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    Development of a model for ultra-precise surface machining of N-BK7® using microwave-driven reactive plasma jet machining
    (Hoboken, NJ : Wiley Interscience, 2019) Kazemi, Faezeh; Boehm, Georg; Arnold, Thomas
    In this paper, extensive studies are conducted as key to overcoming several challenging limitations in applying fluorine-based reactive plasma jet machining (PJM) to surface machining of N-BK7®, particularly regarding the manufacture of freeform optical elements. The chemical composition and lateral distributions of the residual layer are evaluated by X-ray photoelectron spectroscopy and scanning electron microscopy/energy-dispersive X-ray spectroscopy analysis aiming at clarifying the exact chemical kinetics between plasma generated active particles and the N-BK7 surface atoms. Subsequently, a model is developed by performing static etchings to consider the time-varying nonlinearity of the material removal rate and estimate the local etching rate function. Finally, the derived model is extended into the dynamic machining process, and the outcomes are compared with the experimental results.
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    Oral SARS-CoV-2 reduction by local treatment: A plasma technology application?
    (Weinheim : Wiley-VCH, 2022) von Woedtke, Thomas; Gabriel, Gülsah; Schaible, Ulrich E.; Bekeschus, Sander
    The SARS-CoV-2 pandemic reemphasized the importance of and need for efficient hygiene and disinfection measures. The coronavirus' efficient spread capitalizes on its airborne transmission routes via virus aerosol release from human oral and nasopharyngeal cavities. Besides the upper respiratory tract, efficient viral replication has been described in the epithelium of these two body cavities. To this end, the idea emerged to employ plasma technology to locally reduce mucosal viral loads as an additional measure to reduce patient infectivity. We here outline conceptual ideas of such treatment concepts within what is known in the antiviral actions of plasma treatment so far.