Abstract: The invention relates to a method for determining a gas concentration in a flowing gas mixture, wherein the flowing gas mixture includes solids having a defined size distribution, wherein by way of an optical spectrometer the concentration of a gas is measured in the flowing gas mixture, which includes a measurement beam of the optical spectrometer being conducted during the measurement through a measurement channel having walls made of a gas-permeable material. The invention also relates to a device for carrying out such a method.

Abstract: A concentration measuring device for determining a concentration of gas or particles in a measurement volume includes at least one housing having an opening for communication with the measurement volume, a light source for transmitting measurement light through the housing into the measurement volume, a light receiver for receiving the measurement light after its passage through the measurement volume and an evaluation unit which is designed for determining the concentration of gas or particles from the measurement light received at the light receiver. In accordance with the invention at least one body of solid material is arranged in the at least one housing such that the measurement light path largely passes through the at least one solid body within the housing, with the portion of the measurement light path within the at least one housing not passing through the at least one solid body having a specified total length.

Abstract: Optical computing devices are disclosed. One optical computing device includes an electromagnetic radiation source that emits electromagnetic radiation into an optical train to optically interact with a sample and at least one integrated computational element, the sample being configured to generate optically interacted radiation. A sampling window is arranged adjacent the sample and configured to allow transmission of the electromagnetic radiation therethrough and has one or more surfaces that generate one or more stray signals. A first focal lens is arranged to receive the optically interacted radiation and the one or more stray signals and generate a primary focal point from the optically interacted radiation. A structural element defines a spatial aperture aligned with the primary focal point such that the optically interacted radiation is able to pass therethrough while transmission of the one or more stray signals is substantially blocked by the structural element.

Abstract: An optical measuring cell for measuring gas absorption with a light source for introducing light into a measuring volume and a light sensor located approximately opposite the light source in the direction of light propagation and relative to the measuring volume for receiving light that is guided through the measuring volume is provided. The concentration of one or multiple target gases in the measuring volume is detected by an evaluation unit. The measuring volume is constituted by an internal volume of a hollow fiber having an internal diameter less than 1 mm.

Abstract: This invention makes it possible to measure a concentration of a gas component having the adsorption even thought the concentration is low, and to improve a response speed of the measurement of the concentration, and comprises a body that has an introduction port to introduce a sample gas into a measurement cell, a laser light irradiation part that irradiates the laser light on the measurement cell, a heating pipe that applies heat to the sample gas introduced into the introduction port, a flow rate limit part that makes the sample gas at a negative pressure and that introduces the negative-pressurized heated sample gas into the body, and a negative pressure pump that keeps inside of the measurement cell and a flow channel from a downstream side of the flow rate limit part to the measurement cell at the negative pressure.

Abstract: A photoacoustic gas sensor, system and method is generally described. In some examples, a photoacoustic gas sensor includes a MEMS-based wavelength-selective optical modulator and a ring array of acoustic sensors. The MEMS-based optical modulator can be adapted to provide flexible wavelength selectivity such that a large number of chemical compounds may be detected. The ring array of acoustic sensors can be adapted to measure photoacoustically generated acoustic signals without the need for resonant enhancement of a photoacoustic cell of the gas sensor. In some examples, a unique uncorrelated and deterministic signal may be used to modulate each light wavelength of interest. Signal processing may be used that allows the simultaneous measurement of the absorption spectra of multiple optical wavelengths as well as the rejection of unwanted acoustic noise.

Abstract: An optical absorption gas sensor for detecting an analyte gas comprises a gas sample receiving chamber, at least one light emitting diode (LED) and a photodiode or other photosensor. A plurality of light pulses are generated by passing pulses of current through the at least one LED. The current through the at least one LED is measured a plurality of times during each pulse and taken into account when generating a compensated output signal. The transfer ratio between LED current and photodiode output signal is calculated a plurality of times during each pulse. An ADC measures the LED and photodiode currents alternately. The LED pulses are generated by inductor discharge flyback and the period of time for which current is supplied to the inductor prior to each pulse is selected so that the photodiode output current is at an optimal region within the input range of the ADC. At least the temperature of the at least one LED is measured and taken into account when generating the compensated output signal.

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: An optical gas sensor with a light-emitting diode (2), a photosensor (8), a measuring section between the light-emitting diode and the photosensor, and a control and analyzing unit (16), which is set up to determine the concentration of a gas in the measuring section from the light intensity measurement by the photosensor. The control and analyzing unit (16) is set up to measure the forward diode voltage over the light-emitting diode at a constant current, to determine the temperature of the light-emitting diode from the detected forward diode voltage over the light-emitting diode by means of a preset temperature dependence of the forward diode voltage, and to apply a correction function as a function of the light-emitting diode temperature determined, with which the measurement is converted to that of a preset temperature of the light-emitting diode.

Abstract: A GFCR system includes gas cells disposed to receive light energy associated with a field-of-view of an atmospheric region. Each gas cell has contents selected from the group consisting of a vacuum and a gas of unique composition. For each of the gas cells, the light energy passed therethrough is spectrally affected by the contents thereof and then output therefrom as a spectrally-affected beam of light energy associated with the field-of-view. An optical system disposed between the gas cells and an optical detector images each spectrally-affected beam on a unique region of the optical detector. One or more processors generate matched portions of each spectrally-affected beam so-imaged on the optical detector where each such matched portion corresponds to an identical portion of the field-of-view. GFCR computations can then be performed using the matched portions.

Abstract: An apparatus for the non-destructive testing of the integrity and/or suitability of sealed packagings having at least one portion (111,121) at least partially optically transparent, preferably food packagings, in particular through a verification of conformity of the atmosphere inside such food packagings, wherein the apparatus comprises at least one inspection area (20); at least one laser source (11) with an optical axis (A); at least one detector (13) positioned so as to detect at least one portion of back-scattered beams (12?) following the collision of the laser beam (12) emitted by the laser source (11) with a target (100,200) and provide—at the output—a representative datum of an absorption spectrum of the gas. The apparatus includes means for measuring a distance covered by the laser beam (12) and electronic processing means for calculating the concentration of the gas.

Abstract: In the optical gas sensor of the application, a three-dimensional reaction chamber structure is used to replace the traditional simple structure, so that the performance of the gas sensor can be enhanced in a wafer-level size. Besides, a light source, a reaction chamber and a light detector are integrated into one wafer in an exemplary embodiment, so as to achieve the wafer-level integration. In addition, the optical gas sensor can detect various gases simultaneously and has wide application in fields such as home environment monitoring, industrial safety, and disease diagnosis and treatment.

Abstract: A system includes a moisture analyzer configured to detect moisture in natural gas. The moisture analyzer includes an absorption cell that encloses and conducts the natural gas. The moisture analyzer also includes a pressure control device that may reduce a pressure of the natural gas inside the absorption cell. The moisture analyzer includes a light emitting device that may transmit light through the natural gas inside the absorption cell, as well as a photodetector that may detect an intensity of the light transmitted through the natural gas and exiting the absorption cell.

Abstract: A hydrogen purity sensing system includes a light source which provides an optical signal through a fiber optic cable. A hydrogen purity sensor is provided in the system which comprises a multilayered nanostructural film of high refractive index and low refractive index materials for receiving the optical signal. The system further includes a photodetector for receiving a reflected optical signal from the hydrogen purity sensor and a processing circuitry coupled to the photodetector for analyzing the reflected optical signal.

Abstract: A gas analyzer includes a detector section including a detector, a source section including a light source, and a support structure coupling the detector section with the source section and forming a flow channel defining an optical path measuring region. The gas analyzer also includes an air flow device configured to pull air through the flow channel from an intake region in the support structure to an exhaust region. Sampling is done by pulling air into the sampling cell via an intake opening or tube of wide diameter and short to medium at very fast flow rates (e.g., 10-3000 lpm or more) enabling rapid gas sampling. Fast flow rates enable the use of large volume cell for rapid gas sampling, which in turn, enables rapid measurements of many low-concentration trace gases and sticky/reactive gases (e.g., methane, ammonia, isotopes of CO2, H2O, nitrous oxide, etc.).

Abstract: In cavity ring-down spectroscopy (CRDS), scattering into the backward mode of a traveling wave ring-down cavity can degrade conventional CRDS performance. We have found that this performance degradation can be alleviated by measuring the backward mode signal emitted from the ring-down cavity, and using this signal to improve the processing for extracting ring-down times from the measured data. For example, fitting an exponential to the sum of the intensities of the forward and backward signals often provides substantially better results for the ring-down time than fitting an exponential to the forward signal alone. Other possibilities include extracting cavity eigenmode signals from the forward and backward signals and performing separate exponential fits to the eigenmode signals.

Abstract: An air-driven shutter device is used in an optical analyzer. The optical analyzer includes a measurement field to which a sample is supplied, a light-emitting unit measurement field for emitting measuring light to the sample, a light-receptive unit for receiving the measuring light that has passed through the sample, and a purge air supplying unit for supplying purge air. The air-driven shutter device includes a shutter and a shutter opening and closing mechanism. The shutter is disposed between the light-emitting unit and/or the light-receptive unit and the measurement field. The shutter opening and closing mechanism keeps the shutter open with pressure of the gas supplied from the purge air supplying unit, and closes the shutter when the pressure of the gas supplied from the purge air supplying unit becomes lower than a predetermined level.

Abstract: A gas detector (100) for remote gas detection in a target region (106) comprises a light source (102) for emitting a light beam (110) into the target region and a light sensor (112) for sensing light returning therefrom. The light beam is wavelength-modulated around an absorption wavelength of the gas. A controller (108) is operatively connected to the light sensor for detecting a presence of the gas on a path of the light beam based on returning light sensed by the light sensor. An indicator (124) that is operatively connected to the controller indicates the presence of the gas. A scanning device (104) is arranged with respect to the light source so as to scan the light beam through the target region, and with respect to the light sensor so that the light sensor receives the returning light via the scanning device. The indicator cooperates with the scanning device to indicate a position of the gas in the target region.

Abstract: In one embodiment, a block for a physics package of an atomic sensor is provided. The block comprises one or more sections of optically transparent material defining a vacuum sealed chamber, and including a plurality of transmissive and reflective surfaces to define a plurality of light paths intersecting the vacuum sealed chamber. The one or more sections of optically transparent material include a first monolithic section defining at least a portion of the vacuum sealed chamber. The first monolithic section includes a first portion disposed across a first light path of the plurality of light paths such that light in the first light path is incident on the first portion of the first monolithic section.

Abstract: The present invention relates to a gas sensing device comprising a nanoparticle layer (1) and a quantum dot layer (3) separated from each other by a gas absorption layer (2) which has a thickness which changes upon absorption of a gas. The nanoparticle layer (1) is provided for generating a surface plasmon resonance within a plasmon resonance frequency range upon illumination with light within a light frequency range; the quantum dot layer (3) has an absorption spectrum overlapping with said plasmon resonance frequency range of said nanoparticle layer (1) and shows photoluminescence in a photoluminescence emission frequency range upon absorption of energy within its absorption spectrum. The present invention further relates to a method for fabricating such a gas sensing device and to a method of using such a gas sensing device.

Abstract: Apparatus and methods for size-specific detection of particles entrained in fluids are provided. A particle size selector separates particles entrained in a sample fluid stream using a curved channel. Shroud fluid streams are interposed between the sample fluid stream and walls of the channel. Centrifugal forces arising from fluid flow through the curved channel separate differently-sized particles into different transverse sections of the channel. A detector downstream from the particle size selector specifically detects particles in one or more transverse sections of the channel.

Abstract: A non-dispersive gas analyzer comprising a light source, having light that shines through a measuring cuvette containing a measuring gas to be analyzed onto a non selective detector having a downstream evaluation unit, wherein a multi-component gas analysis is made possible using in a simple manner in that the light source is a flash discharge lamp and the evaluation unit is configured to evaluate the temporal pulse curves of the flash shining onto the detector such that it is possible to take advantage of the property of flash discharge lamps in that the emitted wavelength components vary over the duration of the flash.

Abstract: The nitrogen oxide sensing element of the present invention is such that a sensing film (11) is formed on the surface of a substrate (12a), the sensing film including a polymer containing as dispersed therein a porphyrin containing cobalt as a central metal, or a single derivative having a porphyrin skeleton containing cobalt as a central metal or a mixture of derivatives each having a porphyrin skeleton containing cobalt as a central metal; thus, this sensing element is capable of determining the concentration of NO with high sensitivity and satisfactory accuracy under the condition that the cobalt porphyrin is not affected by reaction inhibitors such as O2 and CO even in the atmosphere.

Abstract: A gas concentration measurement device which utilizes a TDLAS measurement method, and in which the phase-sensitive detection can be performed by digital processing using an integer-arithmetic device, is provided. In the gas concentration measurement device according to the present invention, AC components corresponding to integer multiples of a modulation frequency f contained in an input signal are removed by taking a moving average of data obtained from an output signal of a multiplier 62 for a period of time corresponding to one cycle of the modulation frequency f . As a result, a DC component in the output signal of a digital filter 63 relatively increases, making it easier to extract the DC component by a digital low-pass filter 64, so that a sufficiently accurate phase-sensitive detection can be made even if a digital processing based on integer arithmetic is used.

Abstract: Provided herein is an elementary analysis apparatus allowing size and weight reduction and capable of performing atomic adsorption spectrometry by an electrothermal method and of forming plasma without using a gas. A sample is supplied from a liquid feed portion through a flow channel to an atomizing portion, and a voltage is applied between electrodes. When the voltage is applied to the electrodes, electric current and electric field are concentrated in the atomizing portion and bubbles are generated to cause a plasma in the bubbles, and element in the sample is atomized by the plasma. Light that irradiates the atomizing portion from a light source and is transmitted therethrough is received, for example, by an optical fiber or the like and split by a spectrophotometer. The amount of the split light is detected by a detector and analyzed by a computer.

Abstract: A method for sensing a target object using optical mode excitations in microresonators, comprises: preparing at least one cluster including at least two microresonators; obtaining some first spectra of the cluster; adsorbing the target object on a surface of the cluster; obtaining some second spectra of the cluster; and sensing the target object by comparing a lineshape of the first spectra with a lineshape of the second spectra.

Abstract: A chemical analysis method for determining the concentration of carbon monoxide, gaseous water and gaseous hydrocarbon in a combustion gas. The method includes the following steps: (a) directing wavelength modulated light from a single tunable diode laser at a wavelength in the range of from 2 to 2.5 micrometers through the combustion gas to a light detector to produce an absorption profile of the combustion gas (b) digitizing the adsorption profile of the combustion gas; (c) storing the digitized adsorption profile in a digital computer; (d) processing the digitized adsorption profile in the digital computer to produce an output from the computer indicative of the concentration of carbon monoxide, gaseous water and gaseous hydrocarbon in the combustion gas.

Abstract: The instant invention provides apparatuses for measuring the level or concentration of chlorine dioxide gas in a sample and methods of using the same. One aspect of the invention provides an apparatus for measuring a concentration of a chlorine dioxide gas in a sample. The apparatus includes a light emitting diode (LED), a light sensor, and a flow path between the LED and the light sensor, and a filter configured to remove chlorine dioxide from a reference stream. The flow path is capable of containing a sample. The sensor is capable of measuring the level of chlorine dioxide in the sample and the reference stream.

Abstract: A laser gas analyzer which can include a light source unit including a diode laser that irradiates a gas to be measured with laser light while scanning a wavelength thereof; a detection unit including a light receiving element, a gain-variable amplifier into which an output signal of the light receiving element is input, an A/D converter into which the output signal of the amplifier is input, and an arithmetic processing unit that performs a concentration analysis of the gas to be measured; a peak-to-peak detector that detects a peak-to-peak value of the output data of the A/D converter in each scan of the wavelength of the laser light irradiated from the diode laser; and a gain adjustment unit that, when the output signal of the peak-to-peak detector deviates from a preset threshold, adjusts the gain of the amplifier in a direction of bringing the output signal back to within the threshold.

Abstract: An optical gas measurement using a Vertical Cavity Surface-Emitting Laser (VCSEL) and a hollow waveguide connected thereto, wherein the hollow waveguide contains a gas to be measured and conducts light. To this end, the hollow waveguide is made to vibrate. The gas measurement is performed and integrated over a period of time. As a result, disturbances of the measurement caused by interferences are considerably reduced.

Abstract: A gas measurement apparatus measures a target gas. The gas measurement apparatus includes a light source, a first light receiving apparatus, a first phase-sensitive detection apparatus, an R calculation unit, and a setting unit. The light source oscillates a laser light that has a central wavelength determined by a main current and is modulated according to a modulation current, with the central wavelength being varied. The first light receiving apparatus outputs a detection signal according to an intensity of the laser light transmitted through a standard sample. The first phase-sensitive detection apparatus obtains a second harmonic component oscillated at a harmonic frequency ?2 twice as large as a modulation frequency ?1. The R calculation unit calculates a peak-bottom ratio R. The setting unit sets a width of wavelength modulation of the laser light so that the peak-bottom ratio R satisfies a predetermined condition.

Abstract: The invention relates to a gas sampling device comprising a probe for sampling gas, an exploiting device for exploiting the gases sampled, a pipe for transmitting the gases sampled by the probe to the exploiting device, and means for lowering the pressure of the gases sampled in the pipe, to lower the dew point of the gases sampled, the means for lowering the pressure comprising an expansion nozzle arranged in the probe and communicating with the pipe, and a suction device for sucking the gases sampled in the pipe through the exploiting device. Application of the invention to the analysis of hot gases loaded with water vapor.

Abstract: A method for monitoring of siloxane compounds in a biogas includes the step of generating a first absorption spectrum based on a ratio of a first spectral measurement and a second spectral measurement. The first spectral measurement is from a non-absorptive gas having substantially no infrared absorptions in a specified wavelength range of interest and the second spectral measurement is from a sample gas comprising the biogas. The method also includes the step of calculating a concentration of at least one siloxane compound in the biogas using a second absorption spectrum based on, at least, a first individual absorption spectrum for a known concentration of the at least one siloxane compound.

Abstract: Certain embodiments of the invention may include systems and methods for providing optical interrogation sensors for combustion control. According to an example embodiment of the invention, a method for controlling combustion parameters associated with a gas turbine combustor is provided. The method can include providing an optical path through the gas turbine combustor, propagating light along the optical path, measuring absorption of the light within the gas turbine combustor, and controlling at least one of the combustion parameters based at least in part on the measured absorption.

Abstract: Embodiments of the apparatus, systems, and methods relate to a photoacoustic sensor includes an excitation source, a modulator, a quantum dot filter, an interferometer, a gas chamber, and a microphone. The excitation source generates a monochromatic light. The modulator intensity modulates the monochromatic light at a first modulation frequency. The quantum dot filter down converts the modulated monochromatic light into a broadband spectrum of infrared light. The interferometer further intensity modulates the broadband spectrum such that the at least one wavelength component of the broadband spectrum is further intensity modulated at a second modulation frequency. The gas chamber stores a sample gas and receives the plurality of modulated wavelength components. The microphone detects pressure changes within the gas chamber to produce an acoustic signal, which can be used to analyze properties of the sample gas.

Abstract: One or more embodiments of the present invention pertain to a system, method, and apparatus that accurately measures concentration of a greenhouse gas in narrow atmospheric columns above multiple sites utilizing a network of autonomous low-cost beacons that turn on for short unannounced time intervals and point to a receiving satellite. For example, each beacon can activate for short time intervals and transmit a laser beam at eye-safe low transmission power levels to a receiving satellite. The receiving satellite includes a sensor configured to receive the laser beam from one or more activated beacon and generate raw greenhouse gas concentration data based on measurement of the received laser beam intensity at selected wavelengths.

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: Provided is a detecting element that detects a parameter for a predetermined gas or liquid in a surrounding atmosphere by being excited by excitation light and generating light corresponding to the surrounding atmosphere, the detecting element including: a substrate; and nanoscale crystal structures formed on the substrate and constituted by a compound semiconductor light emitting element having a heterostructure well layer, wherein when the nanoscale crystal structures adsorb atoms or molecules of the predetermined gas or liquid, there is distortion of a band of a structure with a smaller bandgap width in the well layer, this distortion brings about a change in transition energy, and this change brings about a change in at least one of an intensity and a wavelength of light generated by the well layer, thereby indicating the parameter for the gas or the liquid.

Abstract: An illustrative cavity ring down gas sensor includes an optical cavity for receiving a gas to be detected and at least two electromagnetic radiation sources. The first electromagnetic radiation source may emit a first beam of light having a wavelength corresponding to an absorption wavelength of the gas to be detected, and the second electromagnetic radiation source may emit a second beam of light having a second wavelength that is off of an absorption wavelength of the gas to be detected. The first beam of light may detect a cavity ring down time decay, which is related to the concentration of the gas to be detected. The second beam of light may be used to detect a baseline cavity ring down time decay, which may be used to help increase the accuracy of the sensor by, for example, helping to compensate the concentration of the gas detected by the first beam of light for sensor variations caused by, for example, sensor age, temperature or pressure changes, and/or other conditions.

Abstract: Cavity ring-down spectrometer systems are described herein. One or more embodiments include a cavity having at least two mirrors, wherein a first mirror of the at least two mirrors is configured to permit light to enter and exit the cavity, a first detector configured to detect light exiting the cavity through the first mirror, and a second detector configured to detect light from the first mirror, wherein the first detector is separate from the second detector.

Abstract: A method and system for recreating a two-dimensional distribution of temperatures in an exhaust plane of a gas turbine engine. Light transmission and detection pairs may be arranged in the annulus of the exhaust of the turbine engine in such a way that the individual rays form a two-dimensional mesh of beams across a sector of the exhaust. Based on the absorption of the rays, the temperature of the sector of the exhaust thru which the ray passes may be determined. Based on these determinations, an image that corresponds to the operation of the turbine engine may be generated.

Abstract: The disclosure relates to a plasmon resonance-based method for H2 sensing in a gas stream at temperatures greater than about 500° C. utilizing a hydrogen sensing material. The hydrogen sensing material is comprised of gold nanoparticles having an average nanoparticle diameter of less than about 100 nanometers dispersed in an inert matrix having a bandgap greater than or equal to 5 eV, and an oxygen ion conductivity less than approximately 10?7 S/cm at a temperature of 700° C. Exemplary inert matrix materials include SiO2, Al2O3, and Si3N4 as well as modifications to modify the effective refractive indices through combinations and/or doping of such materials. At high temperatures, blue shift of the plasmon resonance optical absorption peak indicates the presence of H2. The method disclosed offers significant advantage over active and reducible matrix materials typically utilized, such as yttria-stabilized zirconia (YSZ) or TiO2.

Abstract: An optical arrangement comprising a multi-mode fiber (16) for carrying single mode laser light (12); a randomizer (18) for randomizing spatial modes supported by the fiber and means for averaging, out the randomized spatial modes to recover the single spatial mode.

Abstract: An apparatus, a system and a method use a light-emitting diode (LED) to identify the presence of a material in a gas and/or a fluid and/or to determine properties of the material. The LED and a light detector may be used to determine a chemical compound in the material. The gas and/or the fluid may be located in a chamber. A first light detector may be positioned on the opposite side of the chamber relative to the LED, a second light detector may be positioned on the same side of the chamber as the LED, and/or a third light detector may be positioned inside the chamber. Additional light detectors with coatings may enable measurements to be corrected for the effects of temperature. The light detectors may determine light reflection, light refraction, light transmission, light diffraction, light interference, light diffusion, light collimation, light absorption and/or light focusing of the material.

Abstract: An optical sensor system is disclosed including a source module, a first detection module, and a second detection module. The source module includes a source housing unit having a source window member. The source module may emit a detection signal through the source window member. The first detection module and the second detection module are spaced apart from the source module.

Abstract: An optical sensor system includes a source module and a detection module. The source module includes a source housing unit having a source window member and a source shielding member. The source module emits a detection signal through the source window member. The detection module includes a detection housing unit having a detection window member and a detection shielding member. The detection module is spaced apart from the source module. The detection module detects the detection signal emitted from the source module at the detection window member.

Abstract: The present subject matter relates to an apparatus and related method of high-speed analysis of product samples during production of the product. Light is directed to a portion of a product under analysis and reflected from or transmitted through the product toward optical detectors. Signals from the optical detectors are compared to determine characteristics of the product under analysis. Temperature within the monitoring system may be monitored in order to provide compensation for the signals produced by the optical detectors. The products under analysis may be stationary, moved by an inspection point by conveyor or other means, or may be contained within a container, the container including a window portion through which the product illuminating light may pass.

Abstract: The present invention provides a means of greatly reducing or eliminating the interferences of UV-absorbing compounds, mercury, water vapor and particulates in the UV absorbance measurement of ozone by replacing the internal solid-phase ozone scrubber with a gas-phase scrubber. Reagent gases well suited as a gas-phase scrubber of ozone include nitric oxide and bromine atoms. Nitric oxide may be supplied by a gas cylinder or by photolysis of either N2O or NO2, both in the absence of oxygen. Bromine atoms are conveniently generated by photolysis of Br2 supplied by a permeation tube. Bromine atoms have the advantage of having a faster reaction with ozone than NO and of being catalytic in their reaction. Nitric oxide has the advantage of being generally less reactive with other components of air.

Abstract: A soot number determining device has an intake line for taking in a soot-containing gas through a filter paper that has been introduced into the intake line. A transport apparatus transports a soot spot, which is produced at an intake position by virtue of the gas being taken in on the filter paper, by transporting the filter paper further to an evaluation position. A device is used to determine the extent of blackening of the filter paper.

Abstract: An apparatus and technique are invented that enhance the sensitivity of a spectrometer for trace gas detection by employing wavelength modulation spectroscopy (WMS) and integrating the absolute value of the recorded spectra across multiple absorption lines (features) of the species. The sensitivity is further enhanced by conducting WMS with large modulation depths. This technique is implemented using a continuously tunable external cavity CW quantum cascade laser to record the second harmonic wavelength modulated spectra of NO2 across the peak of the R-branch from 1629.5 cm?1 to 1633.9 cm?1. By integrating the absolute value of the resulting spectra, the detection sensitivity of NO2 is improved by a factor of 40 compared to the sensitivity achieved using single line WMS with the same apparatus. A sensitivity of approximately 6 ppb can be obtained using a short-path cell (a 1 m absorption cell with 2 passes) which can be significantly improved using multipass cells and cavity enhanced techniques.