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Go to Editorial ManagerThe research focuses on studying the effect of microwave energy as an alternative heating method on dyeing and printing pretreatments of cotton fabrics. In this research, a microwave oven was used to heat the solutions which used in de-sizing, scouring, bleaching and mercerizing processes at different energy levels. The results showed the importance of this heating method in improving desizing efficiency where the best result was obtained at 180 W and 24 min and this method was beneficial in saving energy and time. The best result in scouring was obtained at 720 watts and 24 minutes, whereas at 720 watts and 20 minutes was the best result in bleaching. We can save energy, time and chemicals compared with the conventional method. The mercerizing by microwave increased the absorption of dye solutions for the samples compared with the traditional method, where the color strength increased by increasing the treatment time and the level of energy in the microwave and the best result was obtained at 900 watts and 90 seconds.
The stilling basin is a frequently used energy dissipators that converts supercritical flow from a dam's spillway into subcritical flow that is in compatible with the downstream river regime. They serve to prevent scouring, which happens when high-velocity water enters the dam's downstream reach. This scouring not only seriously erodes the downstream area but also damages the dam's foundation. In this research, the behavior of blocks of stilling basin and spillway toe in reducing energy losses and the longitudinal hydraulic jump toe position is evaluated. This research includes two cases ; case1 is a spillway and stilling basin without blocks, and case2 which is a spillway and stilling basin with chute blocks and middle blocks. By increasing the discharge from 0.010 m3/s to 0.020 m3/s, the difference in the dissipation energy for case1 and case2 are (17.6%, 24.7%) respectively, and that the percentage of decrease in the longitudinal hydraulic jump toe position is (83.94%, 85.90%, 86.30%, 87.20%, 88.39%, 87.58%, 80.64%, 77.94%) for the discharges tests from ( 0.010 m3/s to 0.017 m3/s). As a results, The using of blocks in stilling basin and spillway led to a rise in relative energy dissipation and decrease the longitudinal hydraulic jump toe position of stilling basins.