Rebound and scattering of motile Chlamydomonas algae in confined chambers

Motivated by recent experiments demonstrating that motile algae get trapped in draining foams, we study the trajectories of microorganisms confined in model foam channels (section of a Plateau border). We...

Measuring the impact of channel length on liquid flow through an ideal Plateau border and node system

The following work highlights the impact of Plateau border (PB) length, l1, on the apparent surface viscosity, μs, of a flow rate controlled PB and node system using a novel experimental setup.

Modeling the Elastic Properties of Reticulated Porous Ceramics

A model to predict the elastic material properties of reticulated porous ceramics (RPCs) based on the microstructural geometry is presented. The RPC is represented by a repeating unit structure of truncated octahedrons (tetrakaidecahedrons) with the ligaments represented by the cell edges. The deformations of the ligaments in the cellular structure under applied loads are used to determine the effective moduli and Poisson's ratio of the bulk material. The ligament cross section is represented as having a Plateau border exterior surface with a cusp half-angle that is varied between 0 and 90 deg, and a Plateau border interior void with a cusp half-angle of zero, representative of the ranges seen in RPCs. The ligament cross-sectional area is permitted to vary along its length and the distance between internal and external cusps is assumed constant. The relative density of the foam, corresponding to the length, cusp distances, and external-cusp half-angle of the ligaments, is determined using solid geometry. The relative density has the dominant effect on the moduli, while normalized ligament length varies the moduli by 11–49% at a specified relative density. The impact of the external shape of a ligament on the relative moduli is insignificant. The model is validated through comparisons with the measured elastic properties of RPCs in the literature and new data. The model is the first to consider the effect of the microstructural features of ligaments of RPCs on the elastic moduli of the bulk material.

Random equilateral Kelvin open-cell foam microstructures: Cross-section shapes, compressive behavior, and isotropic characteristics

Representative volume elements of random equilateral Kelvin open-cell microstructures were modeled for the open-cell foam. We adopted the periodic boundary conditions developed in our previous research. The quasistatic compression properties of the representative volume elements in random Kelvin open-cell aluminum foam samples, both with different relative densities and different cross-sections of the beams in the structures were investigated. The results show that the features of the stress–strain curves in the representative volume elements with different relative densities and different cross-sections were similar, and the relationships between the yield strengths and relative densities of representative volume elements with four different cross-sections all agreed well with the quadratic power function. Among the representative volume elements with four different cross-sections, the yield strengths of the representative volume elements with a Plateau border cross-section were significantly larger than in representative volume elements with other cross-sections, while the yield strengths of representative volume elements with circular cross-sections were smaller than in representative volume elements with other cross-sections. This indicates that the simulation results of the compression strengths for open-cell foam in which the representative volume elements with circular cross-sections were employed are significantly smaller than their actual values. The main reason for this is that the moments of inertia in the Plateau border cross-sections are significantly greater than in the circular cross-sections of the same area. Our investigation results revealed that the compression responses of the representative volume elements for random equilateral Kelvin open-cell microstructures demonstrate isotropic behavior on the xoy plane, the yoz plane, and the xoz plane.