Dry shake aggregate floor hardeners are commonly applied to the surface of freshly placed concrete to improve wear resistance and occasionally to color a concrete surface. They decrease typical plain concrete negative properties like dusting and liquid absorption by improving the abrasion resistance and reducing surface permeability.
Underfloor heating is a surface heating system, in which the heating surface is the floor of the heated space. The basic devices used are the same as those of conventional systems: burner, boiler, circulator, while any fuel can be used (electricity, oil, gas, etc.).
In 1937, research director Otto Bayer was working on the development of a polyamide-like synthetic fiber. During his experiments he used a reactive group that formed urethane where polyurethanes were born in contact with alcohol.