Abstract: An RF power amplifier system is provided having a DC voltage source for providing an input DC voltage. An RF source provides an RF cattier signal. An RF amplifier serves to amplifier the carrier signal. A DC to DC power supply provides operating voltage to the RF amplifier wherein the operating voltage exhibits a desired percentage of the input voltage. The DC to DC supply includes a low pass filter having a capacitor. A switching device is periodically turned on by turn on pulses for periodically applying the input voltage to the filter which then provides an output voltage across the capacitor. The output voltage serves as the operating voltage. A pulse generator provides the turn on pulses at a frequency synchronized to the frequency of the carrier signal. The turn on pulses exhibit a duty cycle that varies as a function of the value of a control signal. A comparator compares the input voltage with the output voltage and provides the control signal with a value that varies as a function of the comparison.

Abstract: A biomass which can be used directly as panification ferment without previous separation of the culture medium and the biomass and without addition of industrial yeast is prepared by cultivating at least one strain of yeast in a culture medium specified in the description. Preferably, the said ferment comprises as yeast the strain Saccharomyces cerevisiae steineri DSM 9211.

Abstract: A coupling assembly includes a clutch assembly and a brake assembly. The brake assembly includes an annular piston which is formed as one piece with a base member. An annular cylinder chamber is formed as one piece with a second member and telescopically receives the annular piston. Force transmitting surfaces on the two members engage opposite sides of a friction disk. The annular piston and cylinder extend around the outside of the friction disk to at least partially block a flow of contaminants in a radially inward direction toward the friction disk. Passages are formed in a lower portion of the annular piston to accommodate a flow of cooling fluid and to enable any contaminants which enter the brake assembly to flow out of the brake assembly. The brake assembly is advantageously urged to an engaged condition by spring assemblies which include posts and spring elements which extend into a space between the clutch assembly and a flange portion of a flywheel.