Abstract: Lightweight composite structural articles having a shell and core comprising a specially-formulated resin, and methods of manufacturing the same. In particular embodiments, the present invention relates to a composite railroad tie comprising an outer fiber-reinforced polymer shell and a unique core formed from a thermoexpandable resin mixture with microcapsules, which railroad tie is manufactured by extruding or pultruding the shell and core through a specially adapted die having a graded cavity, allowing for controlled expansion of the core as the shell and core are passed through the die.

Abstract: A multi-dimensional sound reproduction system is provided for receiving a binaural or other appropriately produced recording on left and right channels and outputting the recording to localized speakers (58) and (60). The localized speakers (58) and (60) are supported on a pair of glasses (70) in housings (80) and (82). Each of the speakers (58) and (60) are directed rearward toward the pinna (68) of the associated left and right ear of the individual and disposed proximate to the zygomatic arch of the listener (26). In this manner, the localized speakers (58) and (60) are separated from the opposite one of the ears of the listener (26) such as not to disturb the conch resonance or the unique pinna response of the listener's ear. The low frequency end of the frequency spectrum for the binaural recording is filtered from the input to the localized speakers (58) and (60), summed and then output on external speaker (52).