Limit Design in the Absense of a Given Layout: A Finite Element,Zero-One Programming Approach∗

Limit design in three dimensions is discussed and formulated as a constrained minimax problem in kinematic and geometric variables. A finite element discretization is proposed which, combined with piecewise linearization of the yield surfaces, reduces the minimum weight design to a pair of dual problems in linear mixed zero one programming. The relevant duality theory is shown to be useful for the theoretical frame of the mechanical problem. Various ways of reducing the number of variables and constraints are pointed out, in order to make available algorithms economically applicable to practical situations.     

PROFLAVINE-SENSITIZED PHOTOOXIDATION OF METHIONINE

Abstract— A study was made of the kinetics of the proflavine-sensitized photooxidation of methionine to methionine sulfoxide. The reaction is inhibited by the paramagnetic ions Cu²⁺ and Mn²⁺, which suggests that the triplet state of the sensitizer is an intermediate. A mechanism is proposed in which methionine reacts with the first singlet state of oxygen, produced by energy transfer from the triplet sensitizer. The decrease in the rate of photooxidation with increasing proflavine concentration is ascribed to self-quenching of the excited singlet state of the dye.