الفهرس 
Modified surface irrigation systemsOnly 14 pages are availabe for public view
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Abstract
Mohamed El-Sayed Abdel-Rahman: Design of Self-Compensating Nozzle for Gated Irrigation Pipes. Unpublished Ph. D. Thesis, Department of Agricultural Engineering, Faculty of Agriculture, Ain Shams University, 2010. br Gated irrigation pipe is an important tool for improving surface irrigation, it’s development on depends on replacing the gates by designed self-compensating nozzle (poppet nozzle). br The main objective of this study was to improve the distribution uniformity of water discharge along the gated pipe length, by developing a newly designed and locally manufactured self-compensating nozzles (poppet nozzles), to take the place of the gates. br Laboratory experiments were conducted at the Hydraulic Laboratory of Agricultural Engineering Department, Faculty of Agriculture, Ain Shams University, to test and evaluate the hydraulic characteristics of a self-compensating nozzle (poppet nozzle). Three disc diameters (25, 27 and 29mm) were selected for testing under pressure head ranged between 0.33- 3.4 m. br Field experiments were conducted in a maize field at a private farm in Ismailia Government. The poppet nozzle (25mm diameter) was evaluated under operating pressure head 50, 100 and 150cm. br The main results of this study showed the following: br Under operating pressure head ranged between 33cm to 340cm (3.3 to34 kPa), the mean discharge of poppet nozzle with disc diameters of 25, 27 and 29 mm were 0.63, 0.46 and 0.28 l/s, and the mean corresponding discharge coefficients (Cd) were 0.75, 0.79 and 0.9 respectively. Mean water discharge for 25mm disc diameter was constant (0.81l/s) in spite of pressure increasing as a next 10, 30 and 34kPa (100, 300 and 340cm) with mean flow (0.81l/s). While mean discharge for 27mm disc diameters was constant (0.48l/s) in spite of pressure increasing -#102;-#114;-#111;-#109; 6.8, 30 to 33kPa (68, 300and 330cm). Water flow through poppet nozzle with 29mm diameter was shutting at operating pressure 12kPa (120cm). br The mean discharge of poppet nozzles along the pipes with initial pressure head (0.5m, 1.0m and 1.5m) were 0.5, 0.56 and 0.64l/s, with mean coefficient of discharge (Cd) 0.77, 0.75 and 0.72 respectively, br For initial pressure of 0.5, 1.0 and 1.5m the uniformity coefficient were 99, 91.7 and 90.2%, and the manufacture coefficient of variation is 0.094, 0.12 and 0.065 respectively. br Crop yield values were 10.4 and 11.9Mgm /ha for maize grain and one green cut of clover yield crops respectively. The field water use efficiency for maize grain was 1.5 kg/m3, while it was 6.6 kg/m3 for one cut of clover. br Key Words: surface irrigation, gated pipes, poppet nozzle, pressure, br uniformity, maize, clover