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Phoenix dactylifera l. pinnae (the green leaves of dates palm) were used as natural reinforcing (strengthening) fibers to improve the mechanical properties of polyester as a matrix material, the fibers of the green leaves of dates palm were used in two lengths, 10 and 20mm with five rates of 0, 2.5, 5, 10, and 20% , where the reinforcing with the leaves fibers increases the hardness strength from 76.5 to be about 86.55 , the Impact value raised from about 0.313 to 0.461 , in addition to that the flexural strength from 2.66 to be about 55 , and the thermal conductivity increases from 2.54

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In present work, the influence of La2O3 doping on the electrical properties of ZnO varistors, has been investigated, where in the beginning ZnO has been doped with some metal oxides (Bi2O3, Sb2O3, Co3O4, Cr2O3, NiO, and MnO2), and then doped with La2O3.The doping with La2O3 in three concentration rates of 〖10〗^(-3) , 〖5*10〗^(-3) , and 〖10*10〗^(-3), and all samples before and after doping with La2O3 are sintered in air at 1050, 1100, and 1150℃ with heating rate of 5℃⁄min for 2 hours. XRD test shows the existence of ZnO as the main phase and Zn7Sb2O12 as the secondary phase. Electrical tests illustrate an obvious effect of La2O3 on the electrical properties of ZnO varistor, where the doping increases the nonlinearity coefficient, potential gradient, and breakdown voltage, while the leakage current magnitudes decreased after doping. Moreover the grain size has been decreased after doping with La2O3.

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