Why study the rheology of foams? The motivations are widespread and diverse (Weaire and Hutzler 1999). Foams are common in oil extraction and industrial cleaning. Closer to home, an understanding of flowing foams helps to extinguish fires more efficiently and to generate the perfect pint of beer. At low shear-rates a foam behaves as an elastic solid, while at high shearrates it yields like a li...

Ultralight (<10 mg/cm3) cellular materials are desirable for thermal insulation; battery electrodes; catalyst supports; and acoustic, vibration, or shock energy damping. However, most of these ultralight materials, especially ultralight metal foams, are fabricated using either expensive materials or complicated procedures, which greatly limit their large-scale production and practical applicati...

Rigid polyurethane foams were synthesized using a renewable polyol from the simple physical mixture of castor oil and crude glycerol. The effect of the catalyst (DBTDL) content and blowing agents in the foams' properties were evaluated. The use of physical blowing agents (cyclopentane and n-pentane) allowed foams with smaller cells to be obtained in comparison with the foams produced with a che...

Bulk metallic glass alloys were processed into foam by several synthesis routes. These methods utilize the thermodynamic stability and thermoplastic formability of the supercooled liquid state to produce low-density homogeneous foams. The cellular structure is shown to evolve by growth of randomly distributed spherical bubbles towards polyhedral-like cells separated by microscopic intracellular...

Potential applications of metal foams include light weight cores for sandwich panels, shells and tubes where the foam can increase the resistance to local buckling, increase the impact resistance, and improve the energy absorbing capacity of the structure [1,2]. This latter property offers potential uses in transportation applications where, for example, foam-filling of the hollow sections of a...

High surface area Pd foams with roughness factors of more than 1000 and a specific surface area of 60 m(2) g(-1) are obtained by electrodeposition. The foams are composed of dendrites with branches on the 10 nm scale. The resulting electrodes show high activity towards the oxidation of C(2) alcohols.

Metal foams are interesting as lightweight materials that have an excellent combination of mechanical, thermal, and acoustic properties. However, the production process is currently not fully understood. Therefore, the goal of the FreeWiHR project is the development and high performance implementation of a model for simulating the formation process of metal foams based on the lattice Boltzmann ...

This paper proposes simple semi-phenomenological models to predict the sound absorption efficiency of highly porous polyurethane foams from microstructure characterization. In a previous paper [J. Appl. Phys. 110, 064901 (2011)], the authors presented a 3-parameter semi-phenomenological model linking the microstructure properties of fully and partially reticulated isotropic polyurethane foams (...