Behavior In Seawater Research Articles

Spectrum of Atmospheric Turbulence

DR. E. C. S. MEGAW1 opens his valuable contribution to this subject with a challenging remark. He says, “knowledge of the average properties of turbulence in the free atmosphere is almost totally lacking”. Actually, so many meteorologists have published observations that it would be impossible here to give an adequate list of them. As long ago as 1926, I summarized the available facts in the statement that the diffusivity for neighbours is roughly proportional to the four-thirds power of their separation2. That was an empirical induction from observations: the accompanying theory was an aid to description, and did not use any dynamical hypothesis. The separations ranged from 108 cm. (Defant3) to 30 cm. (Richardson4). The theory afterwards started by Kolmogoroff to which Dr. Megaw refers is an independent and fascinating intellectual creation, based on energy and the theory of physical dimensions. Recently, Batchelor5 has related it to the aforesaid summary of observations. The behaviour of sea water is, strange to say, also relevant6. These objections to Dr. Megaw's opening paragraph do not in the least detract from the merit of the rest of his publication.

THE BEHAVIOR OF NICKEL COPPER ALLOYS IN SEA WATER

The author presents a most complete work relative to corrosion of nickel‐copper and copper‐nickel alloys. The subject is handled in such a manner as to avoid controversial matters and proper emphasis has been given to the several factors which must be considered in selecting a particular alloy for a definite purpose.The article contains something new in describing the resistance of certain alloys to edge corrosion and also the rather definite conclusions relative to the copper content of alloys necessary to resist fouling.SUMMARYThe data which have been presented were chosen to illustrate in as general a way as possible the outstanding characteristics of nickel copper alloys with respect to their behavior in sea water. In applying such data to the choice of an alloy for a particular purpose, it is necessary, as was pointed out previously, to consider as well such factors as physical and mechanical properties, availability in the required forms, cost and practical experience. Experience tends in time to integrate all the important factors and for this reason there is appended in Table 14 a list of practical applications of the nickel copper alloys—Monel, 70:30 copper nickel and nickel silver—which have been used most extensively in marine engineering. It is hoped that this list will serve as a useful guide to the choice of the proper alloy for specific purposes.