2 documents found, page 1 of 1
Adsorbed water clusters in garnet cracks detected by impedance and Raman spectr...
Prezas, Pedro; Silva, Hugo; Vinagre, Ana; Graça, Manuel; Moita, Patrícia; Bezzeghoud, MouradThe combination of electric impedance and Raman spectroscopies at the analysis of the supercooled water phase transition enables the detection of adsorbed water clusters in garnet minerals of leucogranite samples. This transition is revealed by a change in the parameters measured by both techniques at low temperatures, Tc ∼ 220 K, and it is attributed to adsorbed water clusters in the walls of garnet cracks. Th...
Low-temperature dielectric measurements of confined water in porous granites
Silva, Hugo; Prezas, Pedro; Vinagre, Ana; Graça, Manuel F.; Monteiro, Jorge H.; Tlemçami, Mouhadyne; Moita, Patrícia; Pinho, António; Bezzeghoud, MouradThree different granitic rocks extracted from Évora (in the south of Portugal) where used to perform dielectric measurements in the frequency range from 100 Hz to 1 MHz and temperatures 100 − 350 K. Thin cylindrical samples were prepared and circular electrodes were established using silver conductive paint. A clear anomaly appears, for T ⇠ 200 − 220 K, in the dielectric measurements of the samples studied. Thi...