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A pilot-scale hybrid constructed wetland with vertical flow and horizontal flow in series was constructed and used to investigate organic material and nutrient removal rate constants for wastewater treatment and establish a practical predictive model for use. For this purpose, the performance of multiple parameters was statistically evaluated during the process and predictive models were suggested. The measurement of the kinetic rate constant was based on the use of the first-order derivation and Monod kinetic derivation (Monod) paired with a plug flow reactor (PFR) and a continuously stirred tank reactor (CSTR). Both the Lindeman, Merenda, and Gold (LMG) analysis and Bayesian model averaging (BMA) method were employed for identifying the relative importance of variables and their optimal multiple regression (MR). The results showed that the first-order-PFR (M) model did not fit the data (P > 0.05, and R < 0.5), whereas the first-order-CSTR (M) model for the chemical oxygen demand (COD) and Monod-CSTR (M) model for the COD and ammonium nitrogen (NH-N) showed a high correlation with the experimental data (R > 0.5). The pollutant removal rates in the case of M were 0.19 m/d (COD) and those for M were 25.2 g/m∙d for COD and 2.63 g/m∙d for NH-N. By applying a multi-variable linear regression method, the optimal empirical models were established for predicting the final effluent concentration of five days' biochemical oxygen demand (BOD) and NH-N. In general, the hydraulic loading rate was considered an important variable having a high value of relative importance, which appeared in all the optimal predictive models.

This paper investigates spin-current transport in a GaMnAs/GaAs/GaMnAs magnetic semiconductor tunnel junctions under applied bias voltages. The 30-band k.p approach is used to describe the materials within the heterostructure, incorporating both spin-orbit and exchange interactions. We use the transfer-matrix formalism to derive numerical solutions for the wave functions. At specific bias values, we calculate the polarization of the spin-current component along the z direction of the structure. We show oscillations of the two spin-current components perpendicular to the magnetization with equal polarization amplitude and characteristic period. The polarization amplitude varies around 10%, reflecting the typical polarization in such type of material. The oscillation period - which relates to the Larmor frequency for spin precession - increases with the bias voltage values.

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