Volume changes, measurement

Sample Treatment Added (Corrected for Volume Changes) Measured by Neutron Activation... 

Figure 5 shows the volume change measured in the samples loaded at different temperatures keeping their water content constant. As it has been observed in saturated materials, the temperature increases the compressibility of the bentonite. A certain reduction in the size of the elastic domain with the temperature can be observed (Hueckel Borsetto 1990), despite the fact that the vertical stresses applied are smaller than the compaction load. 

Figure 5. Volume change measured during loading at different temperatures and constant water content (initial dry density 1.70 g/cm ).

After saturation the samples were loaded under oedometric conditions. The volume changes measured during loading are plotted in Figure 9. 

Compositions of polypropylene with unmodified and modified chalk were obtained by means of a screw extruder at 210 C. The granulated product was used to prepare compression moulded films 0.4 mm thick which were pressed at 190 C and then quenched in iced water. From films obtained in this way oarshaped samples with the dimensions as in Fig. 2 were punched. In all cases the samples were cut out form the same places in compression moulded films in order to provide approximately the same flow-induced orientation of chalk particles relative to the sample axis. For the purpose of tensile properties and volume changes measurements the samples were marked (see Fig. 2). 

Pre-liquefaction coefficient of consolidation (c ) values for each specimen were calculated based on measured hydraulic conductivity (k) and volume compressibility (m ) data for virgin loading shown in Figure 4a. Post-liquefaction c, values were back-calculated using time histories of pore pressure dissipation and volume change measurements obtained during post-liquefaction dissipation tests for each incremental change in effective stresses. Back-calculations of c were... 

R. S. Duran and McKenna, A Torsional Dilatometer for Volume Change Measurements on Deformed Glasses Instrument Description and Measurements on Equilibrated Glasses , J. Rheol. 34, 813-839 (1990). 

Duran, R.S. and McKenna, G.B. A torsional dilatometer for volume change measurements on deformed glasses Instrument description and measurements on equilibrated glasses, J. Rheol. 34, 1990, p. 813-839. 

More recently it has been suggested that if the isotopic flux of water appears to be smaller than the flux calculated from a volume-change measurement, this is due to the existence of a poorly stirred layer of water on either side of the cellular membrane. A stagnant layer obviously does not disturb appreciably the results obtained when measuring an osmotic flow but has a profound influence on the tracer results. 

Observations of nerve mechanical motions during the action potential have been performed with various contact and combined contact/optical techniques, including piezoelectric sensors (2P), volume change measurements 30 measurements of scattering of attached beads (75) and optical lever recordings... 

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