The ISCLT model uses a set of three criteria to determine whether the process of calculating the sector average concentration has "converged." The calculation process will be considered to have converged, and the most recent estimate of the trapezoidal integral used, if any of the following conditions is true:
1) if the number of "halving intervals" (N) in the trapezoidal approximation of the sector average has reached 10, where the number of individual elements in the approximation is given by 1 + 2N-1 = 513 for N of 10;
2) if the estimate of the sector average has converged to within a tolerance of 0.02 (i.e., 2 percent), for two successive iterations, and at least 2 halving intervals have been completed (a minimum of 5 wind direction simulations); or
3) if the estimate of the sector average concentration is less than 1.0E-10, and at least 2 halving intervals have been completed.
The first condition essentially puts a time limit on the integration process, the second condition checks for the accuracy of the estimate of the sector average, and the third condition places a lower threshold limit that avoids convergence problems associated with very small concentrations where truncation error may be significant.
2.2.4 The Long‑Term Open Pit Source Model
The ISC Long Term Open Pit Source Model is based on the use of the long term area source model described in Section 2.2.3. The escape fractions and adjusted mass distribution for particle emissions from an open pit, and the determination of the size, shape and location of the effective area source used to model open pit emissions are described in Section 1.2.4. For the Long Term model, a sector average value for open pit sources is calculated by determining an effective area for a range of wind directions within the sector and increasing the number of wind directions used until the result converges, as described in Section 2.2.3 for the Long Term area source model. The contribution from each effective area used within a sector is calculated using the Short Term area source model described in Section 1.2.3.
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APLICACIONES castellano: DIS CUS DES RAD english: DIS CUS DES RAD
português: DIS CUS DES RAD italiano: DIS CUS DES RAD
français: DIS CUS DES RAD