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Title: Pressure Correction in the Calibration of Heat Dissipation Sensors

Abstract

Heat dissipation sensors (HDSs) infer soil matric potential based on the measured rate of temperature rise from a heat source. The process for calibrating these sensors may use a pressure plate apparatus (PPA) to remove water to a certain calibration point that is controlled by pressure. Conventionally, the pressure within the PPA is released before the temperature change calibration points are measured ( ΔT 0). This conventional HDS calibration approach can take several weeks. We propose that the equilibrated temperature change at pressure ( ΔT p) can be corrected empirically to the value at zero pressure. Based on measurements of 14 HDSs between 0.02 and 0.1 MPa, ΔT p was on average 6.2% larger than ΔT 0. After pressure correction, using an empirical equation, the difference between the corrected ΔT p and ΔT 0 was only 0.28%. These results demonstrate that this empirical approach provides sufficient accuracy to achieve HDS calibration without performing a PPA pressure release.

Authors:
 [1];  [1];  [1]
  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1577978
Report Number(s):
PNNL-SA-142103
Journal ID: ISSN 1539-1663
Grant/Contract Number:  
AC05-76RL01830
Resource Type:
Accepted Manuscript
Journal Name:
Vadose Zone Journal
Additional Journal Information:
Journal Volume: 18; Journal Issue: 1; Journal ID: ISSN 1539-1663
Publisher:
Soil Science Society of America
Country of Publication:
United States
Language:
English
Subject:
47 OTHER INSTRUMENTATION; Vadose Zone; monitoring; remediation; HDS; heat dissipation sensor; PPA; pressure plate apparatus

Citation Formats

Thomle, Jonathan N., Zhang, Z. Fred, and Dai, Gao L. Pressure Correction in the Calibration of Heat Dissipation Sensors. United States: N. p., 2019. Web. doi:10.2136/vzj2019.05.0052.
Thomle, Jonathan N., Zhang, Z. Fred, & Dai, Gao L. Pressure Correction in the Calibration of Heat Dissipation Sensors. United States. doi:10.2136/vzj2019.05.0052.
Thomle, Jonathan N., Zhang, Z. Fred, and Dai, Gao L. Fri . "Pressure Correction in the Calibration of Heat Dissipation Sensors". United States. doi:10.2136/vzj2019.05.0052. https://www.osti.gov/servlets/purl/1577978.
@article{osti_1577978,
title = {Pressure Correction in the Calibration of Heat Dissipation Sensors},
author = {Thomle, Jonathan N. and Zhang, Z. Fred and Dai, Gao L.},
abstractNote = {Heat dissipation sensors (HDSs) infer soil matric potential based on the measured rate of temperature rise from a heat source. The process for calibrating these sensors may use a pressure plate apparatus (PPA) to remove water to a certain calibration point that is controlled by pressure. Conventionally, the pressure within the PPA is released before the temperature change calibration points are measured (ΔT0). This conventional HDS calibration approach can take several weeks. We propose that the equilibrated temperature change at pressure (ΔTp) can be corrected empirically to the value at zero pressure. Based on measurements of 14 HDSs between 0.02 and 0.1 MPa, ΔTp was on average 6.2% larger than ΔT0. After pressure correction, using an empirical equation, the difference between the corrected ΔTp and ΔT0 was only 0.28%. These results demonstrate that this empirical approach provides sufficient accuracy to achieve HDS calibration without performing a PPA pressure release.},
doi = {10.2136/vzj2019.05.0052},
journal = {Vadose Zone Journal},
number = 1,
volume = 18,
place = {United States},
year = {2019},
month = {11}
}

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