Two mathematicians have proved that a straightforward question—how hard is it to untie a knot?—has a complicated answer.

Abstract: The presented research focuses on the design and implementation of a maximum power point tracking (MPPT) system for photovoltaic (PV) panels installed on a sailing yacht. This yacht relies ...

Whether critiques of improved grading are based on misunderstandings, rushed implementation, or reluctance to confront truths ...