in this paper a guided tabu search (gts) is utilized for optimal nodal ordering of finite element models (fems) leading to small profile for the stiffness matrices of the models. the search strategy is accelerated and a graph-theoretical approach is used as guidance. the method is evaluated by minimization of graph matrices pattern equivalent to stiffness matrices of finite element models. comp...

Lyapunov exponents represent important quantities to characterize the properties of dynamical systems. We show that the Lyapunov exponents of two di€erent dynamical systems that can be converted to each other by a transformation of variables are identical. Moreover, we derive sucient conditions on the transformation for this invariance property to hold. In particular, it turns out that the tra...

Sao Paulo Med J. 2007;125(5):286-8. R E V IE W A R T IC L E Komal Bhatia

The Grasso RC12, introduced early 1996, belongs to the largest reciprocating compressors in industrial refrigeration. The high-speed variant, the RC12E, has been introduced in Europe by the end of 1997: the ammonia variant runs at 1500 rpm, whilst the halocarbon variant has a maximum speed of 1200 rpm. The design philosophy will be illustrated focusing on the valve design. The compressor housin...