Abstract: The invention features an apparatus and method for determining and controlling the concentration of a solute in a solute stream by measuring the concentration of an indicator agent.

Abstract: The fat content and and undissolved solids content of a milk sample, taken from a milk processing flow, are separately determined. In addition, the total solids content of the milk flow is determnined. Based on the fat, undissolved solids, and total solids content, the amount of protein and/or casein in the flow is determined. In a control portion of the invention, the fat and undissolved solids are controlled dynamically to standard values, whereby the characteristics of the milk flow are adjusted to standard values useable for whole milk, cheese-making and other uses.

Abstract: A concentrate sense window which defines a variable thickness flow path area is provided for sensing the concentration levels of inks having varying levels of luminance. Sensor window panels are configured in relationship to each other such that an area defined therebetween varies from a first area to a second area. An emitter/detector pair are located on opposite sides of the sensor window. The emitter transmits a signal through the sensor area and at least part of the signal is sensed by the detector. The emitter/detector pair are designed so as to be movable along the surface of the sensor window whereby ink of varying illuminance may be sensed without the need of separate windows or multiple emitter/detector pairs.

Abstract: Disclosed are photometric methods and devices for determining optical pathlength of liquid samples containing analytes dissolved or suspended in a solvent. The methods and devices rely on determining a relationship between the light absorption properties of the solvent and the optical pathlength of liquid samples containing the solvent. This relationship is used to establish the optical pathlength for samples containing an unknown concentration of analyte but having similar solvent composition. Further disclosed are methods and devices for determining the concentration of analyte in such samples where both the optical pathlength and the concentration of analyte are unknown. The methods and devices rely on separately determining, at different wavelengths of light, light absorption by the solvent and light absorption by the analyte. Light absorption by the analyte, together with the optical pathlength so determined, is used to calculate the concentration of the analyte.

Abstract: A reaction vessel for holding a sample for a heat-exchanging chemical process has two opposing major faces and a plurality of contiguous minor faces joining the major faces to each other. The major and minor faces form an enclosed chamber having a triangular-shaped bottom portion. The ratio of the thermal conductance of the major faces to that of the minor faces is at least 2:1, and the minor faces forming the triangular-shaped bottom portion of the chamber are optically transmissive. The vessel also has a port for introducing a sample into the chamber and a cap for sealing the chamber.

Abstract: A contamination sensor is provided for use in a fluid system and machinery to continuously monitor the level of contaminants in a fluid. The contamination sensor includes a source of light that is directed into the fluid stream with three photodetector arrangements detecting light scattered by contaminants contained in the fluid. The first photodetector arrangement is located near the origin of the source of light. The second photodetector arrangement is located farther away from the source of light. The third photodetector arrangement is located perpendicular to the axis of the light beam and spaced from the source of light along the axis of the light beam. The simultaneous detected scattered light from a contaminant in the fluid is converted to electrical signals by the photodetectors, conditioned by a signal conditioning circuit and transferred to a signal processing unit for interpretation.

Abstract: A computer interfaced device for rapidly quantifying levels of toxicity to small aquatic organisms in aqueous environments. The device has a plurality of test chambers containing replicates of a plurality of concentrations of a substance or sample being tested for toxicity. Each chamber also contains a predetermined number of motile aquatic organisms. Light originating on one side of each test chamber is received by a photo-detector on the opposite side. The device's sensitivity is adjusted so that each interruption of a light beam caused by movement of a test organism in each test chamber is recorded for that chamber. Using this device and a toxicity testing protocol both lethality and changes in the frequency of test organism's movement in each concentration of substance or sample is monitored. Toxicity is by convention quantified as the concentration of a substance or sample which causes a predetermined level of lethal or sublethal response usually after a plurality of days.

Abstract: On-board ILS ethyl alcohol sensors based on intracavity laser spectroscopy (ILS) are provided for detecting the presence of ethyl alcohol vapors in a vehicle. The sensor comprises: (a) a laser comprising a gain medium having two opposed facets within a laser resonator and functioning as an intracavity spectroscopic device having a first end and a second end, the first end operatively associated with a partially reflecting (i.e., partially transmitting) surface; (b) a reflective or dispersive optical element (e.g.

Abstract: A disposable first tube (68) extends axially through, and is detachably connected to, an annular main body (10'). An input piezo electric element (38) is attached to a first end of the tubular main body (10'). A second, sensor piezo electric element (40) is attached to the opposite end of the main body (10'). A nozzle (20') having a nozzle passageway (110) and a discharge opening (112) is detachably secured to an outlet end of the first tube (68). A second tube (102) within the first tube (68) delivers a core liquid to the nozzle passageway (110). A sheath liquid is delivered through a space in the first tube (68) surrounding the second tube (102). The nozzle passageway (110) forms the core and sheath liquids into a small diameter jet stream. Electrical energy is delivered to the input piezo electric element (38), to vibrate the nozzle (20') and break the jet stream into droplets.

Abstract: A relative angle detecting system permitting a wider range of detectable angles and offering a small detection error by using polarization and a virtual reality providing system using the same are disclosed. The relative angle detecting system includes a light source having a given polarizing direction and a light reception unit in which a plurality of polarization filters having different polarizing directions other than 90 degree and a plurality of light-receiving devices for receiving light passing through the filters are incorporated, and a relative angle is calculated on the basis of a combination of strengths of output signals of the plurality of light-receiving devices.

Abstract: In order to provide in a simple way a household appliance, operated with water with a sensor (10) for contaminations of a circulated cleaning fluid, said sensor being composed of an element (11) transmitting optical signals and of an element (12) receiving optical signals, in which appliance erroneous measurements of the sensor (10) for contaminations of a circulated cleaning fluid are avoided, according to the invention the sensor (10) is arranged in a flow heater (1).

Abstract: For simplifying the optical measurement of a particle flow in a fluid and in particular for eliminating errors, in a device for measuring a particle flow in a fluid with at least one illumination system having a diaphragm and at least one receiver system having a diaphragm, the invention provides for a diaphragm (6a, 11a) to have an aperture (6, 11) with an edge (6b, 11b) constructed convexly towards the interior of the diaphragm aperture (6, 11). According to a method, the particle flow is illuminated and/or observed through a diaphragm aperture with an edge constructed convexly towards its interior and the maximum intensity of the particle flying through a first optical measuring range is measured and account is only taken of the particle if the intensity on flowing through a second measuring range exceeds a specific minimum percentage of the maximum intensity measured for this particle.

Abstract: Concentration detection of first and second toner particles in a dispersion, including illuminating the dispersion with linearly polarized light having a given polarization direction, detecting an amount of light passed through the dispersion and through an analyzer set at a predetermined angle to the given polarization direction and determining at least the concentration of one of the toner particles utilizing the detected amount of light. Additionally the concentration detection may include further illuminating the dispersion with unpolarized light, and further detecting a second amount of light passed through the dispersion illuminated with the unpolarized light, where both of the toner particle concentrations are determined from the detected and the second detected amounts of light.

Abstract: The present invention discloses a method for rapid antimicrobial susceptibility testing to screen antibiotics in a few hours instead of days by conventional methods. This method can also be used to identify susceptible antibiotics to treat mycobacterial infection in a few days instead of the usual six to eight weeks. Fast screening of antibiotics is achieved by a short period of specimen incubation in different antibiotics embedded media to create differential bacterial counts. The differences of bacterial counts among antibiotics embedded media are subsequently amplified by DNA amplification methods for detection. Following DNA amplification, rapid quantitation and minimum inhibition concentration (MIC) determinations for a panel of antibiotics are achieved in less than one minute by fluorescence quantitation methods.

Abstract: An imaging glass window and an illumination glass window which are opposed to each other define a sample chamber, and the sample chamber holds sample liquid containing particulates. Light from the particulates is magnified by a zoom magnifying glass via the imaging glass window, optical axis angle changing means and optical axis length changing means and imaged by a CCD camera. An image of the sample liquid is supplied to image control means, and the optical axis angle changing means is operated by the image control means to change an optical axis of the light from the sample liquid and shift an image of an intended one of the particulates in the sample liquid to the center a camera lens of the cameraeen. Concurrently the zoom magnifying glass is set at a required magnification by the control means.

Abstract: A transmissometer for measuring a volume attenuation coefficient of a column of water, including a transmissometer housing; a light source, producing an optical light beam; a Y-splitter, splitting the optical light beam into two light beams within the transmissometer housing; a pressure proof connector and two optical fibers, routing the two light beams outside the transmissometer housing; two collimators for collimating outputs of the two optical fibers prior to transmission through the column of water; a reflecting prism, reflecting the outputs of the two collimators back into the transmissometer housing via a sensor view port where a distance between a first of the two collimators and the reflecting prism is R1 and a distance between a second of the two collimators and the reflecting prism is R2; two detectors for detecting intensities I1 and I2 of the two light beams reflected by the reflecting prism; and a processor for determining the volume attenuation coefficient of the column of water according to:.

Abstract: A device (10) and method for monitoring particulate (22) flowing through a conduit (20) has a transmitter (16) and a receiver (18) positioned in optical alignment on opposite sides of the conduit (20). A light beam (50) is transmitted across conduit (20) from the transmitter (16) to the receiver (18). Particulate (22) flowing through conduit (20) interrupts light beam (50) causing a signal to be generated from which particulate concentration is determined. A calibrator assembly (40) has a motor (64) adapted to move a filter (100) having a selected percentage opacity within the path of light beam (50). Movement of the filter (100) modulates light beam (50) and a signal corresponding to the concentration associated with the percentage opacity is generated.

Abstract: A method is provided to test turbidity sensors using a solid block that is particularly formulated to have a predetermined turbidity value. The solid block, which is partially transparent, is made by mixing calcium carbonate with a clear acrylic. A plurality of sample sensors are selected to be used as an intermediate standard to correlate the results achieved when the block is tested to results that would be achieved if liquid turbidity samples are tested. The six sample sensors are used to measure the turbidity of a plurality of liquid samples. The six sample sensors are then used to test the solid block in order to make sure that the turbidity represented by the solid block is within an acceptable range that is normally dictated by either a national standard or a particular customer requirement. Each of the plurality of sample sensors is used to test the solid block a plurality of times to form an average ratio value that can be used as a first representative magnitude for each of the sample sensors.

Abstract: A non-contact optical backscatter insertion probe includes an outer chamber, an electromagnetic energy source positioned within the outer chamber for emitting photons towards a medium to be analyzed, and an inner chamber positioned within the outer chamber. The inner chamber has a reflective outer surface to prevent photons emitted by the electromagnetic energy source in the outer chamber from entering the inner chamber. The probe also includes a sensor positioned within the inner chamber for receiving backscattered photons from the medium. The inner chamber provides the backscattered photons emitted from the medium to the sensor. A processor receives and processes signals output by the sensor.

Abstract: A method is provided to characterize the nature of a washing fluid by measuring the turbidity and conductivity changes during preselected periods, such as rinse sequences. More specifically, the plateau magnitudes, and variability magnitudes, are measured during each of the rinse sequences of a washing procedure and used as input parameters to a fuzzy logic engine. Calculations are performed in order to characterize the fluid as a function of the input parameters. The characterization of the washing fluid is done in terms of the solubles and suspendeds in the fluid and the cycle state of the fluid. The solubles represent chemical elements in solution within the washing fluid and the suspendeds are particulate matters suspended in the fluid. The cycle state represents the aggregation of the solubles and suspendeds in the fluid.

Abstract: An optical illuminator assembly for an analytical instrument, such as a clinical hematology or a flow cytometer instrument, including a laser diode having a diverging laser beam output, a collimating lens to collimate the diverging laser beam, a spatial filter operating on the collimated laser beam to spatially filter the beam, and a focussing lens to focus the spatially filtered beam into a flow cell containing particles suspended in a moving stream. A beam shaping aperture is preferably inserted between the spatial filter and the focussing lens to shape the laser beam. The spatial filter preferably includes an objective lens, a collimating lens, and a filter aperture interposed between the objective and imaging lenses. The filter aperture is preferably rectangular, having a height to width ratio in the range of 1:2 to 1:3 such that each dimension is on the order of tens of micrometers.

Abstract: Calibration curve data is collected by measuring transmitted light intensities of a treating solvent while solvent temperature is varied. Also measured are a standard transmitted light intensity (transmitted light intensity of a standard treating solution prepared at a predetermined concentration and temperature) and a reference transmitted light intensity (transmitted light intensity of the solvent). Estimated transmitted light intensity of the solvent when its temperature is the same as that of the standard treating solution, is derived from the temperature of the standard treating solution and the calibration curve data stored. A correction factor is computed from a ratio between the reference transmitted light intensity and estimated transmitted light intensity. Then, transmittance of the standard treating solution (standard transmittance) is computed from the standard transmitted light intensity, reference transmitted light intensity and a correction factor.

Abstract: The granulometer uses a measuring laser beam (9) to illuminate particulate and, through the measure of the distribution of the light diffused by the examined particulate and gathered by a collecting lens (11), measures the concentration of particulate in the fluid in low concentration standards, the laser beam (9) being a converging one focused on a laser opaque shell (12) that partly covers the same lens.

Abstract: A computer-controlled fluid manipulation and analysis apparatus for chemical, biochemical and clinical analysis, sample preparation, and microscale chemical and biochemical synthesis, having one or more stream selection hubs with multiple ports through which microliter volumes of multiple fluid streams may be accessed, stacked, mixed and otherwise transferred by two or more cooperant pumping systems in a highly repeatable and fully software programmable manner. The inherent or resulting properties of said fluids may be automatically recorded via one or more appropriate electronic detectors and data recording systems. Systems comprised of two or more hubs exhibit higher properties of a flow network, and allow more than one fluid segment to be processed simultaneously. Bi-directional flow may occur in each inter-hub connection, and a plurality of possible transport routes can exist between hubs. This leads to enhanced flexibility in sequential processing of each fluid segment.

Abstract: A device and method is provided for determining the degradation of oil after use of the same in an engine or the like. A test sample material is placed in a transparent container and various intensities of light are passed therethrough. A photovoltaic sensor senses the light polarized by the transparent container and the test sample and generates a first set of signals responsive thereto. The methodology is repeated with a sample of used automotive engine oil. The first and second set of signals are compared, and oil degradation is determined therefrom. Where the sensor detects and generates a signal only when the light intensity is equal to or less than the saturation intensity of the sensor, that is from the instant the light is first detected up until saturation of the sensor.

Abstract: In a method and an apparatus for determining a content of an aliphatic hydrocarbon insoluble matter in a residual fuel oil, the method includes the steps of: (a) measuring absorbances of a sample solution having an aliphatic hydrocarbon insoluble matter suspended in the sample solution at two spaced wavelengths of light in a wavelength range from 500 nm to 1,000 nm; and (b) performing an operation to determine the content of the aliphatic hydrocarbon insoluble matter in the sample solution by inserting the measured absorbances into the specific correlations. The contents of the insoluble matter in aliphatic hydrocarbons and asphaltene in the residual fuel oil can be determined in a precise and rapid manner even if the oil contains the particles of aromatic hydrocarbons such as toluene.

Abstract: A method and apparatus are provided that indicate the amount of gas such as air in a clear liquid such as water. The apparatus includes a transparent pipe (60), an input coupling (16) at a first end of the transparent pipe, and a shutoff valve (20) at the second end of the pipe. The first end of the pipe is connected to a source of water (12) under pressure, whose air content is to be determined. With the valve (20) open, water is allowed to pass through the pipe and valve to purge the pipe of air and any previous water. The shutoff valve is then closed, to contain the water under pressure. The dissolved air in the static, pressurized water, immediately forms microscopic air bubbles, which result in the water having a "milky" appearance. The presence of the milky appearance indicates the presence of a considerable amount of dissolved water (when the water is not under high pressure). The reflectivity of the water indicates the amount of dissolved air per unit volume of water (when not under high pressure).

Abstract: A turbidity sensor is provided with two light sensitive components or elements. One light sensitive component is displaced from a light source, such as a light emitting diode, so that a fluid can pass therebetween. A second light sensitive component is disposed within a common compartment with the light source so that it can measure the intensity of light provided by the light source. The light source and the second light sensitive components can be individual elements, or chips, within a common component package. A regulator is provided to control the magnitude of current provided to the light source so that its light intensity can be regulated. In this manner, the intensity of light emitted by the light source, such as a light emitting diode, can be controlled regardless of the aging of the LED, the variability of LED characteristics and the temperature surrounding the LED.

Abstract: A turbidity sensing mechanism for a dishwasher is connected in the fluid circulation conduit between the pump and the spray mechanism. The mechanism includes a hollow housing enclosing a hollow transparent tube connected in fluid flow relationship with the conduit. A source of electromagnetic radiation and a radiation-to-frequency sensor are positioned inside the housing on opposite sides of the tube.

Abstract: An improved method of monitoring condensate quality in a condensate return system and of controlling the level of particulate matter in the condensate flow so that when this level exceeds an acceptable limit, valves for discharging the condensate flow from the system open automatically or, alternately, an alarm is sounded. Utilization of the method facilitates the conservation of hot steam condensate for reuse in a boiler while preventing water contaminated with particulate matter from returning to the boiler, thereby protecting it from certain types of deposits and corrosion. The improved method includes measuring, on a continuous basis, relative numbers of particulate-type impurities under conditions in which rust or other particles large enough to block flow into a particle counter can be produced in sudden surges. Tests show that a suitable instrument for measuring the impurities under such conditions is a particle monitor.

Abstract: An apparatus and process for accurately determining settling data for the settling of erythrocyte cells from a plasma fluid in a test specimen of blood. The apparatus includes a settling tube, a sensing assembly movably mounted proximate the settling tube. Preferably an infrared emitter and detector are provided in the sensing assembly, and a control assembly is provided which senses data at a high rate and is responsive to the sensed data to sample or store the time at which sensed reflectivity exceeds a threshold level. When the threshold is reached, data is sampled and the tracking head is moved by a very small step. This process is repeated to enable tracking of the descent of the separation boundary between the erythrocyte cells and plasma fluid. The apparatus senses changes in reflectivity of the erythrocyte portion of the specimen below and up to the separation boundary.

Abstract: An arrangement for the measurement of the height of a layer of a first liquid floating on a second liquid which comprises projection means for projecting a beam of optical radiation along an inspection path which is horizontal when the arrangement is in use, detector means for detecting radiation of the said beam after transmission along the inspection path, means for providing relative displacement in a direction which is vertical when the arrangement is in use between the said layer and the said inspection path whereby the said layer traverses the inspection path, the detector means being capable of observing the upper and lower surfaces of the said layer by detecting changes in an optical transmission property of the said beam occurring at the said surfaces and means for measuring the said relative displacement between the locations of the observed upper and lower surfaces.

Abstract: Apparatus for detecting concentrations of colored toner particles in the presence of black or other absorbing toner particles including a light source, a light detector having a field of view of less than about .+-.10 degrees and preferably less than .+-.5 degrees, apparatus for supplying a dispersion of colored toner particles optionally containing undesirable contamination by black toner particles between the light source and the detector and computing circuitry operative for determining the concentration of the colored toner particles utilizing output from the light detector.

Abstract: A system for sensing motion of an object in an underwater environment is vided. The system has a circuit board, a light-emitting diode, an infrared filter, an integrated circuit, and an acrylic transparent housing. The light-emitting diode and the integrated circuit are mounted on the circuit board. The integrated circuit has a photoelectric transducer and a low-noise amplifier. The housing surrounds and seals the diode, the filter, the integrated circuit, and the board from exposure to the underwater environment. The housing also provides a convex lens on one end which corresponds with the direction in which the diode emits infrared radiation. The convex lens spreads the radiation emitted from the diode. The emitted radiation approaches and reflects back from the moving object. The convex lens also spreads this reflected radiation. The infrared filter screens unwanted radiation. The photoelectric transducer converts the filtered radiation into an electrical signal which the low-noise amplifier amplifies.

Abstract: An apparatus for analyzing particles collected from a fluid and deposited on a substrate along a given direction, the apparatus including holding structure for supporting the substrate; a radiation source for directing radiation toward the particles on the substrate; and a radiation detector for receiving radiation incident upon the particles on the substrate and for providing an output based on the concentration of the particles, the radiation detector being cooperative with the radiation source to output substantially continuous profile data indicative of the concentration of said particles along the given direction.

Abstract: An apparatus and process for accurately determining settling data for the settling of erythrocyte cells from a plasma fluid in a test specimen of blood. The apparatus includes a settling tube, a sensing assembly movably mounted proximate the settling tube. Preferably an infrared emitter and detector are provided in the sensing assembly, and a control assembly is provided which senses data at a high rate and is responsive to the sensed data to sample or store the time at which sensed reflectivity exceeds a threshold level. When the threshold is reached, data is sampled and the tracking head is moved by a very small step. This process is repeated to enable tracking of the descent of the separation boundary between the erythrocyte cells and plasma fluid. The apparatus senses changes in reflectivity of the erythrocyte portion of the specimen below and up to the separation boundary.

Abstract: An automatic calibration system is disclosed for an apparatus that measures the presence of s selected component in a test liquid sample. The system includes a transparent test liquid holder having an inlet and outlet for conducting a test liquid into and out of the holder. There is a transparent calibration element immersed in a test liquid in the holder and including a first sealed compartment that contains a full scale calibration standard and a second sealed compartment that contains a zero calibration standard. A pulsed flow of the test liquid is directed through the holder from the inlet to the outlet to reciprocate the calibration element within the holder. A light source is directed at the holder for establishing an incident beam of light that sequentially strikes the full scale standard, the zero standard, and a test liquid sample as the calibration element reciprocates through the holder.

Abstract: A concentration measurement apparatus capable of accurately measuring the concentration of suspended matter in a liquid is provided.A transmitter 1 which transmits sound waves, light waves, or the like, and a receiver 2, which is disposed in opposition to this transmitter 1, are provided, small pipes 3 and 4, which enclose the transmitting surface position of the transmitter and the receiving surface position of the receiver, and which are opened in the direction of transmission and the direction of reception, respectively, are provided, and a mechanism for filling these small pipes with a clean liquid or gas is provided.The transmitting surface of the transmitter and the receiving surface of the receiver are not contaminated by means of the deposition or generation of suspended matter, so that it is possible to conduct the accurate measurement of the concentration in a constant manner.

Abstract: In a stained particle analyzing method and apparatus for staining a test sample containing suspended particles, shooting an image of the stained sample, and classifying the particles and computing the density from the shot image of the sample, the sample, which may not be analyzed precisely, is detected before the start of an image analyzing process. Only the sample, which will be analyzed precisely, is stained and subjected to the image analysis. Color information of the sample before the staining is detected and stored. Color information of an image of the sample shot after the staining is compensated based on the color information of the sample detected before the staining. The sort and density of the particles are classified and computed on the basis of the image after the color compensation.

Abstract: Apparatus for monitoring fluid contaminant level that includes a light source positioned on one side of a fluid sample path for directing light energy into fluid flowing in the sample path, a photosensor positioned on the same side of the sample path, and a reflector positioned on an opposing side of the sample path for receiving light from the source transmitted through the sample fluid and reflecting such light back through the fluid to the photosensor. The photosensor provides an electrical signal as a function of intensity of light incident thereon from the light source after having twice passed through the fluid, and the concentration or level of contaminants in the fluid is indicated as a function of such electrical signal. Thus, the concentration of contaminants that extinguish light energy transmitted through the fluid is indicated as an inverse function of light intensity at the photosensor, and may be compared to a preset target threshold level for indicating an undesirably high contamination level.

Abstract: A method for across-wafer critical dimension uniformity performance monitoring in the manufacture of semiconductor devices employs a number of optical endpoint detectors at sites at the wafer face which are spaced across the wafer face. Each optical endpoint detector is able to directly measure the end point of the process step at its site. One of these optical endpoint detectors is used to control the process, and when the endpoint has been reached for this site the process completion time is predicted and this completion time is used to control the processing equipment. For example, if the process step being monitored is the development of photoresist, then the developing operation is ended based upon this calculated completion time derived from the detected endpoint for the control site. The other sites are used to monitor across-wafer performance.

Abstract: A determination of optimal energy insertion, or input, results from a measurement of opacity at various heights in a fluid coagulating system and at the same time from measuring a deviation width of the opacity at a lower measuring point. Simultaneously, a continuous comparison takes place of the opacity measured at the various measuring points, which changes with time, and a comparison of the deviation width of opacity. The optimal energy insertion in the fluid coagulating system is achieved if, at each point in time, the opacity at all measuring points is maintained approximately the same and the deviation width of the opacity is maintained at or near a maximum.

Abstract: Optical measurements of turbid media, that is media characterized by multiple light scattering, is provided through an apparatus and method for exposing a sample to a modulated laser beam. The light beam is modulated at a fundamental frequency and at a plurality of integer harmonics thereof. Modulated light is returned from the sample and preferentially detected at cross frequencies at frequencies slightly higher than the fundamental frequency and at integer harmonics of the same. The received radiance at the beat or cross frequencies is compared against a reference signal to provide a measure of the phase lag of the radiance and modulation ratio relative to a reference beam. The phase and modulation amplitude are then provided as a frequency spectrum by an array processor to which a computer applies a complete curve fit in the case of highly scattering samples or a linear curve fit below a predetermined frequency in the case of highly absorptive samples.

Abstract: A probe for liquid sample analysis is disclosed which causes radiation to pass through the sample at a gap formed in the probe housing. A single radiation transmission is used to avoid problems of radiation back scatter and sample reliability. Windows are provided on opposite sand and and and and and and ides of the gap to accommodate the shape of the beam in the gap, which may either be collimated, or focused in the gap. A retroreflector may be used to reverse the radiation direction in the probe. The light to and from the probe is preferably transmitted by optical fiber cables. Within the probe, light guides other than optical fibers may be used.

Abstract: In a method for measuring solid concentrations in liquids, the light from two differently modulated sources (Q1, Q2) directed on the liquid is measured at the same time and processed in a combined multi-beam measuring process consisting of a 90.degree. light scatter (Q1, P, D4; Q2, P, D3) and back-scatter process (Q1, P1, D1; Q2, P3, D2) and the solid concentration is found therefrom. The process is suitable for the simultaneous measurement of both extremely low and extremely high solid concentrations by using a 90.degree. light scatter process for low concentrations and a back scatter process for high concentrations. The multi-beam process which is based on two measurements through exactly the same window areas makes it possible effectively to compensate for undesired soiling of the window areas. Mechanical devices for cleaning the window areas and to eliminate interfering light scatter are proposed.

Abstract: The invention provides a method capable of determining the presence or absence of each of a plurality of different ligands in a specimen. The specimen is contacted with a predetermined number of different homogeneous populations of fluorescence beads having one or more predetermined antiligands affixed to their surface. The specimen and bead mixture is analyzed using a means having a single parameter for measuring the fluorescence per ligand to determine the number of nonagglutinated beads, the number of agglutinated beads, the number of bead aggregates, and for each aggregate, the number of beads it comprises. This information is used to correlate the presence or absence in the specimen of each of the different ligands analyzed for. The method of the invention thus provides for the simultaneous determination of a predetermined number of ligands in a specimen using only a single bead contacting step.

Abstract: A system for detecting the presence of bacterial growth in a plurality of sample vials incorporates a single test station moveable along each of the plurality of sample vials. In one embodiment, the sensor station is movably mounted on a rod, and that rod is movably mounted on a pair of spaced rods. The rod which carries the test station may move along the spaced rods to change the location of the test station in a first dimension and the test station is moveable along its rod to change location in a second dimension. In this way, the test station may be moved through two dimensions to move serially to the location of each of the plurality of sample vials. In another aspect of this invention, a bar code is associated with each of the sample vials, and the test station makes a reading of that bar code concurrent with a determination being made as to whether there is any bacterial growth in the sample vial.

Abstract: A flow cytometer includes a plurality of detectors for providing voltage pulse signals over a four decade range as particles pass through an illuminated detection station. Each voltage pulse signal is processed and provided to a first sample and hold for storage. Thereafter, the value in the first sample and hold is amplified by one or thirty-two, depending upon its magnitude, and stored in a second sample and hold for subsequent provision to a sixteen bit analog to digital convertor (ADC), one signal at a time. The first sample and hold is then free to store a new value while the old value is awaiting provision to the ADC. The ADC converts the signal received from the second sample and hold to a fifteen bit digital signal and uses the sixteenth bit to manifest whether the signal stored in the second sample and hold was amplified by thirty-two.

Abstract: In a method and apparatus for examining samples comprising individual objects (28) of macromolecular or similar size, or smaller, an instrument element (14) comprises a substrate (16) overlaid with a thin film layer (18) of a material that is electrically conductive and/or at last partly optically opaque. A discontinuity comprising an aperture (26) or an asperity is formed in or on the element (14) in a known location, and the sample (28) is brought to this discontinuity so that it is not necessary to search for the sample by scanning. Energy (e.g. electrical energy or light) is applied to the element (14) and, with the latter and the sample in intimate association, e.g. with the sample inside the aperture (26), changes in the radiation from the sample site resulting from the presence of the sample are detected.

Abstract: A low cost optical sensor using ordinary non-coherent light reads the polymer content of a processed polymer solution and gives a go/no-go signal in response thereto. The system shuts down in response to the no-go signal. There are no moving parts to pick up or be fouled by polymer.