Simulation of the Hydraulic Performance of Parallel Pivot Weirs with Different Angles

Pivot weirs are one of the most important structures for regulating the water level in rivers and canals. These weirs are constructed with one or more gates in a row in the waterways. Changing the angle of each gate is done individually with an independent system. Based on available information, the hydraulic performance of this type of weirs (especially in several gates and different angles) in different operational conditions has not been investigated. In present study, pivot weirs with two gates are simulated using Ansys CFX software with the angles of 27.8 to 90 degree and the discharges between 40 to 130 L/s. Further, the importance of the open space between the two adjacent weirs with different angles (lack of retail wall) and its hydraulic behavior have been studied. The model was calibrated based on valid laboratory data and using the K-ϵ turbulence model.  Therefore, the weirs with equal angles were studied in the first step. In this case, the effective discharge angle coefficient was studied and its maximum value compared to the vertical angle was obtained 1.076 for the angle of 52°. Furthermore, relationships for discharge coefficient versus upstream water depth were developed. In the next step, the effective length of the crest was found to be increases by 30% under unequal angles operation and the discharge coefficient raised by 1.3 to 2.4 times. Also, it was recognized that, in case of two weirs with unequal angles, about 26% to 69% of the flow passes through the distance between the two weirs. Therefore, the performance of unequal angles operation seems to be more effective in controlling the water level and discharge in different conditions and especially in flood events

Molybdenum (Mo) increases endogenous phenolics, proline and photosynthetic pigments and the phytoremediation potential of the industrially important plant Ricinus communis L. for removal of cadmium from contaminated soil.

Cadmium (Cd) in agricultural soil negatively affects crops yield and compromises food safety. Remediation of polluted soil is necessary for the re-establishment of sustainable agriculture and to prevent hazards to human health and environmental pollution. Phytoremediation is a promising technology for decontamination of polluted soil. The present study investigated the effect of molybdenum (Mo) (0.5, 1.0 and 2.0 ppm) on endogenous production of total phenolics and free proline, plant biomass and photosynthetic pigments in Ricinus communis plants grown in Cd (25, 50 and 100 ppm) contaminated soils and the potential for Cd phytoextraction. Mo was applied via seed soaking, soil addition and foliar spray. Foliar sprays significantly increased plant biomass, Cd accumulation and bioconcentration. Phenolic concentrations showed significantly positive correlations with Cd accumulation in roots (R 2 = 0.793, 0.807 and 0.739) and leaves (R 2 = 0.707, 721 and 0.866). Similarly, proline was significantly positively correlated with Cd accumulation in roots (R 2 = 0.668, 0.694 and 0.673) and leaves (R 2 = 0.831, 0.964 and 0.930). Foliar application was found to be the most effective way to deliver Mo in terms of increase in plant growth, Cd accumulation and production of phenolics and proline