9 DIGITAL PRESSURE CONTROLLERS, COMPUTERIZED UNITS DESIGNED TO DETECT, ENUMERATE, AND IN SOME INSTANCES DETERMINE THE ANTIBIOTIC SENSITIVITY OF MICROORGANISMS AND SUPPLIES FOR SUCH UNITS-NAMELY, LABORATORY CASSETTES IN THE NATURE OF DISPOSABLE PLASTIC PLATES CONTAINING WELLS PREFILLED WITH FREEZE-DRIED MEDIA FOR USE IN TESTS MADE BY SUCH UNITS AND SPECIMEN LOADERS MADE FROM METAL AND PLASTIC FOR SUCH PLATES, AND ELECTRICALLY AND MECHANICALLY OPERATED VISUAL TERRAIN SIMULATING DISPLAYS FOR AIRCRAFT SIMULATORS AND USING PROJECTION SCREENS