{ diff(x1, t) = ((-1)*k14*piecewise(k1/(111/10), k13 = 1, k1/(41/5))*x7*x1 + 1*k14*k1*x2 + 1*k14*k7*x2 + (-1)*k14*k5*x1 + 1*k14*k6)/k14,
  diff(x2, t) = (1*k14*piecewise(k1/(111/10), k13 = 1, k1/(41/5))*x7*x1 + (-1)*k14*k1*x2 + (-1)*k14*k8*x2)/k14,
  diff(x3, t) = (1*k14*k5*x1 + (-1)*k14*piecewise(piecewise(k1*8, k13 = 1, k1*5)/1000, k13 = 1, piecewise(k1*8, k13 = 1, k1*5)/3000)*x5*x3 + 1*k14*piecewise(k1*8, k13 = 1, k1*5)*x4 + (-1)*k14*k10*x3)/k14,
  diff(x4, t) = (1*k14*k8*x2 + 1*k14*piecewise(piecewise(k1*8, k13 = 1, k1*5)/1000, k13 = 1, piecewise(k1*8, k13 = 1, k1*5)/3000)*x5*x3 + (-1)*k14*piecewise(k1*8, k13 = 1, k1*5)*x4 + (-1)*k14*k10*x4)/k14,
  diff(x5, t) = ((-1)*k14*(piecewise(k1/(111/10), k13 = 1, k1/(41/5))*x5*x3 - piecewise(k1*8, k13 = 1, k1*5)*x4)/(k11*k12) + (-1)*k14*k9*x5)/k14,
  diff(x6, t) = 1*k14*k10*x4/k14,
  diff(x7, t) = (-1)*k14*(piecewise(k1/(111/10), k13 = 1, k1/(41/5))*x7*x1 - k1*x2 - k9*x5*k11*k12)*x8/k12/k14,
  diff(x8, t) = piecewise((600*x2/(250 + x2) - 200)*1000, 600*x2/(250 + x2) - 200 > 0, 0) }