Abstract: Apparatus and methods are disclosed for performing a chromatographic separation of a given compound utilizing programmed temperature and mass flow wherein the compound is injected into a pressurized carrier gas and passed through a column and wherein a portion of the column is subjected to a temperature profile, by determining the pressure of the carrier gas and generating a pressure information signal representative of such pressure, storing desired carrier gas mass flow information and temperature profile information, and controlling the pressure of the carrier gas in response to the mass flow information, the temperature profile information and the pressure information signal, so that as the temperature profile information changes with time, the desired mass flow of carrier gas at a corresponding time is maintained by controlling the pressure of the carrier gas.

Abstract: The bar code on the cylindrical surface of an object is accurately read by rotating the object past a bar code reader so that the bar code passes the reader a plurality of times. Each of the readings from the reader is compared with the other readings and a final reading is provided when several of the same readings is obtained in succession. The object may be rotated pass the reader first in one direction and then in the opposite direction to assure a proper reading in the event that the bar code is backwards. Also, the object may be rotated at a varying speed to obtain the optimum scan speed for the particular density of the bar code.