Research on locating control method of ball mill based on prediction
To solve the difficulty of precise locating of large inertia ball mill, a new method based on prediction is put forward. The feasibility of this method was analyzed using the motor theory and analysis on the ball mill kinematics and dynamics. The equipment to install rotary encoder that was connected to the ball mill was designed. And the testing hard ware based on single-chip microcomputer was build, and data of the angle and the rotational speed of the ball mill were acquired. With the tool of Mat lab, data were analyzed. The results shows that the angle predicted from the starting stage is very much closed to the angle which is measured, and the tolerance is very small, and it can meet the application completely.
Research on precise locating control of large inertia ball mill
To solve the problem of difficulty in precise locating of batch ball mill, the kinetic model was build, and parameters relationship between starting and shutting down were analyzed, control system was designed. At the stage of starting of ball mill, load torque, rotary inertia and so on could be acquired. Based on the relationship of ball mill kinetic parameters between starting and shutting off, parameters at the stage of shutting off could be predicted. With these parameters, the angle that the ball mill would roll after power off could be predicted. With the angle, the optimum spot to cut off power of ball mill could be find, and precise locating and stopping of ball mill could be implemented. The control system is simple in structure, easy for installation and suitable for the reconstruction of existing ball mills control.
The costs of identifying undiagnosed prostate cancer in asymptomatic men in New Zealand general practice
Background. Screening for prostate cancer (PCa) using the prostate-specific antigen (PSA) test is widespread in New Zealand. 3 informed testing history in 2007–09 were NZ$8887 compared to NZ$13 870 if the men had PSA tests in 2007–09. If we assumed a PSA test involved a full 15-minute general practice consultation, the estimated costs increased to NZ$26 877 per PCa identified. Conclusions. Screening of asymptomatic men for PCa is widely practiced. Most of the costs of screening were incurred in general practice. Calls for men to receive increased information on the harms and benefits of screening will substantially increase the costs. The current costs could be reduced by better targeting of screening.