Surface Tension vs Interfacial Tension. Both surface tension and interfacial tension are effects based on liquids. Both these effects take place due to the unbalanced intermolecular forces between the liquid or solutions molecules.
Statistical process control (SPC) is a method of quality control which employs statistical methods to monitor and control a process. This helps ensure the process operates efficiently, producing more specification-conforming product with less waste (rework or scrap).
(December 2008). Direct digital control (DDC) is the automated control of a condition or process by a digital device (computer). DDC is considered by many to be a more modern, granular and responsive update to older HVAC control systems based upon PLC technologies.