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The Effect of Wetting and Drying Cycles on Potassium Release in Three Soil Orders

Al-Silevany Baybeen Saeed Hasen, Mehmedany Lazkeen Ahmed Merween

Journal of Ecological Engineering

2023

Vol. 24, nr 1

218--226

This research was conducted to study the potassium release under ten wetting and drying cycles in three soil orders (Mollisols, Vertisols, and Aridisols) collected from three different locations (Sharya, Semeel, and Kanishrin) in Dohuk governorate in Iraqi-Kurdistan region by using Ca-resin capsules, and K+ desorption (Kd) fitted to four model equations to choose the best equation to describe K+. The results of the experiments showed that flocculated water content wetting and drying cycles increased cumulative K-release from Ca-resin capsules until a tenth of the wetting-drying cycle. Potassium desorption according to the kinetic approach showed a significant effect of time on potassium desorption, and potassium desorption conformed to parabolic diffusion equations kinetics was the best equation to describe the Kd of potassium by using Ca-resin with a high coefficient of determination (R2) and low standard error and the order of the equation in terms of their preference in describing the desorption process is as follows: 1 – Parabolic diffusion, 2 – Power function, 3 – Elovich equation, 4 – First-order. The apparent desorption rate coefficient for the parabolic diffusion equation ranged from 0.1084–0.0877–0.1040 cmol kg-1∙day -1 from Mollisols, Vertisols, and Aridisols respectively. The rate coefficient K+ desorption according to the parabolic diffusion equation had a significant and positive correlation with SO42-, K+, T-CaCO3, HCO3, CEC, and Ca2+ but negatively significant correlated with EC and active CaCO3.

Artificial intelligence-based modeling for the estimation of Q-Factor and elastic young’s modulus of sandstones deteriorated by a wetting-drying cyclic process

Rashid Hafiz Muhammad Awais, Ghazzali Muhammad, Waqas Umer, Malik Adnan Anwar, Abubakar Muhammad Zubair

Archives of Mining Sciences

2021

Vol. 66, no. 4

635--658

In this study, a series of destructive and non-destructive tests were performed on sandstone samples subjected to wetting-drying cycles. A total of 25 Wet-Dry cycles were provided to investigate any significant change in the engineering properties of sandstones in terms of their porosity, permeability, water absorption, density, Q-factor, elastic modulus (E), and unconfined compressive strength (UCS). The overall reduction in the values of density, E, Q-factor, and UCS was noted as 3-4%, 42-71%, 34-62%, and 26-70% respectively. Whereas, the overall appreciation in the values of porosity, permeability, and water absorption was recorded as 24-50%, 31-64%, and 25-50% respectively. The bivariate analysis showed that the physical parameters had a strong relationship with one another and their Pearson’s correlation value (R) ranged from 0.87-0.99. In prediction modeling, Q-factor and E were regressed with the contemplated physical properties. The linear regression models did not provide satisfactory results due to their multicollinearity problem. Their VIF (variance inflation factor) value was found much greater than the threshold limit of 10. To overcome this problem, the cascade-forward neural network technique was used to develop significant prediction models. In the case of a neural network modeling, the goodness of fit between estimated and predicted values of the Q-factor (R2 = 0.86) and E (R2 = 0.91) was found much better than those calculated for the Q-factor (R2 = 0.30) and E (R2 = 0.36) in the regression analysis.