The main target of the current study is the assessment of API 5L X52 pipe line containing lack of penetration and undercut welding defects and to study the influence of the defect length and depth on the failure pressure of the pipeline. The failure pressure is calculated by using Finite element software ANSYS ver19. The results from finite element analysis are used to train an artificial neural network for easily predicting the failure pressure with a wide range of defect depths and lengths. Also the results obtained were also used in the regression analysis to find equations linking the maximum pressure to the defects dimensions. The results revealed a Good agreement between finite element modeling and the experimental tests, theoretical values and available design codes with maximum average error of (13.4%). The failure pressure varied significantly as a function of the defect length and depth.

Semi conducting   Znx Se1-x  thin films were prepared at 480nm thickness on glass substrates at room temperature using vacuum evaporation technique .The electrical properties of  Znx Se1-x  thin films have been investigated , such as dc conductivity and Hall effect. The investigation showed that the composition range 0≤x≤0.3 has an influence on the electrical properties of the Znx Se1-x thin films . The dc conductivity experiment in the range of temperature 293-423 ok gave  two activation energies Ea1& Ea2 which represented  two types of conduction mechanisms . Ea1 & Ea2 have values 0.6 & 0.1eV respectively for x=0, while 1.01 &0.107 eV  for x=0.3. Also the study showed that the dc conductivity  σ=5.19x10-7 (Ω. cm)-1 for x=0 , and decreases with increasing zinc to 3.2x 10-7 (Ω. cm)-1 at x=0.3. Hall effect study  appeared that the type of the carriers is p-type, their concentration is 1.6x108cm -3 and increases with increasing the fraction of composition x to 2.6x1010 cm-3  .Also the mobility of the carriers has good relation with zinc content x