From 1994 onwards, they were required to have a Diesel Oxidation Catalyst. From 2008 onwards (in the US), a set of emissions standards requiring highway diesel engines to have a Diesel Particulate Filter went into effect. From 2012 onwards, engines over a certain displacement required a complete aftertreatment system, with a DOC, DPF, and Selective Catalytic Reduction, which uses Diesel Exhaust Fluid (DEF).
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.