title: Instabilities in foam clusters related to the pressures in the bubbles.
abstract: We reinterpret an instability in a two-dimensional free foam cluster previously discussed by Weaire et al. (Eur. Phys. J. E 7, 123 (2002)) in terms of the excess pressure in the bubbles. We conclude that in a free foam cluster no bubble can have a pressure below that of the surrounding gas.
authors.affiliation: ICEMS-Instituto de Ciência e Engenharia de Materiais e Superfícies and Departamento de Engenharia de Materiais, Instituto Superior Técnico, Av Rovisco Pais, 1049-001, Lisboa, Portugal. fatima.vaz@ist.utl.pt
authors.forename: M F
authors.initials: MF
authors.lastname: Vaz
authors.forename: M A
authors.initials: MA
authors.lastname: Fortes