Abstract: A shutter assembly for a receptacle. The shutter assembly may include a first plate, a second plate disposed adjacent the first plate, a shutter disposed between the first plate and the second plate, a first spring that provides lateral movement of the shutter, a second spring that provides transverse movement of the shutter and a plunger for providing a pivot point to the shutter. The plunger may be disposed between the second spring and the shutter. According to an embodiment of the invention, when there are no pins or there is one pin inserted into the shutter assembly, the shutter is in a first position and lugs on the shutter abut locks disposed on the first plate and the second plate, thereby barring access to apertures in the assembly. When two pins, other than the ground pin, either sharp or round edges, are inserted into the shutter assembly, the shutter slides laterally to expose apertures in the assembly, making the receptacle available for use.

Abstract: A book rest includes a primary frame having bottom and top bars connected by opposite side bars for supporting a book thereon and a secondary frame pivoted to the side bars of the primary frame to be movable with respect to the primary frame between a folded position and an expanded position where an included angle is formed between the primary frame and the secondary frame for supporting the book at a corresponding angular position. A Velcro strip has first and second end sections on which hooks and loops are respectively formed. The first end of the Velcro strip is fixed to the bottom bar of the primary frame and the second end of the Velcro is folded over a bar of the secondary frame and overlaps the first end section to releasably fix the included angle between the primary and secondary frame whereby the angular position of the primary frame and thus that of the book supported on the book rest can be adjusted.

Abstract: A leading zero predictor (LZP) in parallel with the full subtraction operation correctly predicts the exact number of leading zeros of a subtraction result. Once the full subtraction operation is completed, the necessary shifts may be performed immediately, without a delay to determine the presence of leading zeros, and without need for a normalization corrector.