Recent content by Kiara

thanks for the info!

yeah, around 5-15 V, right? what I outlined was what I was going to do before I learned of the 555 chip, so I'm not going to try to run 90V through it. what I need is a sustained arc across about 3 mm of air. I read that the breakdown of air is about 30kV per cm, so that comes out to about 9kV...

a lot. what I have so far is a 90 V battery pack (ten 9Vs in series), which I'm going to use a transformer to ratchet up to around 9000V once I figure out how to quickly turn it on and off. a 320 Ah battery pack connects to that and then goes to the load. so the IC itself wouldn't drive very...

huh! never heard of that before. it looks promising. do you know if it can handle 30 Hz?

I want to make a DC current (from a battery) oscillate between full voltage and zero voltage (not negative) really quickly, at least 30 Hz. I tried using an electromechanical switch, but the current from the battery is too low to produce any appreciable electromagnetism, so the switch didn't...

so it's due to the dust's large mass that it's difficult to charge and use as a substitute?

Say you built a magnetic array, and two long electrodes running perpendicular to the magnetic field, whose electric field is then perpendicular both the electrodes and the array. Most magnetoplasmadynamic thrusters (built as previously described) then send current at an enormous voltage through...

Well that's just the magnet. I didn't think you meant for me to include the container and the insulation... that'll add a bit. I don't have a location nailed down yet.

About 26 grams of MgB2 (an ionic solid), and about 342 grams of a nickel alloy. I ran a few calculations, and the current I'm planning to send through the wires will remain under Jc if the temperature stays under 32K. Also, the magnet is there simply to produce a strong magnetic field, the...

I had a cryostat designed, I was just trying to figure out how to cool the system down. I'm working with superconductivity electromagnet experiments. High temperature superconducting wires that superconduct above the boiling point of nitrogen can cost $500 a meter. So I decided that...

I don't need to go all the way down to 4.2K, just below 30. Could I simply build a conventional refrigeration system using helium gas instead of ammonia?

wow, didn't think of that. thanks for the help!

The cryocooler would be for a small superconducting magnet set-up designed to run under 30K. The coolant (helium, of course, but I can't decide whether liquid or gaseous is better) would just need to surround the magnet, so that's a volume of about 0.1 L. The temp would just have to be...

Can anyone think of a cheap way (under $150) to build a cryocooler? Commercially available ones run about $15-20K and I don't have those kinds of resources.

If I know that liquid helium at 4.2 K (boiling point) occupies 0.01065 L, then how do I calculate the pressure exerted on the walls of its containers if the helium evaporates and warms up to 30 K?