الفهرس 
Cover EnglishOnly 14 pages are availabe for public view
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Abstract
The microirrigation systems have been widely used around the world for crop production. The main disadvantage of microirrigation is emitter clogging, especially when using canal water with soil born suspended particles. In order to alleviate this problem, the media filters are introduced to reduce the suspended soil particles, which cause the emitter clogging.The gravel filter capability to remove the suspended soil particles is called Removal efficiency, which can be calculated in accordance with the American Society of Agriculture Engineering (ASAE) rules. The removal efficiency of the gravel media filter depends on the concentration of the suspended soil particles in irrigation water before and after filtration. It is in fact a unique characteristic of the gravel media used. Gravel media size and shape are the most important factors relevant to its performance. In the present work a detailed study has been performed on the determination of the removal efficiency of different gravel media types (sizes), gravel depth and suspended soil particulates concentration by conventional method (oven drying) and laser transmission technique. The main goal is to check the usefulness and validity of using this leaser technique to determine the removal efficiency. In addition, experimental investigation of the proper gravel media has been performed. Three laser types, namely Helium Neon (He-Ne), Helium Cadmium (He-Cd) and Argon (Ar) were used to choose the most suitable and accurate type for the problem under investigation. The results of the measurements of the optical transmission of the suspended particulates adopting different laser sources revealed that He-Ne is the most suitable and accurate laser type to perform such measurements. The comparison between the conventional (oven drying) and laser techniques indicted that, the results of the laser transmission technique using He-Ne in the measurements of the removal efficiency is more convenient, fast, accurate, easy to use and lower in cost in comparison with the conventional method and can be applied in the field.