Of course, you don't want to seem aloof or unapproachable to your coworkers or family. On the contrary, if people know to call you between certain hours if they want to reach you immediately, they'll usually happily comply. After all, they just want to reach you. Also, because you'll have periods of uninterrupted concentration time, you're more likely to be available and at ease at other times. You'll feel better about your work and the progress you're making, and it will show. There's nothing wrong with trying to budget your time a bit to maximize your productivity, and most reasonable people will support you in it.