Abstract: A lightweight solar concentrator of the reflecting parabolic or trough type is realized via a thin reflecting film, an inflatable structural housing and tensioned fibers. The reflector element itself is a thin, flexible, specularly-reflecting sheet or film. The film is maintained in the parabolic trough shape by means of a plurality of tensioned fibers arranged to be parallel to the longitudinal axis of the parabola. Fiber ends are terminated in two spaced anchorplates, each containing a plurality of holes, which lie on a desired parabolic contour. In a preferred embodiment, these fibers are arrayed in pairs with one fiber contacting the front side of the reflecting film and the other contacting the back side of the reflecting film. The reflective surface is thereby slidably captured between arrays of fibers, which control the shape, and position of the reflective film. Gas pressure in the inflatable housing generates fiber tension to achieve a truer parabolic shape.

Abstract: A lightweight solar concentrator of the reflecting parabolic or trough type is realized via a thin reflecting film, an inflatable structural housing and tensioned fibers. The reflector element itself is a thin, flexible, specularly-reflecting sheet or film. The film is maintained in the parabolic trough shape by means of a plurality of identical tensioned fibers arranged to be parallel to the longitudinal axis of the parabola. Fiber ends are terminated in two identical spaced anchorplates, each containing a plurality of holes which lie on the desired parabolic contour. In a preferred embodiment, these fibers are arrayed in pairs with one fiber contacting the front side of the reflecting film and the other contacting the back side of the reflecting film. The reflective surface is thereby slidably captured between arrays of fibers which control the shape and position of the reflective film. Gas pressure in the inflatable housing generates fiber tension to achieve a truer parabolic shape.

Abstract: A heat exchange cell for use in a recuperator includes top and bottom plates spaced apart to define therebetween an internal space. Within the internal space are inlet and outlet header tubes communicating with a plurality of internal matrix fins. The header tubes are rigidly affixed to at least one adjacent header tube and to the top and bottom plates. The header tubes may have a rectangular cross-section and may, for example, be metallurgically bonded to the top and bottom plates and to each other through brazing. Rigidly affixing the header tubes to each other reduces the stress on the fillets that bond the tubes to the top and bottom plates. This in turn permits less structural material to be used in the header portions of the cell and reduces pressure drop across the headers.

Abstract: A lightweight solar concentrator of the reflecting parabolic or trough type is realized via a thin reflecting film, an inflatable structural housing and tensioned fibers. The reflector element itself is a thin, flexible, specularly-reflecting sheet or film. The film is maintained in the parabolic trough shape by means of a plurality of identical tensioned fibers arranged to be parallel to the longitudinal axis of the parabola. Fiber ends are terminated in two identical spaced anchorplates, each containing a plurality of holes which lie on the desired parabolic contour. In a preferred embodiment, these fibers are arrayed in pairs with one fiber contacting the front side of the reflecting film and the other contacting the back side of the reflecting film. The reflective surface is thereby slidably captured between arrays of fibers which control the shape and position of the reflective film. Gas pressure in the inflatable housing generates fiber tension to achieve a truer parabolic shape.

Abstract: A hand-held tool is used to cut soft materials, such as pumpkins, for example in the carving of decorative designs. The tool has an elongated handle that has a forward cavity. A stiff blade extends forwardly of the handle in a longitudinal direction and has a shank portion in the cavity to reduce the danger of fatigue breakage.