Abstract: The systems and methods described here can reduce the storage space required (memory and/or disk) to store certain types of data, provide efficient (fast) creation, modification and retrieval of such data, and support such data within the framework of a multi-version database. In some embodiments, the systems and methods can store each field of a set of records as a vector of values, e.g., a data vector. A set of records can be represented using a vector id vector, or “vid” vector, wherein each element of the vid vector contains a reference to the memory location of a data vector. A header table can store associations between labels and “vid” vectors that pertain to those labels. Identical data vectors can be re-used between different record sets or vid vectors needing that vector, thus saving space.

Abstract: Pre-cast concrete beams for supporting a filterbed have deep downwardly extending flanges for providing an underchannel lengthwise of the beam. The beams generally extend across a flume. For backwashing with an air-water mixture, air should be supplied at substantially the same rate to all of the channels. Cross passages between the channels are an aid to this even distribution. Heretofore, special molding procedures for providing the passages or limbers through the beam flanges have increased manufacturing costs. According to the present invention, such passages are provided without extra molding steps and without extra cost by following a delightfully simple concept of merely omitting the end portions of the flanges where beam strength is not required. The end portion projecting beyond the flanges may have a leg across its end to ensure support and aid sealing.

Abstract: The downcomer through which air is supplied to a header for liberation of air deep in an aeration tank is of straight-line nature to minimize constant waste of power due to air flow friction. The downcomer nevertheless folds when the header is to be raised for inspection or servicing. The folding axis is external of the downcomer, which breaks open as the folding action starts. In one form the header is straight while initially raised, hanging from a first hoist cable, and then as the lower section is raised further by a second cable the upper section is allowed to fold over. In another form, the folding progresses as the structure is raised, the upper section being hinged to the air supply fitting.

Abstract: Diffusers on the bottom of a submerged header each include coarse bubble orifices which discharge a stream of air to form a bubble or film on the underside of a horizontal spreader at the edges of which the bubble is sheared by flowing water into multitudinous tiny bubblets rising in the surrounding liquid as a cloud. A second horizontal spreader, slightly above the first, has a similar action, shearing into fine bubblets any larger bubbles which escape from the first spreader to the second. Edges are staggered to supply air to different parts of the water flow. The rising bubblets set up a conventional rolling action in the body of liquid. It is this rolling action which produces the flow of water past the spreaders to shear the bubbles at their edges. A snap-in screw-tightened band secures each diffuser to the header.