Abstract: A ratiometric method for using optical sensors is provided to measure dissolved oxygen in a fluid sample. The sensor is formulated so as to contain an oxygen permeable membrane of a cured perfluorinated urethane polymer and, incorporated therein, an oxygen-sensitive indicator component and a reference dye component. The emission spectrum from the indicator component is calibrated by comparison with that of the reference dye, which is substantially less sensitive to oxygen-quenching and which has a photodecomposition rate similar to the indicator component. Methods for making and using the membrane and sensor are provided as well.

Abstract: A simultaneous dual excitation/single emission ratiometric method using fiber optic sensors is provided for detecting or measuring a parameter of interest in a sample, including pH, concentration of gases such as CO.sub.2, and the like. The method involves simultaneously providing modulated optical light corresponding to first and second regions of an indicator species' absorption or excitation spectrum, detecting modulated emission signals from the indicator species, demodulating the emission signals, calculating the apparent quantity of analyte present in the sample from the indicator emission signals and correcting the apparent quantity of analyte present for variations resulting from external factors, by determining the ratio of the demodulated indicator emission signals. An apparatus is provided for performing the method as well.

Abstract: A method is provided-for manufacturing a fiber optic sensor for detecting or measuring a parameter of interest in a sample fluid, including pH, concentration of dissolved gases such as O.sub.2 or CO.sub.2, and the like. The sensing chemistry is affixed to the distal end of an elongated optical fiber by way of an adhesive layer typically comprised of an acrylic adhesive composition. Novel optical sensors, fabricated using the aforementioned method, are provided as well.

Abstract: A ratiometric method for using optical sensors is provided to measure dissolved oxygen in a fluid sample. The sensor is formulated so as to contain an oxygen permeable membrane of a cured perfluorinated urethane polymer and, incorporated therein, an oxygen-sensitive indicator component and a reference dye component. The emission spectrum from the indicator component is calibrated by comparison with that of the reference dye, which is substantially less sensitive to oxygen-quenching and which has a photodecomposition rate similar to the indicator component. Methods for making and using the membrane and sensor are provided as well.

Abstract: An optical sensor is provided for measuring dissolved gases such as O.sub.2 or CO.sub.2 in a fluid sample. The sensor is formulated so as to contain a gas permeable membrane of a cured perfluorinated urethane polymer and, incorporated therein, a gas-sensitive indicator component. Methods for making and using the membrane and sensor are provided as well.

Abstract: An optical sensor is provided for measuring the pH of a fluid sample. The sensor is formulated using a fluorescent polymer composition comprising a copolymer of a water-dispersable, polyether-containing urethane olefin precursor and a fluorescent monomer species, wherein the ratio of precursor and fluorescent monomer species is such that a predetermined apparent pKa is provided. The sensor is prepared by coating the distal end of an optical waveguide with the fluorescent polymer composition, and curing the copolymer contained in the composition, e.g., by exposure to radiation of a suitable wavelength.

Abstract: An optical sensor is provided for measuring the pH of a fluid sample. The sensor is formulated using a fluorescent polymer composition comprising a copolymer of a water-dispersable, polyether-containing urethane olefin precursor and a fluorescent monomer species, wherein the ratio of precursor and fluorescent monomer species is such that a predetermined apparent pKa is provided. The sensor is prepared by coating the distal end of an optical waveguide with the fluorescent polymer composition, and curing the copolymer contained in the composition, e.g., by exposure to radiation of a suitable wavelength.

Abstract: An apparatus, for non-destructively testing for flaws in materials, having a housing assembly with a rotor and a stator for passing over the testing material, an ultrasonic probe fixed to the stator, and an eddy current probe mounted on the rotor. In operation the rotor rotates the eddy current probe about the ultrasonic probe and an indexing coil on the ultrasonic probe monitors the relative position of the eddy current probe. The rotating eddy current probe generates eddy currents in the testing material such that internal flaws effect the normal feed back to the probe. Changes in this feed back are monitored to determine, in conjunction with the indexing coil, the existence and location of flaws in the testing material. In the preferred embodiment a rotary transformer electromagnetically bonds the rotating eddy current probe to the housing stator.

Abstract: A fiber optic sensing device for measuring a chemical or physiological parameter of a body fluid or tissue is provided. To one end of the fiber is attached a polymer including a plurality of photoactive moieties selected from the group consisting of chromophores and lumophores, the photoactive moieties spaced apart so as to minimize chemical or physical interaction therebetween while optimizing the density of photoactive moieties. In one embodiment, a polymer chain is covalently bound to photoactive moieties through functional groups such as esters, amides, or the like. In a second embodiment, a polymer chain is inherently fluorescent and is formed from at least one monomeric unit. These devices are particularly useful as pH and oxygen sensors.

Abstract: A ratiometric method for using optical sensors is provided to measure dissolved oxygen in a fluid sample. The sensor is formulated so as to contain an oxygen permeable membrane of a cured perfluorinated urethane polymer and, incorporated therein, an oxygen-sensitive indicator component and a reference dye component. The emission spectrum from the indicator component is calibrated by comparison with that of the reference dye, which is substantially less sensitive to oxygen-quenching and which has a photodecomposition rate similar to the indicator component. Methods for making and using the membrane and sensor are provided as well.

Abstract: An optical sensor is provided for measuring dissolved gases such as O.sub.2 or CO.sub.2 in a fluid sample. The sensor is formulated so as to contain a gas permeable membrane of a cured perfluorinated urethane polymer and, incorporated therein, a gas-sensitive indicator component. Methods for making and using the membrane and sensor are provided as well.

Abstract: Measurements of yarn denier using capacitance transducers are automatically corrected for moisture. Samples of the yarn to be run are tested at different moisture levels at different frequencies in each of two capacitance transducers. The difference in the apparent denier outputs of the two transducers has been found to be proportional to moisture content. The difference is added to one of the measured values to provide a more correct reading. The difference may be further corrected by a factor derived from the slopes of the curves of transducer output vs. moisture and the slope of the curve of skein denier vs. moisture.