Recent estimates of mean meridional motions and eddy diffusion coefficients in the lower stratosphere and upper troposphere are used to study the roles of mean circulation and eddy mixing in determining the spread of tungsten 185 injected into the lower stratosphere in the Hardtack test series of 1958. The observed distribution of bungsten 185 is reproduced satisfactorily for a period of 18 months after the injection, provided that the diffusion coefficients estimated from heat flux data are reduced by a factor of about 8. The mean meridional circulation is found to play a minor role in the transport process, its chief contribution being to raise the center of maximum concentration by 2 to 3 km in the equatorial region, in agreement with the observations. The mean residence time for a tracer injected into the equatorial stratosphere between 18 anti 20 km is found to be about 10
The fission of Ra 226 by 11-Mev protons has been studied by using radiochemical techniques. The massyield curve of fission products shows three humps: a narrow hump centered about mass 112, corresponding to a symmetric fission mode, with two humps on either side, corresponding to an asymmetric fission mode. The measured fission yields of fission fragments at the peaks of all three humps are about the same. The heavy-fragment "wing" of the asymmetric portion of the mass-yield curve is very similar in position and shape to the corresponding member of other asymmetric mass-yield curves. The light-fragment "wing" has accordingly shifted to lower mass numbers, continuing the trend observed in the asymmetric fission-yield curves of elements heavier than radium. The central, symmetric-fission hump is of the same width as the narrow, symmetric-fission curve observed for fission of bismuth by 20-Mev deuterons. The cross section for fission of Ra 226 by 11-Mev protons is measured to be 2=blX10~2 7 cm 2 , and drops by a factor of about 60 when the proton energy is degraded to 9 Mev.
A simple apparatus is described whereby any quantity of CO2 up to several moles can be converted to methane in one step by catalytic hydrogenation using a ruthenium catalyst. The conversion is very rapid, the entire operation being carried out in about 3 hours. The over-all yield is greater than 98%, and the methane is of high purity.
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