Pulsation of Ventilated Cavities

Self-pulsation threshold of Raman amplified Brillouin fiber cavities.

An implicit equation for the oscillation threshold of stimulated Brillouin scattering from Raman amplified signals in fibers with external feedback is derived under the assumption of no depletion. This is compared to numerical investigations of Raman amplification schemes showing good agreement for high reflectivities. For low reflectivities and high attenuation or long fibers, the assumption o...

LINEAR PULSATION CHARACTERISTICS OF MIRA VARIABLE STARS

The linear adiabatic pulsation-periods of Mira variable stars have been derived. Approximately 2701[1]models were calculated for M = 0.7 MΘ to 2 MΘ stars with radii from 180 RΘ to 340 RΘ and luminosities from 2800 LΘ to 10,000 LΘ. The chemical composition of all models is (X,Z) = (0.7,0.02). From the result of this study, linear relations on Luminosity-Period-Mass relationship and luminosity-pe...

Application of Four Pole Parameters for Gas Pulsation Analysis of Multi-Cylinder Compressors with Symmetrically Arranged Gas Cavities

Cepheids: Pulsation, Evolution, Opacity

We describe modeling of the ''beat'' and "bump" Cepheids, using the new radiative opacities. Discrepancies between these models and the evolutionary tracks for stars of appropriate mass are discussed. Finally, we point out some of the difficulties involving the long-period Cepheid sample with periods greater than 20 days.

Cerebrospinal Pulsation Hydrodynamics in a 2D Simulation of Brain Ventricles

In this article, dynamics of the cerebrospinal fluid (CSF) was studied, using computational fluid dynamics. Using MRI images of two special cases, a 2-dimensional model of the ventricular system was made. CSF velocity and pressure distribution in ventricular system have high importance since the flow pattern of this liquid has an important effect on intracranial pressure, i.e., ICP, which has a...