efficient

An artificial kidney these days still means a refrigerator-sized dialysis machine. Such devices mimic[…]real kidneys[…]. But they are nothing like as efficient, and can cause bleeding, clotting and infection—not to mention inconvenience for patients, who typically need to be hooked up to one three times a week for hours at a time.

The motor is only 20% efficient at that temperature.

It was well said of Plotinus, that the stars were significant, but not efficient.

Ye wake no more to anguish;‥ ye have borne

The Chosen, the Destroyer!‥ soon his hand

Shall strike the efficient blow;

Soon shaking off your penal forms, shall ye,

With songs of joy, amid the Eden groves,

Hymn the Deliverer’s praise!