الفهرس 
Physical properties of grainOnly 14 pages are availabe for public view
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Abstract
Grain grading is the process key of determining the grain’s marketability. Grain cleaning is a basic procedure in the grain grading system in which impurities or contaminants are separated from sound grains. Clean grain reduces problems that occur during storage and handling. Clean grain also save storage space and increases marketability. Over the last few years, grain production per feddan was improved significantly as a result of using better seeds and new techniques of mechanization. The present work was carried out in the Central Administration of seed certification, kafr El-sheikh gavernoraate, Egypt during season of 199711998. Wheat seeds variety Sakha-61 was used in this research.Cleaning and grading are two extremely important steps in the production of high- quality grains. Established cleaning and grading procedures have enhanced on orderly marketing of grain and seeds. The average weight of 100 grains was about 4.77 g (0.05 N weight) at 11.4 % moisture content, w.b. The declination angle of the deck was 0.390 (22.4) rad. (degree) and the coefficient of friction value was 0.41. The repose angle of wheat grain was 0.471 (27) rad. (degree). Gravity separator was used in the present research to evaluate its performance under laboratory conditions. The purpose of the laboratory gravity separator is to separate light particle form heavy ones. It is therefore possible to separate heavy kernels with high ability to germinate from light and less valuable kernels. The objectives of the present study as follows: 1 - Complete separation - removal of all contaminating or undesirable material from the seeds; 2- Minimum seed loss - some good seeds are removed along with contaminants in almost every operation, but this loss must be kept at a minimum value; upgrading quality - improvement of seed quality not only through removal of contaminating seed, but also removal of rotten, cracked, broken, insect damaged or otherwise injured or crop seeds of low quality ; 3- Efficiency - the highest consistent capacity with effectiveness of separation.; and 4- Minimum labor requirement - labor is a direct operating cost and cannot be recovered. 5- Specify the optimum conditions of operation, which ensure the highest degree of cleanliness with minimum grain losses. 6- Estimate the energy required for grading and separating processes at different air flow rates.