First, a recap:
In 1992 Eugene Podkletnov reported a possible gravitational field shielding from a rotating, levitated superconductor. NASA tried to duplicate his experiment but didn't complete it. We were able to borrow NASA'S equipment to attempt to replicate Podkletnov's experiment. After quite a bit of research it became clear that none of the replication attempts have succeeded in levitating the semiconductor, (via the Meissner effect and flux pinning), at the magnetic field frequencies specified by Podkletnov. At this point we backed up and decided to study the dependence of the levitation force with respect to frequency. All this is detailed more fully in the presentation below.
I've been working on a torsion balance to measure the levitation force. The balance isn't my design, I found it in the Review of Scientific Instruments.
The balance consists of a stretched steel wire with an attached boom that is free to rotate. When a steel wire is twisted, it behaves like a spring. The force exerted by the wire is proportional to the angle the wire has been twisted through. By measuring the angle, we can measure the force exerted by the electromagnet, (on the tabel), on the superconductor in the sample holder at the end of the boom. So, in the following video, the higher the boom of the balance swings up, the greater the levitation force on the superconductor.
I've been through three different sample holder designs so far. The first utilized a rubber key cover to hold the superconductor. This design mostly didn't work because in the amount of time it took to insert the superconductor, it warmed up to much and reverted back to its normal, non-superconducting state. The second and third designs utilized IC chip holders inverted and suspended from the end of the bin. With this design, the superconductor is immersed in liquid nitrogen, (see below), until the electromagnet is turned on.
Picture of the day
|From Jun 21, 2012|