Abstract: An adder and a comparator form portions of a modular memory address block determination circuit. The starting address of the first block and the enable signal of the first block are added to produce the starting address of the second block. This procedure is repeated for each block. The determined starting address for each block is compared with the requested memory address and, unless the block is utilized or disabled, if equal a signal indicates the match. The circuit is used on a circuit board which emulates three conventionally separate memory circuit boards. The registers for each emulated board are provided and appropriate bus signals are developed.

Abstract: An apparatus for detecting oil and other lighter-than-water contaminants in an effluent stream in a sewage system. The apparatus includes a disposable detector which floats in the effluent stream and detects oil and other contaminants having a specific gravity lighter than the water by absorbing the oil and such contaminants in an oleophilic material, permitting the oil and other contaminants to rise and collect in a collection tube. The acidity or pH of the effluent being monitored is determined by routing a portion of the effluent stream through the lower side of the detector across a litmus paper. The detector is held in the sewage system by a securing system which indicates whether the detector has been tampered with since it was installed.