Hello all friends:

Recently, the way of screwdriver operation has raised the question in our class. Everyone who has worked with screwdriver knows the screwdriver is made up of a tip and a typical hand comprising cylindrical handle of a size and shape to be held by a human hand, and an axial shaft fixed to the handle. The handle and shaft allow the screwdriver to be positioned and supported and, when rotated, to apply sufficient torque and open screws and bolts. The question is why the longer the axial shaft is, the easier the screws are opened? That is, if you have two kinds of same screwdrivers in all aspect except in the length of their shaft, the longer screwdriver open the screws more easily. While in accordance with torsion law, torque which cause to open screws, is not related to the length. (T=τJ/r)

We want to know what the reason of this matter is and what factor cause to do so?Please contribute in this argument and give your opinion.

Thanks,

Dr. Martin at Colorado School of Mines alerted us the unfortunate news of the passing away of Prof. Maurice Jaswon, a pioneer of boundary integral equation/boundary element method. An obituary is published by the London Daily Telegraph:
http://www.telegraph.co.uk/news/obituaries/technology-obituaries/8977347...
You can also read Jaswon's contribution to BEM in this history article: http://www.olemiss.edu/sciencenet/benet/05eabeb.pdf (posted with permission by Elsevier).
As we may publish a memorial article in Engineering Analysis with Boundary Elements, if you would like to contribute, please contact Paul Martin (pamartin@mines.edu). Regards,