Abstract: A flight simulating mobile device is disclosed characterized in that any of a variety of different bird, butterfly or like flying creatures may be fabricated of plastic or like material, readily assembled, and balanced in such manner that when suspended in an air current the same provide a realistic replication of a creature in flight.

Abstract: Heat exchanger elements, particularly for solar panels, comprising metal tubing secured to a metal strip which is wider than the tubing and relatively thin by a weld which is metal of at least one of the tubing and the strip which has melted and cooled, the welding conditions being selected so that molten metal is expelled from between the tubing and the strip at the ends of short intervals and the strength of the weld varies longitudinally of the tubing. High frequency electric welding is used under conditions which cause the expulsion of the molten metal.

Abstract: A single ligament specimen is used to test the tensile properties in the short transverse direction of metal plate. A method of testing the specimen includes holding the specimen on one side of the ligament stationary and applying force to the other side of the specimen to elongate the ligament, and apparatus for implementing the method includes a fixture, a stationary clamp in the fixture, a movable clamp slidably mounted in the fixture, a load cell for measuring applied force to the movable clamp to elongate the ligament of the specimen, and a displacement transducer for measuring elongation.