Abstract: Apparatus and method for determining the amount of oxidative and hydrolytic degradation in the surface of a highly resistive material, such as a polymer. A special probe provides an annular resistance on the surface of a sample of the material. The voltage drop across the sample determines the input to a meter circuit. A guard circuit has an applied voltage that is substantially the same as the voltage at the meter circuit input. This circuitry permits a very low voltage source to be used.

Abstract: An improved magnetostrictive wire based position transducer that has applications in both liquid level measuring systems and in position indicating systems. A cylindrically structured and circularly polarized piezoelectric element directly measures the torsional acoustic waves in the magnetostrictive wire as they are received by the sensor. The cylindrical structure of the sensor eliminates many of the inadvertently detected acoustic and electrical pulses within the wire that are not indicative of the passage of the torsional wave of concern. The present system provides an improved sensor configuration which is selectively sensitive to torsional waves while being insensitive to vibrations in alternate planes. This improved piezoelectric sensor in combination with the electrical configuration allows placement of the magnetostrictive wire apart from the liquid whose level is being measured or from the indicator whose position is of concern.

Abstract: A method of quantitatively monitoring suspended oils in water combining the technologies of reversed-phase liquid chromatography and fiber optics is shown. A specially treated optical fiber collects and concentrates suspended oils on its surface so that optical transmission through the fiber is related to the contaminant concentration. The transmitted light from a treated optical fiber is detected by a photodiode and photocurrent is passed through an amplifier to give an electronic signal. The electronic signal is either recorded or indicated or generates a control signal whereby the light signal is translated into a value that corresponds to the concentration of oils suspended in water. To be sensed by the sensor cell, the fluid containing suspended oils is brought from a storage means to a reservoir and forced through the sensor cell by fluid pressure.

Abstract: An electronically tunable resonant accelerometer is shown wherein the frequency of a resonant peak may be adjusted over a range of frequencies. A piezoelectric element of the accelerometer is used with a seismic mass to generate an output voltage in response to reciprocating motion of the accelerometer. In a compression mode, a feedback loop applies a feedback voltage to a second piezoelectric element mechanically coupled to the first mentioned piezoelectric element. In a cantilever mode, a feedback loop applies a feedback voltage to another location along the first mentioned piezoelectric element which is formed from two bonded piezoelectric elements.