"Grain-boundary displacement, occurring in bicrystals during creep at elevated temperature (350 degrees c), has been measured as a function of the copper content (0.1 to 3 percent) in a series of aluminum-rich aluminum-copper solid-solution alloys. The minimums in stress and temperature, below which grain-boundary motion does not occur, increase regularly with the copper content as would be expected if recovery is necessary for movement. Otherwise, the effects, if any, of the copper solute upon grain-boundary displacement and its rate are too small for identification by the experimental technique employed" (p. 1).

This report covers an investigation of the application of the theory of dynamic longitudinal stability, based on the assumption of small oscillations, to oscillations an airplane is likely to undergo in flight. The investigation was conducted with a small parasol monoplane for the fixed-stick condition. The period and damping of longitudinal oscillations were determined by direct measurements of oscillations in flight and also by calculation in which the factors that enter the theoretical stability equation were determined in flight. A comparison of the above-mentioned characteristics obtained by these two methods indicates that the theory is applicable to the conditions encountered in flight.

"Attention is called in this report to previous investigations of gaseous explosive reactions carried out under constant volume conditions, where the effect of inert gases on the thermodynamic equilibrium was determined. The advantage of constant pressure methods over those of constant volume as applied to studies of the gaseous explosive reaction is pointed out and the possibility of realizing for this purpose a constant pressure bomb mentioned" (p. 479).