The purpose of the bulkhead is threefold: to seal the forward end of the motor, to retain the pyrogen igniter, and to act as a blowout plug in case of motor overpressurization (discussed earlier).
Me from myself thy cruel eye hath taken, And my next self thou harder hast engross'd: Of him, myself, and thee, I am forsaken; A torment thrice threefold thus to be cross'd.
It's a threefold increase on the figure for October when Iraqi forces launched a major assault to retake the city of Mosul, the last major stronghold in Iraq of the Islamic State group.
In the remainder of the present lecture I shall state in outline the view which I advocate, and show how various other views out of which mine has grown result from modifications of the threefold analysis into act, content and object.