Abstract: It is an object to provide a process and an apparatus which allow stable production of ultrashort-cut fibers having fiber lengths of no greater than 0.1 mm while minimizing miscutting, the object being achieved by a process and apparatus whereby numerous individual filament groups are bound to form a fiber bundle, an embedding material which is solidified by cooling and gasified or liquefied by heating is gasified or liquefied, the fiber bundle is embedded with the gasified or liquefied embedding material, and the edge of the embedded fiber bundle is thinly shaved at a temperature at which the embedding material does not gasify or liquefy, to obtain ultrashort-cut fibers having cut fiber lengths of no greater than 1.0 mm.

Abstract: A pneumatic structure in the form of a barrel roof which has openings at the opposite ends thereof includes outer and inner walls of a sheet or membrane material connected by a plurality of partition walls in the form of ribs provided therebetween to define a plurality of air compartments in the form of ribs between the outer and inner walls. The partition walls includes a plurality of openings for fluid communication between adjacent air compartments. The pneumatic structure has specific dimensions defined as follows. 1.20≦b/a≦1.35 1.10≦d/c≦1.35 0.2≦a/c≦0.5 where a: the maximum opening width of the pneumatic structure; b: the total width of the pneumatic structure; c: the effective height (between ground and the maximum height of the inner wall; and d: the total height (between ground and the maximum height of the outer wall.