Engineers at Russia’s nuclear weapons design centre at Sarov in the Nizhny Novgorod region, have solved a centuries-old secret of making church bells, as part of their defence conversion programme. Bell production uses the latest mathematical methods. Musicians including cellist Mstislav Rostropovich visited the centre to here the chimes. Elsewhere in Sarov, engineers have applied their physics skills to making hi-tech diamond jewellery, and annual output is estimated at $2 million with potential for expansion.