Abstract: The present invention relates to a SQUID device for magnetic field measurement. The device is comprised of a body of superconducting material. First and second holes are located therein. A slot is provided joining the first and second holes. A contact unit is provided which is located in the slot thereby forming a weak link across the slot. The dimensions of the first and second holes produce first and second inductances respectively. These inductances have unequal magnitude.

Abstract: A device and method producing a compensated gradiometer signal from an uncompensated gradiometer signal having at least one unwanted term which varies as a function of magnetic field. The device is comprised of a sensing unit for sensing the magnetic field. A generator is provided for producing a first vector signal which is representative of the magnetic field. A function generator is provided for producing a second vector signal which represents a component of one of the at least one unwanted term. A mixer is connected to the generator and the function generator for producing a vector output signal which is equal to the one of the at least one unwanted term. Finally, a subtractor unit is provided which is connected to the mixing means for subtracting the output vector signal from the uncompensated gradiometer signal to thereby produce the compensated gradiometer signal.

Abstract: The present invention relates to a system for the nondestructive testing of the thickness of boiler tubes. The system comprises a probe assembly which includes a mounting unit for mounting the assembly in a mud or water drum of a boiler at the location of a boiler tube to be tested. The probe assembly is comprised of an ultrasonic transducer for transmitting and receiving ultrasonic signals. The probe assembly further includes a motor drive connected to the transducer. A control unit is provided which includes a motor control portion connected to the motor drive to selectively position the transducer at a plurality of locations in the boiler tube to be tested. The control unit also includes an ultrasonic drive for producing an ultrasonic pulse for driving said transducer means. A water control is connected to the control unit, a source of water supply, a drain, and the probe assembly.

Abstract: A device for enabling a diver to determine his relationship to the true horizon in deep and murky waters or when physiological sensations are of little value is described. An attitude sensor, incorporating a series of mercury switches, usually at the back of the diver's helmet or head, is coupled to a series of light emitting diodes equally spaced around the periphery of the face plate of the diving mask or helmet so as to simulate the natural observation that the half space above the horizon is illuminated while the half space below the horizon is not.