This invention is intended to provide a large-capacity servo press apparatus driven by multiple motors, the servo press apparatus enabling a drive at a high efficiency and with reduced torque pulsations in a simple structure. Each ejector mechanism includes a body portion, an abutment and a handle. The invention provides an arrangement for sealing an end section of a tube or of a tubular vessel, which prevents passage of a medium either out of or into the vessel. Embodiments of the present invention provide advantages over existing sequential and radial search methods, significantly reducing the processing and calculations required and providing faster alerts to pilots. The method comprises imprinting a patterned sacrificial layer of etchable material that is positioned on a semiconductor surface that is in turn adjacent a light emitting active region, and thereafter etching the imprinted sacrificial layer and the underlying semiconductor to transfer an imprinted pattern into the semiconductor layer adjacent the light emitting active region.