480 
Combining Eq. 9.6 with Eq. 9.4 and introducing the dissipated enthalpy 
h( Pra) = Elfin) + Po A ( Ip) one obtains 
oO 
21ra,dz,We - / Po dA wat 
ge Fle) 
AbCp tryemizdz, dt: 7 [es us dA At, 
The time ieee of the right member may be assumed to vanish for 
(9.7) 
&=00 . If one subtracts from Eq. 9.7 the expression obtained from that 
equation for R =o » there results the relation 
(7) 
ait dz, D(K) = ppu-as dt, (9.8) 
t(K) 
where oo 
DIR) = | a A (9.9) 
R 
Now, AA =2mirds IQ» where 17 is the unit normal to ols into which 
Az, 1, is transformed by the passage of the wave, and therefore, 
dA = tardz tox (1, Yr) 
La 
Eq. 9.8 becomes 
Qo 
pir) = [rp a [aged Wed] a ; (9.10) 
eR) 
The energy-time integral can be expressed in reduced form, 
DR) = Fp i ie = -KD/pt) log Flies , 
Fe wfldgrld erddrp, FLb- tye, oan 
% © 
y= ii tin Ha +. 
90 
FOR, dH) = F/F, 
ny? 
