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joe-2080
FLUTTER SPEED LIMITS OF SUBSONIC WINGS
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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
Thu Oct 12 1995
Journal Name
International Journal Of Environmental Studies
ON THE SPATIAL AND SEASONAL VARIATIONS OF HEAVY METALS OF THE RAZZAZAH LAKE, IRAQ
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Five heavy metals, namely Cd, Cu, Fe, Mn, and Pb in the surface water and through the water column were studied at 10 selected stations in the Razzazah lake and Karbala drainage canal for the period between November 1990 to October 1991*. pH and total hardness were also measured. Lead was found to be the highest in concentration as overall average values, followed by an manganese, iron, copper then cadmium at the surface as well as along the water column. All the studied metals were below or close to the maximum allowed limits of Iraqi standards for inland water. The spatial and seasonal variations were discussed.

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Publication Date
Mon Dec 30 2013
Journal Name
Journal Of Genetic And Environmental Resources Conservation
Estimation of immunoglobulins levels in the sera of patients infected with liver hydatid cysts
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This study included 46 patients with liver hydatid cyst diagnosed clinically and surgically, control group consist of 22 were naïve from infection had been confirmed by specialist. The patients were divided according to the size of the cysts into more and less than 5 cm diameter size, were 33 and 13 respectively. Also it divided into primary and secondary hydatid cyst infection which were 30 and 16 respectively. The role of immunological response against hydatid cyst parasite, showed a significant increased in humoral immunoglobulins (IgG, IgA, IgM and IgE) which were significantly higher in the hydatid cyst infection than control. Also significant increased in immunoglobulins in secondary infection than primary infection, beside significa

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Publication Date
Thu Feb 28 2019
Journal Name
Journal Of Biodiversity And Environmental Sciences
Estimation of blood lead level and its effect on hormonal responses of exposed men
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Publication Date
Sat Jun 15 2024
Journal Name
Iraqi Journal Of Laser
Estimation of mean photon number based on single photon detection of weak coherent pulses
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The demand for single photon sources in quantum key distribution (QKD) systems has necessitated the use of weak coherent pulses (WCPs) characterized by a Poissonian distribution. Ensuring security against eavesdropping attacks requires keeping the mean photon number (µ) small and known to legitimate partners. However, accurately determining µ poses challenges due to discrepancies between theoretical calculations and practical implementation. This paper introduces two experiments. The first experiment involves theoretical calculations of µ using several filters to generate the WCPs. The second experiment utilizes a variable attenuator to generate the WCPs, and the value of µ was estimated from the photons detected by the BB

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Publication Date
Fri Jan 01 2021
Journal Name
Materials Today: Proceedings
Study of some electronic and spectroscopic properties of ZnO nanostructers by density functional theory
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Publication Date
Mon Sep 16 2024
Journal Name
Plant Protection
In vitro investigation of phytochemical, antioxidant and antimicrobial activities of Harpagophytum procumbens seeds extracts
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Medicinal plants contain bioactive substances that are highly bioavailable in extracts or pure molecules, making them promising for therapeutic applications and precursors for chemo-pharmaceutical semi-synthesis. Harpagophytum procumbens (Devil’s Claw) is widely recognized as one of the most potent therapeutic herbs. This study aimed to extract seeds from H. procumbens using two types of solvents and to assess both qualitative and quantitative aspects of the extracts. The two extracts were evaluated for antibacterial and anti-biofilm activities using agar well diffusion assays against four bacterial isolates and two yeast isolates. Qualitative analysis identified the presence of alkaloids, flavonoids, tannins, saponins, and terpen

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Publication Date
Thu Jun 30 2016
Journal Name
Journal Of Madenat Al-elem University College
Histopathological changes induced after oral administration of acetamiprid in kidneys of male albino mice
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Publication Date
Thu Dec 31 2020
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
Analyzing the reality of the Iraqi market for securities in light of financial globalization
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The Iraqi market for securities in light of financial globalization faces real challenges at the local and international levels, which were reflected in their shadows on the overall economic reality, which imposed the necessity of making fundamental changes in terms of form and content, and from here stems the research problem in the ability of the Iraqi stock market to adapt to the transformations Financial imposed by financial globalization in light of the weakness of the economic structure and its position in the global economy. The research starts from the hypothesis that the Iraqi market for securities in light of financial globalization has an important and significant role in the economic field, through its role in stimula

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Publication Date
Thu Jul 25 2019
Journal Name
The Eurasia Proceedings Of Science Technology Engineering And Mathematics
Impact of the Chemical Mutagenesis on Biomass and Productivity of some Micro Green Algae
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The Eurasia Proceedings of Science Technology Engineering and Mathematics | Volume: 6

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Publication Date
Sun Sep 07 2014
Journal Name
Baghdad Science Journal
Studying the Effect of Water on Electrical Conductivity of Carbon Reinforced Aluminum Composite Material
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The aim of this study is to understand the effect of addition carbon types on aluminum electrical conductivity which used three fillers of carbon reinforced aluminum at different weight fractions. The experimental results showed that electrical conductivity of aluminum was decreased by the addition all carbon types, also at low weight fraction of carbon black; it reached (4.53S/cm), whereas it was appeared highly increasing for each carbon fiber and synthetic graphite. At (45%) weight fraction the electrical conductivity was decreased to (4.36Scm) and (4.27Scm) for each carbon fiber and synthetic graphite, respectively. While it was reached to maximum value with carbon black. Hybrid composites were investigated also; the results exhibit tha

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