Analytical Modeling of Soil Solution Monitoring by Diffusion in Porous Cups
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- 作者：Benjamin D. Shaw ; Atac Tuli ; Jing-Bin Wei and Jan W. Hopmans
- 关键词：Nitrate diffusion ; Soil solution ; Exact analytical solution ; Electrical circuit analog solution ; UV absorption spectrometer ; Stainless steel porous cup
- 刊名：Transport in Porous Media
- 出版年：2010
- 出版时间：January, 2010
- 年：2010
- 卷：81
- 期：2
- 页码：341-360
- 全文大小：420.8 KB
文摘
There is increasing interest toward in situ solution monitoring of soil chemicals for agricultural, industrial, and ecological purposes. Rather than extracting soil solution, a series of laboratory experiments was conducted to evaluate a diffusion equilibration technique, providing for real time in situ soil solution nitrate concentration via UV absorption spectroscopy. Experiments allowed for diffusion of nitrate from an outside reservoir into a porous cup. The experimental data were compared with model predictions using three different analytical solutions: (i) an exact solution (EX model) assuming radial symmetry that includes a porous cup with a porous wall and a finite size outside reservoir, (ii) an approximate solution (RC model) that assumes an infinitely large supply reservoir with a porous cup wall that does not influence ion diffusion, and (iii) and a model based on an electric circuit analog (ECA model). The results indicate that the ECA solution provides the best match overall to the experimental data.