Effective interactions between inclusions in complex fluids driven out of equilibrium

The concept of fluctuation-induced effective interactions is extended to systems driven out of equilibrium. We compute the forces experienced by macroscopic objects immersed in a soft material driven by external shaking sources. We show that, in contrast with equilibrium Casimir forces induced by thermal fluctuations, their sign, range and amplitude depends on specifics of the shaking and can thus be tuned. We also comment upon the dispersion of these shaking-induced forces, and discuss their potential application to phase ordering in soft-materials.Comment: 10 pages, 8 figures, to appear in PR

POLYPYRROLE ELECTRODES, CHARGE TRANSFER TO AQUEOUS AND SOLID POLYMER ELECTROLYTES

Nous avons étudié l'interface entre le polypyrrole conducteur et des polymères électrolytes solides ou aqueux. Le polypyrrole est poreux pour le solvant et les ions de l'électrolyte mais pas pour des polymères électrolytes solides. Les deux types d'interfaces montrent sans ambiguité que la porosité, et donc la surface spécifique réelle, est responsable du rapide taux de transfert de charge vers les ions en solution qui est observé.We have studied interfaces between conducting polypyrrole and aqueous and solid polymer electrolytes. Polypyrrole is porous to solvent and electrolyte ions but not to solid polymer electrolytes. Contrasting the two interfaces shows unambiguously that the porosity, and consequently large actual surface area, is responsible for the observed rapid rate of charge transfer to ionic species in solution

Conductivity measurements of LiTFSI triblock copolymers with a central POE sequence

International audienceA-B-A block copolymers were prepared by the addition of styrene oxide or allyl glycidyl ether (AGE) monomers to oligo poly(oxyethylene) α,ω-dialcoholates. While the PEO central block should provide good conductivity at room temperature, the lateral blocks should ensure the mechanical properties. Although an improvement in mechanical properties is obtained by the addition of poly(oxystyrene) (POS) sequences as expected, the conductivity decreases. The addition of small amounts of AGE units to the POE block, followed by free-radical curing of the allylic double bonds, results in the enhancement of the electrolyte strength. Good conductivities are observed already at room temperature

Empowering Women and Ethnic Minority Groups to Collectively Market non Timber Forest Products from Community Forests in Cameroon

Community forestry (CF) was introduced in Cameroon in 1994 as a way to reduce poverty and enhance sustainable forest management. CF activities have primarily focused on timber exploitation rather than non-timber forest product (NTFP) collection processing or marketing. The study reports on a two year participatory action research project that aimed to test ways of increasing access to income from NTFPs for women and people of the Baka ethnic group in nine CFs around Lomié, East Cameroon. After a participatory diagnosis of problems and stakeholders harvesting NTFPs, approaches to enhance processing, packaging, marketing, monitoring and data collection were evaluated. This led to the development of a market information system that aimed to balance supply and demandby providing information lines on market prices between buyers and sellers. Training support was provided forsustainable harvesting, and to aid harvesters to negotiate prices. This led to 100% price increase in group sales; an increase in selling prices by 39% and an increased sales volume of six NTFPs: Irvingia gabonensis, Ricinodendron heudelotii, Pentacletra macrophylla, Baillonela toxisperma, Tetrapleura tetraptera, Pleurotus tuber-regiumresulting in a sales revenue increaseof 210% (to €72,500) between 2010 and 2012. In a context where logging is restricted to men, supporting access to NTFP markets has led to increased income for women and Baka. These results suggest that support to sustainably harvest and market NTFPs can aid development and access to markets for women and minority ethnic groups. The implications for the revision of the law on small scale commercialization, and the ability of the CFs to continue this system without support from development NGOs are discussed

Aggregate production planning in a green supply chain by considering flexible lead times and multi breakpoint purchase and shortage cost functions.

International audienc

Insight on polymer electrolytes for electrochemical devices applications

Polymer electrolytes (PEs) are of much attention as potential electrolytes of great technological relevance for solid-state electrochemistry, in particular for their possible practical application in devices such as batteries, supercapacitors, fuel cells, smart windows, sensors, and solar cells, among others. Generically, solid polymer electrolytes (SPEs) are mixtures of salts with basic polymers, such as poly(ethylene oxide) (PEO) or poly(ethylene imine) (PEI). However, there are also other polymers used as matrices for ionic conduction, like poly(vinyl alcohol) (PVA), poly(vinylidene fluoride) (PVDF), or natural macromolecules. A brief description of theoretical aspects of different PEs and past and recent trends in development of these materials are presented in this chapter. SPEs have many advantages including high energy density, no risk of leakage, no deleterious issues related to the presence of solvent, wide electrochemical stability window, simplified processability, and light weight. Some examples of prototypes of electrochromic device (ECD), batteries, supercapacitors, fuel cells, sensors, dye sensitized solar cells (DSSCs), and light emitting electrochemical cells are also presented and discussed in scope of this contribution.- (undefined