A stirring implement includes a stirrer having a single stir rod defining a generally triangular shape at a distal end thereof, a rotating guide defining a slot, wherein the single stir rod of the stirrer is inserted through the slot of the rotating guide such that the single stir rod is positioned at an angle with respect to a planar surface of the rotating guide, and a lid releasably engageable to the rotating guide. The stirrer has a handle at a proximal end thereof and the handle rotates circumferentially beyond an outer perimeter of the lid. An apex defined by the single stir rod travels circumferentially along an inner wall of an outer perimeter of a container attached to the lid.

A process for the additive manufacturing of porous gas-permeable shaped articles by selective laser sintering of a polymer powder may include a) Providing a layer of polymer powder within an construction space; b) Heating a polymer layer to a temperature greater than or equal to 0.5? C. and less than or equal to 2.5? C. below the melting point of the polymer powder; c) Spatially resolved melting of a powder bed by means of the introduction of laser energy; wherein steps a-c) are carried out one or more times in the same construction space on consecutively superimposed powder layers and the surface energy contribution to be introduced in process step c) is greater than or equal to 1.7 times and less than or equal to 4.25 times the product of the melting enthalpy, polymer powder filling density and layer thickness of the powder filling.