Quantitative Determination of Methanol and Ethanol with Synthetic Calibration Spectra in Passive Fourier Transform Infrared Remote Sensing Measurements

Abstract

A spectral synthesis strategy is introduced to help obtain estimates of path-integrated concentrations in passive Fourier transform infrared (FT-IR) remote sensing measurements conducted during field-monitoring experiments. Obtaining quantitative information from passive infrared data is challenging because of the joint effects of temperature and concentration on spectral intensities. The collection of calibration data for use in modeling spectral intensities for a given set of experimental conditions is also costly and labor intensive. In the work presented here, a radiance model is defined for use in synthesizing calibration spectra that serve as inputs to partial least-squares (PLS) models that relate spectral intensities to path-integrated concentrations. The field data for which quantitative estimates are desired are used to estimate the background temperature associated with a given time and set of experimental conditions. Sample temperatures can be obtained through either experimental measurement or by estimating one calibration release. Given these temperatures, calibration data can be synthesized and the PLS model developed. This methodology is tested with stack monitoring data obtained from controlled releases of pure and mixture samples of heated ethanol and methanol. Experiments were conducted across 6 days with stack temperatures of 150 to 200 °C and with path-integrated concentrations in the range of 10 to 300 parts per million meters. Median relative errors in the estimates of path-integrated concentration were typically in the range of 20% or less, with the best results observed at the higher stack temperatures.

A review on a novel method for aging evaluation of transformer insulating paper based on methanol

“…The microscopic process of insulating paper aging is the process of cellulose macromolecular chain breaking. Alcohol (CH 3 OH) is a colourless liquid with alcohol smell, which is one of the aging products of insulating paper [59,60]. There is no unified conclusion on the specific mechanism and chemical reaction process.…”

Integrated Near Infrared and Ultraviolet Spectroscopy Techniques for Determination of Hydrate Inhibitors in the Presence of NaCl

“…Moreover, vibrational spectroscopy methods such as NIR and UV spectroscopy can provide information about the evolution of KHI and THI contents in various fluid systems. Several studies were carried out to measure the concentration of EtOH and MeOH in gasoline by combining NIR and chemometric methods. − …”