I work in a big science lab as student worker since a couple of weeks. There occurred several situations where I have been ignored when I tried to talk to people and I want your advice on how I should have handled the situations described below in a way that I make clear that I cannot tolerate bad communication habits around myself but on the other hand not endanger the relationship with my coworkers.
Before we start you should know about me that I talk loud and clear, I keep eye contact and I am the kind of person who (normally) "fills the room" when I talk, I never made the experience of being not listened to or anything. I mention this to avoid speculations about my voice being too quiet.
1) Two of the leading scientists talk to each other in an empty isle. I walk by and say 'Hello Mr. X, hello Mr. Y' as I walk by. Both ignore it and talk to each other as if nothing has happened
2) Two guys at the table next to me are trying to solve some computer problem, I tell them 'Excuse me, the problem is that you did not mount your drive, doing XYZ will solve the problem'. Both keep on discussing the issue as if they did not hear the thing, although they clearly heard my because they both made very short eye contact with me when I started to talk. They did not even let me finish the sentence, after half of it they already went on discussing their own solutions (which I knew would not work).
3) I go to the chill out room and I say to engineer who sat there (he was the only person) whether or not he is going to do XYZ this day. Looks at me and keeps on reading his paper.
Now, normally when someone does a thing like that I say "Excuse me, don't you talk to me or what's the matter?" with a loud and clear voice that makes it impossible to overhear for everyone nearby, but I think as student worker I'm not in the position to confront the engineers and scientists in the lab in such a dominant way. Instead, I just pretended as if I hadn't said anything at all and minded my own business.
What would you do to make yourself clear but still remain professional?