Simulation of sticking of adhesive particles under normal impact

Sticking of adhesive spherical particles under normal impact is investigated numerically by applying the Discrete Element Method. The nonlinear-dissipative contact model with adhesion is applied to model normal contact forces. Loading is described by elastic Hertz and elastic-plastic contact model with history-dependent adhesion. Damping is described by nonlinear Tsuji model. Adhesion limit is of linear character while particle detachment is of non-linear nature. Sticking and detachment behaviour for various damping values are considered in detail. Influence of the adhesion force for a wide range of particle sizes is illustrated by the variation of critical sticking velocity. Comparison of purely elastic with elastic-plastic behaviour is also presente

Adhesion of <i>Pseudomonas fluorescens</i> biofilms to glass, stainless steel and cellulose

Objectives: The adhesion of colloidal probes of stainless steel, glass and cellulose to Pseudomonas fluorescens biofilms was examined using atomic force microscopy (AFM) to allow comparisons between surfaces to which biofilms might adhere. Results: Biofilm was grown on a stainless steel substrate and covered most of the surface after 96 h. AFM approach and retraction curves were obtained when the biofilm was immersed in a tryptone/soy medium. On approach, all the colloidal probes experienced a long non-contact phase more than 100 nm in length, possibly due to the steric repulsion by extracellular polymers from the biofilm and hydrophobic effects. Retraction data showed that the adhesion varied from position to position on the biofilm. The mean value of adhesion of glass to the biofilm (48 ± 7 nN) was the greatest, followed by stainless steel (30 ± 7 nN) and cellulose (7.8 ± 0.4 nN). Conclusion: The method allows understanding of adhesion between the three materials and biofilm, and development of a better strategy to remove the biofilm from these surfaces relevant to different industrial applications

Simulation of sticking of adhesive particles under normal impact

Sticking of adhesive spherical particles under normal impact is investigated numerically by applying the Discrete Element Method. The nonlinear-dissipative contact model with adhesion is applied to model normal contact forces. Loading is described by elastic Hertz and elastic-plastic contact model with history-dependent adhesion. Damping is described by nonlinear Tsuji model. Adhesion limit is of linear character while particle detachment is of non-linear nature. Sticking and detachment behaviour for various damping values are considered in detail. Influence of the adhesion force for a wide range of particle sizes is illustrated by the variation of critical sticking velocity. Comparison of purely elastic with elastic-plastic behaviour is also presente