How many CONTINUOUS HOURS -aday- can you spend studying on your THESIS work?
That will depend entirely on what your thesis research involves.  If you are limited by library hours, or laboratory hours and experimental growth delays, it makes a big difference.\n\nIf you've got enough caffeine and enough limited access to your facilities it is possible to remain awake for 5 to 6 days without sleep, but I don't recommend it.
Like four. And your Avatar picture looks creepy!