How to make your own Pruno
Pruno, a prison wine created from fruit, sugar and ketchup
[…]
[Even though] it tastes so putrid that even hardened prisoners gulp it down while holding their noses, they’ll go to incredible lengths to make it
Category Archives: Experiments
Rube-y Goldberg Tuesday
Halfway There
Not Taking Sides
MOTIS Operandi
An interesting paper was brought to my attention recently, on a new technology for ion beams based on magneto-optic trapping. My only experience with ion beams was with the transport of radioactive ions at TRIUMF (it’s far easier to shuttle your particles around macroscopic distances as ions), but ions beams are also used for etching and implantation in nanofabrication, among other things. There are other ion etching techniques — I’ve used reactive ion etching, but that’s a bulk etch which involves a mask to expose areas to be etched and hide areas to be protected. Using a beam allows you to focus the ions down to a small area and do precision work.
Drawbacks of ion-beam sources available today (see how I avoided the “currently available” pun?) include liquid metal ion source, (LMIS), gas-phase sources and plasma sources, each having a drawback in one of the important areas of energy spread, brightness (ion beam current per unit solid angle, limited by either or both variables) and available elements. A small energy spread is desirable, because different energies will focus differently, leading to the equivalent of chromatic aberration and limiting spot size. Brightness tells you how many ions you can deliver to your target, and limits on the different species of atom you can deliver restricts what kind of structures you can build through implantation.
A Magneto-Optic Trap gives one the advantage of a very cold source of atoms which limits the energy spread of the ion source and reduces the divergence of the beam, which improves the brightness. And there are a large number of species that can be trapped, so this addresses the main shortcomings of ion beams.
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A Physics Rebuttal
OK, after linking to some cool chemistry, here’s a physics demonstration that involves flames.
Dave Letterman, Chemistry Prof.
OK, not really, but it’s a top-10 list:
Top 10 Amazing Chemical Reactions
The neatest stuff from chemistry without actually blowing anything up. (One reaction is labeled an explosion, but nothing goes “boom,” and technically the Meissner Effect isn’t chemistry, but I’m willing to give that a pass because it’s cool.)
I Love My Clipboard
I got a fluorescent clipboard a while back. I love the effect.
The edge is much, much brighter than the rest, though it’s a little easier to see this in person. The clipboard is acting as a waveguide for the emitted fluorescence; any light emitted within the total internal reflectance angle is being transported to the edge, and any light entering through the edge is likewise guided. Except for the places where there is clear tape (holding a Dilbert cartoon on a transparency) where you can see some of the light coupling out through the tape, because the light isn’t totally contained in a waveguide. There is an evanescent wave that can couple to a material of a different index, resulting in frustrated total internal reflection.
No, Mr. Bond, I Expect you To Die
Texans Build World’s Most Powerful Laser. Sort of.
More than a petawatt, but of course it’s pulsed, not continuous. Joules of energy in femtosecond-ish long pulses will yield a petawatt pulse, and it hasn’t earned its title quite yet, but it’s expected to.
The pulse compression, which they do with gratings, can also be done with prisms and chirped mirrors. Pulses tend to disperse, because the speed of light in a medium varies with wavelength, so the blue and red end of the pulse travel at slightly different speeds (normal dispersion will have the blue light going just a little slower than red light). The grating method uses grating pairs in place of mirrors, tilted so the blue end of the pulse travels a shorter distance so it can catch up to the red end; a similar arrangement can be done with pairs of prisms. Chirped mirrors have different reflective layers that allow the red end of the pulse to penetrate further before reflecting. Because this laser is going for high power in addition to short pulse length, they actually stretch the pulse out with gratings in the opposite orientation, before amplifying it (to limit the peak power in the gain medium) and then compressing.
When Everyone is Super, No One Will Be
Scientists Create First ‘Superinsulator’
Titanium nitride thin-film shows a sharp change in resistance when cooled to near absolute zero or the external magnetic field is decreased. Interestingly, it’s effects from Cooper-pairs, just like in superconductors. Nothing with Kryptonite being reported just yet.