Abstract: A process for regeneration of a deactivated hydroprocessing catalyst is provided. The process comprises exposing the catalyst to laser radiation in the presence of an oxidizing gas. The process may be used to regenerate supported or unsupported metal catalysts which have been fouled by coking.

Abstract: A heavy duty chock, for use in preventing the movement of wheeled vehicles, particularly commercial or military aircraft, is triangular, preferably equitriangular in cross-section, has a longitudinal axis, and is divided transverse to its longitudinal axis into a number of triangular sections. The clock has an end section at each end thereof and a number of central sections located between the end sections. Each central section defines at least one space extending longitudinally therethrough. The end and central sections are formed from an elastomeric material which is a synthetic rubber, a natural rubber or a mixture thereof. The chock comprises clamping member, such as a flared hollow pipe, for holding the sections with adjacent triangular faces in tight abutment, and an interlock, such as co-operating abutments and recesses, for preventing relative rotational movement between adjacent sections about the longitudinal axis.