Abstract: An apparatus obtaining a pH level of a tissue comprises an array of at least three optical sensors configured to absorb light shined on the tissue and thereby obtain at least three electronic digital signals, wherein the first electronic signal A1(X,t) represents the light absorbed by the tissue in location X=(X,Y,Z) at time t and at wavelength L1, and similarly the second and third electronic signal A2(X,t) and A3(X,t), and a finite absorption range of the three wavelength L1, L2 and L3 is such that 0<=A3(X,t)<=A2(X,t)<A1(X,t); and an electronic processing unit receives the signals and applies an ordered monotone function, F1, to the tissue, to spatial temporal information of each wavelength, F1 used by a transfer function for presentation as a LookUp Table connecting actual values computed by F1 and an actual pH of the tissue in location X at time t.

Abstract: An optical sensor for detecting hydrogen in a fluid in physical contact with the sensor is provided. The sensor includes an optical fiber, wherein an end portion of the optical fiber is coated with a multilayer including: a sensing layer, including a film of an alloy, the alloy including Mg, Ni, and M, wherein M is at least one of Zr, Ta, and Hf, and wherein the alloy has the composition MgxNiyMz, and wherein x is from 40 to 60, y is from 10 to 40, and z is from 10 to 40, and a catalyst layer including Pd. Further, a detection system for hydrogen, including such an optical sensor, and an electrical device having such a detection system are provided.

Abstract: A Total Suspended Solids (TSS) Device which includes a plurality of calibrated sample containers in a case, such that each calibrated sample container contains a calibrated sample, wherein each calibrated sample is a sample with a known suspended solids concentration prepared from a site sample, such that said TSS device is configured to allow a discharge sample in a discharge sample container to be visually compared to each of the calibrated samples in the calibrated sample containers in said case, where the discharge sample is a sample of a liquid discharge from a site.

Abstract: This invention provides a novel methods and devices for measurement of particle concentration or changes in particle concentration over a wide linear range. The invention comprises one or more radiation sources and one or more detectors contained in a housing which is interfaced to a medium containing particulate matter. The one or more radiation sources are directed into the medium, scattered or transmitted by the particulate matter, and then some portion of the radiation is detected by the one or more detectors. Methods for confining the measurement to a specific volume within the medium are described. Algorithms are provided for combining the signals generated by multiple source-detector pairs in a manner that results in a wide linear range of response to changes in particle concentration. In one embodiment the sensor provides non-invasive measurements of biomass in a bioreactor. In another embodiment an immersible probe design is described, which may be suited for one-time use.

Abstract: A pH measuring method includes: illuminating a medium solution, which includes: a first material; and a second material, with a plurality of light beams, which includes: a first light beam, a wavelength of which corresponds to a first absorption peak; a second light beam, a wavelength of which corresponds to a second absorption peak or a second convergence point; a third light beam, a wavelength of which corresponds to a third absorption peak or a third convergence point; and a fourth light beam, a wavelength of the fourth light beam at which an absorbance of at least one of the first and second materials is converged irrespective of a pH; receiving transmitted or reflected light beams of the first to fourth light beams; measuring absorbances at the wavelengths of the received light beams respectively; and calculating a pH of the medium solution based on the absorbances.

Abstract: A fluid content monitor including a cuvette, a colorimeter adapted to generate a signal indicative of contents of a fluid sample contained in the cuvette, a container for holding a reagent, and a pump assembly for delivering reagent from the container to the cuvette. The pump assembly includes a tube extending from the container to the cuvette, check valves preventing reverse flow in the tube, and a hammer driven by a solenoid for repetitively compressing the tube to pump reagent to the cuvette. The cuvette can be removed for cleaning and replacement.

Abstract: A method and apparatus are provided for detecting and compensating for a kink in an optical fiber. A distal sensor (11) monitors a level of a parameter in an environment in which the distal sensor is immersed. The distal sensor is disposed at a tip of the optical fiber (17) and the optical fiber conveys green light signals and near infrared (NIR) light signals to and from the distal sensor. A photodetector (59') records the signal and reference values for the green light signals and the NIR light signals conveyed by the optical fiber at consecutive data points. A microcontroller (42) is electronically coupled to the photodetector and receives the signal and reference values for the green light signals and the NIR light signals. A kink in the optical fiber is detected when a change between NIR signal values recorded at a pair of consecutive data points recorded by the photodetector is greater than a predetermined threshold.

Abstract: A system for controlling the color of compounded polymer(s) comprises: a compounder for mixing the constituents of the compounded polymer(s) to produce a substantially homogeneous mixture; a sensor for measuring the color of the substantially homogeneous mixture at predetermined intervals; a colorant additive feeder, responsive to a controller, for providing the colorant additive(s) to the mixture at substantially predetermined colorant additive addition rates; and a controller, responsive to the sensor, for controlling the colorant additive addition rate(s) of the feeder.

Abstract: The invention pertains to a method for generating the fluorescence of polyanionic fluorophores in low dielectric media with fluorescence activation produced by specific quaternary onium compounds. The method may be used for measuring an analyte and may be useful in sensor devices.

Abstract: A technique for separating, identifying and measuring ions in solution by capillary zone electrophoresis is described, which provides improved sensitivity and resolution of anionic species. The method involves introducing a sample containing the ionic species into a narrow bore capillary filled with a carrier electrolyte containing a selected light-absorbing anion. An electrical potential is applied across the capillary column causing the ions to elute according to their ionic mobility. Both UV absorbing and UV-transparent ions can be detected and quantitated by UV/visible photometric monitoring.

Abstract: A dual wavelength optical sensor for measuring chemical properties of a particular quantity, the optical sensor including a sensor probe having a thin sensing film whose optical characteristics are responsive to the chemical properties of the measured quantityThe United States Government has certain rights in this invention pursuant to Contract No. ITA87-02 between the U.S. Department of Commerce and Iowa State University.

Abstract: A device for optically detecting a chemical change of fluid comprises a prism placed in fluid to be tested and a layer of color indication material formed on a surface of the prism to thereby detect a chemical change of fluid by means of a transmitted light and a reflected light in the prism.

Abstract: A technique for separating, identifying and measuring ions in solution by capillary zone electrophoresis is described, which provides improved sensitivity and resolution of anionic and cationic species. The method involves introducing a sample containing the ionic species into a narrow core capillary filled with a carrier electrolyte containing a selected light-absorbing anion or cation to an electrical current in a capillary column causing the ions to elute according to their ionic mobility. Both UV absorbing and UV-transparent ions can be detected and quantitated by UV/Visible photometric monitoring.

Abstract: A technique for separating, identifying and measuring ions in solution by capillary zone electrophoresis is described, which provides improved sensitivity and resolution of anionic species. The method involves subjecting a sample containing the ionic species a light-absorbing material and a quaternary ammonium salt to an electrical current in a capillary column causing the ions to elute according to their ionic mobility. The ionic species are detected and quantitated by UV/Visible photometric monitoring.

Abstract: Fiber optic chemical sensors and materials suitable for use in making same are provided. A charged hydrogel matrix membrane is suitable for affixing to the distal end portion and the like of an optical fiber waveguide, which charged hydrogel matrix has dispersed therewithin an oppositely charged ion exchange resin powder, which ion exchange powder has a colorimetric indicator component electrostatically coupled thereto, which colorimetric indicator component has the same charge as the charged hydrogel.

Abstract: In order to eliminate interferences of an optical or chemical nature, preferably in optical sensors, a cover layer is provided which comprises a hydrophilic, ion-permeable polymer membrane containing precious metal pigments deposited by a reduction or reduction/cementation technique for the purpose of suppressing straylight.

Abstract: Colorimetric, fiber optic sensors for measuring pH, PCO.sub.2 and/or other chemical parameters of the blood. The sensors are fabricated using a single optical fiber, which is provided with a chamber at its distal end containing a pH sensitive dye. Located distal to the chamber is a white reflective surface located within 0.04" from the end of the optical fiber, which enhances the performance of the sensor.

Abstract: The apparatus employs a method for accurate, reproducible analytical solution evaluation eliminating the need for a reference sensor by determining the activity of selected species employing species specific sensors and species combination sensors in conjunction with Nernst-type equations. The apparatus includes sensor structures for elimination of edge effects to signals thereby yielding accurate, reproducible measurements, and a cartridge structure adapted to incorporate an array of the new sensors for employment of the new method where the cartridge is particularly adapted for miniaturization, maintaining a fixed volume of solution for analysis and providing an anaerobic testing environment. Lastly, a compact instrument embodying miniaturization especially adapted for field use and use of the cartridge is provided herein.

Abstract: It is intended for measuring a given characteristic of a fluid medium and comprises at least one assembly having an appropriate reagent for said measurement and serving to interact with the fluid medium, reagent support means, an optical fibre (2) called the emitting fibre and used for transmitting light in the direction of the support means and at least one other optical fibre (4), called the receiving fibre and which recovers at least part of the light from the support means when the latter receive the light from the emitting fibre. The support means comprise a single porous or adsorbant element (10) to which is fixed the reagent and which is positioned facing the emitting fibre and each receiving fibre. This element is in direct contact with the fluid medium when the transducer is immersed in it and therefore has no confinement membrane.

Abstract: For detecting changes in chemical or physical parameters an optical fibre core has bonded to its surface a chromophore responsive to the parameter. The core preferably has a porous surface with the chromophore coating extending into the porous structure.

Abstract: A colorimeter for continuously monitoring the concentration of an ionic species in an aqueous solution comprises a source 30 of optical radiation, a flow cell 10 including three flow chambers 11, 12 and 13 interconnected so that a sample of the solution can pass through each flow chamber in succession, and photodetector devices 41, 42 and 43 positioned to respond to radiation transmitted through the solution in the flow chambers 11, 12 and 13, respectively. The lengths of the three flow cells are different from each other to provide a continuous real-time calibration check based upon photodetector responses to radiation transmitted through different quantities of the solution. Electronic circuitry interconnecting the radiation source 30 and the photodetector devices 41, 42 and 43 maintains the intensity of the radiation emitted by the source 30 at a substantially constant value.

Abstract: Method and apparatus for spectrophotometric investigation of products of electrochemical reactions in which a solution containing at least one dissolved initial product is directed essentially axially towards a rotating disc electrode surrounded by an optically translucent ring, the flow being reversed at the rotating electrode into an outwardly directed radial flow, and the concentration of the products formed at the electrode being determined by passing monochromatic light through the radial product flow and the optically translucent ring and by measuring the light absorption, wherein the measurement is performed under quasi-stationary conditions in that the current for the electrochemical reaction is permitted to flow without interruption for at least approximately 0.5 seconds before the measurement is performed.

Abstract: A fiber optic pH probe suitable to be implanted in tissue for physiological studies is disclosed. The probe includes an ion permeable membrane envelope which encloses the ends of a pair of optical fibers. A pH sensitive dye indicator composition is present within the envelope. The probe operates on the concept of optically detecting the change in color of a pH sensitive dye.