The sensitivity of magnetoelectric (ME) sensors is more than an order of magnitude higher at their mechanical resonant frequency fr. By applying a restoring torque to an asymmetric ME sensor, we have increased its effective stiffness and, thus, fr by 20% while maintaining the enhanced sensitivity at resonance. The torque was dependent on both the tensile force from a suspended weight and the length of the wire attaching it. This provides two alternative routes for tuning fr to optimize performance. We have detected fields below 10 pT at both the shifted and unshifted fr of 132.2 Hz.
An order of magnitude model is presented to estimate radiation from detonation of conventional explosives in an attempt to predict frequency bands and signal levels detected by other investigators. An earlier model describing the radiation generated by explosions has been refined to include the contribution of the heat capacity of the detonation products and the temperature dependence of the concentration of ionized particles. Relationships are established between explosions of uncased Composition B, the radiation frequency bands, and the E-and B-field amplitudes as a function of detection distance. The model considers the radiation from particles ionized by passage of the shock wave.
2Q. ABSTRACT fCcnrtfinia an fararaa a£A ft iia<.aaaafy and Idanttty by block numbar) A ram-air-driven power supply for a proposed high-altitude rocket was tested in the Naval Surface Weapons Center supersonic wind tunnel facility. The wind tunnel data that corresponded to points on the trajectory providing the least ram-air energy showed that the generator operated throughout the test and produced a minimum DD , FORM JAN 73 1473 EDIT10H OF I MOV 6S IS OBSOLETE UNCLASSIFIED , SECUmXY CLASSIFICATION OF TWIS PAGE (Wlnrt Data Entarad) UNCLASSIFIED SECURITY CLASSIFICATION OF THIS PAaE(Whmn Dtim Entered; 20. ABSTRACT (Cont'd) of 26.4 Vrms into a simulated fuze load near the apex where pneumatic power input is minimal. A method of predicting generator voltage in flight from laboratory calibration data and expected flight conditions was verified for Mach numbers from 1.5 to 2.02 and free-stream total pressures of up to 20 lb/in.^ abs (137 kPa). UNCLASSIFIED SECURITY CLASSIFICATION OF THIS PAGEfHTion 0«(a En(ored;
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