In this work, results of a mathematical analysis of the role of workpiece preheating in laser keyhole welding were presented. This analysis considered the steady-state welding as well as certain range of boundary conditions over which preheating effect would be indicated. This work is an attempt to interpret the role of preheating to increase welding depth and perform keyhole welding with high quality using physical and thermal properties of steel alloys.
The characterization of ZnO and ZnO:In thin films were confirmed by spray pyrolysis technique. The films were deposited onto glass substrate at a temperature of 450°C. Optical absorption measurements were also studied by UV-VIS technique in the wavelength range 300-900 nm which was used to calculate the optical constants. The changes in dispersion and Urbach parameters were investigated as a function of In content. The optical energy gap was decreased and the wide band tails were increased in width from 616 to 844 eV as the In content increased from 0wt.% to 3wt.%. The single–oscillator parameters were determined also the change in dispersion was investigated before and after doping.
Corruption is a phenomenon that exists in all times and places, they appear in the developing countries and in developed countries, and in all political systems. And its repercussions and economic repercussions on the society in which it is rampant, and lead to the undermining of economic development and obstruction, is also working on increasing poverty and unemployment, as well as its role in the worsening of social problems, and political instability. And corruption is deviant behavior is illegal and contrary to the teachings of the religious and moral values. The emergence of this phenomenon is due to several reasons, including political, economic, social and cultura
... Show MoreThe research aims to identify the effect of Ibn Khaldun educational perceptions on modern science and comparing it with the modern-educational thought as well as exploring the educational perceptions of ibn Khldun by coming cross (the introduction of ibn Khaldun and some other references). In addition to identifying the effect of psychological perceptions of geographical context on people habits and behaviors, the researcher intends to identify the thoughts that relate to methods of teaching and the requirements of learning and teaching, and finally, identifying the psychological thoughts that relate to educational psychology and parapsychology. The study concluded that the purposes of educational aims of Ibn Khaldun are to give a chance
... Show Moreيهدف البحث الى التعرف على اثر استراتيجية نجمتين وامنية في تحصيل مادة الكيمياء عند طلاب الصف الثاني المتوسطولتحقيق هدف البحث تم اتباع المنهج التجريبي ذو الضبط الجزئي وتم تحديد مجتمع البحث بطلاب الصف الثاني المتوسط لجميع المدارس الثانموية والمتوسط التابعة لمديرية تربية الكرخ الثانية وتم اخنيار احد هذه المداس بصورة قصدية لتطبيق تجربة ابلبحث الحالي
The influence of sensing element length of no-core fiber strain sensor has been studied and experimentally demonstrated, four different lengths of 125 μm diameter no-core fiber is fused between two standard single-mode fibers and bi-directionally strained, the highest obtained sensitivity was around 16.37 pm με -1 which was exhibited in the shortest no-core fiber segment, to the best of our knowledge this is the first study of the influence of no-core fiber strain sensors length on sensor sensitivity. The proposed sensor can be used in many opto-mechanical applications such as, structural health monitoring, aerospace vehicles and airplane components monitoring.
The study seeks to clarify the role of International Auditing Standard No. (320) of the relative importance in determining responsibility for planning and implementing the process of auditing financial statements and expressing neutral technical opinion through the analytical procedures of the auditor, whose responsibility is to obtain appropriate and reliable audit evidence that helps the auditor to form a general conclusion about whether The financial statements were consistent with the auditor's understanding of the entity. The relative importance contributes to defining the important accounts that help to set priorities for the auditor to set the necessary analytical procedures for these accounts. One of the most important co
... Show MoreThis study was conducted to estimate some heavy metals cadmium, lead, nickel and iron in 15 samples of Iraqi honey with 3 replicates for each sample which were collected from apiaries near potential contamination areas in five Iraqi governorates, including Baghdad, Karbala, Babylon, Diyala and Salah al-Din. The atomic absorption technique was used to estimate the concentrations of heavy metals, the results showed that there were significant differences at (P≤0.05) between the concentrations of these elements in the honey samples, the highest concentrations of cadmium 0.123 mg/kg were recorded in Baghdad, near the petrochemical production complex, lead 4.657 mg/kg and nickel 0.023 mg/kg in Babylon near the power plant, iron was
... Show MoreWater flow into unsaturated porous media is governed by the Richards’ partial differential equation expressing the mass conservation and Darcy’s laws. The Richards’ equation may be written in three forms,where the dependent variable is pressure head or moisture content, and the constitutive relationships between water content and pressure head allow for conversion of one form into the other. In the present paper, the “moisture-based" form of Richards’ equation is linearized by applying Kirchhoff’s transformation, which
combines the soil water diffusivity and soil water content. Then the similarity method is used to obtain the analytical solution of wetting front position. This exact solution is obtained by means of Lie’s
This present study is aimed at deciding the impact of exercises adapted to the ranges of movements of the arm on the performance of javelin throwing. As long as javelin throwing is quite a complex athletic event that presupposes a considerable amount of strength, speed, and biomechanical accuracy, it is crucial to learn whether the exercises designed to target the peculiarities of arm movements can have a positive effect on the performance of javelin throwers. To the study, experimental research with a single group of six youth javelin throwers was carried out. Before and after the eight-week training program, the pre-tests and post-tests were conducted to find the results of training with a specific focus on resistance exercises. Significa
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