Abstract: A protective arm cover utilizes a set of curved rigid panels to create a firm, structurally-sound guard with an opening for a user's arm. A set of metal ties may be used to join adjacent panels, securing the panels end-to-end. The panels and ties may utilize sets of holes to enable connection and size adjustment, thus preventing the apparatus from consuming too much space on the bed and simultaneously ensuring that the user's arm is comfortably supported during sleep. Shifting aligned holes in the panels and ties allows for adjustment of the diameter of the arm space. An inner padding within the arm opening created by the panels ensures that the user's arm is cushioned from the rigid panels. Similarly, an outer padding prevents the user's head from contacting the panels and ties while the user rests. Thus, the apparatus may prevent damage or discomfort to an extremity during sleep.

Abstract: A method and apparatus for magnetically measuring the amount and location of magnetite (Fe.sub.3 O.sub.4) debris adhering to the exterior of heat exchanger tubes which can be made of Inconel. A probe containing one or more coils of electrical wire is used to traverse the interior of the subject tube. One of the probe coils is energized with direct electric current to magnetize the magnetite coating on the tube exterior as the probe traverses the tube. The thickness of the magnetized coating is deduced from measurement of the voltage generated across a second coil of wire on a probe which traverses the tube at constant velocity.