k1 = a_1
k2 = a_2
k3 = a_3
k4 = b_1__1
k5 = b_2__1
k6 = b_3__1
k7 = e
k8 = alpha_1
k9 = alpha_2
k10 = beta_1
k11 = beta_2
k12 = beta_3
k13 = u_1
k14 = u_2
k15 = compartment