equation icon  ptot w-+-(1-+-2w)r/2c--+-rE/3r- wtot =_ r = 1 + r/2c + r /r , (102) tot [ E ][ ]-1 2 ptot 2 r +-p- -------4rE-------- -------4rE-------- ctot =_ rtot = cs + r + c + 9(r + p)(1 + r/c) 1 + 3(r + p)(1 + r/c) , (103)