In this paper, an analytical solution describing the deflection of a cracked beam repaired with piezoelectric patch is introduced. The solution is derived using perturbation method. A novel analytical model to calculate the proper dimensions of piezoelectric patches used to repair cracked beams is also introduced. This model shows that the thickness of the piezoelectric patch depends mainly on the thickness of the cracked beam, the electro-mechanical properties of the patch material, the applied load and the crack location. Furthermore, the model shows that the length of the piezoelectric patches depends on the thickness of the patch as well as it depends on the length of the cracked beam and the crack depth. The additio

  A theoretical study was done in this work for Fatigue , Fatigue Crack Growth (FCG) and stress factor intensity range for steel .       It also includes Generalized Paris Equation and the fulfillment of his equation which promises that there is a relation between parameters C and n .          Usig Simple Paris Equation through which we concluded the practical values of C and n and compared them with the theoretical values which have been concluded by Generalized Paris Equation .           The value of da/dN and ∆K for every material and sample were concluded and compared with the data which was used in

Scheduling problems have been treated as single criterion problems until recently. Many of these problems are computationally hard to solve three as single criterion problems. However, there is a need to consider multiple criteria in a real life scheduling problem in general. In this paper, we study the problem of scheduling jobs on a single machine to minimize total tardiness subject to maximum earliness or tardiness for each job. And we give algorithm (ETST) to solve the first problem (p1) and algorithm (TEST) to solve the second problem (p2) to find an efficient solution.  

This paper aimed to investigate the relationship between work stress and cognitive failures among administrators of university professors and included a sample by searching from (474) teachers’ administrators and those who obtaining master degree or doctorate. Work stress scale was used, which is prepared by Amina Boashiri supporting by that, a measure of cognitive failures has also been used which is prepared by Khamis Shaeal Al Badri. In order to obtain the results statistical methods were used including (one-sample t-test, Pearson correlation coefficient) results indicated a high level of stress Work stress and high level of cognitive failures among professors as administrators, and also there is a positive correlation, as well as stat

The research aims at identifying the level of family violence directed against the kindergarten child, as well as to identify the significance of the difference in family violence directed against the kindergarten child according to the gender variable

(male-female). It aims also to identify the significance of the difference in family violence directed against the kindergarten child according to the Stage variable (kindergarten-pre-primary). The researcher employed the descriptive correlative approach to conduct the study. The research sample was chosen in a simple random way, as the number of the participants was (130) boys and girls, with (70) males and (60) females, distributed according to the stage with (66) participants in

In this work, the structure properties of nano Lead sulfide PbS thin films are studied. Thin samples were prepared by pulse laser deposition and deposited on glass substrates at wavelength 1064nm wavelength with a various laser energies (200,300,400,500)nm. The study of atomic force microscope (AFM) and X-ray diffraction as well as the effect of changing the laser energy on the structural properties has been studied. It has been observed that the membrane formed is of the polycrystalline type and the predominant phase is the plane (111) and (200). The minimum grain size obtained was 16.5 nm at a laser energy about 200 mJ. The results showed that thin films of average granular sizes (75 nm) could be prepared.As for the optical properties,

Aspergillus flavus was tested for its ability to degrade naphthalene by using solid mineral salts medium (SMS) with different concentrations 100, 300, 500 ppm of naphthalene. Results showed that 100ppm was the best concentration consumed by the fungal test then 300ppm and 500ppm the results for secondary test by using Liquid Mineral Salts Medium (LMSM) 95% of degradation for 100ppm then75% for 300ppm and 30% of degradation for 500ppm then the fungal test was tested for its ability to produce lignolytic enzymes results revealed that lignin peroxidase enzyme was only produced .then fungal test exposed to U.V light and the result showed after 10 minutes of U.V light exposure the degradation ratio were 91% for 100ppm then 79% for 300ppm and