Tables de contingence à trois dimensions : aspects théoriques, applications et analogie avec l'analyse de la variance à trois critères de classification

For contingency table, concepts of independence are not so easy to understand in statistical practice. So, theoretical aspects of the log-linear model are described and applied to a three levels example; an analogy with analysis of variance is also established.Les notions d'indépendance mises en évidence lors de l'étude d'une table de contingence, à trois dimensions au moins, ne semblent pas être évidentes à comprendre en pratique. C'est pourquoi, des aspects théoriques faisant référence au modèle log-linéaire sont détaillés et illustrés, et une analogie avec l'analyse de la variance à trois critères de classification, modèle fixe est établie

Acoustic sensors and instrumentation for in-situ research reactors measurements: Invited speaker to the Workshop on “The coupling of experiments and modeling to enhance experiments in research reactors”

International audienc

Développement d'une technique acoustique en champ proche et applications à la caractérisation locale des matériaux

MONTPELLIER-BU Sciences (341722106) / SudocSudocFranceF

Evaluation of textural properties of mango tissue by a near-field acoustic method

A near-field acoustic (NFA) method was applied to characterize viscoelastic properties of mango pulp tissue. The developed sensor was a stepped horn consisting of a cylindrical body and a coupled cylindrical tip to be inserted into the pulp sample. The properties of the pulp altered the mechanical resonance of the horn and the electrical resonance of the piezoelectric element, which served as both input and output port. The measured acoustic parameters represented the shift of the resonance frequency ([delta]f) and the attenuation of the peak amplitude ([delta](1/Z)) of the probe when its vibrating tip was immersed in air, the reference medium, and then inserted into the pulp sample. Acoustic testing was carried out on each fruit at four locations evenly distributed in the middle parenchyma tissue of an equatorial section. The acoustic data were then compared to the 10 min depth penetration force values obtained for the same four pulp locations. The results obtained for 45 mangoes with a wide range of maturity showed that Af'was very sensitive to the quality of the probe-medium interface, especially for unripe fruit, and poorly correlated with puncture test values. In contrast, the acoustic parameter [delta](1/Z) was significantly correlated with mango pulp firmness Fp (r = 0.92) assessed by puncture test. The relationship between these two parameters was slightly improved by a hyperbolic equation (r = 0.95). The NFA method developed appears to be a promising tool for assessing mango pulp texture and for following texture changes during fruit ripening. (Résumé d'auteur

Ultrasonic waves for characterisation of clay membranes

International audienc