A simulation model for an air-swept ball mill grinding coal

The conventional model for grinding in tumbling ball mills was modified to allow for air-sweeping, for the case where all the material is carried out of the mill in the air stream. It was shown that this type of mill can be treated as a single fully mixed reactor. The values of the internal classification numbers given by the air-sweeping were determined for a 1 m by 1.5 m pilot-scale mill grinding coal. The results showed that only 1 to 2% of the mill charge are exposed to the sweeping action per mill revolution. S and B values determined in a laboratory mill were scaled-up for use in the continuous mill model and the simulations gave product size distributions and mill capacities which agreed with the pilot-scale mill data within the experimental accuracy of the pilot-scale data.     

Estimation of charge distribution on a bulky solid dielectric using regularization technique

We have been studying a multi‐point charge measurement method using an electrostatic probe. In this technique, charge densities x must be estimated from the probe outputs b by an inverse calculation based on an equation A x = b . The matrix A is obtained by applying a numerical field calculation technique. When the matrix A is in ill‐condition, the solution often makes no sense, including extremely large errors. Therefore, we apply the regularized least squares method (RLS) with a penalty term to perform the inverse calculation stably for the ill‐conditioned matrix. The penalty term imposes some constraints on the solutions. In this paper, first, we have analyzed the accuracy of the charge distribution estimated by the inverse calculation. Although the perturbation bound of the solution errors has already been proposed for the least squares method, it has not yet been given for the RLS. We have derived the equations that express the perturbation bound of the solution errors in applying the RLS to evaluate the estimation accuracy. Second, we have applied the above equations to an experimental result for a cylindrical dielectric solid, and estimated the charge distribution represented by 10,140 unknowns. We have utilized an iteration technique and the symmetric configuration of the measured arrangement so as to reduce the amount of operations and memory capacity required for the inverse calculation. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 163(2): 1–13, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20412     

Preparation and reactions of polymers having 1-aroyl-2-(3-pyridyl)ethylenes as photosensitive groups

The reactions of 1-aroyl-2-(3-pyridyl)ethylenes (APE) with polychloromethylstyrene (PCMS) yield polymeric systems which undergo rapid crosslinking upon short exposure to ultraviolet (UV) light. The photochemical reaction of polymers as well as model compounds was followed by the measurement of UV absorption of APE and the analysis of extinction coefficient difference (ED) diagrams.¹