Abstract: A metal-matrix composite of magnetostrictive powder is manufactured by dynamic compaction, such as that provided by the shock waves of an explosive, from a magnetostrictive powder in the presence of a matrix-forming metal. Under the conditions of dynamic compaction, property compromising phases between the powder and the binding metal are not formed, resulting in a composite essentially free of these phases. The composites may be formed by coating a magnetostrictive powder with a matrix-forming metal by a sputtering process and dynamically compacting the coated powder. A coated powder may also be made by sputtering a layered composite of metal-magnetostrictive material-metal, and grinding the layered composite. Metal-matrix composites may also be made by mixing the matrix-forming metal with a magnetostrictive powder and dynamically compressing the mixture. Metal-matrix composites of amorphous magnetostrictive powders may be annealed in the presence of a magnetic field.

Abstract: A telemetry system adapted to monitor earth slope stability comprises a minimum of one earth slope stability sensor connected with timing means, which, upon the sensing of slope instability, initiates transmission of a timed signal of a predetermined carrier frequency, and a superimposed tone frequency, by an associated transmitter. A receiver picks up the transmitted signal along with stray signals and feeds all such received signals to a decoder which produces corresponding pulses. The pulses from the decoder enter a time gate circuit, which determines if the time durations of the respective pulses fall within predetermined maximum and minimum limits and which also produces an output signal if a pulse is within such limits. The output signal is used for alarm purposes.It is ordinarily desired to simultaneously monitor several sites of possible earth slope instability. For this purpose, several sets of stability monitors, timers, and transmitters are provided.