"The number of anomalies is growing" Michael Martin Nieto, Los Alamos National Laboratory
This statement probably sums up all the results of research thus far. One of the first groups to try a similar experiment was Hideo Hayasaka and Sakae Takeuchi of Tohoku University in Japan. The had high-speed gyroscopes with metal flywheels spinning several thousand times per minute. When the gyros rotated clockwise, the Japanese researchers claimed they measured a weight reduction of about 1/100,000. They highly suspected an "antigravity" force at work, but most of their collegues said it was probably just experimental error.
The main, reliable group that is currently researching this is NASA. The picture to the left here is of the NASA Delta G team: from left: Tony Robertson, Neil Tyson, Whitt Brantley, David Noever(no longer working there), Jerald Oakly, Ronald Koczor, and Ning Li, showing off the die for a 12" SC. Now, there are two separate groups in NASA researching, one is a group of NASA scientists formerly headed by David Noever at the Marshall Space Flight Center in Huntsville, Alabama, the other is a NASA funded individual researcher, Ning Li, at the University of Alabama. The Marshall Space Flight Center project has been termed the Delta G Experiment. For Delta G, the goal is to eliminate every possible source of error and figure out the exact nature of the gravity modifiying phenomenon, if it exists. Li's goal, which many think is way too premature, is to actually build a device that uses the new physics that she evidently thinks definatly exists. NASA is still funding her, perhaps so that once the Russian's results are validated (if at all), there will be applications all thought out and ready to build, but who really knows!
Many scientists, both professionals and amatures, have tried to duplicate Podkletnov's experiment. So far, no reliable sources have done that. What's the difficulty? NASA's current difficulty is simple creating a superconducting disk of like size and material to that Podkletnov used. Podkletnov did confer with the NASA scientists, however, he never shared any special tricks he used to create his original disks.
One of the explanations for how the experiment could block gravity
involves thinking of gravity as a wave.
This says that gravity may have a really high natural frequency,
which explains why it penitrates all known materials. A
superconducting disk could resonate and downshift the frequency to a
lower level where it could be blocked by normal matter.
Theoretically, the gravity reduction effect should get weaker with
distance, like gravity.
A related quote from Dr. Noever at NASA is:
"Suppose it's based around a Van de Graaff generator (a high-voltage
machine dating back to the earliest days of electrical research).
Normally there are two spheres, and a spark jumps between them. Now
imagine the spheres are flat surfaces, superconductors, one of them a
coil or O-ring. Under specific conditions, applying resonating fields
and composite superconducting coatings, we can organize the energy
discharge in such a way that it goes through the center of the
electrode, accompanied by gravitation phenomena - reflecting
gravitational waves that spread through the walls and hit objects on
the floors below, knocking them over."
Ning Li's theory that she is currently useing for her experiments she derived directly from Einstein's Theory of Relativity . However, there are other scientists that say that the gravity-blocking effect is inconsistant with the Theory of Relativity. I guess we won't know who's right for another couple years at least. Unfortunatly, I was not able to find any papers by Ning Li, since she has not published anything in the past few years, concentrating fully on her research.
At the Marshall Space Flight Center, the current delay is caused by the lack of the type of superconducting disk they want. They tried to make 12in ones, but the disks tend to fracture to pieces (as in the picture to the right) during the pressing and baking processes. Last year, they paid $600,000 to Superconductive Components Inc. in Ohio to build the disk for them. The main ingredients of the disk are yttrium, barium, and copper oxide. This is a ceramic substance that, strangley enough, is totally nonconductive at room temperature. For the experiment, the disk will be cooled to around 40K with liquid nitrogen and spun. The disk is levitated by powerful magnets. A non-magnetic mass attached to a balance will be placed above the disk and weighed.
Ning Li says she has already completed her experimentation (using smaller disks) and is convinced that the gravity-blocking effect exists. She's now working on applications. Since she has not published any thing in the past years, few people know what she's really up too. She's still being funded by NASA though, so who knows? Perhaps there really is something to this.