J. H. NORMAN AND P. WIFXHELI,
3802
tronic data processing machine. Compositions for a given pressure and enthalpy (involving the calculation of several pressure-temperature points) were clocked at 4 sec. for several six-element systems. The propellant evaluation program with unbuffered input and output averaged less than 0.0025 hr./run. The times indicated above were obtained without extreme measures, such as converting the Fortran coding to machine language, and can probably be reduced. One untried suggestion is to code a logarithm routine which is faster, but is at the expense of the computer memory. This would speed computations because a great portion of time is used by the computer in computing logarithms.
The combination of procedures described in this report is being considered for future applications involving gas imperfection, where, because it still requires no matrix inversion, it will gain a further advantage over the two most widely used methods, which must handlc even larger matrices than required in the study of perfect-gas mix t ures.
(11) F. Boynton, 111, ‘(Computation of Equilibrium Cornpositinlie and Properties in a Gas Obeying the Virial Equation of State.” presented at the Second Conference on Kinetics. Equilibria, and l’eiformance of High Temperature Systems, Western States Section of the Combustion Institute, Los Angeles, Calif., April, 1962.
Mass Spectrometry-Knudsen Cell Studies
of the Vaporization of Uranium Dicarbide*
by J. H. Norman and P. Winchell General Atomic Division of General Dynamics Corporation, J o h n J a y H o p k i n s Laboratory for Pure an,d Applied Science, Sun Diego, California (Received J u n e %?3? 1964)
The presence of UC,(g) is important in the vaporization of uranium dicarbide. In the presence of excess carbon, the vaporization of uranium dicarbide as UC,(g) can be represented by a heat of vaporization of 185 kcal./mole and an entropy of 38.3 cal./OK. mole in the temperature range 2350 to 27OO0I
