The economizer principle is a well-known method to reduce the expansion losses of a refrigeration system. The alternative refrigerant CO2 has a relatively large isentropic exponent. Therefore it has a high potential for raising efficiency by application of this principle. Reciprocating piston compressors are favored for CO2 refrigeration applications due to their small sealing length and theref...

Where are the r-modes of isentropic stars? ABSTRACT Almost none of the r-modes ordinarily found in rotating stars exist, if the star and its perturbations obey the same one-parameter equation of state; and rotating relativistic stars with one-parameter equations of state have no pure r-modes at all, no modes whose limit, for a star with zero angular velocity, is a perturbation with axial parity...

In this article, we consider the compressible Navier-Stokes equation with density dependent viscosity coefficients. We focus on the case where those coefficients vanish on vacuum. We prove the stability of weak solutions for periodic domain Ω = T as well as the whole space Ω = R , when N = 2 and N = 3. The pressure is given by p = ρ , and our result holds for any γ > 1. In particular, we prove ...

SUMMARY The application of a long stroke isentropic free piston compressor as the energy source for an intermittent M = 6.85 hypersonic wind tunnel is described. The advantages of comparatively long running times of up to 0.5 s and uniform reservoir conditions at up to 90 bar and 600 K are discussed. Particular problems arising from the long stroke compression associated with both viscous flow ...

S U M M A R Y New equation of state data for a weathered granite shocked to about 125 GPa are reported and combined with the Westerly granite data of McQueen, Marsh & Fritz (1967). The shock velocity (Us)-particle velocity (Up) relations can be fitted with two linear regressions: Us = 4.40 + 0.6Up for a range of Up up to about 2 km s-' and Us = 2.66 + 1.49Up for a range of about 2 to 5 km s-'. ...

We establish an existence theorem for entropy solutions to the Euler equations modeling isentropic compressible fluids. We develop a new approach for constructing mathematical entropies for the Euler equations, which are singular near the vacuum. In particular, we identify the optimal assumption required on the singular behavior on the pressure law at the vacuum in order to validate the two-ter...