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Carbon dioxide removal (CDR) technologies at a gigaton scale need to be developed and implemented within the next decades to keep global warming below 1.5 °C. Coastal enhanced silicate weathering is one of the proposed CDR techniques that aims to accelerate the natural process of CO 2 -sequestration during marine chemical weathering of silicate minerals. To this end, finely ground rock containing olivine (Mg x Fe 2− x SiO 4) could be dispersed in dynamic coastal environments, where local biotic and abiotic factors potentially enhance the weathering process. However, accurate predictions of the olivine dissolution rate and the associated CO 2 sequestration under in situ conditions are currently lacking and ecosystem impacts remain to be assessed. Previously, it has been hypothesized that in situ grain collisions, induced by bed load transport due to currents and waves, could accelerate the in situ chemical weathering of olivine particles. To examine this, we investigated the effects of continuous grain tumbling on olivine dissolution in natural seawater. A 70-day experiment was conducted in which forsterite olivine sand was continuously tumbled in filtered seawater at different rotation speeds, and dissolution rates were measured on a weekly basis. Results showed that continuously tumbled olivine dissolved 8 to 19 times faster compared to stagnant (no rotation) conditions. Olivine dissolution was complete and stoichiometric (except for Ni release), air-seawater CO 2 exchange was not significantly rate limiting, and minimal particle fragmentation and secondary mineral formation were observed. Hence, we infer that olivine weathering was mainly enhanced via advective pore water flushing, which limits saturation effects at the grain scale. Overall, this study provides evidence that ambient physical stresses in coastal environments could enhance marine silicate weathering, which has implications for both the natural silicon cycle as well as the use of enhanced coastal weathering of silicates as a CDR technique. [ABSTRACT FROM AUTHOR]

For a long time popular music and aesthetics have been considered as mutually exclusive categories within the musicological discourse. Based on the predominance of idealistic autonomy aesthetics, the concept of the (musical) 'work of art', at its core, legitimised the exclusion of popular music from the realm of aesthetics. Since the concept of autonomy constituted the beauty of art as a sphere free from social functions and independent from interests of the culture industries, two antithetical strategies in researching pop music have recently emerged: on the one hand pop music has been described as art, on the other hand it has been considered as a cultural phenomenon solely explored through sociological approaches. This paper looks for an alternative way in order to overcome the dualisms of art and everyday life, aesthetics and society, without neglecting the inherent aesthetic dimension of popular music cultures or the processes of identity-making of the involved people. For this purpose, concepts developed in theatre and ritual studies seem to be fruitful for describing pop music as ritual in social space (musicking), and in terms of an aesthetic of the performative. Based on participant observations and interviews, the paper discusses a rock concert that the Yoon Band from South Korea held in Germany. In view of the event character and of liminal and transformative processes within the performance, it gives an example of how Korean people in Germany negotiate their identities and draw national boundaries through actively participating in and through music. Thereby, the way popular music constitutes the diasporic community can be detected in the underlying social, symbolic, and sound patterns of the performance. [ABSTRACT FROM AUTHOR]

Abstract: Freeform optics enable completely new solutions in optical design for many different optical applications. Complex optical systems usually need a variety of multiple classic spherical surfaces to fulfill their function. The usage of a freeform surface instead makes it possible to replace some of these spherical surfaces by only one freeform element. Therefore, it is possible to build optical systems that are more compact and lighter than existing ones. However, these new possibilities also lead to new challenges regarding fabrication and assembly of the freeform components. Therefore, an efficient production of such elements needs improvement of existing or development of new manufacturing technologies and process chains. This paper describes a new fabrication approach focused on freeform optics by introducing a process chain consisting of an ultrasonic‐assisted grinding process, an ultrafine grinding method using novel resin bond tools and a CO2 laser polishing process for final surface smoothing. [ABSTRACT FROM AUTHOR]