The human ecosystem is made of open and closed systems. While the earth is a closed system for matter but an open system for energy, the human body is considered an open system. There is a growing ...

THIS well-known text-book has been largely rewritten and enlarged for the present fourth edition. In the preface Prof. Bovey states that a number of fresh examples, mostly drawn from actual practice, ...

"In the preparation of this book the senior author's earlier Russian book ("Theory of structures,' by S. Timoshenko, 2d ed., St. Petersburg, 1926) was extensively used."--Pref.

On a crisp fall New England day during my junior year of college, I was walking past a subway entrance when a math problem caught my eye. A man was standing near a few brainteasers he had scribbled on ...