Just because something is open access does not mean it is without copyright. Always license your material which means you/or the publisher retains the copyright but you agree to make the material either free of all restrictions which is putting material in the public domain or you can attach certain conditions to the use/reuse of the material. This is generally done by the use of Creative Commons Licenses which range from public domain called CC-BY to only free to read (Attribution-NonCommercial-NoDerivs CC BY-NC-ND).
The license for all material in Arrow@tudublin is a Creative Commons Attribution Non-Commercial Share Alike 4.0 International Licence. This means that you must be cited as the author and the material must not be used for commercial reasons. This is because any citations the material accrues should be attributed to you as the author and if any commercial development is possible, the university would want to partner in that.