A convex function is a real-valued function defined on an interval with the property that its epigraph (the set of points on or above the graph of the function) is a convex set.
A rectifier is a electrical device that converts alternating current to direct current, a process known as rectification. Rectifiers are used as components of power supplies and as detectors of radio signals. Rectifiers may be made of solid state diodes, vacuum tube diodes, mercury arc valves, and other technologies.
Calorifiers are apparatus used for the transfer of heat to water in a vessel using an indirect means. The source of heat is usually obtained in a coil or pipe that is immersed in the water.he heating instrument uses the principle of thermodynamics whereby the water is heated above its temperature to be used for different purposes. A calorifier is an industry term for a storage vessel that has the capacity to generate heat within a mass of stored water.