PolyOne expects loss for fourth quarter 2002, takes steps to reduce costs

Abstract

Semi-analytical modelling of transient experiments at cylindrical wire or fiber electrodes is hindered by the unavailability of numerical procedures for calculating special functions arising in the models. A theory is developed, of the chronoamperometric Faradaic current for a reversible charge transfer reaction at a cylindrical electrode. Arbitrary potential steps and unequal diffusion coefficients (δ = DO/DR ≠ 1) are assumed. Two procedures (written in C++) are designed, for computing a special function occurring in the theory. One procedure is computationally inexpensive, but has a low accuracy (relative error moduli close to 2% in the worst case, when −0.5 ≤ log (δ) ≤ 0.5). The second is more expensive, but highly accurate (relative error moduli close to 4 × 10−14 in the worst case, when −3 ≤ log (δ) ≤ 3). Numerical experiments demonstrate that the effect of δ ≠ 1 on the current is not negligible, even for δ not much different from unity. Therefore, the theory presented should be taken into account in experimental investigations. The code for the procedures is freely available.