Shot peening is a common procedure to improve the static and cyclic strength of metal components by a combination of work hardening and the introduction of compressive stresses into the surface region. Our investigations through the last years showed that high compressive stresses of more than 1 GPa can also be introduced in brittle ceramics under specific shot peening conditions. These stresses significantly increase the near-surface strength. Based on the findings for ceramics, shot peening procedures have now been developed for cemented carbides and hard chromium platings. Recent investigations showed that, due to the higher fracture toughness of cemented carbides, shot peening could be performed using higher peening intensities leading to a higher gain in strength properties. Although chromium platings are less brittle than ceramics, shot peening of these layers are very challenging due to the formation of a micro-crack network being typically for these coatings. Nevertheless, first results indicate the possibility of a successfully shot peening of these coatings.

Light as a tool in medical therapy and biological research has been studied extensively and its application is subject to continuous improvement. However, safe and efficient application of light-based methods in photomedicine or optogenetics requires knowledge about the optical properties of the target tissue as well as the response characteristics of the stimulated cells. Here, we used tissue phantoms and a heart-like light-sensitive cell line to investigate optogenetic stimulation through tissue layers. The input power necessary for successful stimulation could be described as a function of phantom thickness. A model of light transmission through the tissue phantoms gives insights into the expected stimulation efficiency. Cell-type specific effects are identified that result in deviations of the stimulation threshold from the modelled predictions. This study provides insights into the complex interplay between light, tissue and cells during deep-tissue optogenetics. It can serve as an orientation for safe implementation of light-based methods in vivo.

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Transparent glasses as up- or down-converters are attractive systems to increase the efficiency of solar cells. Er-doped fluorozirconate (FZ) glasses show an intense up-conversion upon excitation at 1540 nm. Transmission spectra show that the absorbance at 1540 nm grows linearly with the Er-doping level. In Eu-doped FZ glasses, which were additionally doped with chlorine ions, the growth of BaCl2 nanocrystals can be observed upon thermal annealing. For high annealing temperatures a phase change from hexagonal to orthorhombic phase BaCl2 can be seen. Upon excitation in the ultraviolet (UV) spectral range these glass ceramics emit an intense blue emission. A combination of a silicon solar cell and an Eu-doped FZ glass ceramic as a down-converting top layer shows an increase in the short circuit current in the UV spectral range compared to a solar cell without a down-converting top layer