網地の磨耗

Abstract

Cotton nets were weared by the rotating drum in water tank as shown in Fig. 1. The coef-ficient of friction was calculated with the records of reading of spring balance S and hanging weight W. Break test on the net pieces were done, the breadth and length of which are 10 meshes respectively, by using the sample in the initial and final stage in our experiment. Where, the time interval of our experiment was 4 hours. The results obtained are as follows:- The value of the coefficient of friction decreases with the increase of the time, and finally it approaches to a certain limiting value (Fig. 2 and Table 1). If the breaking load of the piece of net before and after the treatment of 4 hours be denoted by T0 and T respectively, the value of T/T0 seems to be large in the case of heavy weight and thin cord (Table 1).