Liquid morphologies and capillary forces between three spherical beads

Equilibrium shapes of coalesced pendular bridges in a static assembly of spherical beads are computed by numerical minimization of the interfacial energy. Our present study focuses on generic bead configurations involving three beads, one of which is in contact to the two others while there is a gap of variable size between the latter. In agreement with previous experimental studies, we find interfacial `trimer' morphologies consisting of three coalesced pendular bridges, and `dimers' of two coalesced bridges. In a certain range of the gap opening we observe a bistability between the dimer and trimer morphology during shrinking and growth. The magnitude of the corresponding capillary forces in presence of a trimer or dimer depends, besides the gap opening only on the volume or Laplace pressure of liquid. For a given Laplace pressure, the capillary forces in presence of a trimer are slightly larger than the force of a single bridges at the same gap opening, which could explain the shallow maximum and plateau of the capillary cohesion of a wetting liquid for saturations in the funicular regime

The Multipole Resonance Probe: Simultaneous Determination of Electron Density and Electron Temperature Using Spectral Kinetic Simulation

The investigation of the spectral kinetic model of the Multipole Resonance Probe (MRP) is presented and discussed in this paper. The MRP is a radio-frequency driven probe of the particular spherical design, which is suitable for the supervision and control of low-temperature plasma. The importance of the kinetic effects was introduced in the previous study of the spectral kinetic model of the idealized MRP. Such effects particularly dominate the energy loss in a low-pressure regime. Unfortunately, they are absent in the Drude model. With the help of the spectral kinetic scheme, those energy losses can be predicted, and it enables us to obtain the electron temperature from the FWHM in the simulated resonance curve. Simultaneously, the electron density can be derived from the simulated resonance frequency. Good agreements in the comparison between the simulation and the measurement demonstrate the suitability of the presented model