Estimation of the measurement uncertainty of humidity using a TDR probe

Majerek, Dariusz; Widomski, Marcin K.; Garbacz, Monika; Suchorab, Zbigniew

doi:10.1063/1.5047621

Cited by 3 publications

(6 citation statements)

References 10 publications

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“…The first is the regression uncertainty and ε~N (0, σ ) which comes from the randomization which results in some variability of all estimated regression parameters, that is expressed in covariance matrix σ 2 (X’X) −1 . The second source is a consequence of fact, that it is not possible to reveal the true dependence between the selected predictors and the dependent variable—fitted volumetric water content value may differ from the true value of θ because it is impossible to control all variables affecting it [ 60 ]. Uncertainties type B are neglected from the investigation because they are of lower level comparing to the uncertainty of A type.…”

Section: Methodsmentioning

confidence: 99%

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A Noninvasive TDR Sensor to Measure the Moisture Content of Rigid Porous Materials

Suchorab

Widomski

Łagód

et al. 2018

Sensors

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The article presents the potential application of the time domain reflectometry (TDR) technique to measure moisture transport in unsaturated porous materials. The research of the capillary uptake phenomenon in a sample of autoclaved aerated concrete (AAC) was conducted using a TDR sensor with the modified construction for non-invasive testing. In the paper the basic principles of the TDR method as a technique applied in metrology, and its potential for measurement of moisture in porous materials, including soils and porous building materials are presented. The second part of the article presents the experiment of capillary rise process in the AAC sample. Application of the custom sensor required its individual calibration, thus a unique model of regression between the readouts of apparent permittivity of the tested material and its moisture was developed. During the experiment moisture content was monitored in the sample exposed to water influence. Monitoring was conducted using the modified TDR sensor. The process was additionally measured using the standard frequency domain (FD) capacitive sensor in order to compare the readouts with traditional techniques of moisture detection. The uncertainty for testing AAC moisture, was expressed as RMSE (0.013 cm3/cm3) and expanded uncertainty (0.01–0.02 cm3/cm3 depending on moisture) was established along with calibration of the applied sensor. The obtained values are comparable to, or even better than, the features of the traditional invasive sensors utilizing universal calibration models. Both, the TDR and capacitive (FD) sensor enabled monitoring of capillary uptake phenomenon progress. It was noticed that at the end of the experiment the TDR readouts were 4.4% underestimated and the FD readouts were overestimated for 12.6% comparing to the reference gravimetric evaluation.

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Section: Methodsmentioning

confidence: 99%

“…Using the error propagation law, the combined standard measurement uncertainty (including uncertainties type A and B) may be presented as follows [ 60 , 61 ]:

so:

…”

Section: Methodsmentioning

confidence: 99%

A Noninvasive TDR Sensor to Measure the Moisture Content of Rigid Porous Materials

Suchorab

Widomski

Łagód

et al. 2018

Sensors

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“…The results are compared with gravimetric water evaluation and second order polynomial regression models have been evaluated. Relation between both types of data has been described mathematically using the second order polynomial regression models, which is frequently applied for this type of data [9,12]. The general formula of dependence is the following:…”

Section: Resultsmentioning

confidence: 99%

“…Additionally the uncertainty evaluation of the measurement was calculated for different levels of material moisture. Uncertainty evaluation was conducted according to GUM recommendations [11] and included combined standard uncertainty according to the following equation [11,12]:…”

Section: Figure 1 Measurement Setup Used In Experimentsmentioning

confidence: 99%

Calibration of microwave antenna for porous materials moisture evaluation using frequency domain analysis

Tabiś,

Suchorab,

Szczepaniak

et al. 2023

J. Phys.: Conf. Ser.

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The article presents the possibility to use microwave contactless measuring system for evaluation of moisture of porous media, mainly building materials utilizing the frequency domain analysis. In the article the description of microwave sensing technique is presented and the methods of microwave data analysis described. In the second part of the manuscript, microwave readouts are presented and the apparent permittivity values estimated in the red brick samples depending on moisture. With the calculated data, calibration model is estimated and fitting quality evaluated. Using the achieved data and calculated values the potential of microwave sensing technique is evaluated and advantages and disadvantages presented.

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“…The above-mentioned combined standard measurement uncertainty that includes both A and B type uncertainties can be described using the following formula [ 69 , 72 ]:

so:

…”

Section: Methodsmentioning

confidence: 99%

Comparison of the Moist Material Relative Permittivity Readouts Using the Non-Invasive Reflectometric Sensors and Microwave Antenna

Suchorab

Tabiś²,

Brzyski

et al. 2022

Sensors

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The article concerns the issue of non-invasive moisture sensing in building materials. Two techniques that enable evaluating the value of the relative permittivity of the material, being the measure of porous material moisture, have been utilized for the research. The first is the microwave technique that utilizes the non-contact measurement of velocity of microwave radiation across the tested material and the second is the time domain reflectometry (TDR) technique based on the measurement of electromagnetic pulse propagation time along the waveguides, being the elements of sensor design. The tested building material involved samples of red ceramic brick that differed in moisture, ranging between 0% and 14% moisture by weight. The main goal of the research was to present the measuring potential of both techniques for moisture evaluation as well as emphasize the advantages and disadvantages of each method. Within the research, it was stated that both methods provide similar measuring potential, with a slight advantage in favor of a microwave non-contact sensor over surface TDR sensor designs.

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Estimation of the measurement uncertainty of humidity using a TDR probe

Cited by 3 publications

References 10 publications

A Noninvasive TDR Sensor to Measure the Moisture Content of Rigid Porous Materials

A Noninvasive TDR Sensor to Measure the Moisture Content of Rigid Porous Materials

Calibration of microwave antenna for porous materials moisture evaluation using frequency domain analysis

Comparison of the Moist Material Relative Permittivity Readouts Using the Non-Invasive Reflectometric Sensors and Microwave Antenna

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