First, thank you for your answer.
I don't want ProjeQtOr to manage activities, but in order for me to do so, I need to see what happens in a day and place the start of some activity at the right time.
For example, I have a series of 4 consecutives activities:
1) 30 min (performed by human)
2) 12 h (performed by machine)
3) 15 min (performed by human)
4) 7 days (performed by machine)
5) 15 min (performed by human+machine)
Depending on the time activity 1) starts, I will or won't be able to activity 3) (because of working hours), or activity 5) (e.g. machine not available at this time).
Regarding dependencies, I'm gonna have a look at that