Abstract: A method for detecting of components in a fluid includes emitting a modulated light beam from a modulated light source to the fluid in a chamber, wherein the fluid comprises a liquid and a component in the liquid. The method includes producing an acoustic signal in response to the emitted modulated light beam and detecting the acoustic signal via a pressure sensor disposed in the chamber. The method in one example also includes transmitting the acoustic signal from the pressure sensor to a processor based module and determining at least one of a component and a concentration of the component in the fluid via the processor based module, based on the acoustic signal.

Abstract: A gas cell assembly and applications of the gas cell assembly in absorption spectroscopy. An example gas cell assembly includes a gas cell body with an inlet for receiving a gas sample from a gas source; a first and a second end portions that allow optical transmission into and out of the body, the second end portion being substantially opposite from the first end portion; and a channel providing a path for the gas sample and optical beam(s) between the first end portion and the second end portion. The gas cell assembly also includes reflective surfaces outside the body to receive versions of the optical beams from the body and to reflect each version of the incident beam towards the body. A detector, then, receives a last reflected beam and transmits a corresponding data signal to a processing unit for analyzing the gas sample based on the data signal.

Abstract: A closed path infrared sensor includes an enclosure, a first energy source within the enclosure, at least a second energy source within the enclosure, at least one detector system within the enclosure and a mirror system external to the enclosure and spaced from the enclosure. The mirror system reflects energy from the first energy source to the at least one detector system via a first analytical path and reflects energy from the second energy source to the at least one detector system via a second analytical path. Each of the first analytical path and the second analytical path are less than two feet in length.

Abstract: A system for providing water to the roots of a plant being grown in an aeroponic growth system includes small reservoirs containing water and a mist generator, wherein the mist generator provides mist under low pressure to a channel which directs the mist to the roots of the plant.

Abstract: An infrared detection device can be used to detect coal mine polar gas. The detection device can include a central processor and a gas pool assembly having a moveable optical window. The moveable optical window can include a stationary pool body and a moveable pool body inserted into the stationary pool body.

Abstract: An optical gas sensing apparatus includes an explosion-rated device electronics enclosure. An explosion-rated sensing enclosure has a light transmitting element to allow light to pass out of and into the sensing enclosure. The sensing enclosure is operably coupled to the explosion-rated device electronics enclosure by a feed-through. In one aspect, an internal volume of the sensing enclosure is less than or equal to about one fiftieth of the volume of the explosion-rated device electronics enclosure. In another aspect, the thickness of the light transmitting element is less than or equal to about 3 millimeters. A light source is disposed within the sensing enclosure and is operably coupled to the device electronics. A detector is disposed within the sensing enclosure and is also operably coupled to the device electronics.

Abstract: The invention is directed to methods of detecting lung, gastrointestinal tract, and systemic infections by measuring 13CO2/12CO2 isotopic ratios of gaseous carbon dioxide in exhaled breath samples of a subject after administration of a 13C-isotopically-labeled compound.

Abstract: A system and method for improving supply chain visibility is provided. According to a preferred embodiment, an electronic manifest may be downloaded and linked or attached to an existing purchase order. This electronic manifest is preferably designed to accepted data from RFID devices and other sensors. Further, the electronic manifest is preferably configured to be easily accessed the carriers or others in the chain of custody. According to a further aspect of the present invention, sensor-enabled RFID tags may be employed to track a product through the supply chain, capture temperature data, and to calculate shelf life.

Abstract: A device comprising measurement (7) and reference (3) interferometers is disclosed. Each interferometer is configured to receive light from the same light source (1) and to emit light to respective detectors (6) and has a respective operating point. The measurement interferometer (7) is configured to respond to variations in a physical parameter by varying the intensity of light emitted, whereas the reference interferometer (3) is configured to be unresponsive to variations in the physical parameter. The device further comprises a signal processor for generating a differential output signal depending on respective output signals generated by the detectors (6).

Abstract: The calibration/verification system and method for gas imaging infrared cameras standardizes the procedures to objectively and consistently check performance of gas imaging infrared cameras. This system includes a background board maintaining a uniform temperature, a target cell filled with a target compound and disposed in front of the background board, a reference cell filled with a reference compound and disposed in front of the background board, and an analyzer coupled to the camera that captures images of the gas cell and the reference cell. The analyzer compares the intensity difference and the temperature difference of rays passing through the target cell and reference cell to a reference relationship data of a quality control chart to determine whether the camera is in a working condition. The method is further extended to provide a quantitative measurement of a hydrocarbon plume from a gas imaging infrared camera.

Abstract: An infrared sensor for temperature sensing comprises a cap covering a substrate; an IR-radiation filtering window in the cap transparent to IR radiation; a first sensing element comprising a set of N thermocouples on the substrate covered by the cap, whose hot junctions may receive radiation; a second sensing element comprising a set of N thermocouples on the substrate covered by the cap whose hot junctions may not receive radiation; first connection modules for connecting a number N1 of thermocouples of the first sensing element, second connection modules for connecting a number N2 of thermocouples of the second sensing; connecting means for connecting an output of the first connection modules of the first sensing element with an output of the second connection modules of the second sensing element, and an output of the combined outputs of the sensing elements.

Abstract: In one embodiment, an apparent equilibrium constant involving a clumped isotope in a gaseous sample is measured by acquiring sample spectra of portions of the gaseous sample at different pressures. An external bulb coupled to a sample cell is filled with the gaseous sample. A first portion of the gaseous sample is transferred from the external bulb to the sample cell, where it is at a first pressure. A first sample spectrum is obtained. Then, a second portion of the gaseous sample is transferred from the external bulb to the sample cell, where it is at a second, different pressure. A second sample spectrum is obtained. An apparent equilibrium constant for the clumped isotope is calculated by determining a first isotopic ratio at the first pressure, determining a second isotopic ratio at the second pressure, and taking a product of the first isotopic ratio and the second isotopic ratio.

Abstract: An infrared sensor for temperature sensing comprises a cap covering a substrate; an IR-radiation filtering window in the cap transparent to IR radiation; a first sensing element comprising a set of N thermocouples on the substrate covered by the cap, whose hot junctions may receive radiation; a second sensing element comprising a set of N thermocouples on the substrate covered by the cap whose hot junctions may not receive radiation; first connection modules for connecting a number N1 of thermocouples of the first sensing element, second connection modules for connecting a number N2 of thermocouples of the second sensing; connecting means for connecting an output of the first connection modules of the first sensing element with an output of the second connection modules of the second sensing element, and an output of the combined outputs of the sensing elements.

Abstract: A holographic detection device for a content of a gas in a GIS switch includes a laser and a data process system. The laser includes a laser emitter and a laser receiver which are fixed at a sampling port of the GIS switch and connected with the data process system. A holographic detection method for a content of a gas in a GIS switch includes emitting a laser beam towards the inside of the GIS switch; receiving the laser beam from the inside of the GIS switch, and calculating a content of hydrogen fluoride gas inside the GIS switch according to an intensity of the emitted laser beam and an intensity of the received laser beam. Since the laser beam goes through the inside of the GIS switch, there is a small error in the detection result, which thus can reflect a real state inside the GIS switch.

Abstract: A device for optical detection of a target gas in gas mixtures includes an operation and evaluation unit, a measurement cuvette with optically reflective surfaces on its interior walls and a gas inlet to the environment, a radiation source, a measuring detector and a reference detector unit provided on the measurement cuvette. The measuring detector and the reference detector unit detect the light of the radiation source and produce electrical signals corresponding to the intensity of the detected light. An optical bandpass filter element, constructed to transmit light of a measurement wavelength, is arranged upstream of the measuring detector. An optical double-bandpass filter unit, that transmits light of a first reference wavelength and light of a second reference wavelength, is arranged upstream of the reference detector unit. The operation and evaluation unit operates the radiation source and acquires the electrical signals of the measurement detector and the reference detector unit.

Abstract: A method of determining a concentration of a gas in a sample and/or the composition of a gas using a spectrometer comprises transmitting of radiation whose wavelength substantially continuously runs through a wavelength range, wherein the continuous running through of the wavelength range is overlaid by a wavelength modulation; measuring of an absorption signal as a function of the wavelength of the radiation; converting of the absorption signal into first and second derivative signals; deriving of a first and a second measured gas concentration value from the first and the second derivative signals, respectively; and determining of the concentration and/or the composition of the gas from at least the first measured gas concentration value, wherein the wavelength modulation is adapted in response to a change of a state variable of the gas such that a ratio between the first and the second measured gas concentration values is kept substantially constant.

Abstract: A tunable laser source that includes multiple gain elements and uses a spatial light modulator in an external cavity to produce spectrally tunable output is claimed. Several designs of the external cavity are described, targeting different performance characteristics and different manufacturing costs for the device. Compared to existing devices, the tunable laser source produces high output power, wide tuning range, fast tuning rate, and high spectral resolution.

Abstract: The present application provides a non-dispersive infrared gas sensor. The non-dispersive infrared gas sensor may include an infrared source, an infrared detector, and a waveguide extending about the infrared source and the infrared detector. The waveguide may include a reflective diffuser thereon.

Abstract: A device for identifying refrigerants includes a gas cell, which has a test gas inlet and a test gas outlet, an infrared source that radiates through the gas cell, and at least one sensor that detects the infrared radiation that passes through the gas cell. At least one wide-band filter is provided between the infrared source and the sensor. The passband of the at least one wide-band filter includes the absorption spectra of the refrigerants to be detected and does not include the absorption spectrum of hydrocarbons. The gas cell is connected to a cartridge, which contains the refrigerant to be detected in pure form as a reference gas.

Abstract: A probe assembly for measuring the concentration of exhaust's emissions in a turbine engine. The probe assembly including a first probe member configured and operable to passively generate a beam of light wherein the wavelength of the beam of light is contingent upon the configuration of the first probe member. A second probe member positioned in the probe assembly to receive the beam of light generated by the first probe member, the second probe member configured and operable to attenuate the light passively generated from the first probe member contingent upon the gaseous species present in the exhaust emissions of the turbine engine.

Abstract: A portable breath analyzing device to measure the rate of partial gas that is exhaled in the breath fluid. The device includes a rechargeable power supply unit, a device to emit pulsated infrared radiation, an infrared receiver, and a measuring vessel. The emission device includes a heating element; the measuring vessel includes a metallic tube whose interior surface is polished and coated with a deposit that reflects at least the infrared radiation of wavelengths that are between (9 ?m, 10 ?m) and at each end of the tube, a nozzle comprising a cone-shaped section meant to be placed in the tube axis. The infrared emission device is placed on the longitudinal axis of the tube, at the level of one of the nozzles, and the receiver is placed on the longitudinal axis, at the level of the other nozzle.

Abstract: The invention relates to a chemical species optical sensor comprising: a fluorescent source (3) of incoherent infrared rays, including a chalcogenide glass matrix, doped with rare earth ions and combined with a pump source by means of a first optical fiber (2); and at least one infrared ray detector (5), provided with a spectral selection device (50) and set up to detect the rays that are emitted by said fluorescent source and have passed through a detection area (6), said detector including a fluorescent element (510) formed by a chalcogenide glass matrix that is doped with rare earth ions and combined with a second pump source (530) by means of a second optical fiber (520). Such a sensor can be used for differentially detecting a chemical species, and in particular CO2.

Abstract: A method and apparatus for detecting the presence and concentration of organic and inorganic acids by their infrared absorption characteristics in a refrigeration unit while running. Acids of interest, such of those formed upon decomposition of refrigerant or refrigerant oil, are volatilized and subjected to infrared radiation. Optical filtering is used to limit the infrared radiation to relevant wavelengths. Organic acids are detected by the absorbance of energy between 4-6 microns while inorganic acids are detected by the absorbance of energy between 2-4 microns.

Abstract: A gas sensor device for determining a molar concentration of a gas to be detected, that absorbs light of a measurement wavelength that is characteristic of the gas in the infrared light region, includes a light emission device emitting measurement light of measurement wavelength into a solid angle region of a light absorption path extending through the gas, and a light detector measuring an intensity of at least one component of the measurement light that has propagated through the light absorption path, the light absorption path extending from the light emission device to an object outside the gas sensor device that at least partially reflects the measurement light to the light detector, and being essentially disposed outside of the gas sensor device, and means for determining the length of the light absorption path. A method for determining a concentration of a gas to be detected is also described.

Abstract: What is disclosed is a system and method for image-based determination of carbon dioxide (CO2) concentration in exhaled breath. In one embodiment, an image of the exhaled airstream of a subject of interest is received. The image is captured using a mid-wave infrared camera system having an optical filter tuned to the infrared absorption band of CO2. The image is preprocessed to isolate a region of pixels containing the exhaled airstream and intensity values of pixels in the identified region are normalized by a value of a known radiance such as that of the subject's nose or face. The image is analyzed to determine CO2 concentration levels of the exhaled airstream using a calibration curve which relates pixel intensity to CO2 concentrations. The calibration curve is derived using a physics-based parameterized model. The CO2 concentration levels are determined and communicated to a computer workstation. Various embodiments are disclosed.

Abstract: Method of determining a total HF concentration metric in an environment including measuring an uncorrected HF concentration metric in the environment based on a first infrared absorption measurement at a wavelength corresponding to a vibrational frequency of a non-hydrogen bonded gas phase HF molecule; determining an ambient H2O concentration metric in the environment available for reaction with the non-hydrogen bonded gas phase HF molecules at or about the time of obtaining the first infrared absorption measurement; calculating a HF hydrate concentration metric in the environment based on the uncorrected HF concentration metric, the ambient H2O concentration metric and a reaction equilibrium relationship between the non-hydrogen bonded gas phase HF molecule and the HF hydrate; and determining the total HF concentration metric in the environment based on the uncorrected HF concentration metric and an amount of HF determined by the HF hydrate concentration metric.

Abstract: A light beam generated by a light source having a wavelength corresponding to the ethanol absorption spectrum, preferably in the wavelength range of 3.28-3.52 ?m or in one or more wavelength ranges 6.49-7.46 ?m, 7.74-8.33 ?m, 8.84-10.10 ?m, 10.7-12.00 ?m, is sent through a measuring space containing a sample of exhaled breath, and then the intensity of the light beam passing through the measuring space is measured. Based on the spectral analysis of the dependence of the light intensity to the alcohol concentration, the concentration of ethanol vapor is determined and the information about the level of the ethanol content is provided to a suitable display or device.

Abstract: System flow path designs that minimize the impact of gas diffusion sources and sinks. By reducing the magnitude of parasitic sources and sinks, lower rates of photosynthesis and transpiration can be more accurately measured, e.g., without the need for extensive empirical compensation. According to one aspect, a sensor head for use in a gas exchange analysis system includes a sample chamber defining a measurement volume for analysis of a sample, the sample chamber having an inlet and an outlet, and a flow splitting mechanism located proximal to the sample chamber, the mechanism configured to split a gas flow received at an input port from a remote source to a first output port and to a second output port, wherein the first output port is coupled with the inlet of the sample chamber.

Abstract: A method and apparatus for quantitative and qualitative imaging of fugitive emissions of gas, vapors, or fumes are described. The apparatus includes a filter mosaic for placement in registration over an imaging focal plane array (FPA). The filter mosaic includes at least two filter elements providing transmission response functions for transmitting wavelengths of light corresponding to an absorption wavelength (online wavelength) and a non-absorption wavelength (offline wavelength) of the targeted fugitive emission. Also described is an image processing method for transforming a filtered image into an image of the targeted fugitive emission.

Abstract: A system for locking a laser with a resonant optical cavity includes a laser that emits a laser beam, a resonant optical cavity having at least two cavity mirrors, one of which is a cavity coupling mirror, mode matching optics configured to couple the laser beam to the cavity via the cavity coupling mirror, means for applying a periodic dither or modulation waveform signal to the optical frequency of the incident laser beam or to the laser itself to thereby induce modulation of the intracavity optical power, and means for enabling a portion of the light emerging from the cavity coupling mirror to enter a cavity of the laser while maintaining an optical phase that results in periodic optical feedback locking whereby a mean optical frequency of the laser matches a resonance peak of the cavity.

Abstract: A gas detector includes at least one gas sensing element and a calorimetric sensing material for detection of a different, potentially contaminating gas which can impair the function of the gas sensing element disposed within the detector. The sensing material provides a visual indication of the presence of the potentially contaminating gas.

Abstract: Onboard systems and methods for early detection that an aircraft has flown into a volcanic ash plume embedded within a water vapor cloud having a concentration of a volcanic ash which would be dangerous to an aircraft. The detection method generally comprises the steps of measuring the infrared emission characteristics of a jet engine exhaust and generating a detection signal when the intensity of infrared emissions at or near a spectral peak wavelength exceeds a threshold.

Abstract: Disclosed are methods and apparatuses for detecting mercury species in various gas streams, such as those generated from fossil fuel combustion.

Abstract: A device for measuring oxygen uptake and carbon dioxide production by a respiring subject based on the use of absorption spectroscopy. An absorption spectrometer using cavity enhanced absorption spectroscopy at 763 nm to measure oxygen concentration and direct absorption or wavelength modulation spectroscopy at 2.0035 ?m for carbon dioxide concentration is incorporated into a breathing tube in proximity to the respiring subject. This provides measurements of oxygen and carbon dioxide concentration with a good temporal resolution which can be combined with measurements of flow rate as a function of time to obtain oxygen uptake and carbon dioxide production on a breath-by-breath basis. The device can also measure the concentration of water vapor and of anaesthetic gases in exhaled breath.

Abstract: A method and apparatus for the photo-acoustic identification and quantification of one or more analyte species present in a gaseous or liquid medium in low concentration utilizing a laser and a resonant optical cavity containing the medium and having within the cavity at least two partially transparent mirrors, one of which is a cavity coupling mirror and one of which is moveably mounted on an assembly responsive to an input signal.

Abstract: An apparatus and method (and related kit) for determination of the isotopic ratio of 13C to 12C in a gas sample containing carbon dioxide comprising introducing gas into a gas sample chamber, directing light into the sample chamber from a laser light source, the laser light source being capable of accessing one or more of the wavelength pairs 2054.37 and 2052.42; 2054.96 and 2051.67; or 2760.53 and 2760.08 nanometers, and with a detector detecting the laser light energy after passage through the sample chamber.

Abstract: A method of mapping concentrations of airborne matter from an emission source of interest in an emission plume is provided. The method involves measuring airborne matter at one or more than one identified locations using an optical sensing instrument (OSI) operatively connected with one or more than one matter samplers and mounted on a vehicle. The one or more than one airborne matter samplers are passed through an airspace to be sampled, and one or more concentration measurements are obtained. Geographic positions and altitude values for each of the one or more identified locations are established, and a point concentration measurement for the airborne matter for each identified location determined. The concentration measurements are mapped relative to the geographic position and altitude values for each of the one or more identified locations to obtain an airborne matter concentration distribution map in one or more measurement surfaces through a cross-section or profile of the emission plume.

Abstract: The invention relates to a chemical species optical sensor comprising: a fluorescent source (3) of incoherent infrared rays, including a chalcogenide glass matrix, doped with rare earth ions and combined with a pump source by means of a first optical fiber (2); and at least one infrared ray detector (5), provided with a spectral selection device (50) and set up to detect the rays that are emitted by said fluorescent source and have passed through a detection area (6), said detector including a fluorescent element (510) formed by a chalcogenide glass matrix that is doped with rare earth ions and combined with a second pump source (530) by means of a second optical fiber (520). Such a sensor can be used for differentially detecting a chemical species, and in particular CO2.

Abstract: A method for determining the 14C content of a gas mixture in which 14C isotopes are present as molecule constituents, is provided. The gas mixture is provided in a measuring space, wherein infrared laser radiation is supplied to the measuring space as measurement radiation. The laser radiation to be supplied to the measuring space is deflected such that it passes through the measuring space a plurality of times by interacting with the gas mixture, wherein the laser radiation is supplied to a detector, in order to determine the absorption of laser radiation by the gas mixture and therefrom determine the 14C content. For generating the laser radiation a pulsed laser is used, which as measurement radiation emits laser pulses with a pulse duration of less than 5 ?s, which are supplied to the measuring space.

Abstract: An optical absorption gas sensor comprising a body having an internal wall which defines a chamber, at least one aperture in the body through which a gas sample can enter the chamber, a light source, at least one reflector, a detector assembly which extends into the chamber and has a first side and an opposite second side, a detector which measures light which is incident at least a range of angles on at least a part of a first surface of the detector assembly on the first side of the detector assembly, wherein the light source is located within the chamber on the second side of the detector assembly, the whole being configured such that light from the light source passes through the gas sample and is reflected around the detector assembly, by the at least one reflector, onto the detector.

Abstract: A device and method for gas measurements in body cavities are provided. These may be any body cavity containing a free gas, where there is an interest in detecting and/or measuring the concentration of said free gas by non-invasive or minimally invasive method. According to an exemplary embodiment measurement of free oxygen in cranium cavities is performed by scattering media absorption spectroscopy, and in particular variations of such oxygen. This is particularly useful for diagnostic purposes based on the measurements, for instance for detecting sinusitis or the like.

Abstract: A concentration of ethanol is detected without using any light source such as a lamp by utilizing a face of a human being as a light source.

Abstract: A detector arrangement for detection of a measuring gas component in a gas mixture is provided. The arrangement includes a gas analyzer, a first single-layer receiver and a further single-layer receiver, the first single-layer receiver containing the measuring gas component and the further single-layer receiver containing a transverse gas. A concentration of the measuring gas component in the gas mixture is determined from signals delivered by sensors of the single-layer receivers. An evaluating device includes an n-dimensional calibration matrix for obtaining matrix signal values. Signal values of different known concentrations of the measuring gas component in the presence of different known transverse gas concentrations are stored as n-tubules in the evaluating device.

Abstract: An exhaust gas analysis method comprises applying a laser beam to the exhaust gas discharged from an internal combustion engine, receiving the laser beam that has passed through the exhaust gas, and measuring the concentration of any of the components contained in the exhaust gas based on the received laser beam. The exhaust gas analysis method further comprises detecting the absorption spectrum of the laser beam absorbed in the exhaust gas by using the received laser beam, calculating the concentration of the specific gas component by using the absorption spectrum, calculating the temperature of the exhaust gas by using the absorption spectrum, calculating the pressure of the exhaust gas by using the absorption spectrum, correcting the calculated concentration of the component contained in the exhaust gas by using the calculated temperature, correcting the concentration by using the calculated pressure, and outputting the true concentration value.

Abstract: A method for calibrating a dual-beam NDIR gas sensor for detecting water vapor by obtaining a variant sensor components domain (“G0”) when there is no water vapor gas in the sample chamber, obtaining a physics measurement domain (“G”) for a set of known concentrations of the water vapor gas in the sample chamber, the known concentrations being measurable quantities exceeding zero, using G to calculate a G0i from a known concentration of water vapor in the sample chamber for each of multiple master calibration curves, and then selecting the master calibration curve with the lowest difference between its G0i and the G0 of the NDIR gas sensor as the calibration curve.

Abstract: An NDIR gas sensor methodology for the design of a dual-gas sensor for the detection of two gases having a mutually interfering infrared absorption band such as that for CO2 and H2O at around 2.70? or N2O and CO at around 4.40?. The output of this two-channel NDIR gas sensor remains drift-free over time and is also temperature independent because it uses three detection channels sharing the same sample chamber and all have exactly the same narrow band-pass filter. The first detection channel is filled with 100% nitrogen and its output is proportional to the concentration levels for both CO2 and H2O in the sample chamber. The second detection channel has two cells in series, one filled with a known concentration of H2O and another one with 100% CO2 gas, and its output is proportional principally only to the presence of H2O in the sample chamber. The third detection channel is filled with 100% CO2 gas and its output serves as the biased reference for this dual-gas NDIR gas sensor.

Abstract: A filter 2 for collecting PMs, a microwave transmitter 30 for emitting electromagnetic waves whose frequency is dozens of GHz-a few of THz onto the filter 2, a microwave receiver 31 for detecting an intensity of the electromagnetic waves that have transmitted through the filter 2, and a computing means for computing a collection amount of PMs from the intensity that has been detected with the microwave receiver 31 are included. Since it is possible to detect the distribution of the collection amount of PMs with good accuracy, it is possible to carry out a recycling process in a state where the collection amount does not become too much, and thereby it is possible to make a reducing-agent supply amount into exhaust gases minimum at the time of the recycling process.

Abstract: A device for a continuous indication of illicit substances in the exhalation air of face of the machine operator comprises an IR source and an IR detector being sensitive to wave length having an absorbance of the illicit substance, whereby the beam path of the IR source to the detector runs in front of the face of the operator.

Abstract: Apparatus for remote laser-based detection of a analyte in a remote target region; comprising a reference container for housing a reference substance identical with the analyte; a laser unit which constituted to emit a laser beam of a tuneable wavelength towards the target region to be analysed and along a reference path which passes through the reference container for detecting the reference substance; a laser control means constituted to control wavelength of the laser beam during detection periods such that the laser wavelength is changed to allow detection of an optical absorption profile of the analyte during detection periods; an analytical detection unit which detects light from the target region and generates analytical signals during the detection periods, a reference detection unit which detects laser light passed through the reference container and generates reference signals during the detection periods; and an analysing means constituted to analyse the similarity of the analytical and reference s

Abstract: An unmanned integrated RES 12 integrates all of its components except the reflector 22 into a single console 30 that is positioned at the side of a road and has a CPU 36 that controls calibration, verification and data gathering. The RES's source 32 and receiver 34 are preferably stacked one on top of the other such that the IR beam 24 traverses a low and high path as it crosses the road 14. This allows the RES to detect both low and high ground clearance vehicles. To maintain the vehicle processing and identification throughput, the speed sensor 54 and ALPR 48,50 detect the passing vehicles at steep angles, approximately 20 to 35 degrees. In a preferred system, a manned control center 16 communicates with a large number of the unmanned integrated RES to download emissions data, perform remote diagnostics, and, if necessary, dispatch a technician to perform maintenance on a particular RES.