Mechanical Engineering deals with the design and manufacture of mechanical systems. Mechanical engineers make an impact in almost every aspect of modern society, due to the vital roles they play in the design and production of all material goods. Areas of study include machine design, robotics, manufacturing processes, thermodynamics and engines, fluid flow, composite materials properties, dynamics, acoustics, finite element analysis, computer-aided design and welding metallurgy. Specific fields of study can range from biomechanics and assistive technologies for the disabled to automation and robotics systems, engine and propulsion systems, and the design of ships, submarines, aircraft and spacecraft.