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Aeroelastic response and limit cycle oscillations for wing-flap-tab section with freeplay in tab
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A linear and nonlinear theoretical and experimental aeroelastic investigation of a wing-flap-tab typical section model undergoing two-dimensional incompressible airflow is described. The linear flutter velocity (LFV) and frequency are predicted using linear analysis. Then a freeplay structural nonlinearity is considered in the tab. The structural equations of motion have been coupled with Theodorsen aerodynamic theory to produce the theoretical aeroelastic model which is analyzed by a state space method to predict the LFV and flutter frequency. Linear piecewise function has been used to introduce the tab spring stiffness in the freeplay state. The ground vibration test is used to measure the model structural dynamic characteristics. Then the experimental aeroelastic model is placed in a low speed wind tunnel to measure the LFV and the limit cycle oscillation (LCO) of the physical model induced by freeplay. The root main square amplitude value of the pitch, flap pitch, tab pitch and plunge degrees of freedom of the tab nonlinearities are normalized with freeplay gap size to produce a bifurcation diagram with normalized airflow velocity as the bifurcation parameter. The results show that the LCO frequency jumps from low to high frequency at a yet higher flow velocity. At the same flow velocity, the pitch and plunge motion response amplitudes drop while the flap pitch and tab pitch degrees of freedom response amplitude increase. In general the experimental measured LCO is more complicated than the theoretically calculated LCO in terms of the harmonic content of the response. On the other hand there is good agreement between the theoretical and experimental result of the linear system as well the LCO for the tab freeplay nonlinearities

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Publication Date
Sun Jun 04 2017
Journal Name
Baghdad Science Journal
Estimating of Fatty Acids, Tcopherols, Tocotrienols, Total Carotens, Study The Physiochemical Properties And Unsaponifiable Matters Extraction From Crude Red Palm Oil(1)
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The percentage of fatty acids, quantity of tocopherols, tocotrienols, carotens and physiochemical characteristics of crude red palm oil have been evaluated, in addition to specific chemical detection of active compounds unsaponifiable matters. Results of Gas Liquid Chromatography showed:- The major fatty acids in red palm oil is palmitic (44.36%) then oleic (39.65%), linolenic (10.55%), stearic (3.56%), myristic (1.22%), arachdonic (0.24%) and palmotic (0.19%). Red palm oil contains ? – ?- ?- ? – Tocopherols with concentration 258 , 121 , 259, 109 m/kg oil , ? – ?- ?- ? – Tocotrienol with concentration 462.77 , 571.03, 619.18, 509.07 m/kg oil respectively. Total tocopherols & tocotrienols 2909.05 m/kg oil and

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Publication Date
Fri Jul 28 2023
Journal Name
Journal Of Optics
Estimated the nanoparticles size of CdS from UV–Vis spectrum absorption by effective mass approximation model (EMA) using capping and complex agent
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Publication Date
Thu May 05 2022
Journal Name
Karbala International Journal Of Modern Science
Heterogeneous catalytic degradation of dye by Fenton-like oxidation over a continuous system based on Box–Behnken design and traditional batch experiments
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In this study, iron was coupled with copper to form a bimetallic compound through a biosynthetic method, which was then used as a catalyst in the Fenton-like processes for removing direct Blue 15 dye (DB15) from aqueous solution. Characterization techniques were applied on the resultant nanoparticles such as SEM, BET, EDAX, FT-IR, XRD, and zeta potential. Specifically, the rounded and shaped as spherical nanoparticles were found for green synthesized iron/copper nanoparticles (G-Fe/Cu NPs) with the size ranging from 32-59 nm, and the surface area was 4.452 m2/g. The effect of different experimental factors was studied in both batch and continuous experiments. These factors were H2O2 concentration, G-Fe/CuNPs amount, pH, initial DB15

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Publication Date
Mon Jun 15 2020
Journal Name
Al-academy
Saudi society’s trends towards visiting museums and art galleries: منال بنت مرشد الحربي -حنان بنت يوسف الأحمد-مها بنت عبد الله السنان
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The aim of the research is to identify the trends of Saudi society towards visiting art galleries and museums in light of economic and social transformations after the implementation of the 2030 vision plans. The importance of the research is to track the reasons behind the reluctance of members of society to visit such cultural institutions, and to plan proposals and recommendations for how to attract members of society and motivate them. This research followed the descriptive approach, and the study sample reached 103 members of the Saudi community. several research tools were used in this research such as questionnaire, personal interviews in addition to the researcher notes. The results concluded that the art galleries attract the ap

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Publication Date
Mon Dec 01 2014
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
The impact of exercising occupational hypocrisy on organizational strategic success: An Empirical study on university of kufa faculty of administration and economic
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This research aims to identify the relationship between occupational hypocrisy and organizational strategic success, It was done by analyzing the correlations and influence between variables,  applied to a random sample of university professors at the University of Kufa faculty of administration and economic.

 The main tool for data collection is the survey were questionnaires were distributed randomly to the professors , and (43) questionnaires were returned, and test its validity by using (SEM) (Structural Equation Modeling), Hypothesis has been tested by using Statistical Package for Social Sciences (SPSS v. 18), The research found a set of conclusions:(The occupational hypocrisy has

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Publication Date
Thu Feb 01 2024
Journal Name
Journal Of Thermal Analysis And Calorimetry
Heat transfer and fluid flow characteristics over a backward-facing step (BFS) containing square-rectangular ribs integrated as forward-facing steps (FFS)
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Publication Date
Wed Nov 01 2017
Journal Name
Journal Of Economics And Administrative Sciences
The role of administrative supervision scope and the single window to increase the efficiency of investment (Case study: Sudanese Ministry of Investment)
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Investment drives the wheel of the development of different developed and developing countries. Sudan is a model for a developing country facing a lot of difficulties in the field of both local and foreign investment. The present study was focused on the problem of poor diversification and efficiency of both local and foreign investment in Sudan. Also, it clarified the important role of administrative supervision to strengthen the efficiency of investment, taking the experience of the Sudan as a model. The researchers used the well-known descriptive and analytical tools (questionnaire, interview, observation) to complete this study. A well designed questionnaire was used. It included all questions that could cover all aspects of

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Publication Date
Tue Jun 15 2021
Journal Name
Al-academy
Listening to music and its reflection on the artistic output of the students of the Department of Art Education: سميعه فاضل كعود
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The relationship between music and plastic arts can be viewed as an interdependent relationship, as they both develop imagination, focus and sensory perception, as well as the presence of some artistic concepts that music shares with the art of drawing, on this basis the rationale for this research aimed at identifying (the influence of music) was dealt with On the artistic output (drawing) of students of the Department of Art Education - College of Fine Arts) In the first chapter the problem of research, importance, terminology, boundaries and goal was addressed, and in the second chapter the researcher dealt with in the first topic the relationship between music and painting, and in the second topic the use of music in education. As fo

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Publication Date
Wed Feb 01 2023
Journal Name
Journal Of Engineering
Effect of the Proposed Outlets on the Hydrodynamic Behavior and Water Quality of the South-West Part of the Al Hammar Marsh
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The current study aims to find a new plan to manage the water quality of the western part of the Hammar Marsh to reduce the salts that cause problems for the marshes and preserve their environmental life by isolating the southwestern part of the Hammar Marsh by closing the outlet under the railway embankment. The outlet is discharging saline water to the east-western part of Al Hammar Marsh. After isolating the southwestern part of the marsh, a new outlet is proposed. The impact of the flow hydrodynamics on improving the water quality was simulated using the SMS model. The hydrodynamics and water quality simulation models for the marsh are : a hydrodynamic model and average depth (SMS RMA2) and a two-dimensional water quality model (SMS

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Publication Date
Wed Mar 23 2022
Journal Name
Journal Of Educational And Psychological Researches
The perceptive image of volunteering and its relationship to the motives towards volunteering among a sample of Al-Quds Open University students.
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This study aimed to identify the perceived mental image of volunteering, and its relationship to volunteer motivation among a sample of Al-Quds Open University students, as well as to identify the differences in the perceived mental image of volunteering due to variables (gender, year of study, place of residence, college). The researcher has used relational descriptive approach. The researcher has used two questionnaires, the first was used to measure the perceptive mental image of volunteering, and the second to measure the motivation towards volunteering, and the study population may consist of all students of Al-Quds Open University Hebron Branch during the first semester of the academic year 2021/2020 and their number (3462)Male and

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