الفهرس 
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Abstract
The main aim of this work is to study the effect of drying temperature and plant layer thickness on the weight losses of basil and marjoram, drying time, final moisture content, drying rate, energy requirements and drying costs. To achieve that different drying temperatures (50, 60 and 70 °C) and plant thickness layers (1, 2 and 3 cm) were used. The obtained results indicated that, the accumulated weight loss of basil leaves increased from 80.10 to 80.50, 81.09 to 81.80 and 83.52 to 83.54 % %, in hybrid solar drying system and it increased from 79.07 to 82.37, 81.38 to 82.29 and 82.73 to 82.97 % in oven drying system and for marjoram leaves in hybrid solar system increased from 73.22 to 74.19, 73.07 to 73.45 and 73.81 to 75.51 %, and oven drying system increased from 59.28 to 85.90, 46.62 to 83.57 and 41.21 to 82.98 %, when the drying temperature increased from 50 to 60 °C, respectively, for 1, 2 and 3 cm thickness layers. The moisture content of basil dried in hybrid solar drying increased from 402.64 to 440.38, 487.29 to 507.10 and 412.89 to 507.63 % d.b., and it increased from 377.83 to 441.08, 467.62 to 507.09 and 467.36 to 487.26 % d.b., in oven drying and for marjoram leaves in hybrid solar system increased from 273.39 to 282.11, 315.14 to 333.17 and 287.53 to 308.48 % d.b., and it increased from 4258.02 to 326.1, 294.76 to 322.94 and 312.81 to 333.04 % d.b., in oven drying when the drying temperature increased from 50 to 60 °C, respectively, for 1, 2 and 3 cm thickness layers. The drying rate of basil leaves dried in hybrid solar drying system increased from 190.26 to 389.19, 154.33 to 241.74 and 87.69 to 201.10 gwater kg-1 h-1 and it increased from 179.39 to 382.22, 148.86 to 238.63 and 96.30 to 195.28 gwater kg-1 h-1 in oven drying system, when the drying temperature increased from 50 to 60 °C, respectively, for 1, 2 and 3 cm thickness layers. For marjoram leaves dried in hybrid solar drying, the drying rate increased from 135.7to 204.6, 82.95 to 156.75, and 51.04 to 106.53 gwater kg-1 h-1, and it increased from 130.36 to 223.73, 74.6 to 154.21, and 53.98 to 112.31 gwater kg-1 h-1 in oven drying system, when the drying temperature increased from 50 to 60 °C, respectively, for 1, 2 and 3 cm thickness layers. The highest values of the basil and marjoram oil content (1.8 and 2.80 %) was obtained when the basil dried by hybrid solar drying system at 50 °C. the energy consumption for drying basil and marjoram decreases with increasing drying temperature and plant thickness layers for hybrid solar and oven drying systems. The total cost indicate that the highest cost of drying basil was at a drying temperature of 50 and the thickness of the plant layers 1 cm was 9.85 LE/kg, and the lowest cost at a temperature of 60 with a thickness of the product layer 3 cm was 9 LE/kg in the hybrid solar drying system. As for oven drying, it was the highest cost was at a temperature of 50 and a product layer thickness of 1 cm was 14.53 LE/kg and the lowest cost was at a temperature of 70 and a product layer thickness of 3 cm was 10.84 LE/kg g. As for marjoram, the highest cost was at a temperature of 50 and a thickness of 1 product cm, and it was 9.65 LE/kg, and the lowest cost consumption was at 60 degrees with a thickness of 3 cm, and it was 8.92 LE / kg in the hybrid solar system. As for ovens, the highest cost was at a temperature of 50 and a thickness of 1 cm, and it was 13.48 LE/kg. and the lowest cost consumption was at 70 degrees with a thickness of 3 cm, and it was 10.58 LE/kg.