scholarly journals In-situ measurement of water-vapor in fire environments using a real-time tunable diode laser based system

2020 ◽  
pp. 103114
Author(s):  
Shruti Ghanekar ◽  
Rajavasanth Rajasegar ◽  
Nicholas Traina ◽  
Constandinos Mitsingas ◽  
Richard M. Kesler ◽  
...  
Keyword(s):  
Water Vapor ◽  
Real Time ◽  
Diode Laser ◽  
In Situ Measurement ◽  
Tunable Diode Laser ◽  
In Fire

In Situ Measurement of the Water Vapor 18O/16O Isotope Ratio for Atmospheric and Ecological Applications

2005 ◽  
Vol 22 (5) ◽  
pp. 555-565 ◽  
Author(s):  
Xuhui Lee ◽  
Steve Sargent ◽  
Ronald Smith ◽  
Bert Tanner
Keyword(s):  
Water Vapor ◽  
Standard Deviation ◽  
Isotope Ratio ◽  
In Situ Measurement ◽  
Tunable Diode Laser ◽  
Cold Trap ◽  
Mixing Ratio ◽  
Dewpoint Temperature ◽  
Ecological Applications

Abstract In this paper a system for in situ measurement of H216O/H218O in air based on tunable diode laser (TDL) absorption spectroscopy is described. Laboratory tests showed that its 60-min precision (one standard deviation) was 0.21‰ at a water vapor volume mixing ratio of 2.67 mmol mol−1 (dewpoint temperature −10.8°C at sea level) and improved to 0.09 at 15.3 mmol mol−1 (dewpoint temperature 13.4°C). The TDL measurement of the vapor generated by a dewpoint generator differed from the equilibrium prediction by −0.11 ± 0.43‰ (mean ± one standard deviation). Its measurement of the ambient water vapor differed from the cold-trap/mass spectrometer method by −0.36 ± 1.43‰. The larger noise of the latter comparison was caused primarily by the difficulty in extracting vapor from air without altering its isotope content. In a 1-week test in Logan, Utah, in August 2003, the isotope ratio of water vapor in ambient air was positively correlated with the water vapor mixing ratio and also responded to wetting events (rain and irrigation) in an expected manner. This system has been in continuous operation in New Haven, Connecticut, since December 2003. It is suggested that such uninterrupted measurement may open a new window on the hydrologic cycle, particularly processes involving phase changes of water, and can increase the power of the isotope method in ecological applications.

In situ measurement of stratospheric nitric oxide using a balloon-borne tunable diode laser spectrometer

1984 ◽  
Vol 23 (8) ◽  
pp. 1140 ◽  
Author(s):  
Christopher R. Webster ◽  
Robert T. Menzies
Keyword(s):  
Nitric Oxide ◽  
Diode Laser ◽  
In Situ Measurement ◽  
Tunable Diode Laser ◽  
Laser Spectrometer ◽  
Diode Laser Spectrometer

In-Situ Optical Measurements of Water Vapor Concentration and Temperature in a Proton Exchange Membrane Fuel Cell at Steady State and Under Dynamic Cycling

2009 ◽  
Author(s):  
Ritobrata Sur ◽  
Thomas J. Boucher ◽  
Michael W. Renfro ◽  
Baki M. Cetegen
Keyword(s):  
Water Vapor ◽  
Fuel Cell ◽  
Partial Pressure ◽  
Diode Laser ◽  
Pem Fuel Cell ◽  
Tunable Diode Laser ◽  
Cathode Side ◽  
Vapor Concentration ◽  
Water Vapor Concentration

A robust, accurate and fast in-situ sensor was developed for detection of water vapor partial pressure and temperature simultaneously at the anode and cathode channels of a PEM fuel cell. Tunable diode laser absorption spectroscopy (TDLAS) utilizing wavelength modulation (WMS) was employed for these measurements. This method determines the ratio of the second and first harmonics (2f/1f) of the spectroscopic absorption profile of water vapor by the aid of a software lock-in amplifier. Measurements were taken using a diode laser emitting around a wavelength of 1471 nm where the water vapor absorption exhibits significant sensitivity to partial pressure and temperature. Measurements of water vapor concentration and temperature in were taken at steady and dynamic operating conditions in the anode and cathode gas channels near the inlet and outlet ports of a serpentine channel PEM fuel cell with Nafion membrane of active area 50 cm2. Different load and inlet humidity conditions were tested to characterize the operation at different conditions. The partial pressure of water vapor increases towards the exit of both the gas channels, but the increase is found to be more significant on the cathode side. The dynamic operation of the fuel cell was also examined in this study as well as the simultaneous measurements at the anode and cathode gas channels.

Simultaneous diode-laser-based in situ measurement of liquid water content and oxygen mole fraction in dense water mist environments

2006 ◽  
Vol 31 (7) ◽  
pp. 900 ◽  
Author(s):  
Andrew R. Awtry ◽  
James W. Fleming ◽  
Volker Ebert
Keyword(s):  
Water Content ◽  
Diode Laser ◽  
Mole Fraction ◽  
Liquid Water ◽  
Liquid Water Content ◽  
Water Mist ◽  
In Situ Measurement ◽  
Dense Water ◽  
Oxygen Mole Fraction

Wavelength-modulated tunable diode-laser absorption spectrometry for real-time monitoring of microbial growth

2016 ◽  
Vol 55 (9) ◽  
pp. 2339 ◽  
Author(s):  
Jie Shao ◽  
Jindong Xiang ◽  
Ove Axner ◽  
Chaofu Ying
Keyword(s):  
Real Time ◽  
Diode Laser ◽  
Microbial Growth ◽  
Absorption Spectrometry ◽  
Tunable Diode Laser ◽  
Real Time Monitoring ◽  
Laser Absorption ◽  
Diode Laser Absorption

In-situ CO measurement of gas and oil combustion flame using near infrared tunable diode laser with direct and modulated absorption signals

2013 ◽  
Vol 306 ◽  
pp. 99-105 ◽  
Author(s):  
Qun-xing Huang ◽  
Fei Wang ◽  
Hai-dan Zhang ◽  
Jian-hua Yan ◽  
Ming-jiang Ni ◽  
...  
Keyword(s):  
Diode Laser ◽  
Near Infrared ◽  
Tunable Diode Laser ◽  
Combustion Flame
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