Mechanical engineering including mechanical and chemical engineering. At its simplest, thermodynamics is the study of energy, its use and transformation through a system. Typically, engineering thermodynamics is concerned with changing energy from one form to another. As an example, automotive engines convert chemical energy (enthalpy) from the fuel into heat, and then into mechanical work that eventually turns the wheels. Thermodynamics principles are used by mechanical engineers in the fields of heat transfer, thermofluids, and energy conversion. Mechanical engineers use thermo-science to design engines and power plants, heating, ventilation, and air-conditioning (HVAC) systems, heat exchangers, heat sinks, radiators, refrigeration, insulation, and others.
Biproduct If the product formula_9 and coproduct formula_10 both exist for some pair of objects "A", then there is a unique morphism formula_11 such that It follows that the biproduct formula_15 exists if and only if "f" is an isomorphism. If C is a preadditive category, then every finite product is a biproduct, and every finite coproduct is a biproduct. For example, if formula_9 exists, then there are unique morphisms formula_17 such that To see that formula_9 is now also a coproduct, and hence a biproduct, suppose we have morphisms formula_22 for some object formula_23. Define formula_24 Then formula_25 is a