Microstructure modelling of hot deformation of Al–1%Mg alloy

This study presents the application of the finite elementmethod and intelligent systems techniques to the prediction of microstructural mapping for aluminium alloys. Here, the material within each finite element is defined using a hybrid model. The hybrid model is based on neuro-fuzzy and physically based components and it has been combined with the finite element technique. The model simulates the evolution of the internal state variables (i.e. dislocation density, subgrain size and subgrain boundary misorientation) and their effect on the recrystallisation behaviour of the stock. This paper presents the theory behind the model development, the integration between the numerical techniques, and the application of the technique to a hot rolling operation using aluminium, 1 wt% magnesium alloy. Furthermore, experimental data from plane strain compression (PSC) tests and rolling are used to validate the modelling outcome. The results show that the recrystallisation kinetics agree well with the experimental results for different annealing times. This hybrid approach has proved to be more accurate than conventional methods using empirical equations

MRAI Optimization for BGP Convergence Time Reduction without Increasing the Number of Advertisement Messages

AbstractThe primary cause for the slowness of the Border Gateway Protocol (BGP) convergence delay is the Minimum Route Advertisement Interval (MRAI). The MRAI is a timer with a default value of 30seconds, which forces the BGP routers to wait for at least that amount of time before sending an advertisement for the same prefix. This process can delay important BGP advertisements. To date, there has been no specific value used by all the networks around the Internet. This paper aims to find the optimum value for the MRAI timer that maximally reduces the convergence time without increasing the number of advertisement messages. The optimal MRAI value founded by this paper reduced the convergence time by minimum 45%