Abstract: An aerator for mixing an ambient gas with a liquid and agitating the liquid incorporates at least three bearings that are rigidly connected to an aerator housing. A propeller is driven by a central shaft that is rotatably mounted in the aerator housing using the bearings. Two bearings are located near the ends of the central shaft. At least one additional bearing is located between the ends, for example, in a intermediate position. This additional bearing may absorb some of the force that would otherwise be transferred to the bearing near the propeller end of the central shaft. The bearings are thus subjected to lower stress and may exhibit a prolonged useful lifespan.

Abstract: A control system for a grain harvester. The control system monitors the output of a grain sensor and uses the monitored value to actuate one or more relays having different energization levels. As each relay is actuated it completes a circuit, which is used to modify power that is fed into a control mechanism and which is used to control an operational parameter of the harvester. Depending upon the monitored value of the sensor, the control system will modify the power that supplies a control mechanism that is used to control an operational parameter of the harvester, such as the groundspeed. If the output from the sensor is less that a predetermined threshold, the harvester will operate normally. If the output of the sensor is above a first threshold, the control system will modify the supply voltage. If the output of the sensor is greater than a second threshold, the control system will modify the supply voltage accordingly, and so forth.

Abstract: A block for use in constructing a retaining wall having a bottom with a non-planar portion which creates a gap between the bottom surface and the top surface of a lower course of similar blocks when the block is placed thereon. Preferably, the block's bottom surface further comprises a plurality of grooves. It is envisioned that these grooves be “V” shaped, thereby having angled walls which act to funnel the larger stones into an area of adequate clearance when the block is being placed on a lower course of similar blocks.