With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: George W. Bush's paternal grandfather was a United States Senator from Massachusetts.
text_B: The exoskeletal engine -LRB- ESE -RRB- is a concept in turbomachinery design .. turbomachinery. turbomachinery. Current gas turbine engines have central rotating shafts and fan-discs and are constructed mostly from heavy metals .. gas turbine. gas turbine. They require lubricated bearings and need extensive cooling for hot components .. They are also subject to severe imbalance -LRB- or vibrations -RRB- that could wipe out the whole rotor stage , are prone to high - and low-cycle fatigue , and subject to catastrophic failure due to disc bursts from high tensile loads , consequently requiring heavy containment devices .. rotor. Turbine. To address these limitations , the ESE concept turns the conventional configuration inside-out and utilizes a drum-type rotor design for the turbomachinery in which the rotor blades are attached to the inside of a rotating drum instead of radially outwards from a shaft and discs .. turbomachinery. turbomachinery. rotor. Turbine. Multiple drum rotors could be used in a multi-spool design .. multi-spool. Turbofan#Turbofan configurations
not_related.