Getting Down to the Wire

A few months later, at a Boston meeting on superconductivity, a somewhat different response was indicated by Shoji Tanaka, who had led the University of Tokyo team that confirmed IBM s discovery of superconductivity in the lanthanum compound. Asked to comment on recent reports that the Japanese had made great progress in firing a ceramic into a serviceable wire, Tanaka said, My work is not in that direction, adding, after a fairly long pause, but in any event that might be a secret, I think.  

Tanaka s reluctance was understandable. High-temperature superconductivity has enormous commercial, as well 

But the distance between the laboratory and the marketplace is often long. Space engineers didn t invent rockets one day and send men to the moon the next. Some twenty years elapsed between the discovery of the double-helix structure of DNA and the first transplantation of a gene from one organism to another. The atomic bomb came forty years after Albert Einstein gave us the theory behind it and his formula that linked energy and matter E = me2. As Donna Fitzpatrick of the Department of Energy recalls  

When the transistor was invented, everybody said, well, that s kind of interesting, and so it was licensed to the Japanese because we didn t know exactly what to do with it. Now just about every home appliance has a transistor in it, and a little microprocessor to program it, your microwave oven, VCR, and a lot of other things. Some people have said we probably haven t even thought of the applications that will have an impact. Who 

While no one is saying it will easy, researchers are somewhat consoled by the fact that one of the common, old superconductors—niobium-tin, an extremely brittle alloy— is wound into thousands of miles of wire every year. And so in laboratories throughout the world, ceramists grind their new materials into fine powders, fire them black in hot ovens, then blend them with binders, plasticizers, and wetting agents (a popular binder is oil of menhadden, a herringlike fish used as bait and fertilizer). 

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Stick a cork in it. A cotton plug really. Mayo et al. suggest that you push a small cotton ball way down into the narrow part of the pipet with a copper wire, rinse the cotton with 1 ml of methanol and then 1 ml of hexane, and let the cotton dry before use (Fig. 41a). On all your pipets. Well, sure, once you get good at it, it won t take all lab period to prepare them. Of course, you could just get good at being careful with this solvent pressure phenomenon. 

If you have space for another basket, you could propagate another batch of strawberry plants and get more berries the following year. Strawberries make new plantlets at the end of runners. Hang the second basket right next to the first one. In early fall lift up several of the runners from the main basket and lay the plantlets onto the soil of the second one. Pin down each runner with some galvanized wire. 

I dashed back to the Pantiles, panting to get the word on the wire that the British general had said he d attack any Arab invading army. Sandy was all set to start. He began pawing the air when I said there d be a slight delay. I sat down at a battered old typewriter to bang out my yam. 

The conclusion from this argument, which was verified by experiment, was that the adhesion force decreases as the wire diameter is reduced. But instead of the force going down with contact area, that is d, it goes with In other words, the stress required for adhesion failure increases for finer wires. The adhesion seems to get stronger with d. Some numbers are plotted in Fig. 13.4 for elastic platinum wires on a silicon substrate. 

If the circuit of Fig. 10.2 on the previous page is assembled with the 9 volts going into the primary (two heavily insulated black wires), it will still be used in the "step-down" mode, and the neon bulb will not light when hooked up to the secondary (lightly insulated yellow wires), because it requires much more than 9 volts, and instead it will probably be getting less. (Actually, it could be lit if the battery was connected or disconnected fast enough to make up for the unfavorable ratio of turns, but probably neither operation can be done fast enough here.)... 

There are two modules in a strip chart the electronics and the mechanical. The trick is to look at one at a time. Disconnect the detector leads, turn off the bed, and watch the pen. Does it sit quietly or chatter up and down Noise at this point comes from the strip chart electronics. If it s quiet, turn on the bed and let the pen trace to see if the baseline is flat. If so, short across the leads and make sure the pen deflects without sticking (this would show up as a plateau in a chromatogram). Lubrication or drive wire replacement would fix the problem. Do not get much oil on the slide bar it just traps dust. Spray some WD40 on a Kimwipe. Wipe the bar, then wipe off the excess. Next, use a stopwatch and time the bed. Is it accurate at 0.5cm/min where you will be using it If it passes these tests, we re ready to hook up the detector leads and move on. 

Check Cables for Proper Orientation A common problem when putting a computer back together is putting a cable on upside down (this frequently happens when installing cables for floppy drives). When this happens, the computer will get erroneous signals from the device. A rule of thumb for internal cables is to orient the cable so that the red wire is toward pin 1. A common indication that the floppy cable is on upside down is that the floppy light will be on constantly. 

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