A device for detecting water penetration into a marine acoustic streamer with segments interconnected by connectors. Each connector positioned between any two adjacent segments is provided with sensors which are constituted by flexible printed circuits having two distinct and interleaved conductive combs thereon. A bifilar line interconnects the sensors, and an emitting and receiving circuit allows a sensor whose impedance has been changed by the infiltration of water into the connector to be located by means of a reflectrometric method, whereby the operating condition of such marine acoustic streamer can be supervised efficiently and at low cost.

A method and system for measuring rock electrical properties using time-domain spectroscopy. The rock to be measured is place in direct contact with the substantially flat face of a sample cell. A voltage pulse is launched into a coaxial line connected to the sample cell. The pulse propagates through the sample cell and reflects from the rock. The incident voltage pulse and reflected voltage signal are analyzed to determine the rock's conductivity as well as the rock's dielectric constant over a broad frequency range.

A method for measuring the thickness of a refractory laid-up against the interior surface of the steel shell of a metallurgical apparatus includes placing at least one monitoring device in a critical wear area of the apparatus in a manner such that the free end of the device is at a known distance from the hot face of the refractory and the confined end extends beyond the outer surface of the steel shell. The device is connected to an electronic time-domain reflectometer by electrical connecting means. Timed pulses are generated and impressed in the device by the instrument and reflections of the pulses are received by and are visually displayed on the reflectometer. The length of the device appears on the display as a straight line bounded by two inflections. The straight line is indicative of the thickness of the refractory. The device includes a metallic conductor coaxial with an outer metallic sheath and separated therefrom by a refractory having a desired dielectric constant. The device has a free end and a confined end. The confined end may be contained in a junction box provided with electrical connecting means. Electric insulating packing may be used in the junction box.

Apparatus for providing a temperature profile of the ocean for a towed so array. A towing cable for the array comprises a central cable and a protective outer jacket. Thermistors are disposed at spaced positions along the outer jacket and connect to conductors embedded in the protective outer jacket. The conductors terminate onboard ship to provide continuous signals representing temperatures at various ocean depths.

An integrated fiber-optic tow cable is described having both optical fibers and armor wires located outside the cable core to avoid high strain on the optical fibers when the cables is under stress during deployment. The optical fibers have integral temperature sensors near the outermost portion in order to measure accurately the temperature of the fluid coming in contact with temperature sensors. A beam of light is shown on the optical fibers which is reflected by the optical fibers and reaches the receiver and processed by the processor which may also include a display unit.