A horizontally mounted heat exchanger with recessed fins is disclosed. Systems and methods may also include recovering heat from an exhaust of the generator to deter the formation of frozen condensate on the outdoor heat exchanger by diverting at least a portion of a hot exhaust fluid discharged by the generator onto the outdoor heat exchanger. Molten plastic is extruded into the peripheral impression of the wheel, with a layer of controlled film overlying the peripheral impression. At least one of the seals of the annular space is arranged in a fixed location with respect to the cylinder, and at least another one of the seals is arranged in a fixed location with respect to the outer tube, so that the annular space has a volume which varies as a function of the reciprocating position of the shock absorber. The lateral short-channel DMOS also includes an N+-type well 140 that is formed in the N\u2212-type epitaxial layer 110 and includes a concentration of N-type dopant higher than the N\u2212-type epitaxial layer 110 and lower than the N+-type drain region 118, with the N+-type drain region 118 being formed in this N+-type well 140. Data from analyzing oxidized black liquor samples, and from analyzing one or more black liquor samples which may be subjected to black oxidation, may be used in a black liquor oxidation system for monitoring andor controlling sulfur emissions from a kraft process.