The observed phenomenon of a superimposed axial stress pulse traveling at an elastic stress wave velocity down a rod which was axially stressed in the plastic region initially, has been explained by taking into account three-dimensional stress effects [l], 3 and Lee [2]. Rate-dependent theory also explains the phenomenon, as in a recent publication by Nicholas [3]. There is a need for analytical studies of three-dimensional stress effects for stress pulses in initially plastically stressed rods and tubes. The assumption by Banerjee and Malvern of a two-dimensional stress state in the tubes which were tested may not be accurate.

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Combined cycle systems have been recognized as efficient power systems in which exhaust gas from the topping cycle provides the available energy to the bottoming cycle. Since most heat sources available to the bottoming cycle are sensible‐heat sources, there may be a better thermal match, and an increase thermodynamic efficiency, on reducing the entropy generation of the simple combined cycle. To increase the efficiency of the Rankine cycle working with sensible heat, two conventional methods have been proposed: one is to incorporate a multipressure boiler; the other is to implement a supercritical cycle. An alternative method is to use a multicomponent working fluid boiling at a variable temperature with a change in the liquid composition of the components, and yielding a better thermal match with the sensible‐heat source than the constant temperature boiling process. The Kalina cycle is an implementation of this concept, where ammonia/water mixtures are used as the working fluid. The purpose of this study is to conduct a preliminary study of the Kalina power cycle system in connection with a combined cycle system, comparing the Kalina cycle and the Rankine cycle. This study is performed using new thermodynamic properties of ammonia/water mixtures developed by the authors.

Liquid-vapor phase compositions are given for 11 isotherms of the system normal-hydrogen-helium over the range 15.5° to 29.8°K at pressures to 1500 Ib/in.2 In this range, the mixture critical curve is located, the freezing points are shown, and the locus is determined for the barotropic phenomenon (gravitational phase inversion). Two isotherms are duplicated with the substitution of parahydrogen.

Liquid-vapor equilibrium phase compositions for the binary system normal hydrogen-helium have been determined for 11 isotherms in the range lS.50o-32.50oK and at pressures up to 500 psia. The vapor recirculation method of obtaining equilibrium was used in conjunction with a liquid hydrogen vapor-pressure controlled cryostat. Analyses were made on a mass spectrograph. The results are presented in both tabular and graphical form, and the general behavior of the system discussed. An agreement with some previous investigations is demonstrated, and conflicts in existing data are resolved. Some problems of theoretical correlation of the data are discussed.