Conversations on grief and hope: A collaborative autoethnographic account exploring the lifeworlds of international youth engaged with climate action

This paper explores the lifeworlds of international youth involved in climate and/or environmental social action, narratives that have been largely absent from a literature that has tended to focus on ‘traditional’ youth activists located in the urban Global North. Written as a novel collaborative autoethnography involving youth as co-authors, the paper a) collectively reflects on the stories of youth from different countries and cultures on their journeys towards climate action, and b) foregrounds an emotional framing to examine these experiences. The youth co-authors, whose experiences are the focus of this paper, form part of innovative international Youth Advisory Board, set up to provide peer support to youth new to climate and environmental social action, as part of our British Academy Youth Futures-funded participatory action research project. We examine the youth’s narratives exploring opportunities and barriers they have navigated, their inspirations and the intersections with a range of other socio-cultural factors

Kriging and expected Improvement applied to an industrial context-Prediction of new geometries increasing the efficiency of fans

In automotive industry, client needs evolve quickly in a competitiveness context, particularly, regarding the fan involved in the engine cooling module. This study has been done in cooperation with the automotive supplier Valeo. Here, we propose to use the Kriging interpolation and the Expected Improvement algorithm to provide new fan designs with high performances in terms of eciency. As far as we know, such a use of Kriging and Expected Improvement methodologies are innovative and provide really promising results.This study has been done in cooperation with the automotive supplier Valeo. In automotive industry, client needs evolve quickly in a competitiveness context, particularly, regarding the fan involved in the engine cooling module. The practitioners are asked to propose "optimal" new fans in short times. Unfortunately, each evaluation of the underlying computer code may be expensive whence the need of approximated models and specific, parsimonious, and efficient global optimization strategies. In this paper, we propose to use the Kriging interpolation combined with the expected improvement algorithm to provide new fan designs with high performances in terms of efficiency. As far as we know, such a use of Kriging interpolation together with the expected improvement methodology is unique in an industrial context and provide really promising results. Résumé : Cette étude résulte d'une collaboration avec Valeo, partenaire industriel. Dans l'industrie automobile, les besoins du marché évoluent très rapidement dans un contexte où la concurrence est forte et tout particulièrement concernant les systèmes de ventilation qui jouent un rôle clef dans le système de refroidissement du moteur. Les ingénieurs doivent dans ce contexte proposer des géométries de pales "optimales" dans des délais très courts. Malheureusement, les codes numériques sont coûteux à évaluer et des méthodes d'approximations et des techniques d'optimisation spécifiques doivent être developpées. Nous proposons de combiner l'interpolation par krigeage et l'algorithme d'optimisation d'amélioration attendue pour déterminer des géométries de pales ayant de bonnes performances en termes de rendement. Une telle application industrielle basée sur le krigeage et l'amélioration attendue semble inédite et fournit d'excellents résultats

Ultrathin electrochemically driven conducting polymer actuators: fabrication and electrochemomechanical characterization

International audienceElectronic conducting polymer based-actuators have attracted lots of interest as alternative materials to traditional piezoelectric and electrostatic actuators. Their specific characteristics such as their low operating voltages and large strains should allow them to adapt better to soft microstructures. Recently, poly (3,4-ethylenedioxythiophene) (PEDOT) – based ionic actuators have overcome some initial stumbling blocks to widespread applications in the microfabricated devices field. These trilayer bending microactuators were fabricated (i) by sequential stacking, using a layer by layer polymerization (LbL) of conducting polymer electrodes and a solid polymer electrolyte and (ii) by micro-patterning, using standard microsystems processes. While microfabrication processing of a trilayer actuator, involving no manual handling has been demonstrated, their bending performances remain limited for practical applications. Moreover, the complete characterization of their electrical, electrochemical, and mechanical properties has never been investigated. This paper describes the optimization of PEDOT electroactive electrodes synthesized with a vapor phase polymerization process. Influence of synthesis parameters on thickness, electronic conductivity and volumetric charge density were studied to determine the guidelines for synthesizing highly efficient electrodes. Afterwards, these parameters are used to guide the LbL synthesis process of ultrathin trilayer actuators. Electrochemical and mechanical properties of the resulting microactuators have been thoroughly characterized. Bending deformation and output force generation have been measured and reached 0.5% and 11 μN respectively. This constitutes the first characterization of ionic PEDOT-based microactuators operating in air of such a thin thickness (11 μm dry and 18.3 μm swelled in 1-Ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EMImTFSI)). These actuators and their actuation properties are promising for future soft microsystem devices where the use of polymer actuators should be essential

New insights into the effect of medium‐chain‐length lactones on yeast membranes. Importance of the culture medium

International audienceIn hydrophobic compounds biotechnology, medium-chain-length metabolites often perturb cell activity. Their effect is usually studied in model conditions of growth in glucose media. Here, we study whether culture on lipids has an impact on the resistance of Yarrowia lipolytica to such compounds: Cells were cultured on glucose or oleate and submitted to gamma-dodecalactone. After a 60-min exposure to 3 g L(-1), about 80% of the glucose-grown cells (yeast extract peptone dextrose (YPD) cells) had lost their cultivability, 38% their membrane integrity, and 31% their reducing capacity as shown with propidium iodide and methylene blue, respectively. For oleate-grown cells, treatment at 6 g L(-1) did not alter cultivability despite some transient loss of membrane integrity from 3 g L(-1). It was shown with diphenylhexatriene and 1-(4-trimethylammoniumphenyl)-6-phenyl-1,3,5-hexatriene that oleate-grown cells had membranes more fluid and less sensitive to the lactone-induced fluidization. Analyses revealed also higher contents of ergosterol but, for YPD- and minimum-oleate-grown cells (YNBO cells), the addition of lactone provoked a decrease in the concentration of ergosterol in a way similar to the depletion by methyl-beta-cyclodextrin and an important membrane fluidization. Ergosterol depletion or incorporation increased or decreased, respectively, cell sensitivity to lactone. This study shows that the embedment of oleate moieties into membranes as well as higher concentrations of sterol play a role in the higher resistance to lactone of oleate-grown cells (YPO cells). Similar oleate-induced increase in resistance was also observed for Rhodotorula and Candida strains able to grow on oleate as the sole carbon source whereas Saccharomyces and Sporidiobolus cells were more sensitive after induction

Ionic skin and other ionic devices

International audienc