Discriminant Genetic Algorithm Extended (DGAE) model for seasonal sand and dust storm prediction

Here we use a Discriminant Genetic Algorithm Extended (DGAE) model to diagnose and predict seasonal sand and dust storm (SDS) activities occurring in Northeast Asia. The study employed the regular meteorological data, including surface data, upper air data, and NCEP reanalysis data, collected from 1980–2006. The regional, seasonal, and annual differences of 3-D atmospheric circulation structures and SDS activities in the context of spatial and temporal distributions were given. Genetic algorithms were introduced with the further extension of promoting SDS seasonal predication from multi-level resolution. Genetic probability was used as a substitute for posterior probability of multi-level discriminants, to show the dual characteristics of crossover inheritance and mutation and to build a non-linear adaptability function in line with extended genetic algorithms. This has unveiled the spatial distribution of the maximum adaptability, allowing the forecast field to be defined by the population with the largest probability, and made discriminant genetic extension possible. In addition, the effort has led to the establishment of a regional model for predicting seasonal SDS activities in East Asia. The model was tested to predict the spring SDS activities occurring in North China from 2007 to 2009. The experimental forecast resulted in highly discriminant intensity ratings and regional distributions of SDS activities, which are a meaningful reference for seasonal SDS predictions in the future.

A modern and robust methodology for modeling anisotropic creep characteristics of Ni-based DS and SC superalloys

According to more recent work, the Wilshire equations have shown good prediction accuracy in a wide range of materials and stress-temperature conditions, particularly in extrapolation of short term results to long term predictions. In the current paper, this methodology was further developed for modeling anisotropic creep characteristics （i.e. minimum creep strain /~n, stress rupture life q and time to a specified strain t~） of four typical Ni-based directionally solidified （DS） and single crystal （SC） superalloys, where a simple orientation factor related to the ultimate tensile strength （UTS） was introduced. The application of these simplistic approaches showed that the anisotropic creep characteristics in a wide range of stress-temperature conditions can be accurately simulated. Meanwhile, during the application of the modified Wilshire equations, break points occurring at the specified stress levels agree well with the transition of creep deformation mechanisms occurring in different stress regions, which provides confidence for using this method.