Electrical Capacitance Tomography Measurement of the Migration of Ice Frontal Surface in Freezing Soil

Abstract

The tracking of the migration of ice frontal surface is crucial for the understanding of the underlying physical mechanisms in freezing soil. Owing to the distinct advantages, including non-invasive sensing, high safety, low cost and high data acquisition speed, the electrical capacitance tomography (ECT) is considered to be a promising visualization measurement method. In this paper, the ECT method is used to visualize the migration of ice frontal surface in freezing soil. With the main motivation of the improvement of imaging quality, a loss function with multiple regularizers that incorporate the prior formation related to the imaging objects is proposed to cast the ECT image reconstruction task into an optimization problem. An iteration scheme that integrates the superiority of the split Bregman iteration (SBI) method is developed for searching for the optimal solution of the proposed loss function. An unclosed electrodes sensor is designed for satisfying the requirements of practical measurements. An experimental system of one dimensional freezing in frozen soil is constructed, and the ice frontal surface migration in the freezing process of the wet soil sample containing five percent of moisture is measured. The visualization measurement results validate the feasibility and effectiveness of the ECT visualization method.

The Performance Tested of Multichannel Data Acquisition System In Measurement of Soil Moisture

“…The direct method utilizes a transducer/sensor that is direct contact with the object to be measured as well as the LVDT sensor [6], strain gage [1], probe [7] etc. While the indirect method, the sensor is not in contact with the object, for example, image processing technique [8,9], frequency [10,11], satellite [7] and computation technique [5,10]. Various developments of measurement techniques to obtain better results have also been made, not only on the methods but also on the equipment that accompanies the measurement like a type of microcontroller, communication data method etc [12][13].…”