# Time-Dependent Kinetic Rate

Hello,

I am working on a project similar to the “Solute transport including kinetic reaction” benchmark.

The reaction rate described in the benchmark is:

dc/dt=U(c_synthetica/(K_m+c_syntheticb ))

The reaction rate that I want to define is:

dc/dt=U(c_synthetica/(K_m+c_syntheticb ))*e^(-t/t_d )
t_d is a time constant,t is time.

The rate definition in the benchmark is:

Moles = rate * TIME, in this definition, TIME is the time interval defined previously, right?
Can I define a curve scaled parameter for e^(-t/t_d ) outside the chemical system and insert it in the statement? Would that work? How I can solve this issue?

Thank you.

Hello again,

I think I can just write the equation as it is and insert SIM_TIME for t. SIM_TIME is the simulation time that I needed in this case.