Abstract: A surface-modified fibrous material which includes hydrocarbon polymer fibers having cationic or anionic groups on the surfaces thereof and coated with a polyelectrolyte having a net charge opposite to that of the cationic or anionic groups on the surfaces of the fibers. The hydrocarbon polymer may be, by way of illustration, a polyolefin, such as polyethylene or polypropylene. The cationic or anionic groups may be carboxylic acid, sulfonic acid groups, or quaternary ammonium groups. Examples of polyelectrolytes include chitosan, poly(methacryloxyethyltrimethylammonium bromide), poly(acrylic acid), and poly(styrene sulfonate). Also disclosed is a method of making the surface-modified fibrous material. The surface-modified fibrous material may be used as a filtration medium for liquids.

Abstract: A method and apparatus for the noninvasive real-time characterization of samples using coherent backscattering is disclosed. The sample is illuminated by a laser, and the radiation that is coherently backscattered is measured. The line width or line shape of the coherent backscattered radiation, or in some cases just the existence of coherent backscatter, is then used to characterize the sample under test. This characterization is then used for the real time control of a process acting upon the sample.