A language-neutral model is employed to represent a compile unit to facilitate transformation of a representation of the compile unit to one or more other languages or to language implementations. In some embodiments, the methods for making such diester-based lubricants utilize a biomass precursor material from which mono-unsaturated free lipid species can be provided or otherwise generated, wherein such mono-unsaturated free lipid species are converted to isomeric diol species en route to the synthesis of diester species for use asin the diester-based lubricant compositions. In another embodiment, an actual ramp time for a given injection is measured and used to predict future ramp times. Furthermore, when the air quantity is being determined, if need be the position of an adjustable preliminary guide row is also taken into account.