Abstract: A differential absorption spectrum for a reactive gas in a gas mixture can be generated for sample absorption data by subtracting background absorption data set from the sample absorption data. The background absorption data can be characteristic of absorption characteristics of the background composition in a laser light scan range that includes a target wavelength. The differential absorption spectrum can be converted to a measured concentration of the reactive gas using calibration data. A determination can be made whether the background composition has substantially changed relative to the background absorption data, and new background absorption data can be used if the background composition has substantially changed. Related systems, apparatus, methods, and/or articles are also described.

Abstract: A differential absorption spectrum for a reactive gas in a gas mixture can be generated for sample absorption data by subtracting background absorption data set from the sample absorption data. The background absorption data can be characteristic of absorption characteristics of the background composition in a laser light scan range that includes a target wavelength. The differential absorption spectrum can be converted to a measured concentration of the reactive gas using calibration data. A determination can be made whether the background composition has substantially changed relative to the background absorption data, and new background absorption data can be used if the background composition has substantially changed. Related systems, apparatus, methods, and/or articles are also described.

Abstract: A differential absorption spectrum for a reactive gas in a gas mixture can be generated for sample absorption data by subtracting background absorption data set from the sample absorption data. The background absorption data can be characteristic of absorption characteristics of the background composition in a laser light scan range that includes a target wavelength. The differential absorption spectrum can be converted to a measured concentration of the reactive gas using calibration data. A determination can be made whether the background composition has substantially changed relative to the background absorption data, and new background absorption data can be used if the background composition has substantially changed. Related systems, apparatus, methods, and/or articles are also described.

Abstract: Thermodynamic properties of a natural gas stream can be determined in real time utilizing modeling algorithms in conjunction with one or more sensors for quantifying physical and chemical properties of the natural gas. A first data signal produced by a first sensor can include intensity as a function of wavelength. At least one region in the wavelength range outside of a selected absorption transition can be fitted to a function to obtain a zero-absorption baseline, and a carbon dioxide concentration can be determined based on a line strength at the selected absorption transition corrected by the zero-absorption baseline. A total hydrocarbon concentration in the gas stream can be inferred based on a database of characteristic natural gas concentrations, and an algorithm can be implemented that determines an energy content of the gas stream. Related techniques, apparatus, systems, and articles are also described.

Abstract: Thermodynamic properties of a natural gas stream can be determined in real time utilizing modeling algorithms in conjunction with one or more sensors for quantifying physical and chemical properties of the natural gas. Related techniques, apparatus, systems, and articles are also described.

Abstract: Thermodynamic properties of a natural gas stream can be determined in real time utilizing modeling algorithms in conjunction with one or more sensors for quantifying physical and chemical properties of the natural gas. Related techniques, apparatus, systems, and articles are also described.

Abstract: A differential absorption spectrum for a reactive gas in a gas mixture can be generated for sample absorption data by subtracting background absorption data set from the sample absorption data. The background absorption data can be characteristic of absorption characteristics of the background composition in a laser light scan range that includes a target wavelength. The differential absorption spectrum can be converted to a measured concentration of the reactive gas using calibration data. A determination can be made whether the background composition has substantially changed relative to the background absorption data, and new background absorption data can be used if the background composition has substantially changed. Related systems, apparatus, methods, and/or articles are also described.

Abstract: A differential absorption spectrum for a reactive gas in a gas mixture can be generated for sample absorption data by subtracting background absorption data set from the sample absorption data. The background absorption data can be characteristic of absorption characteristics of the background composition in a laser light scan range that includes a target wavelength. The differential absorption spectrum can be converted to a measured concentration of the reactive gas using calibration data. A determination can be made whether the background composition has substantially changed relative to the background absorption data, and new background absorption data can be used if the background composition has substantially changed. Related systems, apparatus, methods, and/or articles are also described.

Abstract: A differential absorption spectrum for a reactive gas in a gas mixture can be generated for sample absorption data by subtracting background absorption data set from the sample absorption data. The background absorption data can be characteristic of absorption characteristics of the background composition in a laser light scan range that includes a target wavelength. The differential absorption spectrum can be converted to a measured concentration of the reactive gas using calibration data. A determination can be made whether the background composition has substantially changed relative to the background absorption data, and new background absorption data can be used if the background composition has substantially changed. Related systems, apparatus, methods, and/or articles are also described.

Abstract: Moisture can be detected in a refrigerant background such as HFC (Hydrofluorocarbon) HFC-134A and HFC-152A and exampled by HFC-23, HFC-32, HFC-143A, HFC-125, HFC-245FA, HFC-227EA, and the like. The system can include a light source operating at any one of several wavelengths within the water absorption bands at wavelengths such as 1.4, 1.9 and 2.7 ?m and a detector that measures the transmitted light intensity through the HFC samples. In one variation, the light source is a tunable diode laser and the moisture level is determined by direct absorption and harmonic spectroscopy. Related techniques, apparatus, systems, and articles are also described.

Abstract: Thermodynamic properties of a natural gas stream can be determined in real time utilizing modeling algorithms in conjunction with one or more sensors for quantifying physical and chemical properties of the natural gas. Related techniques, apparatus, systems, and articles are also described.

Abstract: A differential absorption spectrum for a reactive gas in a gas mixture can be generated for sample absorption data by subtracting background absorption data set from the sample absorption data. The background absorption data can be characteristic of absorption characteristics of the background composition in a laser light scan range that includes a target wavelength. The differential absorption spectrum can be converted to a measured concentration of the reactive gas using calibration data. A determination can be made whether the background composition has substantially changed relative to the background absorption data, and new background absorption data can be used if the background composition has substantially changed. Related systems, apparatus, methods, and/or articles are also described.

Abstract: Thermodynamic properties of a natural gas stream can be determined in real time utilizing modeling algorithms in conjunction with one or more sensors for quantifying physical and chemical properties of the natural gas. Related techniques, apparatus, systems, and articles are also described.

Abstract: Concentrations of a target analyte in a gas mixture containing one or more background analytes having potentially interfering spectral absorption features can be calculated by compensating for background analyte absorption at a target wavelength used to quantify the target analyte. Absorption can be measured at a reference wavelength chosen to quantify the concentration of the background analyte. Using a background gas adjustment factor or function, the absorption measured at the reference wavelength can be used to calculate absorption due to the background analyte at the target wavelength and thereby compensate for this background absorption to more accurately calculate the target analyte concentration in real or near real time. Additional background analytes can optionally be compensated for by using one or more additional reference wavelengths.

Abstract: Thermodynamic properties of a natural gas stream can be determined in real time utilizing modeling algorithms in conjunction with one or more sensors for quantifying physical and chemical properties of the natural gas. Related techniques, apparatus, systems, and articles are also described.

Abstract: A differential absorption spectrum for a reactive gas in a gas mixture can be generated for sample absorption data by subtracting background absorption data set from the sample absorption data. The background absorption data can be characteristic of absorption characteristics of the background composition in a laser light scan range that includes a target wavelength. The differential absorption spectrum can be converted to a measured concentration of the reactive gas using calibration data. A determination can be made whether the background composition has substantially changed relative to the background absorption data, and new background absorption data can be used if the background composition has substantially changed. Related systems, apparatus, methods, and/or articles are also described.

Abstract: Concentrations of a target analyte in a gas mixture containing one or more background analytes having potentially interfering spectral absorption features can be calculated by compensating for background analyte absorption at a target wavelength used to quantify the target analyte. Absorption can be measured at a reference wavelength chosen to quantify the concentration of the background analyte. Using a background gas adjustment factor or function, the absorption measured at the reference wavelength can be used to calculate absorption due to the background analyte at the target wavelength and thereby compensate for this background absorption to more accurately calculate the target analyte concentration in real or near real time. Additional background analytes can optionally be compensated for by using one or more additional reference wavelengths.

Abstract: Low concentrations of water vapor in a gas stream can be detected and quantified using absorption spectroscopy in the infrared spectral region. Absorption spectra can recorded using tunable diode lasers as the light source. Modulation of the laser signal and demodulation of the resultant detector response yields dependable measurements that may be conducted with very little maintenance in demanding environments.

Abstract: An arrangement for controlledly removing material from an effective surface of a workpiece includes a mounting member which is mounted on a support for movement relative thereto at least in and opposite to a predetermined direction toward and away from the effective surface and a working member which is caused to rotate relative to the mounting member about a rotational axis that extends substantially normal to the predetermined direction. A pressing force acting in the predetermined direction is applied to the mounting member so that successive regions of an outer circumferential surface of the working member which is centered on the rotational axis act on a predetermined zone of the effective surface of the workpiece during the rotation of the working member with local pressures dependent on the magnitude of the pressing force and sufficient to remove material from the workpiece.