An air entanglement system having a housing, a first rotatable surface disposed with the housing, and a second rotatable surface disposed with the housing proximate the first rotatable surface is described herein. The first rotatable surface may comprise a first plurality of air jets configured to air entangle a preform in situ. The second rotatable surface may be disposed with the housing proximate the first rotatable surface. The second rotatable surface may comprise a second plurality of air jets configured to air entangle the preform in situ. The air entanglement system may be configured to achieve negative pressure in response to being under suction.

The present disclosure provides systems and methods for forming a composite structure comprising rotating a base layer of an apparatus for forming the composite structure about an axis of rotation, transferring carbon short fibers from a first vibratory feed ramp onto the base layer in order to form a plurality of fibrous layers in the composite structure, and vibrating the first vibratory feed ramp during the transferring the carbon short fibers. The base layer may comprise an annular shape.

A method of forming a fiber reinforced composite material includes cutting a plurality of reinforcing fibers to a selected length, directing the plurality of reinforcing fibers through a fiber alignment mechanism, orienting the plurality of reinforcing fibers in a selected direction via the fiber alignment mechanism, and adhering the aligned plurality of reinforcing fibers to a substrate material to form the fiber reinforced composite material. A system for manufacturing a fiber reinforced composite material includes a feed mechanism to direct a substrate material along a selected path, a cutting mechanism to cut a plurality of reinforcing fibers to a selected length, and a fiber alignment mechanism to orient the plurality of reinforcing fibers in a selected direction before adhering the plurality of reinforcing fibers to the substrate material.

A method of forming a fiber reinforced composite material includes cutting a plurality of reinforcing fibers to a selected length, directing the plurality of reinforcing fibers through a fiber alignment mechanism, orienting the plurality of reinforcing fibers in a selected direction via the fiber alignment mechanism, and adhering the aligned plurality of reinforcing fibers to a substrate material to form the fiber reinforced composite material. A system for manufacturing a fiber reinforced composite material includes a feed mechanism to direct a substrate material along a selected path, a cutting mechanism to cut a plurality of reinforcing fibers to a selected length, and a fiber alignment mechanism to orient the plurality of reinforcing fibers in a selected direction before adhering the plurality of reinforcing fibers to the substrate material.

Provided is a carbon-fiber nonwoven cloth with low resistance to gases or liquids passing through, and low resistance in the thickness direction to heat or electricity, which is particularly appropriate for a gas diffusion electrode of a polymer electrolyte fuel cell; the cloth having an air gap with a diameter of at least 20 μm, at least some of the carbon fibers being continuous from one surface to the other surface, and the apparent density being 0.2-1.0 g/cm.sup.3, or, having an air gap with a diameter of at least 20 μm and at least some of the carbon fibers being mutually interlaced, and further, at least some of the carbon fibers being oriented toward the thickness direction and the apparent density being 0.2-1.0 g/cm.sup.3.

Provided is a carbon-fiber nonwoven cloth with low resistance to gases or liquids passing through, and low resistance in the thickness direction to heat or electricity, which is particularly appropriate for a gas diffusion electrode of a polymer electrolyte fuel cell; the cloth having an air gap with a diameter of at least 20 μm, at least some of the carbon fibers being continuous from one surface to the other surface, and the apparent density being 0.2-1.0 g/cm.sup.3, or, having an air gap with a diameter of at least 20 μm and at least some of the carbon fibers being mutually interlaced, and further, at least some of the carbon fibers being oriented toward the thickness direction and the apparent density being 0.2-1.0 g/cm.sup.3.

A carbon fiber mat has discontinuous carbon fibers dispersed in the form of monofilaments, wherein the orientation direction of the monofilaments of the discontinuous carbon fibers is random, number average fiber length (L.sub.n) is at least 1.5 mm and up to 15 mm, and proportion in number (Pa) of the discontinuous carbon fiber monofilaments having a fiber length in the range of median fiber length (L.sub.c)±20% is at least 40% and up to 99%.

A carbon fiber mat has discontinuous carbon fibers dispersed in the form of monofilaments, wherein the orientation direction of the monofilaments of the discontinuous carbon fibers is random, number average fiber length (L.sub.n) is at least 1.5 mm and up to 15 mm, and proportion in number (Pa) of the discontinuous carbon fiber monofilaments having a fiber length in the range of median fiber length (L.sub.c)±20% is at least 40% and up to 99%.

The disclosed methods and apparatus improve the fabrication of solid fibers and microstructures. In many embodiments, the fabrication is from gaseous, solid, semi-solid, liquid, critical, and supercritical mixtures using one or more low molar mass precursor(s), in combination with one or more high molar mass precursor(s). The methods and systems generally employ the thermal diffusion/Soret effect to concentrate the low molar mass precursor at a reaction zone, where the presence of the high molar mass precursor contributes to this concentration, and may also contribute to the reaction and insulate the reaction zone, thereby achieving higher fiber growth rates and/or reduced energy/heat expenditures together with reduced homogeneous nucleation. In some embodiments, the invention also relates to the permanent or semi-permanent recording and/or reading of information on or within fabricated fibers and microstructures. In some embodiments, the invention also relates to the fabrication of certain functionally-shaped fibers and microstructures. In some embodiments, the invention may also utilize laser beam profiling to enhance fiber and microstructure fabrication.

The disclosed methods and apparatus improve the fabrication of solid fibers and microstructures. In many embodiments, the fabrication is from gaseous, solid, semi-solid, liquid, critical, and supercritical mixtures using one or more low molar mass precursor(s), in combination with one or more high molar mass precursor(s). The methods and systems generally employ the thermal diffusion/Soret effect to concentrate the low molar mass precursor at a reaction zone, where the presence of the high molar mass precursor contributes to this concentration, and may also contribute to the reaction and insulate the reaction zone, thereby achieving higher fiber growth rates and/or reduced energy/heat expenditures together with reduced homogeneous nucleation. In some embodiments, the invention also relates to the permanent or semi-permanent recording and/or reading of information on or within fabricated fibers and microstructures. In some embodiments, the invention also relates to the fabrication of certain functionally-shaped fibers and microstructures. In some embodiments, the invention may also utilize laser beam profiling to enhance fiber and microstructure fabrication.