The asymptotic behavior of nonlinear Schrdinger equations

A mixer especially for mixing materials such as cement and sand with water and with a fibrous reinforcing material such as glass fibre. The mixer consists of a tubular casing containing a skeletal rotor constructed from a plurality of rods extending longitudinally of the casing and spaced apart laterally of each other at positions circumferentially spaced apart around the axis of rotation of the rotor and the longitudinal axis of the casing. The rods are supported on end plates and a central shaft or stub shafts extending from the end plates. The rods are enveloped along at least part of the axial length of the rotor by a helical, outwardly-directed flight having widely-spaced convolutions to impart a component of movement to the mix along the inside of the tubular casing to an outlet. The fibrous reinforcing material is either poured through an inlet duct into the mix in the rotor near to the outlet from the casing so that the rotor effects mixing of the reinforcing material into the initial mix, or the initial mix discharged from the outlet is fed with the fibrous reinforcing material into a further mixer where the fibrous reinforcing material is mixed by a folding action into the initial mix.