d_parent = - (alpha/beta) * 1/((time/beta) + 1) * parent
d_A1 = + f_parent_to_A1 * (alpha/beta) * 1/((time/beta) + 1) * parent - k_A1 * A1
d_B1 = + f_parent_to_B1 * (alpha/beta) * 1/((time/beta) + 1) * parent - k_B1 * B1
d_A2 = + f_A1_to_A2 * k_A1 * A1 - k_A2 * A2

FOMC, three sequential and parallel mets

DFOP, three sequential and parallel mets

d_parent = - ifelse(time <= tb, k1, k2) * parent
d_A1 = + f_parent_to_A1 * ifelse(time <= tb, k1, k2) * parent - k_A1 * A1
d_B1 = + f_parent_to_B1 * ifelse(time <= tb, k1, k2) * parent - k_B1 * B1
d_A2 = + f_A1_to_A2 * k_A1 * A1 - k_A2 * A2

d_parent = - k_parent * parent
d_A1 = + f_parent_to_A1 * k_parent * parent - k_A1 * A1
d_B1 = + f_parent_to_B1 * k_parent * parent - k_B1 * B1
d_C1 = + f_parent_to_C1 * k_parent * parent - k_C1 * C1

d_parent = - (alpha/beta) * 1/((time/beta) + 1) * parent
d_A1 = + f_parent_to_A1 * (alpha/beta) * 1/((time/beta) + 1) * parent - k_A1 * A1
d_B1 = + f_parent_to_B1 * (alpha/beta) * 1/((time/beta) + 1) * parent - k_B1 * B1
d_C1 = + f_parent_to_C1 * (alpha/beta) * 1/((time/beta) + 1) * parent - k_C1 * C1

d_parent = - ifelse(time <= tb, k1, k2) * parent
d_A1 = + f_parent_to_A1 * ifelse(time <= tb, k1, k2) * parent - k_A1 * A1
d_B1 = + f_parent_to_B1 * ifelse(time <= tb, k1, k2) * parent - k_B1 * B1
d_C1 = + f_parent_to_C1 * ifelse(time <= tb, k1, k2) * parent - k_C1 * C1

d_parent_in_water = - k_parent_in_water_sink * parent_in_water - k_parent_in_water_parent_in_sediment * parent_in_water + k_parent_in_sediment_parent_in_water * parent_in_sediment
d_parent_in_sediment = + k_parent_in_water_parent_in_sediment * parent_in_water - k_parent_in_sediment_sink * parent_in_sediment - k_parent_in_sediment_parent_in_water * parent_in_sediment

d_parent_in_water = - k_parent_in_water_sink * parent_in_water - k_parent_in_water_parent_in_sediment * parent_in_water - k_parent_in_water_A1_in_water * parent_in_water + k_parent_in_sediment_parent_in_water * parent_in_sediment
d_parent_in_sediment = + k_parent_in_water_parent_in_sediment * parent_in_water - k_parent_in_sediment_sink * parent_in_sediment - k_parent_in_sediment_parent_in_water * parent_in_sediment
d_A1_in_water = + k_parent_in_water_A1_in_water * parent_in_water - k_A1_in_water_sink * A1_in_water