Figure 5. BCA channel frequency test results, (A) Magnetization direction of each BCA and intensity and direction or each magnetic field, and (B) Experiment result of fluid flow for 80 seconds for each BCA channel and each magnetic field
Based on the frequency with the best performance, fluid tests were conducted using configured BCA channels to confirm the tendency of fluid flow through the movement of the particles. When the strike magnetic field was applied, a strong pumping of the fluid flow appeared in the symmetric BCA channel (Figure. 6A(i) and Movie S3 ), where the average particle factor where the particles were located was 143 at t = 0 s and 195, with a standard deviation of 26.3 at t = 100 s, which implies that the fluid flow moved forward uniformly with little mixing. However, in the asymmetric BCA channel (Figure. 6A(ii) and Movie S4 ), most of the particles seemed to advance slowly up to 9 mm; however, after passing 9 mm, the particles did not move well (Figure. 6B(ii)). When the rotating magnetic field was applied, the fluid was mixed by both the symmetric BCA channel and the asymmetric BCA channel (Figure. 6A(iii), (iv)); however, in the symmetric BCA channel, for 100 s, the particles were dispersed with a standard deviation of 26.3 (Figure. 6B(iii) and Movie S5). In the asymmetric BCA channel, the particles took approximately 60 s to spread evenly with a standard deviation of 9.9 (Figure. 6B(iv) and Movie S6). Consequently, the application of the strike magnetic field to the symmetric BCA channel was suitable for the pumping of the fluid because it maintained the particle concentration and advanced quickly, and the application of the rotating magnetic field to the asymmetric BCA channel was the fastest to make the particle distribution uniform, making it suitable for mixing.