Power regressions of versus the parameters of chlorine decay models are presented in Table 6. The parameters of existing models are affected negatively by and show strong correlations (R2 > 0.86). The parameter a (the proportional coefficient of regression equation) tends to decrease as the order n increases for the nth-order and limited nth-order models, and the converse tendency is apparent for the parameter b (the power coefficient of regression equation), except in the case of the fourth-order model, for which R2 values are small relative to those of other models (see Table 6).

Table 6

Regression equations between and model parameters (y) using y=axb and the corresponding determination coefficients (R2) for all models

ModelyXabR2
1st order   1.869 −2.487 × 10−1 0.980
2nd order   1.670 −2.611 × 10−1 0.958
3rd order   1.474 −2.741 × 10−1 0.928
4th order   1.657 −3.143 × 10−1 0.892
Limited 1st order   1.951 −2.519 × 10−1 0.988
Limited 2nd order   1.677 −2.578 × 10−1 0.959
Limited 3rd order   1.557 −2.750 × 10−1 0.936
Limited 4th order   1.498 −2.925 × 10−1 0.861
Parallel 1st order w  1.845 −1.151 × 10−1 0.968
k1  1.892 −2.500 × 10−1 0.978
k2  1.827 −2.463 × 10−1 0.983
nth n  2.868 −1.861 × 10−1 0.740
k  1.494 −2.118 × 10−1 0.983
Limited nth n  2.978 −1.952 × 10−1 0.751
k  1.513 −2.120 × 10−1 0.977
Combined ‘1 + 1’ w  1.426 −6.217 × 10−1 0.975
k1  1.878 −2.491 × 10−1 0.978
k2  1.834 −2.477 × 10−1 0.980
w  61.96 −8.330 × 10−1 0.790
Combined ‘1 + n’ k1  230.3 −9.147 × 10−1 0.941
n  0.02066 3.857 × 10−1 0.816
k2  0.4503 −7.087 × 10−1 0.596
c*  0.0066 2.653 × 10−1 0.901
w  0.6310 −1.379 × 10−1 0.892
Combined ‘n+n’ n1  10.39 −4.009 × 10−1 0.717
k1  104.2 −7.918 × 10−1 0.925
n2  0.006321 5.443 × 10−1 0.680
k1  0.6737 −1.344 × 10−1 0.915
c*  6 × 10−5 7.537 × 10−1 0.855
ModelyXabR2
1st order   1.869 −2.487 × 10−1 0.980
2nd order   1.670 −2.611 × 10−1 0.958
3rd order   1.474 −2.741 × 10−1 0.928
4th order   1.657 −3.143 × 10−1 0.892
Limited 1st order   1.951 −2.519 × 10−1 0.988
Limited 2nd order   1.677 −2.578 × 10−1 0.959
Limited 3rd order   1.557 −2.750 × 10−1 0.936
Limited 4th order   1.498 −2.925 × 10−1 0.861
Parallel 1st order w  1.845 −1.151 × 10−1 0.968
k1  1.892 −2.500 × 10−1 0.978
k2  1.827 −2.463 × 10−1 0.983
nth n  2.868 −1.861 × 10−1 0.740
k  1.494 −2.118 × 10−1 0.983
Limited nth n  2.978 −1.952 × 10−1 0.751
k  1.513 −2.120 × 10−1 0.977
Combined ‘1 + 1’ w  1.426 −6.217 × 10−1 0.975
k1  1.878 −2.491 × 10−1 0.978
k2  1.834 −2.477 × 10−1 0.980
w  61.96 −8.330 × 10−1 0.790
Combined ‘1 + n’ k1  230.3 −9.147 × 10−1 0.941
n  0.02066 3.857 × 10−1 0.816
k2  0.4503 −7.087 × 10−1 0.596
c*  0.0066 2.653 × 10−1 0.901
w  0.6310 −1.379 × 10−1 0.892
Combined ‘n+n’ n1  10.39 −4.009 × 10−1 0.717
k1  104.2 −7.918 × 10−1 0.925
n2  0.006321 5.443 × 10−1 0.680
k1  0.6737 −1.344 × 10−1 0.915
c*  6 × 10−5 7.537 × 10−1 0.855

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