Abstract: In accordance with embodiments of the present disclosure, a flextensional transducer for underwater operation includes a driving element and a stave. The stave is made from a material with elastic properties and has a porous structure. The porous structure is adapted to be modelled such that when in use, said porous structure of the stave is of an arbitrary alignment with respect to, for instance, the driving element, and has a degree of porosity. The degree of porosity is such that the elastic properties and vibrational frequency response of the stave can be customised with respect to its intended use.

Abstract: In accordance with embodiments of the present disclosure, a flextensional transducer for underwater operation includes a driving element and a stave. The stave is made from a material with elastic properties and has a porous structure. The porous structure is adapted to be modelled such that when in use, said porous structure of the stave is of an arbitrary alignment with respect to, for instance, the driving element, and has a degree of porosity. The degree of porosity is such that the elastic properties and vibrational frequency response of the stave can be customised with respect to its intended use.

Abstract: The present invention relates to the manufacture of ferrous picrate and the preparation of fuel additives containing ferrous picrate. A process for producing ferrous picrate includes dissolving picric acid in a mixture of an aromatic hydrocarbon and an aliphatic alcohol in the presence of a trace amount of water and a metallic iron, thus forming a ferrous picrate solution. The ferrous picrate solution is blended with an organic solvent to form the fuel additive. Ferrous picrate produced by the product is also described.