Abstract: An infrared source comprising an electrically powered, hollow cylindrical rod which operates at lower temperatures and yet has no decrease in output power is configured by increasing the outside diameter of the rod and inserting grooves therein which provide cavities increasing the apparent surface emissivity of the rod.

Abstract: A fluid .[.Flow Restrictor.]. .Iadd.flow restrictor .Iaddend.especially suitable for reducing the pressure of gases or liquids is described. The restrictor comprises a series of rows of baffles placed in the path of fluid flow, with the baffles in succeeding rows staggered with respect to those in adjacent rows so that as the fluid flows, it is constrained to change its direction repeatedly. The restrictor is preferably constructed with an increasing cross sectional area along the direction of flow. One suitable physical construction comprises a plurality of thin circular plates with a central bore, arranged in a stack. Each plate has a baffle pattern formed on one or both sides, for example, by etching. Fluid flow is from the central bore, between adjacent plates, to the circumference of the stack.