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Sensors 2012, 12(12), 17058-17073; doi:10.3390/s121217058
Article

Improved Membrane-Based Sensor Network for Reliable Gas Monitoring in the Subsurface

*  and
Received: 8 October 2012; in revised form: 21 November 2012 / Accepted: 5 December 2012 / Published: 12 December 2012
(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Germany 2012)
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Abstract: A conceptually improved sensor network to monitor the partial pressure of CO2 in different soil horizons was designed. Consisting of five membrane-based linear sensors (line-sensors) each with 10 m length, the set-up enables us to integrate over the locally fluctuating CO2 concentrations (typically lower 5%vol) up to the meter-scale gaining valuable concentration means with a repetition time of about 1 min. Preparatory tests in the laboratory resulted in a unexpected highly increased accuracy of better than 0.03%vol with respect to the previously published 0.08%vol. Thereby, the statistical uncertainties (standard deviations) of the line-sensors and the reference sensor (nondispersive infrared CO2-sensor) were close to each other. Whereas the uncertainty of the reference increases with the measurement value, the line-sensors show an inverse uncertainty trend resulting in a comparatively enhanced accuracy for concentrations >1%vol. Furthermore, a method for in situ maintenance was developed, enabling a proof of sensor quality and its effective calibration without demounting the line-sensors from the soil which would disturb the established structures and ongoing processes.
Keywords: gas; monitoring; soil; greenhouse gases; CO2; membrane; sensor gas; monitoring; soil; greenhouse gases; CO2; membrane; sensor
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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MDPI and ACS Style

Lazik, D.; Ebert, S. Improved Membrane-Based Sensor Network for Reliable Gas Monitoring in the Subsurface. Sensors 2012, 12, 17058-17073.

AMA Style

Lazik D, Ebert S. Improved Membrane-Based Sensor Network for Reliable Gas Monitoring in the Subsurface. Sensors. 2012; 12(12):17058-17073.

Chicago/Turabian Style

Lazik, Detlef; Ebert, Sebastian. 2012. "Improved Membrane-Based Sensor Network for Reliable Gas Monitoring in the Subsurface." Sensors 12, no. 12: 17058-17073.



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