Quench oil aging and its propensity to cause fouling may be evaluated by determining the amount of a precipitant necessary to cause the flocculation of polymer species present in the quench oil. The computing device includes a receiver to receive at least one of a first input from a first object or a second input from at least two second objects, a look-up-table module to store a second set of functions associated with the at least two second objects, and a mapping module to map one type of the first input from the first object to a corresponding one of the second set of functions. The apparatus improves the recovery rate of the reactive power by applying the magnetic coupled inductor to an energy recovering circuit at the time of chargingdischarging the PDP and by connecting the source electrode of a switching device in the energy recovering circuit to the ground. In compounds of the invention, wherein: Q1 at each occurrence is independently selected from hydrogen, hydroxy, halogen, CO alkyl and Cphenyl, and Q2 is selected from hydrogen, halogen, O\u2014alkyl, O\u2014alkenyl, phenyl, indolyl and naphthyl, where phenyl may be mono- or di-substituted with NO2 or halogen, and indolyl may be substituted with alkyl or phenyl .