Abstract: A fiber optic refractometer is disclosed for use in on-line measurement of the refractive index of a process fluid. The refractometer does not require light to pass through the process fluid and is hence unaffected by the presence of light diffusing particulate matter in the process fluid. A particular application for which the refractometer is well-suited is the on-line measurement of the hydrogenation state of edible oils (which correlates with refractive index) during the partial hydrogenation process.

Abstract: The integrity of mine roofs and rock bolts is tested by determining the natural frequencies of the roof and bolt. The roof is struck at a plurality of locations and the resulting vibrations sensed with accelerometers. The output of each accelerometer is separated into a plurality of signals of different frequencies by a comb filter having selected band passes. The amplitude of the outputs of each of the band passes of the filter are used to determine the condition of the roof and bolt adjacent each accelerometer. The high amplitude signal resulting from the initial impact of the striking implement is electrically gated from the accelerometer output.

Abstract: A fluid level indicator circuit is used in cooperation with a probe attached to a long wire where the probe has first and second electrodes for contacting the surface of the fluid and leads communicating to the indicator circuit. The water level indicator has a low current high gain transistor and a power source which has sufficient potential to not only properly reverse bias the transistor when the probes are out of contact with the fluid but also properly forward bias when the probes are in contact with conductive fluid. A meter and current adjusting device are provided in series with a collector and emitter to provide an indicator when the probes are in or out of the water. The circuit also has a light to give a visual indication.

Abstract: A portable apparatus for determining the moisture content in welding electrode coatings is described. The apparatus is suitable for field use, and comprises a source of low voltage direct current, a means for transforming low voltage direct current to high voltage direct current, an electrical circuit including a current indicating means and contacts attachable to a welding electrode whereby the welding electrode coating is included in the electrical circuit. A method of operating the apparatus to determine the amount of moisture in a welding electrode coating is also described.

Abstract: An improved electrical energy storage battery is provided having a case, at least two porous electrolyte containers positioned within the case, a solid hydrogel positioned within the case and between the electrolyte containers, the hydrogel containing an effective amount of an electron transferring agent to render said hydrogel conductive, at least one anode positioned within at least one of the electrolyte containers, at least one cathode positioned within at least one other of the electrolyte containers, a second solid hydrogel positioned within the container for the cathode, said gel being saturated with a compound selected from the group consisting of zinc chloride, zinc oxide, cadmium chloride, and cadmium oxide to render same conductive, and a third solid hydrogel positioned within the container for the anode, said gel being saturated with a compound selected from the group consisting of chromium chloride, chromium oxide, and alkali metal-containing chromate salts to render same conductive.