\begin{document}
\input{subfileprefix}
-\chapter{Acknowledgements}%
+\ifSubfilesClassLoaded{\chapter*{Acknowledgements}}{\chapter{Acknowledgements}}%
\label{chp:acknowledgements}
%\begin{center}
\noindent%
Sjoerd Crooijmans,
Willem de Vos.
-I give special thanks to my mentors who never stopped having faith me:
+I give special thanks to my mentors:
Jos Baack, Francisco Torreira, Franc Grootjen, Louis Vuurpijl, and Larry Caruthers.
And of course my friends and acquaintances that supported me throughout the process.