Abstract: A system for delivering customized audio content to customers. A central processing site (120) is coupled with content providers (110) through a network (142). The central processing consists of a number of components, namely content classification system (200), user preference management (400), content conversion system (500), content delivery system (600), and user authentication (300).

Abstract: A flat, very thin fluid heat exchanger of up to about 1/8 inch in thickness is formed from a pair of etched blanks. The blanks are provided with at least a pair of projecting tabs for locating the blanks relative to each other. The tabs are secured prior to brazing of the blanks and are thereafter removed. Posts are provided for facilitating securance of the heat exchanger to objects with which it is to be associated. A thin fluid flow passageway is provided between the blanks, and the heat exchanger provides fluid flow inlet and outlet openings communicating with the fluid flow passageway.

Abstract: A method of chemical machining utilizing selective plating techniques to form a metal component from sheet metal sheets, in which each sheet is degreased, rinsed in deionized water, and thoroughly dried, then is coated with a positive photoresist. The photoresist is cured, and then the image of the component to be formed is photographically applied to either side of the sheet utilizing photomasks, the photographically exposed photoresist is removed from the sheet, and the sheet etched to provide the basic component configuration. Selective plating is effected by further photographically exposing the photoresist of the sheet that overlies the portions of the sheet to be plated, by utilizing photomasks delineating the areas to be plated, after which the freshly exposed photoresist is removed, the sheet baked to better condition the resist for plating, and then suitably electroplating the areas of the sheet metal thus exposed. After plating, the completed component is soaked in acetone to remove the resist.