the conversion process of heavy hydrocarbons to the valuable products such as gasoline is an important operation in the oil refineries.one important process is the “fluidized catalytic cracking” (fcc).feed injection in fcc process has an important role in the selectivity and properties of the products.performance of the feed injection system is dependent on the atomizers.the size and contributi...

This study after reviewing  construction methods of generators in Archimedean copulas (AC),  proposes several useful lemmas related with generators of AC. Then a new trigonometric Archimedean family will be shown which is based on cotangent function. The generated new family is able to model the low dependence structures.