Abstract: The present invention relates to aquariums or reef tanks and especially those in which living corals reside. Besides providing a pleasing visual effect, alternating currents within the aquarium are beneficial to the proper health of living corals. Pressurized water from a pump or powerhead is directed by a shuttle valve to one of two outlets. A rod is attached to a plunger through a seal. The rod moves axially by the influence of the pump or powerhead. In operation, a moving seal shuttles back and forth, alternately sealing one of a pair of valve bodies. When moved, the plunger with the attached rod is pulled in, thereby blocking flow to one valve body, while opening flow through the other valve body. By alternately moving the perspective plungers, flow of water within the aquarium tank is alternately diverted from one valve body to the other, providing the desired wave motion in the aquarium tank.

Abstract: A method of determining source areas of pollution aerosol. Selected pollution derived, fine particle tracer elements from within the source region are measured. The measured results are expressed as ratios to one of the tracer elements. A signature of the source region is determined from modes in the logarithmic frequency of the ratios of the tracer elements. Measurements are made of the tracer elements from a receptor region and elemental ratios constructed. The elemental ratios from the receptor region are compared with the signatures from possible source regions to determine the most probable source region.