Éditeur(s) : HAL CCSD Springer Verlag
Résumé : 4 pages
International audience
We show that a point is solution of the Minty variational inequality of subdifferential type for a given function if and only if the function is increasing along rays starting from that point. This provides a characterization of the monotone polar of subdifferentials of lower semicontinuous functions: it is a common subset of their graphs which depends only on the function.
ISSN: 1862-4472

hal-00842670
https://hal.archives-ouvertes.fr/hal-00842670
ARXIV : 1307.1826
DOI : 10.1007/s11590-013-0693-7

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
Radial trends of vibrational properties, including the specific dynamic modulus (E'/r) and damping coefficient (tand), were investigated for 3 tropical rainforest hardwood species, Simarouba amara, Carapa procera and Symphonia globulifera by free-free flexural vibration test. The microfibril angle (MFA) was estimated through X-Ray diffraction. Consistent patterns of radial variations were observed for all studied properties. E'/r was found to decrease from pith to bark, which is strongly related to the increasing pith-bark trend of MFA. The variation of tand along the radius can be partly explained by MFA, and partly by the gradient of extractives due to heartwood formation. The coupling effect of MFA and extractives could be separated through the analysis of log(tand) - log(E'/r) diagram. For the studied species, the extractive content putatively associated to heartwood formation generally tends to decrease the wood damping coefficient. However, this weakening effect of extractives was not observed for inner part of the heartwood, suggesting the mechanical action of extractives was reduced during their chemical ageing.
ISSN: 1435-0211

hal-00797055
https://hal.archives-ouvertes.fr/hal-00797055
https://hal.archives-ouvertes.fr/hal-00797055/document
https://hal.archives-ouvertes.fr/hal-00797055/file/Radial_variations_vibrational_Zhang_al.pdf