Fractional derivatives of constant and variable orders applied to   anomalous relaxation models in heat-transfer problems
  In the present paper, we address a class of the fractional derivatives of constant and variable orders for the first time. Fractional-order relaxation equations of constants and variable orders in the sense of Caputo type are modeled from mathematical view of point. The comparative results of the anomalous relaxation among the various fractional derivatives are also given. They are very efficient in description of the complex phenomenon arising in heat transfer. 
Xiao-Jun Yang
physics.class-ph