As I understand it, you're looking for feedback over the questionnaire form itself? If so, what are your real goals and perspective for this study?
Secondly, if you're looking for advice over recruitment, it looks like you've got a fairly small sample group, so you could probably contact companies that fit the kind of scope you're looking for and see if you can get an interview with someone who matches the background you're looking for.
Does your college have local industrial partners you could potentially draw on contacts with?
(By the way: your initial post is a bit ambiguously worded. If you're going to be writing letters / emails to recruit from companies, you might want to focus on being especially specific over what you're seeking and what they can do to help you. If they're uncertain or unclear, it might hurt your response rate.)