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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
Thu May 06 2010
Journal Name
Dirasat, Pure Sciences
A Study of the Effects of the Solar Cycle 22, on the Critical Frequencies of F1 Layer over Baghdad
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This paper aims to study the effects of the long term solar activity on the critical frequencies of ionospheric F1 layer over Baghdad city, during the solar cycle 22, within (1988- 1995). It is found that the critical frequency of this layer is closely related to the sunspots number during the years of the solar cycle 22, at a middle latitude region of the world. The study discussed the effect of sunspot numbers and solar events on the electron densities of F1 layer, which is the most important ionospheric parameter.

Publication Date
Sat Dec 31 2016
Journal Name
Al-kindy College Medical Journal
Diagnostic Value Of Post Exercise Systolic Blood Pressure Response In Ischemic Heart Disease
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 Background: The normal decline in systolic blood pressure during recovery phase of treadmill exercise dose not occur in most patients with coronary artery disease, in others recovery values systolic blood pressure may even exceed the peak exercise value. Objectives: Treadmill exercise test parameters indicating the presence and extent of coronary artery disease have traditionally included such as exercise duration, blood pressure and ST-segment response to exercise. The three –minute systolic blood pressure ratio is another important indicator of presence and significance of coronary artery disease is useful and obtainable measure that can be applied in all patients who are undergoing stress testing for evaluation of suspected is

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Publication Date
Sun Mar 01 2009
Journal Name
Baghdad Science Journal
Wheat response to increase levels of Urea fertilizer
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Pots experiment was conducted in the green house of Biology Department, College of Education ( Ibn-AL-Haithum), University of Baghdad , during the growing season of 2005-2006 , to study the effect of five levels of urea fertilizer (0,50,100,150and 200) mg/pot in on vegetative growth of one wheat cultivar (Adanania) upon randomized complete block design with four replications. The results showed that significant difference between urea fertilizer levels above in vegetative growth characteristics ( plant height , leaf area , chlorophyll content, dry matter weight , relative efficiency and relative yield ) It was also showed that 200 mg/pot level was superior to urea fertilizer levels others in above charac

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Publication Date
Mon May 02 2022
Journal Name
International Journal For Research In Applied Sciences And Biotechnology
Article Review: Immune Response against Some Bacterial Toxins
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Bacterial toxins are considered to be virulence factors due to the fact that they interfere with the normal processes of the host cell in which they are found. The interplay between the infectious processes of bacteria and the immune system is what causes this impact. In this discussion, we are going to focus on bacterial toxins that act in the extracellular environment, especially on those that impair the activity of macrophages and neutrophils. These toxins are of particular interest since they may be found in a wide variety of bacteria. We will be concentrating our efforts, in particular, on the toxins that are generated by Gram-positive and Gram-negative bacteria. These toxins are able to interact with and have an effect on the many dif

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Publication Date
Thu Jun 07 2018
Journal Name
Al-nahrain Journal Of Science
Response of Yucca gloriosa “Variegata” to Tissue Culture
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To explore the potential for in vitro rapid regeneration of Spanish dagger (Yucca gloriosa 'Variegata'), different concentrations of 6-Benzyladenine (BA), 1-naphthaleneacetic acid (NAA) and combinations of both were evaluated for callus induction initiated on leaf and bud (terminal and axillary buds) explants using Murashige and Skoog (MS) medium. Callus response induction percentage, fresh weight, color and texture of the callus were assessed after 1.5 and 6.0 months in culture. The appropriate medium for callus initiation on leaf explants was MS medium supplemented with 6.0 mg/L NAA. A combination of 0.2 mg/L BA and 1.5 mg/L NAA also exhibited a remarkable callus induction on bud explants. Effect of thidiazuron (TDZ) addition to the cultu

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Publication Date
Mon Jan 01 2024
Journal Name
The Scientific World Journal
Mathematical Modeling and Experimental Investigation of the Dynamic Response for an Annular Circular Plate Made of Glass/Polyester Composite Under Different Boundary Conditions
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Fiber‐reinforced elastic laminated composites are extensively used in several domains owing to their high specific stiffness and strength and low specific density. Several studies were performed to ascertain the factors that affect the composite plates’ dynamic properties. This study aims to derive a mathematical model for the dynamic response of the processed composite material in the form of an annular circular shape made of polyester/E‐glass composite. The mathematical model was developed based on modified classical annular circular plate theory under dynamic loading, and all its formulas were solved using MATLAB 2023. The mathematical model was also verified with real experimental work involving the vibration test of the f

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Publication Date
Sun Jan 01 2023
Journal Name
Journal Of Population Therapeutics And Clinical Pharmacology
IGG and IGM response in a group of Iraqi health care worker following SARS-CoV-2 mRNA vaccine
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Publication Date
Mon Jan 01 2018
Journal Name
International Journal Of Agricultural And Statistical Sciences
Response of broad bean growth and early yield to exposure periods of vernalization
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Publication Date
Wed Jan 01 2020
Journal Name
Iop Conference Series: Materials Science And Engineering
Study the synergistic Effect between Nanoparticles and Spiramycin on Immunological Response Against Toxoplasmosis
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Abstract<p>This investigation was carried out to estimate the antiparasitic potential of silver and Chitosan nanoparticles loaded with spiramycin against toxoplasmosis infected. After mice injected intraperitoneal in a dose 10<sup>3</sup>viable tachyzoites for acute infection; then treated with spiramycin, chitosan nanoparticles and silver nanoparticles as a single or combined therapy given for seven days. Peritoneal fluid examination revealed a significant decrease in the number of<italic>T. gondii</italic>tachyzoites in all treated infected mice compared with infected non-treated. The combined therapy presented better results than the single one. The best effect was observed in a group of </p> ... Show More
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Publication Date
Mon Jan 27 2020
Journal Name
Medico-legal Update
Indications and Adverse Outcomes of Emergency Lower Segment Cesarean Section at 1St and 2Nd Stages of Labor at Al-Elwiya Maternity Teaching Hospital
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