Abstract: A fan assembly includes a plurality of discrete platforms disposed between adjacent rotor blades extending radially outwardly from a rotor disk. Each platform includes forward and aft axially spaced apart ends, and radially upper and lower spaced apart surfaces extending between the ends. Forward and aft retainer rings capture the platform to the disk with a predetermined clearance therebetween for allowing the platform to move radially upwardly under centrifugal force for retention by the retainer rings, while also allowing the platform to move radially inwardly under a radially inwardly directed impact load on the platform, which impact load is channeled through the platform lower surface at both the forward and aft ends into the rotor disk.

Abstract: An electromagnetic lock which mounts at the top of a door frame and magnetically bonds with an armature employs both an ultrasonic sensor and a passive infrared sensor to detect the approach of an individual at the doorway. Both the ultrasonic sensor and the passive infrared detector have fan-shaped sensing regions which are positioned forwardly from the doorway. Upon detection of an individual approaching the doorway, the lock is capable of automatically releasing to allow egress through the doorway.

Abstract: An ultrasonic system and method for examining the structure of a subject body is disclosed. The system includes an improved ultrasonic transducer and power circuitry for electrically stimulating the transducer to produce an incident ultrasonic energy beam along a path extending into the subject. The incident beam produces echoes within the subject, some of which propagate back toward the transducer. The transducer, in response to received echoes, produces electrical signals bearing information about the structure of the subject. The system further includes circuitry for processing the electrical signals and a display apparatus responsive to the processed electrical signals for producing a visual display of subject structure.The transducer includes a concavo-convex piezoelectric emitter for producing ultrasonic energy having a dominant frequency, an acoustical impedance matching transformer and a coupling element.