USA As Represented by Secretary of the Navy

John R Welch

Thomas S Ramotowski

Andrew J Hull

Gerald J Roche

Shawn M Amorino

A software system and method is presented that calculates the sensor directivity at all spatial angles, and stores these values in a two dimensional matrix. These values are then used as additional 'weighting' coefficients in the equation for the pressure detected by an array of directive sensors. The azimuthal and polar angles of a particular sensor normal vector are used to 'rotate' the sensor directivity matrix to account for the angular orientation of each sensor within the array. The software system receives as input sensor and array geometry, shading functions, sensor shape, array structure baffling, steering, and shading. A sensor can have the shape of a point, line, plane, volume, baffled ring, or circular plane piston. The sensors within the array can either be baffled by the array structure or retain their free field directivity response, and array as a whole can have steering or no steering.

System and method for calculating the directivity index of a passive acoustic array

A method and test apparatus for carrying out testing on a variety of samples of polymer bonded to metal wherein the samples are subjected to an accelerated cathodic reaction causing cathodic delamination of the samples. In particular, the method and test apparatus include a closed vessel that is partially filled with synthetic ocean water. An impressed current system is employed to protect the metal component of the samples. The synthetic ocean water is heated with an external band heater raising the temperature of the synthetic ocean water to thermal levels exceeding normal ocean temperatures in order to accelerate the reaction. Pure oxygen is then introduced into the closed vessel at a desired pressure to dissolve the oxygen into the synthetic ocean water to further simulate natural ocean conditions.

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Westport, MA, United States of America

John R Welch