SYNOPSISThe accessibility of starch in polyethylene starch blends was investigated by computer simulation, percolation theory, and acid hydrolysis experiments. The object of this work was to model the bilateral invasion of microbes in polyethylene-starch blends as a function of starch concentration ( p ) , and thickness of the material. It was found that computer simulations in three dimensions were in agreement with both percolation theory and the acid digestion experiments. In computer simulation the accessibility is highly dependent on the percolation threshold concentration ( p , ) , which is 31.17%. Similarly, the accessibility of starch is highly dependent on an apparent percolation threshold near 30% by volume or approximately 40% by weight of starch. At p < p c a small amount of starch is removed from the surfaces only, but at p > p c connected pathways existing throughout the bulk of the material facilitate large amounts of starch extraction. The sharpness of the transition at pe increases with the ratio of sample thickness to starch particle size. The results of this work have application to conduction and reacting systems where one component is dispersed in a matrix of the other.

In order to investigate the effect of ultra-fine smash on the separation results of Shenfu semi-coke, the impact crusher was used to explore the relation between the degree of dissociation and the particle size and ash content. Additionally, the operating parameters of separation device of impact crusher was analyzed by the orthogonal experiment method and then it was optimized. The result of particle size analysis and oil absorption measurement to the ultra-fine smash of semi-coke reveals that both the ash content and oil absorption decrease with the increase of particle size, which indicates that the minerals of semi-coke are enriched in the fine fraction and the surface area of semi-coke ratio is increased after the ultra-fine smash. The proportion of ash content is 5.81%, the d 97 is 82.09μm and the productive rate is 22.67%, respectively, while keeping the air inlet half-open, the speed of crusher 2900 r/min and the speed of classifier 700 r/min. In conclusion, the experimental results reveal that the volume of air inlet, the speed of crusher and the speed of classifier take the dominant effect on the particle size and purification of Shenfu semi-coke, moreover, the impact crusher has an extra impact of separation while smashing the ultra-fine of the semi-coke.