Abstract: A low profile electrical cable (10), suitable for use in an oil well where a high temperature corrosive atmosphere is present, and being comprised of a plurality of conductors (12) wherein each conductor is insulated by wrapping it in at least one heat-sealed layer (14) of an insulating material, such as a polyimide plastic. The insulation layer around each conductor is then jacketed by an extruded layer (16) of a material which is mechanically and chemically stable to at least about 400.degree. F. A layer of polyvinyl fluoride tape (18) is disposed around the jacket (16); a braid (20) is wound around the jacket (16) and tape (18) of each conductor to enhance the overall strength characteristics of the cable, and this subassembly is, in turn, further jacketed with a layer (22) of a highly permeable nitrile polymer which provides mechanical and chemical protection for the braid, while preventing gas build-up under the jacket.

Abstract: A tubular workpiece (10) undergoes axial and rotational movement relative to a collar (12) filled with an acoustically coupling medium (14). Longitudinal waves are emitted into the coupling medium and the workpiece from a first transducer (22) and acoustic echoes are received thereby. From the coupling medium travel times between the transducer and the surface of the workpiece, a contour reconstruction apparatus (58) reconstructs the peripheral contour of the workpiece. The workpiece travel times are stored in a memory (92) until the longitudinal velocity of the acoustic wave in the workpiece is determined. Transducers (24, 26) emit and detect a Rayleigh wave which travels around the workpiece circumference. A divider (80) divides the workpiece circumference as determined by the contour reconstruction apparatus by the Rayleigh wave travel time to determine the Rayleigh wave acoustic velocity.