Mid-infrared dual-gas sensor for simultaneous detection of methane and ethane using a single continuous-wave interband cascade laser.

A continuous-wave (CW) interband cascade laser (ICL) based mid-infrared sensor system was demonstrated for simultaneous detection of atmospheric methane (CH) and ethane (CH). A 3.337 µm CW ICL with an emitting wavenumber range of 2996.

CW EC-QCL-based sensor for simultaneous detection of HO, HDO, NO and CH using multi-pass absorption spectroscopy.

A sensor system based on a continuous wave, external-cavity quantum-cascade laser (CW EC-QCL) was demonstrated for simultaneous detection of atmospheric HO, HDO, NO and CH using a compact, dense pattern multi-pass gas cell with an effective path-length of 57.6 m. The EC-QCL with a mode-hop-free spectral range of 1225-1285 cm operating at ~7.

Compact TDLAS based sensor design using interband cascade lasers for mid-IR trace gas sensing.

Two compact TDLAS sensor systems based on different structural optical cores were developed. The two optical cores combine two recent developments, gallium antimonide (GaSb)-based ICL and a compact multipass gas cell (MPGC) with the goal to create compact TDLAS based sensors for the mid-IR gas detection with high detection sensitivity and low power consumption. The sensors achieved minimum detection limits of ~5 ppbv and ~8 ppbv, respectively, for CH and CH concentration measurements with a 3.

Simultaneous atmospheric nitrous oxide, methane and water vapor detection with a single continuous wave quantum cascade laser.

A continuous wave (CW) quantum cascade laser (QCL) based absorption sensor system was demonstrated and developed for simultaneous detection of atmospheric nitrous oxide (N(2)O), methane (CH(4)), and water vapor (H(2)O). A 7.73-µm CW QCL with its wavelength scanned over a spectral range of 1296.

Atmospheric CH₄ and N₂O measurements near Greater Houston area landfills using a QCL-based QEPAS sensor system during DISCOVER-AQ 2013.

A quartz-enhanced photoacoustic absorption spectroscopy (QEPAS)-based gas sensor was developed for methane (CH₄) and nitrous-oxide (N₂O) detection. The QEPAS-based sensor was installed in a mobile laboratory operated by Aerodyne Research, Inc. to perform atmospheric CH₄ and N₂O detection around two urban waste-disposal sites located in the northeastern part of the Greater Houston area, during DISCOVER-AQ, a NASA Earth Venture during September 2013.

A PARAFAC-based long-term assessment of DOM in a multi-coagulant drinking water treatment scheme.

A parallel factor (PARAFAC) analysis approach was used to study the character and composition of dissolved organic matter (DOM) in a multicoagulant (two aluminum-based coagulants) full scale drinking water treatment plant. A three year, long-term assessment was conducted based on deconstruction of the excitation-emission matrices (EEM) of over 1000 water samples collected before and after parallel coagulation treatment basins. Two humic moieties and a protein-like group were identified in the raw and treated waters.

Assessment of dissolved organic matter fluorescence PARAFAC components before and after coagulation-filtration in a full scale water treatment plant.

Fluorescence monitoring of the raw and treated water after coagulation-filtration in a drinking water treatment plant in Northeast Ohio was conducted during a period of 32 months. Principal fluorophore groups present in the dissolved organic matter (DOM) of the raw, treated, raw-treated combined water and differential fluorescence data sets comprising over 680 samples were determined through Parallel Factor (PARAFAC) analysis. Four components (two humic-like and two with protein nature) were identified in each model and their degree of similarity was evaluated using the Uncorrected Matrix Correlation (UMC), a measure of spectral overlapping.