vvacuumvacuum columnvacuum distillationvacuum gaugevacuum pumpvacuum residuumvalencevaluevalvevalve seatvanevapourvapour pressurevapourizevariablevariable frequencyvariablenessvariancevariationvariativevariometervarnishvelocityvelocity coefficientvelocity headvelocity of flowventvent stackvent valveventageventilateventilationventilatorvertexverticalvertical linevesselvibratevibrationvibration isolatorvibrativevisbreakerviscoseviscosityvolatilevolatilityvoltvoltagevoltage drop