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Symbols and Acronyms

jacketed pump   A pump equipped with jackets around the cylinders, heads, and stuffing boxes through which steam or other heat may be forced to permit the handling of such materials as pitch, resin, and asphalt that are solid when cold but melt on heating; when the pump handles materials at high temperatures, cold water may be substituted for steam or heat.

Jackson turbidity unit (JTU)  A standard unit of turbidity based on the visual extinction of a candle flame when viewed through a column of turbid water containing suspended solids. It varies with the solids composition (barium sulfate, diatomaceous earth, and so on). The JTU has largely been replaced by the more reproducible nephelometric turbidity unit.

jar test  A laboratory procedure for evaluating coagulation, flocculation, and sedimentation processes in a series of parallel comparisons.

jet  The stream of water under pressure issuing from an orifice, nozzle, or tube.

joint  (1) A surface of contact between two bodies or masses of material of like or different character or composition. (2) A connection between two lengths of pipe, made either with or without the use of a third part. (3) A length or piece of pipe.