Is there a convention regarding frames around plots in engineering? I am writing my PhD thesis in engineering at a research university in the US.

My question is about using frames (or boxes) around a plot, specifically simulation results plotted as a function of time.  These figures are intended to span the entire width of the type-area (i.e. paragraph width) and are to be displayed prominently.

Here is a simple example for comparison between the two options (framed and open):





Is there any convention regarding such frames, e.g., as documented by prominent style guides? I am all up for minimalism (use greyscale, avoid clutter etc), but I wonder if removing the surrounding frame itself is too much (and may surprise exam committee in unexpected ways) due to going against existing conventions.

My university doesn’t have a style guide. And when I checked with the research support office, they said that as long as it adheres to acceptable scientific style, it is fine.

PS:

When this question was originally asked on the graphic design SE site, a user recommended that the x-label should not be near the bottom edge of the frame, but rather a horizontal axis should be drawn at y = 0, and the labelling of the x-axis should be done near this. I am skeptical of this advice, since most engineering software (eg. MATLAB) does not do this.
There is no convention or guide on this, at least none with appreciable universality. Having said that, one doesn't need a style guide for things like this. 

The intention is to be clear to the reader. Minimalism or any other aesthetic ideal is secondary. In engineering, the values on graphs are potentially of interest, not just the trend. So a reader could potentially want to know the value of y(x), and your graph of y vs x should make it as easy as possible for him/her to do so. The top and right  axes make it easier to read out values, because (a) you now have two sets of axes to check your value against, (b) a point on the top-right is as easy to read as a point on the bottom-left.

Given that, I wouldn't recommend removing the frame or the ticks on the frame.