TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The inorganic precursor is selected from titania precursors, silica precursors, alumina precursors, zirconia precursors, bioceramic precursors, bioactive glass precursors, methodoxides, ethoxides, and/or sec-butoxides; or hydrolysable metal compound.    TECHNOLOGY FOCUS - POLYMERS - Preferred Method: The nano fibers are formed at a rate of greater than or equal to 2 g/minute. The dispersion medium is flowed at a flow rate of greater than or equal to 30 ml/second. The fiber precursor solution is introduced at a flow rate of greater than or equal to 5 ml/minute. The conduit comprises an inlet into which the dispersion medium enters, an outlet, a length from the inlet to the outlet, and a cross-sectional flow area having a characteristic dimension, and the ratio of the length to the characteristic dimension is greater than or equal to 10. The conduit comprises an inlet into which the dispersion medium enters, an outlet, and a cross-sectional flow area, where the cross-sectional flow area is constant from the inlet to the outlet, or the cross-sectional flow area at the outlet is less than the cross-sectional flow area at the inlet. The cross-sectional flow area is reduced gradually from the inlet to the outlet. The cross-sectional flow area is reduced at at least one transition between the inlet and the outlet. The conduit comprises an inlet into which the dispersion medium enters, an outlet, a cross-sectional flow area, and a transition between the inlet and the outlet, where the cross-sectional flow area has a first shape upstream of the transition and a second shape downstream of the transition, and the second shape is substantially reduced in at least one dimension relative to a corresponding dimension of the first shape. The fiber precursor solution is introduced into the dispersion medium in a direction selected from: the same direction as the flow of the dispersion medium, the direction opposite to the flow of the dispersion medium, and a direction orthogonal to the flow of the dispersion medium. The conduit through which the dispersion medium flows is a first conduit, and introducing the fiber precursor solution comprises flowing the fiber precursor solution through a second conduit comprising an outlet communicating with the first conduit, and further comprising adjusting a radial position of the outlet relative to a central axis of the first conduit. The fiber precursor solution is introduced into the dispersion medium in the form of pre-formed dispersion of droplets, which are further sheared to form nano fibers. The method (M1) involves introducing an additive to the dispersion medium, where the nano fibers comprise the polymer and the additive retained by the polymer, and introducing occurs at a time selected from: before introducing the fiber precursor solution into the dispersion medium, while introducing the fiber precursor solution into the dispersion medium, after introducing the fiber precursor solution into the dispersion medium; controlling a shear stress applied to the dispersed-phase components while shearing by controlling a parameter selected from: a viscosity of the dispersion medium, and/or flow rate of the dispersion medium through the conduit; and controlling an average diameter of the nano fibers by controlling a shear stress applied to the dispersed-phase components while shearing. The step of shearing the dispersed-phase components includes applying a shear stress of 10-1000 Pa. The step of flowing the dispersion medium involves flowing the dispersion medium through the conduits, and introducing the fiber precursor solution comprises introducing the fiber precursor solution into the dispersion medium flowing through each conduit. The fiber precursor solution comprises a mixture of a polymer solution and an inorganic precursor, where the polymer solution comprises the polymer dissolved in the polymer solvent, and shearing the dispersed-phase components causes phase separation between the polymer and the inorganic precursor such that the inorganic fibrils are formed in each Nano fiber. The method (M1) involves introducing an additive to the dispersion medium, where the composite Nano fibers comprise the polymer, the inorganic fibrils, and the additive retained by the polymer, and introducing occurs at a time selected from: before introducing the mixture into the dispersion medium, while introducing the mixture into the dispersion medium, after introducing the mixture into the dispersion medium; forming an inorganic compound from the inorganic precursor reacting the inorganic precursor with a reagent, where the inorganic fibrils comprise the inorganic compound, and the inorganic compound is formed by adding the reagent to the dispersion medium before introducing the mixture, adding the reagent to the dispersion medium while introducing the mixture, adding the reagent to the dispersion medium after introducing the mixture, and/or separating the composite Nano fibers from the dispersion medium and exposing the separated composite Nano fibers to the reagent. The step of forming the inorganic compound includes irradiating the inorganic precursor with thermal or electromagnetic energy. The method involves removing the polymer from the inorganic fibrils having average diameter of 1-1000 nm. The step of removing the polymer from the inorganic fibrils includes subjecting the polymer to a process selected from calcining, chemical treatment, thermal oxidation, dissolution, and/or enzymatic degradation. The step of removing the polymer from the inorganic fibrils includes calcining the composite nano fibers at greater than or equal to 200 degrees C. Preferred Components: The polymer nano fibers have an average diameter of 40-5000 nm. The dispersion medium has a viscosity of greater than or equal to 1 cP. The ratio of viscosity of the fiber precursor solution to viscosity of the dispersion medium is 0.1-200. EXAMPLE - No suitable example given.