Abstract: An auxetic material comprises an outer component of a relatively compliant material, and an inner component of a relatively stiff material, wherein the inner component is located within a cavity provided within the outer component, the cavity being of non-linear form in the longitudinal direction of the material when the material is at rest.

Abstract: A fibrous assembly includes two components. The first component provides a visual indication of when a pre-determined tensile load is applied to the assembly or when the fibres of the assembly have been over-extended. The first and second components are movable relative to each other, the visual indication being provided by the first component being substantially concealed by the second component and becoming at least partially exposed when the pre-determined tensile load is applied to the assembly or when the fibres have been over-extended. The first component comprises auxetic yarn.

Abstract: A high frequency transducer having a dome diaphragm with a configuration of a bisected ellipse to overcome the distortion and breaking point of prior art even domes at frequencies above 30 kHz. The dome diaphragm having an annular skirt extending therefrom in an integral fashion and connecting to a disc shaped plate of the transducer. A voice coil of cylindrical section being directly connected to the skirt at a region of close proximity to said dome. The dome being constructed of a rigid material such as a metal, an alloy, a metalloid such as, but not limited to, titanium, aluminum, and boron, or a combination thereof. The dome being constructed in accordance with a general formula for an ellipse (x2/a2)+(y2/b2)=1, and a>b. Wherein a is half of the distance of major axis and b is half of the distance of a minor axis.