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.
Crime is considered as an unlawful activity of all kinds and it is punished by law. Crimes have an impact on a society's quality of life and economic development. With a large rise in crime globally, there is a necessity to analyze crime data to bring down the rate of crime. This encourages the police and people to occupy the required measures and more effectively restricting the crimes. The purpose of this research is to develop predictive models that can aid in crime pattern analysis and thus support the Boston department's crime prevention efforts. The geographical location factor has been adopted in our model, and this is due to its being an influential factor in several situations, whether it is traveling to a specific area or livin
... Show MoreThe research aims to study the effect of an increase in funding the Equity by issuing new common shares on revenues ordinary shares, despite the issuance and marketing costs and the introduction of new shareholders that companies incur when issuing new common shares but it is the most important methods used to finance the Equity is funding the common shares it provides money sufficient to finance the large investments of the company and enhance the confidence of dealers with the company, so I designed this research in order to identify the impact of increased funding Equity issue new common shares to common shares revenues.
This research has included some of the theoretical concepts to each of the Equity
... Show MoreThe aim of the study was to know the factors analysis of scale Bar-On & Parker, post analysis is found fourteen factors for the first degree of the scale. Also we extracted five factors from the second degree.
The scale consists of (60) items , applied on sample of (200) students (Male &Female ) age (15-18) years randomly chosen from preparatory schools . The scale unveiled satis factors validity and reliability. An others aims is to low the emotional Intelligence level and know the difference of statistical in sex , age variable and the specialization variable .The result was no difference of statistical in sex and specialization variable , but the difference appear
... Show MoreForm recurrence of financial crises phenomenon disturbing and attention , and returns the reasons so that its negative effects were sharp and dangerous , because of the nature and cause of Ncaha , threatened political and economic stability of the countries in which they occur these crises , in addition to Machmlh these crises spread of contagion across multiple channels to include other countries many developed and developing , and the reason for this to the openness of the economic and financial witnessed by the countries affected by crises and other countries concerned, the financial crisis is a case of financial turmoil appears in one of the sections of the financial system one and extends to
... Show MoreThe research aims to enrich the subject of marketing deception, which is still in the concept stage at the level of the research sample and to allow future researchers to contribute to addressing the concept of marketing deception and linking it with other variables. The research problem is that is there a correlation between marketing deception and organizational reputation in Baghdad assets. What is the reflection of marketing deception on the organizational reputation in the assets of Baghdad? The research is concerned with shedding light on the reputation of the organization in terms of frequency of purchase, place of purchase, brand loyalty, and knowing the impact of marketing deception on these fact
... Show MoreThe photo-electrochemical etching (PECE) method has been utilized to create pSi samples on n-type silicon wafers (Si). Using the etching time 12 and 22 min while maintaining the other parameters 10 mA/cm2 current density and HF acid at 75% concentration.. The capacitance and resistance variation were studied as the temperature increased and decreased for prepared samples at frequencies 10 and 20 kHz. Using scanning electron microscopy (SEM), the bore width, depth, and porosity % were validated. The formation of porous silicon was confirmed by x-ray diffraction (XRD) patterns, the crystal size was decreased, and photoluminescence (PL) spectra revealed that the emission peaks were centered at 2q of 28.5619° and 28.7644° for et
... Show MoreThe aim of this study is to compare the effects of three methods: problem-based learning (PBL), PBL with lecture method, and conventional teaching on self-directed learning skills among physics undergraduates. The actual sample size comprises of 122 students, who were selected randomly from the Physics Department, College of Education in Iraq. In this study, the pre- and post-test were done and the instruments were administered to the students for data collection. The data was analyzed and statistical results rejected null hypothesis of this study. This study revealed that there are no signifigant differences between PBL and PBL with lecture method, thus the PBL without or with lecture method enhances the self-directed learning skills bette
... Show MoreCeramics type Yttrium oxide with Silicon carbide. were selected to investigate its sintered density, microstructure and electrical properties, after adding V2O5, of 100 nm grain size. Different weight percentages ranging from (0.01,0.02,0.03 and 0.04) were used. Dry milling applied for twelve hours. The pelletized samples were sintered at atmospheric of static air and at sintering temperature 1400 ˚C, for three hours. The crustal structure test shoes the phase which is yttrium silicon carbide Scanning electron microscopy, scan sintered microstructure. Samples after sintering were electrically investigated by measuring its capacitance, dielectric constant and their results showed increasing after added V2O5 particles at the combinat
... Show MoreZnTe possesses the proper optoelectronic properties as a candidate for device development. The structure and optical properties of ZnTe semiconductor thin films of 500 nm were studied using thermal evaporation technique. The influence of annealing temperatures on ZnTe thin films in the range ( R.T - 473 K). XRD and surface morphological analyses are used to examine the films. The ZnTe films are comparatively polycrystalline and cubic in phase, according to the XRD analysis. with a lattice constant of 0.61 nm upon an (111) orientation. The intensities of all the peaks rapidly increase though they show the same tendencies; it shows the crystallinity of the films becomes higher crystal size diameters (from 8.41 to 12.18nm) both increas
... Show MoreThe research aims to assess the local accounting procedures related in one of developments that have taken place, and largely on the structure of the Iraqi economic activity. But a partnership between the (public and private sector), or one of the types of joint arrangements, and through the use of the analytical method and extrapolate the reality of the accounting treatments in Company research sample. Research found to a number of conclusions that the unified accounting system applied in the economic units that deal with contracting joint arrangements formula suffers from obvious shortcomings, and reflected the common arrangements suffer from obvious shortcomings. and reflected on the quality of financial reporting, and the urgent need
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