A History of Pi – Petr Beckmann


 

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A History of Pi

Petr Beckman

©1971, The Golem Press

1993 Ed. Barnes &Noble, Inc

ISBN  0-88029-418-3

Rating: 1 of 5  I will not finish reading this book.

I think this is a poorly written book.  His history is uneven. He often makes statements that I think demand explanation, and his explanations are weak (kind of like this sentence).  I do not follow his proofs.  Much of this may be due to a lack of definitions.  The figures do not help, because he refers to them in unclear (or even misleading) ways.  I think the editor had no understanding of the topic.  The editor was out of this league.

The author shows that this topic has the potential for an interesting book.  However, this is not it.  I have many other books to read, and will stop wasting my time on this one – right now.

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Newton’s Clock – Ivars Peterson


Newton’s Clock: Chaos in the Solar System

Ivars Peterson

W.H.Freeman and Company, New York

ISBN 0-717-2396-4

QB351.P48 1993

Rating: 5 of 5  This book gave me a new appreciation for difficulty of the many-body problem, and what insights are possible.  It gave me a new respect for those people who pursue those difficult problems.

One of the opportunities I have during retirement is to revisit my library, to reread books I have enjoyed in the past, and to read some of the books I bought, but never got around to reading. This is one of those books I’ve had for a long time, possibly over 20 years, but never read. Now I wish I had read it much earlier. I’d like to have read it while in graduate school. However it was not yet available, indeed much of the work discussed, had not been accomplished yet.

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An Alternative Extruder-Base Alignment Procedure for FlashForge Creator X


Bad Print 1

Figure 1. Bad area on bottom.

I’ve been having a lot of fun printing prototype pieces for a potential high altitude balloon box (more on that another time). Unfortunately this is a lot like the old days, when printers replaced typewriters. As I made corrections to a document, I’d reprint it. WYSIWYG was not really any help. The paper copy was always a little different. Suddenly I could go through reams of paper perfecting a small document. Unfortunately, I use my 3D Printer the same way, exploring new ideas and finalizing fits.

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Printing an Ogive Nosecone for Model Rockets

BT-50 Nose cone assembled

I took my own advice and bought the Flashforge Creator X 3D printer. It has two MK8 print heads, for printing two colors, and an aluminum plate. So far I like it. I’m using ABS plastic and so far have had no jams. I’ve replaces the Kapton(tm) build plate covering once so far. I beat it up after seven or eight builds. The initial instructions suggest a plate temperature of 90C. I’ve had better luck with parts sticking to the build plate at 110C.

 

My initial interest in 3D printing is to make model rocket nose cones with a capability of carrying small payloads. Getting a 3-D printer has given me a opportunity to develop some ideas. I’d like to have a nosecone that can carry small circuit board payload. The version described here does not have that capability, but it is a step toward that goal. It includes a shell of a nosecone. I’ve included some internal bulkheads, though I’m not sure they are needed. The nosecone needs to survive the launch pressures. The bulkheads will need to be reduced, but could be thickened, to carry a payload.

Printing a nose cone

Printing a nose cone

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