Abstract: A system for making computer software consumable is provided. The software comprises a set of units, each of the units being an interactive activity between the program and the user which can be separately completed from the interactive activities of the other units in the set. The completion of units is monitored by means of a copy-protected region of a recording medium and when all units have been completed, further access to the software is denied. Among the applications for the system are academic tests composed of different subject categories, games having different levels of difficulty, and workbooks having different tasks to be performed.

Abstract: Apparatus and methods for durability (fatigue) testing of prosthetic heart valves or other check valves. The apparatus is circular in plan and includes a test fixture in which the valves are circularly arranged, located with communicating passages, such passages communicating with bellows closed at one end. The bellows are carried by a swash plate journalled to a motor by a coupling providing an adjustable tilt axis. The tilt axis determines the amplitude of the motion or flow of the fluid, as the bellows alternately expand and contract. A central bypass chamber includes orifices which are selectively varied in effective cross section to control an amount of the test fluid which bypasses the test samples, thereby determining fluid pressure differential across the sample valves. Fluid in the apparatus can be heated by an electric heater to temperatures similar to human blood, a temperature probe monitoring the temperature for its control.