Abstract: A laminated noise attenuation panel for both sound absorption and sound transmission loss having as its principal layers an expanded thermoplastic core with alternately inverted cavities, half opening to each side of said core and a sheet of cured resinous material having hollow microspheres with substantially reduced atmospheric pressure randomly dispersed in said resinous material, said cured resinous sheet facing away from the noise source. The cavities of said core panel facing away from said noise source may be filled with cellulose. The side of said core panel toward the noise source may include a laminated layer of a perforated material and a decorative layer. The side of said panel away from the noise source may also include a layer of other materials and a decorative layer. Data for the noise attenuation properties of various combinations of laminations are presented.

Abstract: A structure that is preferably constructed in sheet form and that provides improved sound attenuation with a relatively small thickness. The materials comprising the structure include a myriad of hollow glass microspheres interspersed, preferably by a blending process, into a curable resin base. Improved acoustic attenuation is provided by employing microspheres of the type containing a vacuum and selecting a resin base that has good flexure qualities and is relatively soft with a relatively low indentation hardness.

Abstract: An acoustic destructive aerial target seeker having recognition-guidance cuitry which is adapted to detect and recognize the characteristic sound emitted from an armored vehicle and to launch and direct the system toward destructive impact with the target.