No abstract

The measurements reported in this list have been carried out in the Isotope Laboratory of the Institute of Geophysics and Planetary Physics during 1964. They are a continuation of the previously reported date lists UCLA I, II and III. The same counting procedure has been continued: CO2 proportional counting at 1 atm of pressure in a 7.5 L counter with three energy channels. Dates have been calculated according to the recommendations of the Fifth Radiocarbon Conference, Cambridge, 1962, on the basis of a radiocarbon half-life of 5568 yr (Godwin, 1962). The modern standard for organic samples has been based on 95% of the count rate of NBS oxalic acid for radiocarbon laboratories. Background measurements are determined with CO2 derived from marble. The ages of carbonate-containing substances such as shells and tufa have been calculated on the basis of estimates for the corresponding contemporary C14 activity (Broecker and Walton, 1959), as discussed in the respective sample descriptions. New methods of sample preparation are described in context with the date listings.

No abstract

No abstract

The application of nonisothermal kinetic methods to the hydrodesulfurization of coal is described. The results indicate that with only a few exceptions, the hydrogen-induced release of sulfur as hydrogen sulfide can be described adequately, in a practical kinetic sense, by five processes. We have designated the five processes in terms of the source of sulfur as Organic I, Organic II, Pyrite, Sulfide, and Organic III. Preexponential factors and activation energies are determined for each. The importance of the back-reaction of H2S with partially desulfurized coal is discussed and it is shown that the most important of the back-reactions in the inhibition of H2S release is reaction with iron. It is also shown that Organic III Is most likely formed by back-reaction of H2S with carbon in the partially desulfurized coal.