Abstract: This invention comprehends torsional strengthening of two-phase metal materials. One application of the torsionally strengthened material is in the field of springs wherein the energy storage capacity is increased. The invention provides for methods and processes for increasing the torsional strength of two-phase metal materials. Also comprehended is an apparatus that provides the increased torsional strength by its novel combination of machines.

Abstract: An improved sound attenuating device characterized by several novel structures which include (1) a foraminous conduit covered by (2) a layer of sound absorbing material of increasing static flow resistance from the inlet end to the outlet end, and (3) a housing surrounding the conduit and defining a plurality of quarter-wave standing wave cavities in series after the inlet end in operative association with the covered conduit. The present structure provides an attenuating device having a continually changing flow resistance to match the decreasing sound pressure level of the fluid flow passing through the attenuator. The structure takes advantage of the interaction that exists between the sound pressure level and changes in the static and dynamic flow resistance, such that for decreasing sound pressure levels, the dynamic flow resistance will be maintained at an optimum for the system by increasing the static flow resistance.

Abstract: A metallic velvet material comprising a woven textile pile fabric wherein at least a portion of the woven base fabric and/or the velvet surface-forming pile yarns is metallic. The metallic yarn may comprise a blended yarn formed of staple metal fibers and conventional nonmetallic textile fibers, or may be formed of continuous metal filament material. The metal fibers, or filaments, are preferably formed with rough unmachined, unburnished, fracture-free outer surfaces for improved retention in the velvet pile fabric.