The trough caused the hurricane to decelerate and turn slightly to the north, and a ridge behind the trough caused Ella to become nearly stationary for 24 hours.

These would fire at the last instant to decelerate the materiel to a safe landing speed.

Whereas a proportional hazards model assumes that the effect of a covariate is to multiply the hazard by some constant, an AFT model assumes that the effect of a covariate is to accelerate or decelerate the life course of a disease by some constant.

If a drive sprocket rotates at constant RPM, then the chain (and the driven sprocket) must accelerate and decelerate constantly.