جستجوی مقالات مرتبط با کلیدواژه « Scale » در نشریات گروه « مهندسی آب »

Scaling is known as one of the most important issues and limitation in aqueous systems, which involved several industries. Applying an efficient, economic and environment friendly solution to control scale formation is challenging. Scaling prevents efficient heat transfer by forming an insulated layer on the surface of heating elements. Moreover, scaling increases the pressure drop in the process and consequently it raises maintenance costs and even leads to system shut down. Using antiscalants is considered the most promising method to control scale formation. To this end, antiscalants are added to the process water. These compounds have received a lot of attention due to the fact that they can control the deposition by the low values and coverage of several mechanisms and can be used simultaneously with the process and do not have significant waste. Antiscalants disrupt the scaling process through a variety of mechanismsincluding threshold effect, crystal modification, dispersion or sequestration. In the current study, scale formation process and the role of antiscalants are discussed.

SWAT model is used to predict the effects of management methods on water cycle, erosion simulation and agricultural chemicals transfer in vast and complex catchment areas. The main objective of this study was to test the SWAT model performance and usage in simulating the runoff flow in areas with different scales. In distributed and semi- distributed models such as SWAT,before calibration, it is necessary to identify parameters that are sensitive to obtain a better output. Therefore, sensitivity analysis was performed using SUFI2 method. In order to evaluate the performance of the model in simulating the runoff flows of different catchment scales, the calibration model was conducted for four stations: Karehsang, Razan, Chelav and Panjab from 1995 to2004 and the model was evaluated from 2005to 2009. To evaluate the ability of the SWAT model in simulating runoff, 3 indices, namely R2, NS, and MSE were used. The results of calibration and validation showed that Karehsang station with an area of 3285 km2. and the coefficients of 0.80-0.87, 0.77-0.75 and 93.20-71.10 had the highest accuracy, respectively. Also, Panjab station, with an area of 130 km2 and the coefficients of 0.68-0.75, 0.55-0.70 and 7.2 67.0 had the lowest accuracy, respectively. The overall results showed that the model has good performance for estimating the runoff.