Investigation of water to ice phase change in porous media by ultrasonic and dielectric measurements

International audienceThe main objective of this paper is to study the evolution of the ice content of porous media submitted to sub-zero temperatures by dielectric and ultrasonic measurements. Dielectric measurements are made by a capacitive sensor-based apparatus. The amount of ice formed within the tested sample is estimated from the global dielectric constants of the sample and of all the phases that form the tested composite material. On the other hand, ultrasonic measurements are based on the evolution of the ultrasonic wave velocity through the tested sample during a freezing-thawing cycle. These two methods lead to very close results and appear to be cheaper alternatives to low temperature calorimetry. The ice content curves are analyzed with the help of thermoporometry concepts in order to characterize the pore size distribution. Results appear to be complementary to mercury intrusion porosimetry ones. Moreover the commonly observed hysteresis of the ice content during a freezing-thawing cycle is investigated with respect to material microstructure

Utilisation des galets ouvragés du site de Ponthezières à Saint-Georges-d'Oléron (Charente-Maritime)

ABSTRACT On about five acres, the site of Ponthezières shows one of the specifications of its Artenacian handicraft. The presence of shaped pebbles, as well as little awls, was the key to understanding it.RESUME Sur environ deux hectares, le site de Ponthezières nous livre une des spécifications de son artisanat Arte- nacien. La présence des galets ouvragés ainsi que des petits perçoirs en était la clef.Ricou Christian, Esnard Thimus. Utilisation des galets ouvragés du site de Ponthezières à Saint-Georges-d'Oléron (Charente-Maritime). In: Bulletin de la Société préhistorique française, tome 93, n°4, 1996. pp. 546-548

THESES || DISPVTATIONIS XI.|| DE INFIR=||MATIONE TESTA-||MENTORVM ET TIT. XVII. & XVIII. LIB. II. INSTIT. & CON-||cordantib. Iuris civilis textib.|| desumptae.|| QVAS,|| Triuno nimine favente,|| PRAESIDE || Nobilißimo, Consultiß. at́q; Ampliß. Viro || DN. ARNOLDO DE REYGER I. V. D || & in illustrissima Ienensium Academia publico || Pandectarum Professore || Ingenij exercendi gratiâ excutiendas|| proponit || IOHANNES PAVLVS HOʹE || VIENN. AVSTRIACVS.|| Ad diem 30. Novembris hora & loco consuetis.||

Jena, Univ., Jur. Disp., 1594Vorlageform des Erscheinungsvermerks: IENAE Tyrigetarum,|| Ex typographéo Tobiae Steinmanni.|| Anno M D XCIV.|

Étude expérimentale concernant la fabrication de perles en coquillage de deux sites artenaciens oléronais

Abstract The discovery on the island of Ol éro n of Artenacian cockleshell bead production sites reveals the emergence of the first organised production structures. The wealth of archaeological material found on these sites, as well as the marks corresponding to each stage of shaping and fabrication, provide the elements necessary to decipher the techniques developed at that time.Résumé La découverte sur l'île d'Oléron de sites artenaciens de production de perles en test de card i и m nous révèle l'émergence des premières structures de production organisée. La richesse du mobilier archéologique récolté sur ces sites, ainsi que les stigmates afférents à chaque phase de façonnage, constituent les éléments de décryptage des techniques développées.Ricou Christian, Esnard Thimus. Étude expérimentale concernant la fabrication de perles en coquillage de deux sites artenaciens oléronais. In: Bulletin de la Société préhistorique française, tome 97, n°1, 2000. pp. 83-93

Étude technique et expérimentale d'un galet compresseur non identifié en provenance de sites artenaciens oléronais

Ricou Christian, Esnard Thimus. Étude technique et expérimentale d'un galet compresseur non identifié en provenance de sites artenaciens oléronais. In: Bulletin de la Société préhistorique française, tome 95, n°4, 1998. pp. 596-598

Caractéristiques physiques, mécaniques et rhéologiques d'un sol argileux lors de sa congélation: application à l'argile de Boom

dissertn: Diss. Doct

P-wave attenuation in creeping rock and system identification

The aim of this paper is to contribute to the evaluation of rock cracking using ultrasonic wave propagation. The rock specimens (siltstone sampled from a coal mine at a depth of 820 meters in Belgium) are subjected to incremental creep. The study of the rock transfer function shows P-wave attenuation in the direction of loading as a function of stress and time during the test: this attenuation becomes more significant at the stage at which the rock dilates. It is obvious from the specimen dimensions that the signal is affected by reflection phenomena. So, we have modelled the output signals with a model containing reflections. The simulations obtained from the model and input signal are very conclusive and the model validation is satisfying