If you've ever worked while resting a laptop computer on your lap, you know that computers emit heat, and the more powerful the computer, the greater the heat produced. This is a problem because electronics really don't enjoy elevated temperatures. A hot computer is a slow computer or, worse, a computer that will cease functioning.

The current conflict in Iraq is proving to be a war of amputations. If it's any consolation, an extremely well engineered prosthetic, the Boston Digital Arm (BDA), promises to reproduce much of a lost limb's functionality. The BDA's operating principle has been well demonstrated—the user's remaining muscles and nerves activate the device and control its movements. This arm goes beyond conventional prosthetics, though, by having five axes of motion as well as a variable gripping force in the hand that gives the user the ability to "sense" a held object.