Two caesium vanadium hydrogenphosphates with tunnelled structures: Cs2V2O3(PO4)(HPO4) and Cs2[(VO)3(HPO4)4(H2O)].H2O

International audienceDicaesium divanadium trioxide phosphate hydrogenphosphate, Cs2V2O3(PO4)(HPO4), (I), and dicaesium tris[oxidovanadate(IV)] hydrogenphosphate dihydrate, Cs2[(VO)3-(HPO4)4(H2O)] H2O, (II), crystallize in the monoclinic system with all atoms in general positions. The structures of the two compounds are built up from VO6 octahedra and PO4 tetrahedra. In (I), infinite chains of corner-sharing VO6 octahedra are connected to V2O10 dimers by phosphate and hydrogenphosphate groups, while in (II) three vanadium octahedra share vertices leading to V3O15(H2O) trimers separated by hydrogenphosphate groups. Both structures show three-dimensional frameworks with tunnels in which Cs+ cations are located

The Willingness to Pay for Cider Products: Results of a Survey on Habits and Consumption Behavior

Purpose : The objective of the paper is to investigate the impact of habits and consumption behavior on the willingness to pay (WTP) for cider by surveying young consumers. Method : The analysis is based on a questionnaire distributed to a group of 433 French business students from December 2017 to January 2018. Specifically, the questionnaire is designed to test whether young consumers would pay a premium price or not for quality ciders with respect to a traditional sweet cider with similar characteristics. We are modelling the premium that consumers are willing to pay for an organic cider, a farmer cider and rosé cider. To accommodate the feature of a significant proportion of zero or negative premiums in dependent variables, the Heckman two-stage estimation procedure is performed. Results : Results show that the young generation consider cider as a cheap, festive and non-organic beverage and is willing to pay a premium for quality ciders like specifically rosé and farmer ciders. Conclusion : The results from this research have useful implications not only for the cider market but also in the understanding of the characteristics of competitive beverages that young consumers may prefer and value

Le moulage. Pratiques historiques et regards contemporains

Souvent considéré comme éloigné de l’expression artistique, le moulage est longtemps resté une pratique d’atelier, un outil. Au XIXe siècle, parallèlement à la diffusion massive de moulages de sculptures de tous styles, âges et civilisations, la demande scientifique généralise la production d’empreintes à titre documentaire et à des fins de diffusion. La circulation des moulages entre les musées européens est même officiellement encouragée lors de l’Exposition universelle de 1867, avec la rat..

Engineering of non-linear optical crystals displaying a quasi perfect polar alignment of chromophores

Four non-linear optically active crystals based on organic salts obtained by bis-protonation of four diamines (trans-(± )-1,2-, trans-(1R,2R)-(-)-, cis-1,2-diaminocyclohexane or R-(-)-2-methylpiperazine) by 2-methoxy-4-nitrophenol have been prepared. Their crystal structures and non-linear optical efficiencies have been studied. The two adjacent proton acceptor sites in 1,2-diaminocyclohexanes play an important role in aligning the 2-methoxy-4-nitrophenolate chromophores in a quasi-perfect polar arrangement by anchoring through short hydrogen bonds. In the case of the methylpiperazinium derivative the symmetrical 1,4 location of proton acceptor sites directs the chromophores to near antiparallel alignment by forming short hydrogen bonds. The second harmonic generation efficiencies at 1.064 μ m of Nd3+:YAG laser light are equivalent to that of POM (3-methyl-4-nitropyridine-1-oxide) for the three diammoniocyclohexane derivatives and equivalent to twice that of urea for the methylpiperazinium derivative

Visible camera cryostat design and performance for the SuMIRe Prime Focus Spectrograph (PFS)

We describe the design and performance of the SuMIRe Prime Focus Spectrograph (PFS) visible camera cryostats. SuMIRe PFS is a massively multi-plexed ground-based spectrograph consisting of four identical spectrograph modules, each receiving roughly 600 fibers from a 2394 fiber robotic positioner at the prime focus. Each spectrograph module has three channels covering wavelength ranges 380~nm -- 640~nm, 640~nm -- 955~nm, and 955~nm -- 1.26~um, with the dispersed light being imaged in each channel by a f/1.07 vacuum Schmidt camera. The cameras are very large, having a clear aperture of 300~mm at the entrance window, and a mass of $\sim$280~kg. In this paper we describe the design of the visible camera cryostats and discuss various aspects of cryostat performance

A relationship between non-exponential stress relaxation and delayed elasticity in the viscoelastic process in amorphous solids: Illustration on a chalcogenide glass

International audienceInorganic glasses are viscoelastic materials since they exhibit, below as well as above their glass transition temperature, a viscoelas-tic deformation under stress, which can be decomposed into a sum of an elastic part, an inelastic (or viscous) part and a delayed elastic part. The delayed elastic part is responsible for the non-linear primary creep stage observed during creep tests. During a stress relaxation test, the strain, imposed, is initially fully elastic, but is transformed, as the stress relaxes, into an inelastic and a delayed elastic strains. For linear viscoelastic materials, if the stress relaxation function can be fitted by a stretched exponential function, the evolution of each part of the strain can be predicted using the Boltzmann superposition principle. We develop here the equations of these evolutions, and we illustrate their accuracy by comparing them with experimental evolutions measured on GeSe 9 glass fibers. We illustrate also, by simple equations, the relationship between any kind of relaxation function based on additive contribution of different relaxation processes and the delayed elastic contribution to stress relaxation: the delayed elasticity is directly correlated to the dispersion of relaxations times of the processes involved during relaxation