Copasetic Flow

 Fun with superconductors on a Monday morning. Did you know that Type II superconductors like the YBCO one shown below can pin magnetic flux? Consequently, if you freeze in the field lines, you've got a superconductor that behaves like a magnet.

 I'm getting some bandwidth to put more work into my book about Boleslaw Gladych and his connections to the gravity (and antigravity) research communities that included characters like Agnew Hunter Bahnson Jr. during the 1950s.  I found an article [pdf], (pamphlet? it's 42 pages), that sheds more light on the work DeWitt did with superconductors and gravitomagnetic fields in the '60s. Take a look at page 34 where DeWitt comments on the work he did to try to verify Bahnson's fringe pet project: Thomas Townsend Brown's gravitators. There you'll find a reference to DeWitt looking into superconductor theory .  I also found a nice little JSTOR blog post on the whole Babson and Bahnson Gravity Days era. I haven't seen anything new in it yet, but I aslo haven't taken the time to focus on it. Speaking of DeWitt, this history of the UNC Field Institute is interesting in that it mentions DeWitt's work related to 'large spaceships'.  One final note, W...

While doing research for an article I'm writing about Janet Tate and her Gravity Probe B experiment[4], I found a few cool things regarding superconductors, frictionless bearings, and the Egg of Columbus experiment this morning. The Egg of Columbus demonstration was first performed by Nicola Tesla in 1893 at the World's Columbian Exposition [1].  Here's a brief video from MIT showing a modern day version of the demonstration[2]: The MIT site[2] describes the apparatus as follows: "A toroid with three different wire windings is connected to 220 VAC 3-phase voltage. The voltage phase of each of the three windings lags 120 degrees behind the next, creating a changing induced magnetic field. The changing field causes metal objects to rotate when placed inside. Motors using this principle are very common. In fact, power lines are often seen in sets of three because they are carrying three phases. For more information on 3-phase voltage," Alfred Leitner made ...

If you're new to the experiment, scroll to the bottom for background that will catch you up with what's going on. Liquid Nitrogen Fill The liquid nitrogen Dewar has been filled.  It’s initial and final weights were 146 and 170 pounds, respectively.  I’m guessing I must have read the initial weight incorrectly, but we may be paying too much for ’45 liters’ of nitrogen which might be closer to 13. liters/pound 0.5606 start 146 finish 170 net 24 Total Liters 13.4544 I’m doing the same measurement as yesterday with the sample immersed in liquid nitrogen.  There seems to be no change.  I have however invented a reasonably good vibration detector for the vacuum pump across the room, see video here . I’m going to try a new configuration of the two coils next.  Pancake coils will be constructed with one placed on each of the opposi...

Lab Book 2014_12_30 Today I worked on getting a qualitative susceptometer up and running.  By qualitative I mean that we won't be attempting to analyze the returned data to accurately determine any characteristics of the superconducting materials that are to be studied, only the state of the materials, and the existence, or not of a hysteresis curve for the material. The why of it all I’m experimenting with a quick and dirty susceptometer that can be used with the hray experiment to determine when we’ve quenched the superconductor.  Today’s work is using a ferromagnetic core, not a superconductor.  The responses are similar and I don’t have to worry about cooling a superconductor. Experimental Setup Something old and something new I’m pressing a General Radio 1311-A audio oscillator and a Tektronix TDS 210 into service together. The general radio signal generator is being used to drive the coil surrounding the iron core.  The...

I was back in the lab this morning.  I’m working on getting the four point measurement to work on the YBCO sample.  In the grand scheme of things, this is low priority, but it’s important to know that we can successfully make these measurements here before we have a large bucket of liquid helium evaporating with a sample inside.  Here’s what the four point probe measurement looked like: There are still no conclusive results.  With any luck this is a consequence of me not being able to interpret the results more than a bad experimental setup.  The table below details the four point probe readings in ohms as the superconductor cools Table of four point readings Time Resistance kohm Comments 0 -0.35444 Negative reading is probably from swapped sense wires. 16 -0.36735 Immediately after nitrogen pour 59 -0.34466 Near minimum 101 ...

The lab book today was a bit sparse and a bit dry.  This is a bit odd considering I got to play lab yesterday...  You'll see. First, here's an archival video of the presentation I did last Sunday for the TX APS section meeting here in College Station.  I fumble a few times, but the content is all there.  If you have any questions, they are very, very welcome! The second video has some kind of cool stuff in it.  Not stuff that went the way I had hoped mind you, but cool nonetheless.  Here's the deal; we'd hoped to make a spiffy little superconductor visibly quenching video.  The idea was to suspend a superconductor as a pendulum in a magnetic field.  It was hoped that as the field increased, the superconductor would swing away from the pole of the magnet, (it did), and that as the field increased more, the superconductor would quench and fall from it's suspended state, (it didn't).  Our melt-texture growth superconductor from CAN just wo...

I spent most of yesterday travelling between Austin and College Station, but I did manage to get a little bit of research in.  I'm looking for other experiments related to Hirsch's theories we can do in conjunction to the search for H-rays.  One of the measurable predictions of Hirsch's theory is a change in the coefficient of sliding friction when a material enters it's superconducting state. All about friction [6] New to the lab book?  Scroll to the bottom for background and a summary of the experiment. Hirsch mentions [1] that a finding of reduced friction in superconductors might be evidence in support of his hole theory of superconductivity. Furthermore, the electronic layer outside the surface is likely to affect the friction properties of the superconductor, by providing a ‘lubricating layer’ on top of which another material would slide. As a matter of fact, an abrupt drop in sliding friction between a lead surface and solid nitrogen has be...

Lab Book 2014_06_20     Hamilton Carter New to the lab book?  Scroll to the bottom for background and a summary of the experiment. Pulling the Dewar from the Table The spray Styrofoam was shaved off the Dewar this morning revealing that the Dewar had originally been installed on a piece of regular Styrofoam and the spray coating was added later The plan is to peel away as much of the spray foam as is practicable, and then do a two person lift of the Dewar out of the table.  The Dewar will be immediately placed in a padded box. The Dewar was successfully removed!  Next, I’ll remove the shelf and put the magnet in place.  There’s one cooling tube that was knocked off the magnet as it turns out, so that will have to be fixed. Vacuum Pump Down! The leak detector vacuum pump appears to be broken.  The reading on it is a much worse vacuum than from the auxiliary one on the lower shelf of the cart ...

Scroll to the bottom for background on the experiment. Checked that the pole faces of the yoke magnet retract fully leaving enough room for the glass Dewar.  The poles do retract far enough, but there is a trick to it.  The rotator that advances and retracts the pole piece should have two metal collars associated with it.  On the side I initially tried to adjust, one of the collars was missing and the pole would not move.  When I moved the second collar to that side of the magnet, the pole piece moved after applying a little bit of force Here's how it works  The collar the handle protudes from is threaded on the inside.  It turns on the threads that are visible and are attached to the pole piece.  If the second collar is in place, then the torque created by the handle is applied to the threads of the pole piece and it slides back and forth through the treads of the handled piece along a small rail at the bottom of the threaded pole.  A...