Tribogenics (http://tribogenics.com/) turned this discovery in to an actual product. I think they moved from tape to using disks that oscillate to connect and disconnect. (http://singularityhub.com/2013/11/16/southern-california-sta...)

It looks like they use a single band looped over a rod. It appears to be very similar to a Van De Graaff generator.

http://tribogenics.com/wp-content/uploads/2015/08/Eli-Paper-...

Applied Science tried to reproduce this:

https://www.youtube.com/watch?v=7sRPUjcd2SA

Follow up http://benkrasnow.blogspot.com/2012/07/attempting-to-make-x-...

Thanks. I just lost about 3 hours looking at Applied Science videos. :)

You can see the same blue glow when you open envelopes and, as indicated in the article, when you rub two sugar cubes against each other. No vacuum chamber required.

According to the video, you need vacuum because in air the surfaces will discharge before they are separated to the point where the potential large enough to generate x-rays.

I tried the glue on envelopes and I tried sugar cubes and have seen both of them emit a faint blue glow. And I assure you I was not standing in a vacuum chamber when I tried it. Just try it yourself in a dark room. It actually doesn't have to be exceptionally dark, it's pretty visible.

And there are of course also videos showing the effect, here with duck tape outside a vacuum chamber. [1]

[1] https://youtube.com/watch?v=54R6q2_-4Yo

I think they specifically meant x-rays, rather than blue light; the x-rays would require more energy, so their explanation makes sense to me.

You are right, if you are after x-rays specifically this might not work. But I can't see x-rays so I am happy with some blue light.

yes, you are generating ~430nm light

x-rays (0.1-10nm) are much higher energy and need a greater potential to be created, which can only be done in a vacuum

*duct tape (plumbing)