Unusual Indentation Behavior of Alkali Metaphosphate Glass Above Glass Transition Temperature

The mixed alkali metaphosphate glass 12.5Li₂O–12.5Na₂O–12.5K₂O–12.5Cs₂O–50P₂O₅ (mol%) compressed under uniaxial stress shows unusually large recovery of its shape during heating above its glass transition temperature (T_g). To clarify the mechanism, the viscous, elastic, and plastic behavior of the metaphosphate glass was investigated with the depth‐sensing indentation method. From the load‐displacement (P–h) curves of the glass, a large recovery of the depth displacement was found during unloading above T_g. By analyzing the P–h curves with a viscous–elastic–plastic model, the large recovery was concluded to be due to larger elastic deformation than viscous deformation even above T_g. The phenomenon can be attributed to relaxation to the randomly oriented ‐P–O–P– chain structure from the oriented chain structure formed under stress in the metaphosphate glass .     

Solid—liquid mass transfer in a shaking vessel for a bioreactor with “current pole”

A shaking vessel with “current pole”, which is a center pole installed at the bottom, had shorter mixing time than a shaking vessel with a cone at the bottom. The mass transfer rate on the suspended particles was also measured in the shaking vessel where ion-exchange resin beads were used as the suspended particles. The dependence of the solid-liquid mass transfer coefficient on the circulating frequency changed at the critical circulating frequency for complete suspension N_JS. For a circulating frequency higher than N_JS, the mass transfer coefficient was correlated with the power consumption per unit volume, regardless of presence or not of the current pole.