A nitride wet etch in which liquid TEOS is flowed directly into the hot phosphoric acid bath before wafer etching begins. The illuminating range of some of the plurality of beams is made smaller than the illuminating range of the other beams. The jet of hot gas directed into the upper region of the shaft can include recirculated flue gas, a mixture of air and recirculated flue gas, or combustion products that are generated by a burner. Detection of the RFID tag may indicate that the container has been opened or the article has been accessed. A user account can include a set of user-defined alerts triggered by the juxtaposition of users, geographic locations andor events.