Abstract: A cutter element for use in a drill bit, comprising a substrate and a plurality of layers thereon. The substrate comprises a grip portion and an extending portion. The layers are applied to the extending portion such that at least one of the layers is harder than at least one of the layers above it. The layers can include one or more layers of polycrystalline diamond and can include a layer in which the composition of the material changes with distance from the substrate.

Abstract: A centralizing device is provided for a riser of an offshore well platform having an opening through which the riser passes from the platform to a subsea wellhead. The riser has generally planar fins extending radially outward from its outer diameter. The centralizing device has a frame which is mounted to the platform about the riser. A plurality of centralizing rollers are mounted to the frame and are radially extensible relative to the riser. The centralizing rollers bear against the riser and retain it laterally. A plurality of torsional rollers are mounted to the frame and are extensible towards the fins. The torsional rollers bear against the fins and retain the riser torsionally.

Abstract: A rod guide for a cylindrical rod. The rod guide includes a cylindrical body surrounding and coaxial with the rod. A first pair of opposed fins extends from the cylindrical body, each first fin having a pair of planar sidewalls parallel to each other and parallel to the diameter of the cylindrical body. A second pair of opposed fins, each has a pair of radiused sidewalls wherein each second fin extends outward radially from the cylindrical body to a terminal end with the fin widest at its terminal end.

Abstract: The surface acoustic wave device of the invention comprises a piezoelectric substrate of lithium niobate or lithium tantalate and electrodes formed on the substrate for propagating surface acoustic waves. The substrate has a cut plane and a surface acoustic wave propagation direction which are (.phi., .theta., .psi.) as expressed in Eulerian angles and within ranges substantially equivalent thereto. When the substrate is made of lithium niobate, .phi., .theta. and .psi. are 0.degree.-86.degree. or 95.degree.-180.degree., 73.degree.-118.degree. and 0.degree.-44.degree., respectively. When the substrate is made of lithium tantalate, .phi., .theta. and .psi. are 0.degree.-87.degree. or 91.degree.-180.degree., 80.degree.-120.degree. and 0.degree.-44.degree., respectively. This enables the device to exhibit high performance.