Abstract: Heat is supplied to chemical reactions, especially reactions involving the cracking of hydrocarbons for producing gas, by the combustion of fuels with heated combustion air followed by a heat exchange extraction of sensible heat from the flue gases produced by the combustion for heating air for the combustion. The hot reaction product is at least partly air cooled and the resulting heated cooling air is passed at least partly through the air preheater before the air is used as heated combustion air.

Abstract: Means and method of reducing the distortion or channel separation due to interference voltages between the reproduction channels in multi-channel reproduction of acoustic sounds in systems having at least two different channels are described. The steps are deriving a control voltage from the low and high interference voltages which occurs in a channel which is proportional to the magnitude of the interference voltages, and using the control voltages as an adjustment to control the distortion or channel separation. The control voltages may be derived from a single channel. The control voltages may be combined to yield a single control signal. Both equal-phase distortion and phase-opposition distortion may be suppressed.

Abstract: A display device having a rectangular area of variable shape and cross-section with a pair of movable line markers defining the horizontal boundaries and another pair of movable line markers defining the vertical boundaries, means for moving each pair of line markers to vary the distance therebetween to obtain the rectangular area of desired shape and cross-section. Simultaneous movement and regulated separation of pairs of line markers may be obtained by rotating elliptical cams connected to the line markers.