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FLUTTER SPEED LIMITS OF SUBSONIC WINGS

Flutter is a phenomenon resulting from the interaction between aerodynamic and structural dynamic forces and may lead to a destructive instability. The aerodynamic forces on an oscillating airfoil combination of two independent degrees of freedom have been determined. The problem resolves itself into the solution of certain definite integrals, which have been identified as Theodorsen functions. The theory, being based on potential flow and the Kutta condition, is fundamentally equivalent to the conventional wing-ection theory relating to the steady case. The mechanism of aerodynamic instability has been analyzed in detail. An exact solution, involving potential flow and the adoption of the Kutta condition, has been analyzed in detail. The solution is of a simple form and
is expressed by means of an auxiliary parameter K. The use of finite element modeling technique and unsteady aerodynamic modeling with the V-G method for flutter speed prediction was used on a fixed rectangular and tapered wing to determine the flutter speed boundaries. To build the wing the Ansys 5.4 program was used and the extract values were substituted in the Matlab program which is designed to determine the flutter speed and then predicted the various effects on flutter speed. The program gave us approximately identical results to the results of the referred researches. The following wing design parameters were investigated skin shell thickness, material properties, cross section area for beams, and changing altitude. Results of these calculations indicate that structural mode shape variation plays a significant role in the determination of wing flutter boundary.

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Publication Date
Wed Apr 28 2021
Journal Name
Journal Of Engineering
Deasphalting of Atmospheric Iraqi Residue using Different Solvents

Different solvents (light naphtha, n-heptane, and n-hexane) are used to treat Iraqi Atmospheric oil residue by the deasphalting process. Oil residue from Al-Dura refinery with specific gravity 0.9705, API 14.9, and 0.5 wt. % sulfur content was used. Deasphalting oil (DAO) was examined on a laboratory scale by using solvents with different operation conditions (temperature, concentration of solvent, solvent to oil ratio, and duration time). This study investigates the effects of these parameters on asphaltene yield. The results show that an increase in temperature for all solvents increases the extraction of asphaltene yield. The higher reduction in asphaltene content is obtained with hexane solvent at operating conditions of (90 °C, 4/1

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Publication Date
Fri Sep 22 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Comparison Study Demosaicking of Bayer Color Filter Array

Image capturing in most still and  motion  digital  cameras  employs a charge  coupled  device  covered  with  a monolithic array  of color  filters such   that   each   pixel   samples  only   one  color   band.   Interpolation   is necessary   to  restore  the  missing  color  samples  in the  resulting mosaic, this process referred  to as demosaicking.

This  paper   gives  an  overview   of  demosaicking,  presents  few

methods   proposed   in  the &nbsp

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Publication Date
Sun Feb 03 2019
Journal Name
Journal Of The College Of Education For Women
THE USE OF AMBIGUOUS IRONY IN ANDALUSIAN POETRY

Among the findings of the research are:
1. This type of ambiguity is old in use and was adopted by the Arab poets as a
reaction against hyperbole and as a tendency towards compression of expression that
results in an. amusing suspension through the use of irony. The Andalusian poets
tended to employ this form because it involves interaction and interrogation,
2. Furthermore, it indicates the poet’s insight, talent and skill and it is, therefore,
regarded as a form. Of verse discourse that appeals to the reader, in contrast to
hyperbole.
3. Its presence in Andalusian poetry is evident n eulogy and descriptive poetry and it
held a place of prominence as a poetic form in achieving these purposes.
4. Through i

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Publication Date
Tue Nov 01 2011
Journal Name
Iraqi Journal Of Applied Physics
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Publication Date
Thu Oct 01 2009
Journal Name
Journal Of The Faculty Of Medicine Baghdad
Study on hydrocephalus and complications of surgical treatment

Background: Shunt operations are performed for different reasons mainly hydrocephalus congenital or acquired. It’s associated with certain morbidity and mortality.
Patients and method: A prospective study from Jan 2004 to Jan 2006, 226 patients under went shunt operation in the specialized surgical hospital in Baghdad. The patients were divided into two groups according to the way of applying the upper end catheter. In group A49 patients where posterior parietal approach was used, and group (B) 174 where parietal or temproprietal approach was used.
Results and discussions: different complications were recorded, but the most frequent was upper end obstruction by choroids plexus or by debris. In group

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Publication Date
Sun Jun 30 2002
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
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Publication Date
Thu Aug 31 2023
Journal Name
Journal Of Legal Sciences
The Legal Qualification of the Marriage Mediation Contract

Although the profession of a marriage mediator is dominated by a social character, and it is also characterized by its practice in the midst of strict secrecy, because Eastern societies innately reject this method of searching for a life partner. The two parties play a prominent role of the will in the events of legal effects, and the obligations and rights owed by the contracting parties, which leads us to consider the agreement between the mediator and the one who wants to marry going to the purely contractual nature, and thus requires the correct legal adaptation on the contractual relationship that is achieved between the marriage mediator and his clients from Those who want to get married and therefore we will divide this research i

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Publication Date
Sun Sep 30 2007
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Concentration of Hydrogen Peroxide by Batch Distillation Column

An investigation was conducted to study the concentration of hydrogen peroxide by vacuum distillation. The effect of the process variables (such as vacuum pressure, reflux ratio, time of distillation, and packing height of the column used in the distillation process) on the concentration of hydrogen peroxide were investigated. During the third stage of distillation (95 wt.%) concentration was obtained.

Box-Wilson central composite rotatable design is used to design the experimental work for the mentioned variables. It was found that the concentration of hydrogen peroxide increases with Increasing vacuum pressure, decreasing reflux ratio, increasing the time of distillation and increasing the packing height.

The second ord

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Publication Date
Wed Apr 12 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Spectrophotometric Determination of Mefenamic Acid in Pharmaceutical Preparations

  A simple, accurate and precise spectrophotometric method has been proposed for the determination of Mefenamic acid(MA) in dosage forms. Proposed  method based on the reaction of cited drug with 1,2-Naphthoquinone-4-Sulfonic sodium (NQS). The optimum experimental condition have been studied. Beer's Law is obeyed in the concentration range 0.5-10.0 µg/mL at 450nm with detection limit of 0.189µg/mL.  Effect of pH, reaction time, and volume of NQS on the determination of Mefenamic acid, have been examined. The proposed method has been successfully applied for the determination of  Mefenamic acid in pharmaceutical preparations.
 

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Publication Date
Sun Jul 03 2016
Journal Name
Journal Of The Faculty Of Medicine Baghdad
Immunohitochemical expression of Bcl-2in human colocrectal carcinoma

Background: Colorectal carcinoma is the most frequent type of malignancy in terms of incidence,it is the third most common cancer world wide in both sexes . bcl_2 expression has been described as been a better prognostic factor in colorectal carcinoma.
Objcetives: To determine the frequency and the pattern of Bcl-2 expression in colorectal carcinoma by immunohistochemical technique and to correlate this expression with different clinicopathological parameters.
Material and method: Thirty cases of colorectal carcinoma were studied, these cases were diagnosed in private laboratories in Baghdad / Iraq from January 2015 to Juan 2015. Clinicopathological parameter such as age, gender , pathological diagnosi

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