Natural sonic crystal absorber constituted of seagrass (Posidonia Oceanica) fibrous spheres

[EN] We present a 3-dimensional fully natural sonic crystal composed of spherical aggregates of fibers (called Aegagropilae) resulting from the decomposition of Posidonia Oceanica. The fiber network is first acoustically characterized, providing insights on this natural fiber entanglement due to turbulent flow. The Aegagropilae are then arranged on a principal cubic lattice. The band diagram and topology of this structure are analyzed, notably via Argand representation of its scattering elements. This fully natural sonic crystal exhibits excellent sound absorbing properties and thus represents a sustainable alternative that could outperform conventional acoustic materials.This article is based upon work from COST Action DENORMS CA15125, supported by COST(European Cooperation in Science and Technology). The authors gratefully acknowledge the ANR-RGC METARoom (ANR-18-CE08-0021) project, the project HYPERMETA funded under the program Etoiles Montantes of the Region Pays de la Loire, and the project PID2019-109175GB-C22 funded by the Spanish Ministry of Science and Innovation. N.J. acknowledges financial support from the Spanish Ministry of Science, Innovation and Universities (MICINN) through grant "Juan de la Cierva - Incorporacion" (IJC2018-037897-I). The authors would like to thank V. Pagneux and R. Pico Vila for useful discussions and J. Barber and C. Dordoni for their help in collecting the samples.Barguet, L.; Romero-García, V.; Jimenez, N.; García-Raffi, LM.; Sánchez Morcillo, VJ.; Groby, J. (2021). Natural sonic crystal absorber constituted of seagrass (Posidonia Oceanica) fibrous spheres. Scientific Reports. 11(1):1-8. https://doi.org/10.1038/s41598-020-79982-9S1811

Ultrasonic evaluation of the morphological characteristics of metallic powders in the context of mechanical alloying

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Oxide dispersion strengthened ferritic steels: a basic research joint program in France

International audienceAREVA, CEA, CNRS, EDF and Mecachrome are funding a joint program of basic research on Oxide Dispersion Strengthened Steels (ODISSEE), in support to the development of oxide dispersion strengthened 9-14% Cr ferritic-martensitic steels for the fuel element cladding of future Sodium-cooled fast neutron reactors. The selected objectives and the results obtained so far will be presented concerning (i) physical-chemical characterisation of the nano-clusters as a function of ball-milling process, metallurgical conditions and irradiation, (ii) meso-scale understanding of failure mechanisms under dynamic loading and creep, and, (iii) kinetic modelling of nano-clusters nucleation and alpha/alpha' unmixing. (C) 2014 Elsevier B.V. All rights reserved