The bending beam method for measurements of stress in thin films deposited on an elastic substrate in the form of a thin stripe has been improved by the introduction of a laser beam deflection system and of a laser spot position detector. With this improvement, stress measurements have been performed in situ during the electrochemical reactions of palladium hydride formation and of valve metal anodic oxidation. Stress changes in the thin films of 107 N/m 2 can be measured with a time response better than ls. This allows the detection of rapid reactions (like H diffusion in a Pd thin film) and of the electrostriction effect even in anodic films with thickness below 20 nm.

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The fluid flow patterns and associated concentration fields in Y-mixers are investigated using lattice Boltzmann method-based models. The focus lies on the impact of the mixing angle on the flow and concentration fields, with the mixing angle varying between acute (q = 10°) and obtuse (q = 130°) angles. Residence time distributions are determined to study the effect of the angles on the mixing and velocity patterns, in particular, different flow regimes, i.e., stratified laminar, vortex, and engulfment flow. The results from the simulations are validated with literature data and found to be in good agreement. Maximum mixing occurs in the 100°obtuse-angle Y-mixer, attributed to the extensive engulfment of flows in the mixing channel.

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