A fuel injector has an injector body extending along a given axis; a tubular valve body housed inside a hole in the injector body and coaxial with the injector body; and an annular chamber defined by the injector body and the valve body. The filter can be made from discrete pieces of polymeric filter material. The method includes providing data to the agents using two or more distinct peer groups. A method of separating cesium and strontium from an aqueous feed is also disclosed, as are dialkyloxycalix4arenebenzocrown-6 compounds and an alcohol modifier. The textured image is combined with the original image to produce the output image based on the barcode and transition regions. The openings in the perforated plate give rise to a homogeneous mixture of the water to be treated and the air bubbles that result from the pressurized water being injected into the mixing zone by the one or more spray nozzles.