An article of manufacture that includes a wall portion having a wall inner surface and a wall outer surface. The article of manufacture also includes a base portion having a base inner surface and a base outer surface. At least a portion of the wall portion and the base portion form a vessel to retain a fluid therein. The article of manufacture also has a shaped portion of the base inner surface and/or a shaped portion of the wall inner surface. A first section of the shaped portion may have a first surface area in thermal contact with the fluid. A second section of the shaped portion may have a second surface area in thermal contact with the fluid. The first and second surface areas may be different thereby inducing convection within the fluid that increases heat transfer from the heat source to the fluid.