Wireless strain and temperature monitoring in reinforced concrete using Surface Acoustic Wave (SAW) sensors

Monitoring the health of civil engineering structures using implanted deformation, temperature and corrosion sensors would further improve maintenance and extend the service life of those structures. However, sensor integration poses a number of problems, due to the presence of cables and on-board electronics. Passive, wireless SAW sensors offer a very promising solution, here. We used commercial SAW devices mounted on steel rebars to carry out an initial feasibility study. Without cables or embedded electronics, we were able to measure the deformation of a concrete beam subjected to bending load. We were also able to measure the temperature continuously over a three-week period

Influence of the punch geometry and sample size on the deep-drawing limits in expansion of an aluminum alloy.

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Strain capacities limits of wrought Magnesium alloys: tension vs. expansion.

International audienceLightening structure is one of the goals of many fields of research. As a result, magnesium alloys are studied due to their low density. However, one drawback of these alloys is their low formability at room temperature due to their hex-agonal closed-packed structure. In the present work, the forming capacity of an AZ31 Mg alloys has been studied using a mini deep-drawing device, image correlation techniques and tests (tension and expansion) at temperatures contained between 20°C and 200°C. To investigate formability limits of Mg alloys in expansion, major and minor strains data were generated using hemispherical punch tests and analyzed with 3D digital images correlation techniques. Thanks to images correlation, strains on the surface of the samples were observed by means of a double digitization of the sample in three dimensions before and after deformation by using stereoscopic vision and triangulation. Image correlations have also been used in 2D to measure strains on the surface of the tensile test samples. These tests gave interesting in-formation on the evolution of various parameters such as hardening coefficient, strain rate sensitivity parameter, and Lankford coefficient, which may affect the behavior of the alloys. Finally, the forming limits in both configurations (tension and expansion) were compared and discussed

Charge Transfer at Hybrid Interfaces: Plasmonics of Aromatic Thiol-Capped Gold Nanoparticles

International audienceAlthough gold nanoparticles stabilized by organic thiols are the building blocks in a wide range of applications, the role of the ligands on the plasmon resonance of the metal core has been mostly ignored until now. Herein, a methodology based on the combination of spectroscopic ellipsometry and UV-vis spectroscopy is applied to extract dielectric functions of the different components. It is shown that aromatic thiols allow a significant charge transfer at the hybrid interface with the sand d bands of the gold core that yields ``giant'' red shifts of the plasmon band, up to 40 nm for spherical particles in the size range of 3-5 nm. These results suggest that hybrid nanoplasmonic devices may be designed through the suitable choice of metal core and organic components for optimized charge exchange

When the West Meets the South on Screen

Like the classic movies on the Far West, the quintessential film narratives of the Deep South have greatly impacted the popular understanding of American history and American values. While the canonized Western has relentlessly foregrounded the idea of individual freedom and the conquest of the wilderness, the more elusive and controversial Southern genre bears the persistent ideological traces of slavery and segregation. However, this Revue LISA/LISA e-journal issue “When the West/ern meets the South/ern” explores the jarring and often unexpected connections between the two basically distinct generic categories, well before the 2012 release of Django unchained, Quentin Tarantino’s provocatively Westernized Southern (or Southernized Western). Numerous earlier films were already engaged in a play with the representational codes of the West and the South in cinema and literature. When the Western and the Southern cross and blend, the resultant “genre trouble” generates a more complex image of America, challenging its grand narratives and myths. À l’instar des films classiques sur le Far West, les récits cinématographiques sur le Sud profond (« the Deep South ») ont considérablement influencé la compréhension populaire de l’histoire et des valeurs américaines. Alors que l’Ouest canonique a inlassablement mis en avant l’idée de la liberté individuelle et celle de la conquête de la wilderness, le genre Southern, plus controversé et plus difficile à cerner, continue à porter les stigmates de l’esclavage et de la ségrégation. Pourtant, ce numéro spécial de la Revue LISA/LISA e-journal intitulé « Quand l’Ouest rencontre le Sud à l’écran » explore les rapprochements, souvent inattendus et stimulants, entre deux catégories génériques a priori distinctes, bien avant Django Unchained de Quentin Tarantino (2012), un Southern westernien (ou un Western southernien). De nombreux films antérieurs jouaient déjà avec les codes de représentations de l’Ouest et du Sud à l’écran et dans la littérature. Lorsque le Western et le Southern se croisent et s’hybrident, le « trouble dans le genre » qui en résulte génère une image plus complexe de l’Amérique tout en interrogeant ses grands récits et mythes