An Equilibrium Model for the Nta Complexation of Metal Ions in Natural Waters
Abstract The equilibrium distribution of NTA among several naturally occurring metal ions has been calculated from previously reported complex ion formation constants. Competition among chelators for the same metals is deduced by introducing the additional model ligands cysteine and citrate to the system. The fraction of NTA, and in the mixed system the fractions of each ligand, bound to each metal at 25°C and pH 7.4 are reported. It is concluded that the most important NTA complexes are those of copper and zinc, and because of their predominance and known biological properties there should be no new toxicological problems arising because of chelation of metal ions already present in the environment as a result of the substitution of NTA for phosphates in detergents.
This paper deals with the study of free transverse vibrations of rectangular plates with an internal line hinge and elastically restrained boundaries. The equations of motion and its associated boundary and transition conditions are rigorously derived using Hamilton’s principle. The governing eigenvalue equation is solved employing a combination of the Ritz method and the Lagrange multipliers method. The deflections of the plate and the Lagrange multipliers are approximated by polynomials as coordinate functions. The developed algorithm allows obtaining approximate solutions for plates with different aspect ratios, boundary conditions, including edges elastically restrained by both translational and rotational springs, and arbitrary locations of the line hinge. Therefore, a unified algorithm has been implemented. Sets of parametric studies are performed and the results are given in graphical and tabular form.