Abstract: An instrument for computing resistivity based upon measurements of thickness and conductance. A conductance transducer is a solenoid in an annular ferrite cup connected to a tank circuit for an eddy current measurement of conductance. Within the center of the annular ferrite cup concentric acoustic wave sending and receiving channels are disposed for making an acoustic pressure wave measurement which is used for a thickness measurement using two gauge heads, spaced on opposite sides of an article to be measured. Each gauge head contains identical conductance and thickness transducers. The thickness measurement is divided by the conductance measurement to derive resistivity.

Abstract: A deflectable drill collar having strictive material deflectable elements is connected in a drill string of drilling apparatus. Energization of the strictive material deflectable elements, such as magnetostrictive elements, deflects the drill collar, thereby altering the axes of the drilling apparatus connected at opposite ends of the deflectable collar from a colinear relationship to a non-colinear relationship. Energizing means associated with the deflectable drill collar energizes the strictive material elements during preselected intervals of rotation of the drilling apparatus to place the cutting elements of a drill bit into more effective cutting relation with gage corner material of the borehole, or to articulate the drill string and force the drill bit in a desired direction.

Abstract: A magnetometer assembly wherein a magnetometer detector suspended from a gimbal is immersed in a wax so as to immobilize the detector. Desired gimbal operation is achieved by heating the wax in the vicinity of the detector.

Abstract: A combination seismic/magnetic transducer capable of detecting movement in a magnetically-permeable body or vibration within the body while it is stopped.

Abstract: The surface defect detecting apparatus for rotating cylindrical metal pieces which move in a lengthwise direction relative to a sensor block, has a plurality of eddy-current flaw detecting coils facing the test piece. The sensor block rotates about a horizontal axis extending vertically with respect to the axis of the test piece to follow up deflections of the test piece in the direction of the axis of rotation. Front and rear ends of the sensor block, have a pair of guide wheels that engage the piece; also present are color marking nozzles for marking defective areas in response to detector signals. Relative movement in the longitudinal direction of the test piece is carried out by means of a carriage carrying the sensor block. Each guide wheel is spaced from another in a plane transverse to the longitudinal direction of the test piece.

Abstract: Coded binary signals are coupled to an automotive vehicle by a magnetic signpost embedded in a traversed roadway lane. The signpost includes polarity coded magnetic pole faces having vertically directed flux lines at differing spaced longitudinal regions along the lane. Pole faces are arranged so a flux null is between adjacent longitudinal regions. Differing signals are coupled to vehicles going in opposite directions in adjacent lanes by unambiguously coding the signpost in opposite directions and arranging the pole faces so that magnetic flux continuously extends across a majority of both lanes. A detector on a vehicle includes a magnetic field concentrator including a pair of vertically extending and aligned low reluctance magnetic pole pieces having an air gap between them, in which a Hall plate is positioned. The pole piece closest to the road has shorter length than the pole piece remote from the roadway.

Abstract: In electromagnetic testing method for tubes is disclosed, which is used during continuous production of tubing from strip being formed into a tube followed by welding the adjoining edges. A magnetic field is applied from the outside, possibly being a field accompanying the welding process, and a pickup transducer is inserted from the tube forming location to scan the interaction of the penetrating field with the tube particularly the seam and adjacent zones.

Abstract: Continuous testing apparatus for determining the magnetic characteristics of a strip of moving material including a flux inducing and pick-up device to induce a quantity of flux into the material and dual voltage output producing coils for producing different voltages from material having the same magnetic permeability, and circuit means coupled with the dual coils to produce an output voltage which is a characteristic of the ratio of the voltage produced by one of the coils and the difference between the voltages produced by both of the coils. The invention also includes the method of obtaining a profile of the coil of the material throughout the entire length thereof.

Abstract: An improved ring core second harmonic flux gate magnetometer is constructed as a module for use as a ferrous metal detector. Pairs of modules may also be used as gradiometers. Various uses and winding arrangements on the ring cores are disclosed.