Equation Icon  wC(r,z) = --------YC---------{σC E (r,z )2 + (1 − 2σC )[(Err(r,z) + Eϕϕ(r,z))2 2(1 + σC )(1 − 2σC) − 2E (r,z)E (r,z) + E (r,z)2]} (8.52 ) rr ϕϕ zz