Optimal arrangement for pressure measurement points in working chamber of earth pressure balance shield

In order to exactly provide scientific basis for pressure dynamic balance control of working chamber of earth pressure balance shield (EPBS),study on optimal arrangement of pressure measurement points in working chamber was conducted. Based on mathematical description of optimal arrangement for pressure measurement points,fuzzy clustering analysis and discriminant analysis were used to divide pressure regions of nodes on bulkhead. Finally,the selection method of optimal measurement points was proposed,and by selecting d6.28 m EPBS as study object,the case study was conducted. By contrast,based on optimal arrangement scheme of pressure measurement points,through adopting weighted algorithm,the absolute error mean of equivalent pressure of working chamber is the smallest. In addition,pressure curve of optimal arrangement points presents parabola,and it can show the state of pressure distribution on bulkhead truly. It is concluded that the optimal arrangement method of pressure measurement points in working chamber is effective and feasible,and the method can provide basis for realizing high precision pressure control of EPBS.

Study of Cotton Seeds as a Processing Material

The purpose of this research is to improve the qualitative and quantitative indicators of fiber, lint and seeds by improving the technology of preparing cotton seeds for processing. The state of the seeds after the gin was studied and their division into fractions according to the degree of pubescence was recommended, the probabilities of the seeds emerging from the gin with varying degrees of pubescence were investigated, the geometric sizes and shapes of cotton seeds were studied. It has been established that when seeds come out of gin, they have different pubescence. The conditional movement of seeds without separation from the surface has been determined;found a formula describing the movement of seeds without detaching from the surface;the movement of seeds in a micro-flight is determined;the sizes of the cells of the mesh surface were determined as a function of d_c, α and on the speed of seed movement. The aim of the research work is to increase the yield of cotton fiber by improving the processing technology of germinated seeds, to improve the quality indicators of seeds and lint. In order to achieve this goal, a mesh surface device was created to sort the seeds into fractions. Sorting technology was developed on this device and operating modes were determined. In addition, the law of surface distribution of the fractions separated from the cotton stream moving along the surface of the net was determined, and based on the results of practical and theoretical research, a mode of sorting of cotton seeds was developed.