In current research Copper was employed for preparing a ternary system of Al–Si alloy in different (0.2–2.5 wt. %) the best was taken is (1.5%wt) of copper that circumstances of solidification for improving the mechanical performance of the available in aluminium alloy. Cast iron molds were prepared to obtain tensile strength testing specimens. Alloys were prepared by employing gas furnaces. The molten metal was poured into a preheated cast-iron mold. The obtained alloy structures were studied using an X-ray diffractometer and optical microscopy. The mechanical performance of the prepared alloys was examined under the influence of different hardening conditions in both heat and non-heat-treated conditions. The outcomes showed at the ideal input status of friction stir processing, the cast alloy microstructure was enhanced in terms of refinement of eutectic and primary Si particles, homogeneous dispersion of Si, and the reduction in porosity. The mineral compounds formed during the hardening process were examined using an optical microscope. The highest maximum tensile strength (UTS) was 120 MPa for sample Al-22.5Si, and 147 MPa for sample Al-21Si-1.5Cu, while the highest hardness was 77 HB for sample Al-22.5Si, and 90 HB for sample Al-21Si-1.5Cu.
Computer theoretical study has been carried out on the design of five electrode immersion electrostatic lens used in electron gun application. The finite element method (FEM) is used in the solution of the Poisson's equation fro determine axial potential distribution, the electron trajectory under Zero magnification condition . The optical properties : focal length ,spherical and chromatic aberrations are calculated,From studying the properties of the designed electron gun. we have good futures for these electron gun where are abeam current 4*10-4A can be supplied by using cathode tip of radius 100 nm.
The design and construction of an optical communication system was carried out
using a transverse opto-electronic effect (Pockels effect) to transfer an acoustic signal
using LiNbO3 crystal as an opto-electronic modulator in a new method and studying the
mechanism of the electronic circuits then analyzing the resulted signal.
The reaction paths of the C-C and C-H bond cleavage in the anthracene and phenanthrene aromatic molecules are studied by applying the ab-initio DFT method. It is found that the C-C bond cleavage proceeds via a singlet aromatic transition state, compelled through a disrotatoric ring opening reaction. A suprafacial H atom shift follows the transition state, leading to the formation of a methylene -CH2 and an acetylenic or allenic moiety. The calculated activation energies for anthracene range from 158.81-208.90 kcal/mol and the reaction energies from 96.106-156.976 kcal/mol. For phenanthrene, the energy values are 157.39-202.34 kcal/mol and 62.639-182.423 kcal/mol, respectively. For the C-H cleavage reactions, the calculated reaction energies
... Show MoreBackground: Nasal obstruction is common in otorhinolaryngology outpatient visitors. The diagnosis of such compliant is by history, clinical examination and diagnostic procedures. Nasal endoscopy and computerized tomography scan are common diagnostic investigations. Nasal obstruction is either anterior or posterior (nasal septal deviations, hypertrophied turbinate pathological cyst, polyps, mass etc), or postnasal obstruction (hypertrophied turbinate, adenoid hypertrophy, nasopharyngeal cyst or nasopharyngeal tumors).
Aim of study: Prospective study to compare endoscopic finding and computerized tomography of nose, paranasal sinuses and postnasal space as diagnostic methods for nasal obstruction and other nose, p
... Show MoreThe inorganic phosphate content and antioxidant activity of fresh fruit juices and canned fruit juices commonly consumed in Bahrain were compared. The fruits considered in this study were kiwi, guava, black grape, strawberry, apple, and pineapple. The inorganic phosphate content of the juices was determined by a colorimetric method using a UV/VIS spectrophotometer. Among the fresh juices, the highest inorganic phosphate content was measured for black grape juice (17.330 ±0.068 mg/L), and among the canned juices, the highest inorganic phosphate was measured for black grape canned juice too (16.020 ±0.141 mg/L, brand 3). The antioxidant activity was determined in-vitro by measuring the percentage of 2,2-diphenyl-1-picrylhydrazyl
... Show MoreThe study aimed to recognize the impact of polygamy on academic achievement and self-confidence among Sattam bin Abdul Aziz University students. To achieve this goal, the researchers used the Descriptive Analytical method using The Self Confidence measurement ,that has been prepared for the purposes of this study, consists set of 29 questions, then applied to the students sample that emerges from polygamy and one- wife families, study sample consists of randomly selected 230 students registered for the year .1435-1436
The results of the study showed presence of medium statistical impact on the significance level (a 4 0.05), this proof significant statistical effect of polygamy on self-confidence among the sample of Prince Sat-tam Univ
The organizational culture is an effective control mechanism that dictates the behavior of employees and according to their intellectual and social orientations, so it is considered a more powerful way to control employee orientations and determine their management according to organizational rules and regulations, as it was one of the most important factors determining the performance of organizations, while organizational performance is a measure of what the organization has achieved from the objectives of the scheme To ensure that it faces various changes and remains within the global competition, and to reach that it was necessary to identify the most prominent and most important research problems in knowing the extent of com
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