6-18-12
I came into the lab today and Prof. Kandel and I tested the system with the AC input controller rather than the Variac that we had been using. One of our first attempts
exploded the gold. We searched for a resistor in the old Jacobs lab and found a 100 Ohm resistor. I cut one of the wires and placed the resistor in the series. Later when we were trying to heat the gold and we were failing, Prof. Kandel connected the two alligator clips on the ends of the two wires and supplied the voltage from the AC power supply. After turning it up a fairly high amount, the resistor exploded. We tried to think of a setup to make sure the gold heats up. Prof Kandel suggested that I make new clips that will contact the gold in a parallel manner rather than in one spot. This will give a greater area of contact between the two surfaces. I spent the rest of the day cutting and forming one of the clips. This was necessary becfause we saw the sample consistently only heating up in one spot, causing the gold in that small spot to vaporize and blow the circuit.
6-19-12
For most of the day, I worked on cutting and morphing sample holder clips. At the end of the day I was successful in getting one of the sample clips to have the shape that we needed to make the parallel contact. I used bronze to make the clips.
6-20-12
The first thing I did when I came in today was that I shaped the other bronze clip to be flat. After that, Prof. Kandel came in and we tested the clips with the AC power supply. He turned it on and the resistor got very hot but we could not notice any change in the temperature of the gold. Prof Kandel shortcircuited the system with alligator clips to circumvent the resistor. He turned the power on and turned the knob slightly up. There was a loud popping noise and there was a region on the gold that vaporized. This was a much larger vaporized region than any I have seen. After, I changed the 100 Ohm, 10 Watt resistor to a 4 Ohm, 25 Watt resistor so it could handle more power. I tested the system to see if I could heat the gold sample and I vaporized the gold before I could check if it had gotten hot. It vaporized a similarly large portion of the gold as it did in our last trial. I think that we need a power supply with smaller increments of voltages to prevent the large jumps from no applied current to the vaporization of the gold. After lunch, I tested another sample that read 5.3 Ohm before and shortly after I turned the supply on, the circuit was disconnected. I decided to reshape the clips and cut a new piece of ceramic insulating material. The old piece was beginning to crumble and was not providing a stable base for the gold sample. After doing these things, I charged a different sample with the AC power supply. It exploded after the first turn of the dial. Perhaps I will add another resistor to the series but I will talk to Matt and Prof. Kandel

6-21-12
I came in today and tested the sample clips using stainless steel as a sample instead of gold. The first time I did it, the stainless steel got hot as did the resistor. The second time, I exploded the resistor. Dr. Kandel came in with the copper plating for his plans on building a system that runs on DC power. He also brought a transistor. Matt had me draw out the setup on the copper board and he drilled the holes and cut the piece. Then I soldered the transistor to the plate. I soldered the ground and the output wires to the back of the plate. I will attach a wire from the back to the ground of the DC power supply tomorrow. It will be a system that sends 5 V at 1 Amp. :I also helped teach Jolae about the portable STM and about the theory behind Scanning tunneling microscopy. I showed her how to use the software, how to cut and change tips, and various other standard laboratory procedures
6-22-12
.Today I came in and Matt drilled larger holes in the copper plating for me so I could screw the board on to the top of sample holder. After that I soldered a wire to the back of the copper board and a wire to the input of the voltage regulator. I connected the input wire to the "+V" spot on the DC power supply. I connected the wire from the back to the ground spot on the supply. Then, I cut a wire and connected it from the "-V" spot to the ground spot on the supply. I took the hot white wire and connected it to the "L" position, which stands for line. I placed the neutral black wire in the "N" spot for neutral and the green ground wire to the ground spot. I checked the temperatures of the copper when plugged in from several different spots. I have indicated spots 1-5 on a diagram I have recreated of the copper plating and voltage regulator.
Temperature Tests
I would turn the system on and take temperature readings as it heated up every 5 seconds for 60 seconds. Then, I would turn off the system and record the temperature as it cooled down every 5 seconds for 60 seconds.
All temperatures are in Celsius.
The temperature drops were so severe when I turned the system off that I was unable to record a starting temperature.
Time(s)
Heating





Cooling






1
2
3
3
4
5
1
2
3
3
4
5
0
23.6
23.2
23.2
22.0
23.6
24.6






5
88.6
178.8
120.2
72.8
86.0
101.9
78.9
96.4
78.5
80.2
70.4
112.2
10
121.9
190.9
190.5
183.4
109.1
137.8
81.8
100.8
76.6
79.8
72.4
105.3
15
125.8
192.3
196.4
195.8
108.5
149.8
81.7
94.2
74.3
78.3
71.6
97.5
20
129.7
198.3
206.6
201.3
108.7
156.5
81.6
89.2
71.4
76.9
69.5
94.8
25
135.3
201.9
208.7
204.9
109.9
162.2
80.9
86.3
68.7
75.5
68.0
93.2
30
136.3
203.8
208.3
207.9
112.9
167.3
79.0
81.2
64.5
73.2
65.8
85.3
35
137.2
209.8
215.4
212.3
114.3
171.1
77.8
74.8
63.0
69.8
63.8
80.6
40
139.1
209.0
215.7
213.6
116.4
169.6
76.1
71.4
64.7
66.2
62.6
76.9
45
144.7
208.4
218
213.8
117.9
172.9
73.9
70.5
63.1
64.3
60.6
71.7
50
148.8
207.6
218.5
215.6
119.5
172.2
70.7
65.5
60.3
60.5
58.0
67.5
55
151.9
211.3
219.0
220.4
121.4
173.0
67.6
64.0
56.3
58.4
56.4
63.9
60
154.3
211.9
220.2
232.5
123.0
175.0
65.9
62.2
53.6
55.5
54.8
63.7
Prof. Kandel had me run exponential regressions on the cooling data because the sample should be cooling in a way where it loses the same amount of heat in twice the amount of time that it took before.

For Test #1, the regression gives Y= 86.08(.996)^x. The r^2 value is .809 and the r value is -..899 There is a decently strong correlation between the data and the equation. The equation accounts for approximately 80.9% of the data.
For Test #2, the regression gives Y= 106.38(.991)^x. The r^2 value is .976 and the r value is -.988. There is a stronger correlation here than in test #1 as the equation accounts for 97.6% of the data.
For Test #3, the regression gives Y= 81.23(.994)^x. The r^2 value is .960 and the r value is -.980 This has a similar convincing correlation to that from test #2.
For Test #3 part two, the regression gives Y = 87.07(.993)^x. The r^2 value is .960 and the r value is -.980. There is a very convincing correlation here between the data and the equation.
For Test #4, the regression gives Y= 76.06(.995)^x. The r^2 value is .957 and the r value is -978.
For Test #5, the regression gives Y= 117.50(.989)^x. The r^2 value is .991 and the r value is -.995. This is by far the most convincing of all of the equations because it accounts for 99.1% of the data.
Most of the regressions accounted for a very large portion of the data except for the one from Test #1. Perhaps I did not take the data at the proper time or the thermocouple was not properly attached to the surface.