Abstract: An activated-sludge sewage treatment plant employs a hybrid aeration chamber comprising a primary, complete-mix section to which sewage influent and recycle sludge are introduced and treated by aeration and mixing sufficient to provide an effluent having biological oxygen demand in the range of approximately 15 to 75 parts per million, and a secondary hydraulic plug-flow section which receives the effluent. In the secondary section the effluent is treated by incrementally introducing air thereto as the same flows through the secondary section to progressively reduce the biological oxygen demand and thereby provide a final, treated effluent having a biological oxygen demand of approximately 5 parts per million.

Abstract: An attachment for use in conjunction with radio control transmitters, especially for use with model cars, which has a steering wheel and a fork-shaped lever extending therefrom. The lever is adapted to fit over the directional control stick of the transmitter, whereby the rotary motion created by turning the steering wheel translates into the rectilinear motion which actuates the control stick. Realism and enhanced operator control are achieved.

Abstract: Differential-gearing devices are disclosed in which the differential pinion gears are controlled to induce a speed difference between output shafts, provide a locking and limited slip differential to equalize the speeds of the output shafts or limit their speed difference, provide a clutch for controlling the coupling and uncoupling of an input shaft to an output shaft, and provide a variable speed transmission. These operational modes are implemented by mounting hydraulic motor or pump units on the rotating carrier of the differential apparatus, the pinion gears being fixed to the shafts of the respective units. A controllable external fluid source independent of the carrier is in fluid communication with the units via conduits through the stationary housing of the differential device and the rotating carrier. Fluid flow may be either blocked, limited or unimpeded between the source and the units to effect the desired control of the pinion gears to, in turn, determine the operational mode of the apparatus.

Abstract: Removable door guard for use on an exterior portion of an automotive vehicle or the like to prevent damage to the exterior finish from objects such as the doors of adjacent automobiles. The door guard comprises at least two light-weight, elongated members joined together by resilient and nonresilient elements. Attachment means at both ends of the door guard arrangement are adapted to secure the door guard to the door of an autombile. When the door guard is attached to the door, the elongated members fit flush against the door, and the relative positioning of the resilient and nonresilient elements provides tension to positively retain the door guard in this position. The elongated members include a feature which allows the door guard to accommodate existing protective strips permanently attached to the exterior portion of the automoile. The door guard is easily put into a compacted arrangement for convenient storage.