diff --git a/SimCAD/configuration/utils/__init__.py b/SimCAD/configuration/utils/__init__.py
index 27da8c9..8034a14 100644
--- a/SimCAD/configuration/utils/__init__.py
+++ b/SimCAD/configuration/utils/__init__.py
@@ -41,7 +41,7 @@ def time_step(dt_str, dt_format='%Y-%m-%d %H:%M:%S', _timedelta = t_delta):
 
 t_delta = timedelta(days=0, minutes=0, seconds=1)
 def ep_time_step(s, dt_str, fromat_str='%Y-%m-%d %H:%M:%S', _timedelta = t_delta):
-    if s['mech_step'] == 0:
+    if s['sub_timestep'] == 0:
         return time_step(dt_str, fromat_str, _timedelta)
     else:
         return dt_str
@@ -50,7 +50,7 @@ def ep_time_step(s, dt_str, fromat_str='%Y-%m-%d %H:%M:%S', _timedelta = t_delta
 def exo_update_per_ts(ep):
     @curried
     def ep_decorator(f, y, step, sL, s, _input):
-        if s['mech_step'] + 1 == 1:
+        if s['sub_timestep'] + 1 == 1:
             return f(step, sL, s, _input)
         else:
             return (y, s[y])
diff --git a/SimCAD/engine/simulation.py b/SimCAD/engine/simulation.py
index 66f065f..558283f 100644
--- a/SimCAD/engine/simulation.py
+++ b/SimCAD/engine/simulation.py
@@ -43,7 +43,7 @@ class Executor:
 
         self.apply_env_proc(env_processes, last_in_copy, last_in_copy['timestamp'])
 
-        last_in_copy["mech_step"], last_in_copy["time_step"], last_in_copy['run'] = m_step, t_step, run
+        last_in_copy["sub_timestep"], last_in_copy["time_step"], last_in_copy['run'] = m_step, t_step, run
         sL.append(last_in_copy)
         del last_in_copy
 
@@ -53,7 +53,7 @@ class Executor:
         m_step = 0
         states_list_copy = deepcopy(states_list)
         genesis_states = states_list_copy[-1]
-        genesis_states['mech_step'], genesis_states['time_step'] = m_step, t_step
+        genesis_states['sub_timestep'], genesis_states['time_step'] = m_step, t_step
         states_list = [genesis_states]
 
         m_step += 1
@@ -83,9 +83,9 @@ class Executor:
             states_list_copy = deepcopy(states_list)
             head, *tail = self.block_pipeline(states_list_copy, configs, env_processes, time_seq, run)
             genesis = head.pop()
-            genesis['mech_step'], genesis['time_step'], genesis['run'] = 0, 0, run
+            genesis['sub_timestep'], genesis['time_step'], genesis['run'] = 0, 0, run
             first_timestep_per_run = [genesis] + tail.pop(0)
             pipe_run += [first_timestep_per_run] + tail
             del states_list_copy
 
-        return pipe_run
\ No newline at end of file
+        return pipe_run