*2.3. Experimental Set-Up for Measurement of Saturatedpermeability*

The same experimental set-up sketched in Figure 2 was used also for the measurement of saturated permeability. In this case, the ultrasonic probe was not used since a gravimetric measurement method was adopted. A becher filled with the test fluid was placed on a balance and, after turning on the vacuum pump, the inlet valve was opened leading the fluid to flow through the preform. Out-of-plane saturated permeability was measured after achieving steady state conditions. When the preform was saturated with the fluid, the quantity of fluid that entered from the inlet was equal to the quantity that came out from the outlet. A constant flow rate, measured by gravimetric method, under a constant pressure generated by vacuum was produced across the thickness of the different preforms. During the test, the weight of the fluid was measured as a function of time using a balance with a precision of 10−<sup>4</sup> g.
