An image forming apparatus have a light source, rotational polygon mirrors, reflecting mirrors, lenses. A large number of the composite structures may be confined within a vessel adapted to receive a flow of fluid containing chlorocarbon compounds sought to be removed. To do this, the invention calculates the fan’s air volume flow rate based on a specific volume of air downstream of the adsorption heat exchanger and an air mass flow rate of the fan. The method controls the keys with the operating system to dynamically illuminate only valid keys that correspond to input requests of the currently selected application being currently displayed on the visual display. Optionally, the first surface portion may be in the form of outwardly-extending ridges around the terminal openings, and configured to direct water or other liquids away from the terminal openings associated with the terminals. Background images obtained with selected settings of the elliptical analyzerpolarizer, but without the sample present, are used in some embodiments to improve the measurement.