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The long-term goals of this research are to develop an understanding of wave groups and wave breaking in random seas, including the interrelations between the two. The specific objectives of this project are as follows: (1) Study wave groups and wave breaking, develop a laboratory database using measurements made in the Naval Academy's 380-ft wave/towing tank, and develop appropriate statistical descriptions and theory for the observed phenomena; and (2) Investigate the influence of the laboratory system on measurements. Statistics were derived from laboratory wave records of random seas. Theoretical concepts were established from similarity arguments, general statistical theory, existing theories of wave statistics and wave groups, wave mechanics and extensions to include nonlinear effects. The influence of the laboratory system on measurements is examined by varying the measurement location in the wave tank, by comparison of results with full-scale ocean data, and by comparison with results from computer simulations., See also ADM002252.

X-ray diffraction line broadening studies were conducted on polycrystalline nickel samples subjected to shock pressures of 70, 150, 270, 375 and 615 kilobars. Lattice strains and small domain sizes are given as a function of shock pressure. Results indicate a linear correlation between lattice strains and shock hardening. A discontinuity in both the hardening and lattice strain data at a shock pressure between 270 and 375 kilobars suggests the possible occurrence of twinning. (Author)