Discusses a project in which researchers were able to generate over 1000 diffraction spots from a graded photonic super-crystal with a unit super-cell size of 12a × 12a where a is the lattice constant and hole radii are gradually changed in dual directions.

This article describes pneumatic energy being converted into solid particle kinetic energy as a solid-particle-entrained gas that flows downward through a vertical nozzle. For the conditions studied, the solid particles serve as a heat exchange medium to enable a gas expansion that is nearly isothermal. Also, the kinetic energy associated with the two-phase fluid is predominantly that associated with subsonic solid-particle motion. The kinetic energy of the solid particles is converted into other forms using a low-speed turbine. A theoretical description of the process is presented, and the initiation of an experimental effort to study the process is described.