The relation between the permeability of structured dispersions and the viscoelastic properties of the dispersed phase

It is shown that not only the average particle size and compression modulus, but also the viscoelastic properties of the network affect the rate of liquid removal out of a concentrated disperse system that is unilaterally compressed. A Maxwell-like constitutive equation is introduced to express these viscoelastic properties. The rate of liquid removal is calculated for a set of values of the elastic modulus and the time constant that appear in the constitutive equation. It is shown that permeability measurements on concentrated fat dispersions can be interpreted in terms of network properties also when the network is viscoelastic, i.e., it is assumed that processes take place inside the network that involve energy dissipation

The 3-Dimensional Structure of NGC 891 and M51

We investigate the three-dimensional structure of the nearby edge-on spiral galaxy NGC 891 using 3D Monte Carlo radiative transfer models, with realistic spiral structure and fractally clumped dust. Using the spiral and clumpiness parameters found from recently completed scattered light models we produce lower resolution SED models which reproduce the global UV-to-FIR SED of NGC 891. Our models contain a color gradient across the major axis of the galaxy - similar to what is seen in images of the NGC 891. With minor adjustment our SED models are able to match the majority of M51's SED, a similar galaxy at a near face-on different inclination.Comment: 3 pages, 1 figure. To appear in the Conference Proceedings of IAU Symposium No. 284: The Spectral Energy Distribution of Galaxies, R.J. Tuffs & C.C. Popescu, ed