Effect of antimony surface treatment on nitrogen absorption during batch annealing of an electrical steel sheet

Nitrogen absorption is usually observed during batch-type hot-band annealing of electrical steel sheets containing aluminium. This nitrogenizing causes the deterioration of magnetic properties, such as core loss and induction. In order to prevent nitrogenizing, we investigate an antimony treatment on the hot strip surface of electrical steel sheets containing aluminium. Potassium antimonyl tartrate and colloidal antimony oxides (Sb2O5) are effective against nitrogenizing. It seems that active sites on the surface of the hot strip after pickling are covered with antimony oxides to block the adsorption of nitrogen. Magnetic properties, after cold-rolling and continuous annealing of the nitrogenizing hot band, deteriorate due to small grains near the surface whose boundaries are pinned by aluminium nitrides.     

Control of unstable mechanical system Control of pendulum†

This paper relates to the design of a control system for a mechanical system which contains an unstable mode and to an experiment for demonstrating that the control theory may be applied to practical real systems. In this paper the object treated is the control of the pendulum-cart system, which has been studied by many control theorists and engineers as an inverted pendulum problem, and a composite control system is designed not only to stabilize the inverted pendulum but to swing the pendulum from the natural pendent position up to the inverted position, which is actually made. The experimental results are presented.