Abstract: Residue-free production of ethanol and unicellular protein in a gas-fluidized bed, in which ethanol production takes place in a gas-fluidized bed (stirred fluidized bed, fluid column), the particle fraction of which consists of a wet microorganism mass, e.g. Saccharomyces cerevisiae. A nutrient solution with fermentable carbohydrates is sprayed onto the fluidized particles. The ethanol, which evaporates with the water, is precipitated in a condenser on the discharge side, so that the fluidized bed serves as bio-reactor as well as one-stage distillation plant (together with the cooling system). Thus, the mash column, which is normally used for alcohol production with the submersion method, is not needed in the present invention. In place of the residue, a protein-rich product with 30-40% dry mass is formed, which, during continuous operation, can be removed at certain intervals from the bioreactor and can be dried to the desired degree.

Abstract: A volume control arrangement for an electro-acoustic system, said arranget having an adjustable amplification factor and a frequency characteristic dependent thereon, and comprising a frequency selective circuit which has an amplitude/frequency characteristic curve having at least one maximum lying within the audio frequency range and equivalent to the pass range of a band filter, and a circuit arrangement for varying the frequency and amplitude of the maximum in dependence on the adjustment of the amplification factor.