We describe the design and testing of a new all-metal differential ebulliometer which is capable of working in the range 230 to 400 K at pressures to 3 MPa. It can be used to measure pure fluid vapor pressures and P ,T,x,y and infinite dilution activity coefficient data for binary mixtures. Tests for superheating and adjustments for condensed vapor holdup are described. Results are shown for pu...

Condensation of atoms from the vapor into a third sound resonance is expected to be capable of acoustic amplification. This results from normal to superfluid conversion that coherently accommodates atoms into the third sound velocity field. Consideration of third sound in light of the equilibrium detailed balance between vapor particles and the superfluid film provides further evidence that aco...