diff --git a/dependencies/asm3_class.js b/dependencies/asm3_class.js
index ce44f96..b5c795e 100644
--- a/dependencies/asm3_class.js
+++ b/dependencies/asm3_class.js
@@ -65,7 +65,7 @@ class ASM3 {
     this.stoi_matrix = this._initialise_stoi_matrix()
   }
 
-  _initialise_stoi_matrix(){ // initialise stoichiometric matrix
+  _initialise_stoi_matrix() { // initialise stoichiometric matrix
     const { f_SI, f_XI, Y_STO_O, Y_STO_NO, Y_H_O, Y_H_NO, Y_A, i_CODN, i_CODNO, i_NSI, i_NSS, i_NXI, i_NXS, i_NBM, i_TSXI, i_TSXS, i_TSBM, i_TSSTO, i_cNH, i_cNO } = this.stoi_params;
 
     const stoi_matrix = Array(12);
@@ -121,7 +121,7 @@ class ASM3 {
     return rates;
   }
 
-  compute_dC(state){ // compute changes in concentrations
+  compute_dC(state) { // compute changes in concentrations
     // state: S_O, S_I, S_S, S_NH, S_N2, S_NO, S_HCO, X_I, X_S, X_H, X_STO, X_A, X_TS
     return math.multiply(this.stoi_matrix, this.compute_rates(state));
   }
diff --git a/dependencies/reactor_class.js b/dependencies/reactor_class.js
index 5863dd0..4db5522 100644
--- a/dependencies/reactor_class.js
+++ b/dependencies/reactor_class.js
@@ -3,17 +3,31 @@ const math = require('mathjs')
 
 class Reactor_CSTR {
     
-    constructor(initial_state){
+    constructor(initial_state) {
         this.state = initial_state;
         this.asm = new ASM3();
 
         this.Vl = 10.0; // fluid volume reactor [m3]
         this.F = 1.0; // fluid debit [m3 d-1]
         this.C_in = Array(13).fill(0.0); // composition influent
-        this.OTR = 1000.0; // oxygen transfer rate [g O2 d-1]
+        this.OTR = 100.0; // oxygen transfer rate [g O2 d-1]
+
+        this.currentTime = Date.now(); // milliseconds since epoch [ms]
+        this.timeStep = 1/(24*60) // time step [d]
     }
 
-    tick_fe(time_step){ // tick reactor state using forward Euler method
+    // expect update with timestamp
+    updateState(input) {
+        throw new Error("Not implemented yet");
+
+        let newTime = input.payload;
+
+        const day2ms = 1000 * 60 * 60 * 24; 
+
+        let n_iter = (newTime - this.currentTime) % (this.timeStep * day2ms);
+    }
+
+    tick_fe(time_step) { // tick reactor state using forward Euler method
         const r = this.asm.compute_dC(this.state);
         const dC_in = math.multiply(this.C_in, this.F/this.Vl);
         const dC_out = math.multiply(this.state, this.F/this.Vl);
@@ -33,7 +47,7 @@ let initial_state = [0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1,
 const Reactor = new Reactor_CSTR(initial_state);
 Reactor.C_in = [0.0, 30., 100., 16., 0., 0., 5., 25., 75., 30., 0., 0., 125.];
 N = 0;
-while (N < 15) {
+while (N < 500) {
     console.log(Reactor.tick_fe(0.001));
     N += 1;
 }
\ No newline at end of file