Abstract: Position change sensing apparatus including at least one audio signal transducer for emitting audio signals and receiving audio signals and computer software embodied in a medium readable by the apparatus and having anti-theft functionality including learning functionality and theft-prevention functionality.

Abstract: Position change sensing apparatus including at least one audio signal transducer for emitting audio signals and receiving audio signals and computer software embodied in a medium readable by the apparatus and having anti-theft functionality including learning functionality and theft-prevention functionality.

Abstract: Apparatus or method for identifying and/or validating stacked substantially flat items, comprises: stacking items having markings identifiable from an edge, viewing said stack from at least one angle selected so that edges of said items are in view, capturing an image from said at least one angle, carrying out image processing over said image to produce at least one output indicative of one of edges and edge markings in view, and using said output to obtain information of items in said stack. The items may have edge-on viewable markings that identify themselves individually or as part of a given set or both.

Abstract: An improved method and apparatus for rapidly, accurately and inexpensively counting stacked objects, preferably by imaging, from below, a stack of flat objects which is standing on its side, preferably on its long side. The objects need not be identical in surface appearance or in configuration. The objects preferably may be of substantially any size or thickness and need not be less than some maximum size or within some narrow range of thicknesses.

Abstract: There is provided a process for rendering certain layers impervious to the seepage of water through same. Such layers are of value in preventing water seepage into structures, and also from ponds, from water reservoirs and the like. The water impervious layers are produced from mixtures of sand (about 98.5 to 90 weight percent) and montmorillonite (about 1.5 to 10 weight percent), which are compacted and contacted with salt water having a salt content at least equal to that of sea water, and washing the layer until the wash waters are essentially free of sodium.