We have investigated the phenomenon of flow-induced aggregation in highly concentrated colloidal dispersions exposed to strongly converging flow fields. This phenomenon is relevant not only for classical technical operations like coating, pumping or filtration, but also for the application of concentrated suspensions in upcoming processing technologies based on microfluidic devices. A ring-slit device (gap height 10 micrometers to 25 micrometers), which allows for a variation of flow kinematics in a wide range, has been developed in order to investigate this phenomenon. Various polymer dispersions with different particle surface properties have been used as model systems. Our experiments exclude, that channel clogging is due to retention of pre-existing aggregates, fouling or hydrodynamic bridging. Instead, we demonstrate that clogging of the microchannel is induced by hetero-coagulation between primary colloidal particles and micron-sized impurities present at concentrations on the order of 100 ppm to 1000 ppm. Clogging can occur even if the diameter of these impurities is less than a tenth of the gap height. Aggregation takes place in the converging flow field at the channel entrance, but not in the shear field within the slit. It can be suppressed by appropriate stabilization of the primary particles

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Timber engineering sets high expectations on adhesive bonding as a joining method to overcome a series of limitations related to partly obsolete traditional techniques. Research on adhesively bonded timber joints has proved their superiority over mechanical fasteners in terms of strength and stiffness, but this research was often limited to softwood. Despite its abundant availability in Central Europe and its high mechanical resistance, beech is only rarely considered as a structural material. Furthermore, research on adhesively bonded timber joints almost exclusively focused on tests at room temperature. Elevated temperatures, however, are critical in conjunction with adhesives, making it paramount to shed more light on that particular aspect. Based on experimental and numerical investigations, it was found that the capacity of adhesively bonded hardwood joints increased asymptotically with overlap length to a ceiling value; furthermore, it was concluded that temperature negatively impacts capacity. Glass transition temperature, T g , marked a clear transition, but joints still sustained relatively high loads beyond T g . A probabilistic approach was validated and successfully applied to predict the joint capacity. The research contributes to fill knowledge gaps by offering the basis for subsequent dimensioning methods that at term will enable practitioners to design their structures accordingly.