precipitation number

precipitation number

[prə‚sip·ə′tā·shən ‚nəm·bər]
(analytical chemistry)
The number of milliliters of asphaltic precipitate formed when 10 milliliters of petroleum-lubricating oil is mixed with 90 milliliters of a special-quality petroleum naphtha, then centrifuged according to American Society for Testing and Materials test conditions; used to determine the quantity of asphalt in petroleum-lubricating oil.
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Pennsylvania's Drought Task Force will meet Friday, April 14 to review the current precipitation numbers and overall status of surface water and groundwater resources.
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