Abstract: Disclosed herein is a speaker system for mounting in a vehicle wherein a passive radiator is provided in the interior of the speaker system. The speaker system is mounted on the rear window tray or shelf of the vehicle so that the radiating surface of the passive radiator faces the rear glass window of the vehicle to thereby produce a horn effect. Due to the horn effect, the lower sound spectrum is fully reproduced.

Abstract: A process is disclosed for calcining cement-clinkers by using a calcination apparatus having a generally cylindrical calcining furnace which is composed of (a) a throat part, (b) a spouted bed and (c) an uppermost chamber longitudinally connected in series with an upper part of a combustion chamber having a separate heat source. The calcining apparatus is disposed between a suspension type raw material preheating device and rotary kiln or a fluidized bed calcining device wherein, cement raw materials, which have been partly calcined in the said raw material preheating device, are fed in the vicinity of the upper end of the said spouted bed while a jet fluid of a high temperature flue gas passing through the throat part under high speed from the said combustion chamber and rising upwards is admixed with a tangential flow of a high temperature exhaust gas introduced into the vicinity of the upper end of the said spouted bed from the said rotary kiln or from the fluidized bed calcining device.