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Showing 3 results for ShahiNejad

B. Shahinejad, A. Parsaei, A. Haghizadeh, A. Arshia, Z. Shamsi,
Volume 26, Issue 3 (Fall 2022)
Abstract

In this research, soft computational models including multiple adaptive spline regression model (MARS) and data group classification model (GMDH) were used to estimate the geometric dimensions of stable alluvial channels including channel surface width (w), flow depth (h), and longitudinal slope (S) and the results of the developed models were compared with the multilayer neural network (MLP) model. To develop the models, the flow rate parameters (Q), the average particle size in the floor and body (d50) as well as the shear stress (t) as input and the parameters of water surface width (w), flow depth (h), and longitudinal slope (S) were used as output parameters. Soft computing models were developed in two scenarios based on raw parameters and dimensionless form independent and dependent parameters. The results showed that the statistical characteristics in estimating w, the best performance is related to the MARS model, whose statistical indicators of accuracy in the training stage are R2 = 0.902, RMSE=1.666 and in the test phase is R2 = 0.844, RMSE=2.317. In estimating the channel depth, the performance of both GMDH and MARS models is approximately equal, both of which were developed based on the dimensionless form of flow rate as the input variable. The statistical indicators of both models in the training stage are R2 » 0.90, RMSE » 8.15 and in the test phase is R2 » 0.90, RMSE = 7.40. The best performance of the developed models in estimating the longitudinal slope of the channel was related to both MARS and GMDH models, although, in part, the accuracy of the GMDH model with statistical indicators R2 = 0.942, RMSE = 0.0011 in the training phase and R2 = 0.925, RMSE = 0.0014 in the experimental stage is more than the MARS model.

B. Shahinejad, A. Parsaei, H. Yonesi, Z. Shamsi, A. Arshia,
Volume 26, Issue 4 (Winiter 2022)
Abstract

In the present study, the flow rate in flues containing lateral semi-cylinders (SMBF) was simulated and estimated under free and submerged conditions using back vector machine models (SVM), spin multivariate adaptive regression (MARS), and multilayer artificial neural network (MLPNN) model. In free flow mode, the dimensionless parameters extracted from the dimensional analysis include the ratio of upstream flow to throat width and contraction ratio (throat width to channel width), and in the submerged state, in addition to these two parameters, the depth-to-throat width, and bottom-depth parameters upstream depth were used as input and the two-dimensional form of flow rate was used as the output of the models. The results showed that in free flow mode in the validation stage, the MARS model with statistical indices of R2 = 0.985, RMSE = 0.008, MAPE = 0.87%, and the SVM model with statistical indices of  R2 = 0.971, RMSE = 0.0012, MAPE =1.376%, and MLPNN model with statistical indices of R2 = 0.973,  RMSE = 0.011, MAPE = 1.304% have modeled and predicted the flow rate. In the submerged state, the statistical indices of the developed MARS model were R2 = 0.978, RMSE = 0.018, MAPE = 3.6%, and the statistical indices of the SVM model were R2 = 0.988, RMSE = 0.014, 2%. MAPE = 4, and the statistical indicators of the MLPNN model were R2 = 0.966, RMSE = 0.022, and MAPE = 5.7%. In the development of SVM and MLPNN models, radial kernel and hyperbolic tangent functions were used, respectively.

Jalil Kermannezhad, Hassan Torabipoodeh, Elham Ghanbari-Adivi, Babak Shahinejad,
Volume 30, Issue 3 (Fall 2026)
Abstract

Conventional methods for desalination of water and wastewater are usually not economically viable for providing the water required for agricultural production due to high energy consumption and equipment costs. This study aimed to evaluate the efficiency of magnetic nanobiochar produced from sugarcane bagasse to remove sodium ions from agricultural wastewater under the influence of a magnetic field. Non-nanoactive, nanoactive, and magnetic nanoactive adsorbents were produced using a pyrolysis process in an electric furnace at 600 °C, chemical activation with potassium hydroxide, and magnetization with a combination of hexahydrate ferric chloride and heptahydrate ferric sulfate. The results showed that the highest removal rates of chloride ions (44.6%) and sodium ions (58.3%) were obtained in the magnetically activated nano-biochar under the influence of a magnetic field of 0.5 Tesla, for an activator-to-biochar ratio of 3, a microwave power of 400 W, and an activation time of 10 minutes. Surface analyses including FT-IR spectroscopy and scanning electron microscopy (SEM) confirmed that the hydroxyl, carboxyl, and carbonyl functional groups on the surface of the adsorbent play a key role in the adsorption of sodium and chloride ions. It was also observed that the application of a magnetic field improved the orientation of the ions towards the adsorbent and weakened the hydrogen bonds in water, which led to an increase in the efficiency of the adsorption process. This study shows that magnetic nano-biochar, under a magnetic field, could be an economical and sustainable solution for reducing the salinity of agricultural wastewater.
 


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