Abstract: Alumina (Al2O3) is one of the most practical ceramics used in making ceramic-metal armours. To improve the properties of alumina, some other materials are added to it. In this paper, SiC material as Nano powder is added to alumina, and four armour samples of this new ceramic with different volume fractions (V.F. ) including 0%, 5%, 10% and 15% of SiC particles are made. Then, the samples are warmed up by hot press and their fracture toughness, bending strength and density are measured. Then, it is found that the armour sample made of alumina with V.F. of 10% of SiC particles shows more desirable properties as compared to the other armour samples. So, the computer simulation and ballistic test are done using alumina with V.F. of 10% of SiC particles and the obtained results are compared with those of ballistic test of pure alumina. In the simulations, it is observed that the pure alumina with the thickness of 10 mm and aluminum substrate of thickness 4.8 mm is broken due to the normal impact of a projectile with 800 m/s speed, but the new armour made of the present new ceramic is able to withstand the same conditions and no fracture is observed after impact. The ballistic tests were also done using the present new ceramic-Aluminum armour samples with ceramic thicknesses of 6, 8 and 10 mm, respectively to determine the smallest thickness at which the fracture is occurred. It was found that the armour with the ceramic layer thickness of 6 mm got fractured, whereas the others were able to withstand the conditions of the ballistic test. تفاصيل المقالة

Both stocking rate and housing systems are main factors influencing the occurrence of feather pecking in laying hens raised in conventional cage system. This study examines the effects of different type of cage and stock density on feather pecking behaviour in hens. Total of 216 Hisex Brown hens at 16 weeks of age were randomly selected and put into 2 types of battery cages: conventional cages and modified cages fitted with perch. Each groups comprised 3 subgroups: 2 hens per cage (943 cm2/hens), 3 hens per cage (627.7 cm2/hens), and 4 hens per cage (417.5 cm2/hens). The feather pecking behavior was observed at 25, 28, 31, 34, 37 and 40 weeks of age using time sampling scanning technique. Feather scoring of the hens was done at 42 weeks of age, neither cage type effect nor their interactions with stock densities on feather pecking behaviour and feather score were evident. The results showed that there were significant effect of stocking density on feather pecking behaviour, and feather score (P<0.05). Hens in 3 and 4 hens per cage displayed higher feather pecking bouts than those in 2 hens per cage (P<0.05). The feather condition scores in the areas of breast, wing, rump, tail, and belly of the birds in 2 hens per cage were better than those in other groups (P<0.05). The hens in 2 hens per cage also had higher body weight change than those in the other densities (P<0.05). This study demonstrated that the stock density had considering higher impact on feather pecking behavior than the type of cage. Therefore, using optimum stocking rate would be a potential choice following welfare consideration together with appropriate housing system currently applied. تفاصيل المقالة