Geometry-material coordination for passive adaptive solar morphing envelopes

The cost-intensive and mechanical complexity natures of the adaptive facades of the past decades drifted designers and researchers’ interest towards passive material-based actuation systems. Architectural applications using the latter showed, however, a few limitations restricting the output possibility space to options that rely entirely on one material’s phase characteristic. This study aims to investigate the potential of expanding a shape memory alloy-actuated facade’s output from one that is limited and hardly controllable in the case of entirely passive actuation to one that can produce a specific desired performative target. This is explored through coordinating between geometry movement connections of an adaptive component of four integrated shape memory alloys, which work on tailoring the geometry-material-climate relations of the responsive system. The research findings suggest that the integration of geometry, material, and their connections in the design of a SMA solar morphing envelope lead to the development of a wider range of behavioural system outputs. The variety instilled through these added dimensions promoted diversity and adaptability of output for a flexible range of responses and higher performative gains

Impact des changements climatiques et de la fréquentation humaine sur la biodiversité des îles subantarctiques françaises

L’invasion des écosystèmes par des espèces exotiques constitue, en conjonction avec les changements climatiques, une des plus grandes menaces pour la biodiversité mondiale, après la destruction des habitats. Même dans les régions antarctiques et subantarctiques, des espèces étrangères à la faune et à la flore locales ont été introduites dès la fin du 18e siècle. La majorité de ces introductions sont associées à la fréquentation humaine et aux visites des navires. Par ailleurs, comme le prédisent la plupart des modèles, les régions de hautes latitudes sont les plus sensibles aux changements climatiques. Les observations faites à Kerguelen confirment cette tendance et attestent de l’impact déjà bien visible des augmentations de température (1,3°C depuis le milieu des années 1960) et des déficits hydriques estivaux récurrents ces dernières années. Avec ces changements climatiques rapides, une augmentation du nombre d’introductions d’espèces et de leur succès d’établissement est attendue, de même que la fragilisation de la faune et la flore locales, d’où de notables conséquences prévisibles quant à la biodiversité de ces régions très particulières.Biological invasions, in connection with climate changes, are amongst the most significant threats to biodiversity worldwide. Even in antarctic and subantarctic regions, alien species arrived since the end of the 18th century. Most of these introductions are obviously associated with human activities and ship landings. Otherwise, as predicted by many global circulation models, rates of warming are expected to be stronger at higher latitudes. Our study on the Kerguelen Islands confirms this trend and demonstrates that the effects of warming (+ 1.3°C since the mid 1960s) and summer droughts on plants and invertebrates are now visible. With climate change occurring rapidly, both the numbers of introductions and the success of colonisation by alien species are likely to increase, with as consequence subsequent impacts on the entire ecosystem

Variability of ecomorphological and metabolic traits in plant species across abiotic gradients in the Kerguelen Islands (sub-Antarctic)

National audienc

Polyamines, development and stress responses in plants: outcomes from the research on the subantarctic ‘Kerguelen cabbage'

Poste

Polyamines, development and stress responses in plants: outcomes from the research on the subantarctic ‘Kerguelen cabbage'

Poste

Response of subantarctic plants to climate change: From physiological adaptations to the diversification of species traits along environmental gradients.

conférence invitéeInternational audienc

Evolution and biogeography of Lyallia and Hectorella (Portulacaceae), geographically isolated sisters from the Southern Hemisphere

The Southern Hemisphere contains many monotypic taxa, for which phylogenetic relationships are important to illuminate biogeographical history. The monotypic genus Lyallia is endemic to the sub-Antarctic Iles Kerguelen. A close relationship with another monotypic taxon, the New Zealand endemic Hectorella, was proposed. They share a dense cushion growth habit with small coriaceous leaves that lack stipules. The solitary flowers are bicarpellate with two sepals, 4–5 petals, 3–5 stamens and a bifid style. The fruit is an indehiscent capsule with 1–5 seeds. The flowers of Lyallia kerguelensis are hermaphroditic with four petals and three stamens whereas the flowers of Hectorella caespitosa are female, male or hermaphroditic, with five petals and five stamens. Lyallia kerguelensis is rare on Kerguelen, whereas Hectorella caespitosa is confined to the South Island of New Zealand. Our phylogenetic analysis of trnK/matK intergenic spacer and rbcL sequences provides evidence supporting a close relationship between Lyallia and Hectorella. The two species form a well-supported clade that is nested within the Portulacaceae. Divergence estimates suggest they shared a common ancestor during the late Tertiary long after the fragmentation of Gondwana. Such relationships underscore the importance of transoceanic dispersal and extinctions for plant evolution in the Southern Hemisphere