The effect of internal acoustic excitation on the leading-edge, separated boundary layers and the aerodynamic performance of NACA23015 cross section airfoil are examined as a function of excitation location with ranging frequency range (50-400) Hz of the introduced acoustic. Tests are separately conducted in two sections, open type wind tunnels at the Reynolds number of 3.3x105 for measurement at angle of attack (0, 3, 6, 9 &12) deg. and 3x104 for the visualization at angle of attack (12) deg. based on the airfoil chord. Results indicated that the excitation frequency and the excitation location are the key parameters to alter the flow properties and thus to improve the aerodynamic performance. The most effective excitation frequency is found to be equal to the shear layer instability frequency and on excitation location close to the separation point. Moreover, the lift is increased and drag reduced dramatically. The corresponding boundary layers are visualized to be reattached to the surface.
This paper presents an experimental and numerical study which was carried out to examine the influence of the size and the layout of the web openings on the load carrying capacity and the serviceability of reinforced concrete deep beams. Five full-scale simply supported reinforced concrete deep beams with two large web openings created in shear regions were tested up to failure. The shear span to overall depth ratio was (1.1). Square openings were located symmetrically relative to the midspan section either at the midpoint or at the interior boundaries of the shear span. Two different side dimensions for the square openings were considered, mainly, (200) mm and (230) mm. The strength results proved that the shear capacity of the dee
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This paper presents an experimental and numerical study which was carried out to examine the influence of the size and the layout of the web openings on the load carrying capacity and the serviceability of reinforced concrete deep beams. Five full-scale simply supported reinforced concrete deep beams with two large web openings created in shear regions were tested up to failure. The shear span to overall depth ratio was (1.1). Square openings were located symmetrically relative to the midspan section either at the midpoint or at the interior boundaries of the shear span. Two different side dimensions for the square openings were considered, mainly, (200) mm and (230) mm. The strength results proved that the shear capacity of the dee
... Show More
(24)
The aim of this study tousethree remedial method to the learning for mastering which :(learning for mastery incooperative small groups)and style (Re teaching using presentations by PowerPoint ), and style (homeworklearning by Microsoft word ) to in learning Movement Concatenation On Horizontal Bar in artistic gymnastics for men, as the aim of the research to identify any better methods to learn the movement in question , use the the experimental method to design with pretest and posttest equal totals , the subject of the study included on students second class in physical education and sport sciences , Baghdad University (2014-2015) ,The species used the specific manner by lot for selection , the subject divided into three empirical groups
... Show MoreThe name of princesses Ashraf Bhlwi was associated with very important events influnced on social polical Iranian fact through second half of twentieth century, with access Dr.Mosaddeq to cabinet on May 1951, The conflict seemed between him and princesses Ashraf in creasingly, when Mosaddeq came to authority he had many projects deal with oil industry laws in Iran and reform the elections laws, reducing terms of reference of Al shah and made it honorable only, This matter disturbance Royal court especially, Ashraf, she started to coordinate with members of the shura council and other military personalities in order to over throw Mosaddeq cabinet but she failed because Mosaddeq supported by Irani
... Show MoreThis research is an attempt to study and evaluate the maintenance function at Factory 7 - The State General Company for Leather Industries, and to design a computerized preventive maintenance system to design and to analyze preventive maintenance. To accomplish the objectives of this research, data were gathered and analyzed according to the reliability engineering criteria for the period 2/1– 30/6/2005, then a preventive maintenance plan was designed for each machine of the sample study using the computerized system designed in this research. A Monte Carlo Simulation methodology was used for the purpose of evaluating the performance of the preventive maintenance plan of each machine for one year. The simulation res
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And the necessity for the progress of modern societies Because the scientific and objective characteristics that characterize modern societies and distinguish them from traditional societies, Is represented by the extent of its innovative achievements in the theoretical, applied and material scientific and spiritual fields. It should be noted that quality and innovation in modern societies is based on two main pillars, Standard measures for measuring and evaluating innovations to achieve their high quality, And the dissemination of the culture of innovation to spread awareness of the importance and conditions of success, and this is done by the advanced industrial countries, However, despite the great disparity between developed industri
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The objective of the current research is to identify the effective of the suggested instructional design that based on the teaching strategy for understanding in achievement for students(girls) of mathematics in the fifth grads secondary school. To achieve the research goal, the empirical research method is depended. In this method a realistic empirical design pre-test of two equivalent sets to determine the students’ grade is used. The following zero hypotheses is formulated “There is no statistical difference for the faction at 0.05 between the mean grad for the students of the empirical group who studied the subject using the Instructional design based on the teaching strategy for understanding and those who studied the same subje
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