Influence of calcium doping on the conduction band structure and dynamics of the Fermi level in Y0,75-xCaxPr0,25Ba2Cu3Oy system

Two techniques for calculation of a posteriory error bounds of numerical solutions of boundary value problems of solid mechanics are suggested. The former termed the direct error norm evaluation technique, does not require solving any system of algebraic equations and the latter assumes solution of dual problems. We show that both provide guaranteed reliable error bounds and are fast in respect of computational cost. Numerical experiments support effectiveness.