Wednesday, July 9, 2008

Diagnostic Testing


Today, the power at UCSB was going on an off. As the wildfires reached some critical distance from the power lines in the Goleta foothills, the power for UCSB was shut off as a precaution. I allowed myself to become frustrated for a moment, then realized that being able to anneal some YBCO pellets paled in comparison to the importance of protecting those whose homes are jeopardized.

The power outtages were unannounced, so we couldn't really predict when they would happen. All furnaces and power-requiring devices were shut down. I always knew but never really thought about how dependent we are on electric power. The lab was really shut down except for the "wet chemistry" room which didn't require too much gadgetry.

To adjust our own work, we performed four diagnostic tests on our pellets and track. These tests were:
1. Finding the maximum distance between magnets on a straight track that would still allow for continuous movement
Results: 2 mm was the maximum distance. At 3 mm, the car would not move. It would move across a few magnets, then stop.
2. Finding the maximum distance between the outer magnets on a curved track.
Results: 3-4 mm allowed for continuous movement around a curve. When the curve was stretched to 4-5 mm between outer magnets (making for a sharper turn) the car would either veer off the edge of the curve or stop its motion.
3. Finding the maximum mass that 5 of our best pellets can levitate.
Results: 1.8 g

4. Average levitation height for a pellet.
Results: ~6 mm (This was tough to measure precisely, but it was in the range of 5-6 mm)

5. Average levitation time for pellets and styrofoam cars
One pellet (no insulation)
Highest Time: 17.06 s
Lowest Time: 7.31 s
Average Time: 10.52 s
Three-Pellet Car (used the three best pellets, taped to bottom of styrofoam car)
Highest Time: 45.63 s
Lowest Time: 38.61 s
Average Time: 41.07 s
Five-Pellet Car (used the best five pellets, taped to bottom of styrofoam car)
Highest Time: 63.85 s
Lowest Time: 52.68 s
Average Time 60.50 s

Without much more that we could do, we broke for the day. We seem to have found a maximum curve that we can make a car move around. Also, we have found a design that works well. We have used 84 magnets to make this track, and we may need to purchase more in order to make a complete oval track. I am not sure if that is in our budget, but it now seems that we are only making small tweaks.

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