Theory of porosimetry hysteresis

From the previous discussion it can be shown that a complete intrusion-extrusion cycle is composed of the following steps  

Intrusion with contact angle 6 into pores with area A, for which the corresponding work, Ifi, is 

By adding the area of entrapped mercury, T, to A in the above equation, the work associated with the contact angle change, W g, becomes the work necessary to alter the contact angle over the entire length of the pore, not only that portion which extrudes. Thus, W g can be expressed as 

Extrusion with contact angle is accompanied by an amount of work, 

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