.5931

The researchers have used a GaInSn liquid metal to connect severed nerves in frogs, and it resulted in connectivity similar to a healthy nerve, allows for the nerves to grow back, and is easily removed once it is no longer necessary.

55:00 fun prank for dinner parties: cast spoons out of low-temperature melting metals, and give them to your friends to stir their coffee. The spoon will melt in their drink, likely poisoning them! (not a fun prank.)

Links to the music used in this week’s episode:
Intro: Luv Rulez (Original version of ES) – Crying (Return to Olde World)
bumper music: Vacation – Crying
Outro: Dreams are Maps – The Wild (Dreams are Maps)