Doctoral exam vacuum reverberatory furnace design error

Tom's reference to the tin-pest kinetics question being on his own doctoral exam — a self-deprecating anecdote about whether he could still do the calculation. The cluster name from the aggregate refers to a different doctoral-exam anecdote; this may be a separate one. Flagging for editorial review of whether to extend the cluster or create a new one.

It happened to the Russians in World War II. They had a big stockpile of tin outdoors that they were storing, and the winter came along, everything got covered with snow, and in the spring when the snow melted, they found they had a pile of not tin ingots but tin powder, because it got to minus 18° centigrade, or thereabouts, which is the maximum transformation temperature. This question was on my doctoral exam, by the way — not tin pest, but the maximum transformation temperature of gray tin to white tin, and going through the kinetics. If I'm a Russian general, I'm just irritated I've got a bunch of tin oxide now rather than tin ingots. But I could calculate it at that time in my life — at least I guess I could, I don't remember if I could or not. I got a pass, who cares.

One of my favorite gradings of doctoral exams was back in my second year on the faculty. Professor Bowen, who's no longer here — he's retired from Harvard Business School now, but he was a professor of ceramics before he went up there — asked a question on the general exam asking a doctoral candidate to design furnaces for three different applications. One student had a reverberatory furnace, but for whatever the application was, he wanted to do it in a vacuum. So he had this flame shooting right into the vacuum, and he had a picture of it. I was grading this question, and Professor Clark, who was in charge, had his office right next to mine. I went over and said, "Did you make this up? This couldn't be a student's answer. Is this real?" And we looked at it — no, he hadn't, he wasn't trying to pull an April Fool's joke. It was real. We sent it back to Professor Bowen and graded it with a very low score. Actually it was the student's second time around, and he never did get a doctorate. So MIT does have some standards. Our standards may be low, but we have them.