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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 Jan 02 2020
Journal Name
Journal Of The College Of Languages (jcl)
Some of the Grammatical Rules of Writing: Zu einigen grammatischen Erscheinungen im Schreiben
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    Language contains various kinds of grammatical rules that are used to express thoughts and feelings. The present paper studies some of the German language grammatical rules as being the most important basics needed to master and develop the art of writing for the German language learners. Writing is one of the productive language learning skills that transform thoughts into a written form. Hence, constant exercising on the use of the language to master the grammatical rules enables German language learners to develop their creative writing skills.

     The present study discusses the importance of grammatical exercises in developing the language learning abilities. The study provides a gener

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Publication Date
Thu Oct 12 2023
Journal Name
Egyptian Journal Of Biological Pest Control
Evaluation of the effectiveness of some mycorrhizal fungi isolates against charcoal rot disease
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Abstract<sec> <title>Background

The sunflower plants are attacked by serious seed and soil-borne pathogens including charcoal rot disease that caused by Macrophomina phaseolina. This disease has serious damages to sunflower crop. This study aimed to assess the efficacy of Arbuscular mycorrhizal fungus against charcoal rot disease as fungicide alternative.

Results

Morphological and molecular identification was done, using universal primers for molecular identification. Finally, a greenhouse experiment was conducted, and

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Publication Date
Sat Sep 01 2012
Journal Name
Journal Of Economics And Administrative Sciences
Testing the Assumption of Linearity for Sales of State Company for Electrical Industries
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In this study, the four tests employed for non-linear dependence which is Engle (1982), McLeod &Li (1983), Tsay (1986), and Hinich & Patterson (1995). To test the null hypothesis that the time series is a serially independent and identical distribution process .The linear structure is removed from the data which is represent the sales of State Company for Electrical Industries, through a pre-whitening model, AR (p) model .From The results for tests to the data is not so clear.

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Publication Date
Wed Nov 07 2018
Journal Name
Iraqi National Journal Of Nursing Specialties
Assessment of Factors Associated with Prehospital Delay of Patients with Acute Myocardial Infarction
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Objective(s): to assess the factors which are associated with the prolonged prehospital delay of patients with
acute myocardial infarction.
Methodology: A descriptive study was conducted at the Coronary Care unit (CCU) in Al-Yarmok Teaching
Hospital, Ibn AL-Nafis Hospital for Cardiovascular Diseases, AL-Kadumia Teaching Hospital, Baghdad Teaching
Hospital, and AL-Kindy Teaching Hospital during the period of the study from February 2
nd
, 2009 to October 30th
,
2009. A random sample of (160) paƟent who were admiƩed to the hospitals were selected one by one. A
questionnaire was constructed for the purpose of the study, which is comprised of four parts that include (1)
sociodemographic data; (2) prehospital d

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Publication Date
Thu Mar 19 2015
Journal Name
Al-academy
The importance of social acceptability of the universal design: عبد الكريم علي حسين
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The industrial development and raise the level of income that has emerged clearly in the middle of the last century in many rich and medium rich countries has great influence on the risen of the health care level. Which led to a significant increase in the reconstruction of people over 65 years and this in turn has produced markets for products and services through modifications to the existing products to meet their physical needs. The importance of research also has the universal design of a comprehensive actually so that it covers as much as possible from human physical & cultural activities. The importance of research locally is to concentrate on this subject who has not been taken into consideration so far to accommodate the eld

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Publication Date
Fri Dec 01 2023
Journal Name
Nano Biomedicine And Engineering
The Impact of Modified Metallic Nanoparticles on Thermomechanical Properties of PMMA Soft Liner
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Publication Date
Mon Apr 01 2024
Journal Name
Iraqi Postgraduate Medical Journal
Estimation of Prevalence rate of Sjogren’s syndrome among Rheumatology clinic patients in Iraq
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Publication Date
Thu Feb 01 2018
Journal Name
Journal Of Engineering
Statistical analysis of the removal of Chromium(VI)by Iron Oxide Nanoparticle (Fe3O4)
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Investigation of the adsorption of Chromium (VI) on Fe3O4 is carried out using batch scale experiments according to statistical design using a software program minitab17 (Box-Behnken design). Experiments were carried out as per Box-Behnken design with four input parameters such as pH (2-8), initial concentration (50–150mg/L), adsorbent dosage (0.05–0.3 g) and time of adsorption (10–60min). The better conditions were showed at pH: 2; contact time: 60 min; chromium concentration: 50 mg/L and magnetite dosage: 0.3 g for maximum Chromium (VI) removal of (98.95%) with an error of 1.08%. The three models (Freundlich, Langmuir, and Temkin) were fitted to experimental data, Langmuir isotherm has bette

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Publication Date
Sun Apr 01 2018
Journal Name
Journal Of Geophysical Research: Space Physics
Properties of the HPS‐ICME‐CIR Interaction Event of 9–10 September 2011
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Abstract<p>During 9–10 September 2011 the ACE, Wind, and SOHO spacecraft measured the complex interaction between an interplanetary coronal mass ejection (ICME) and a corotating interaction region (CIR) associated with the heliospheric sector boundary. Except for a few short periods, the suprathermal electrons are unidirectional, suggesting that the ICME magnetic field has opened through interchange reconnection. Signatures of interaction are distributed throughout the event suggesting that the structures have become entangled or embedded. Since the ICME speed is relatively low, the strong forward shock must be caused by the ICME‐CIR interaction. Other interesting features are the upstream heating flux disc</p> ... Show More
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Publication Date
Tue Sep 01 2020
Journal Name
Results In Engineering
Performance evaluation of asphalt concrete mixes under varying replacement percentages of natural sand
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Frequently, load associated mode of failure, rutting and fatigue, are the main failure types found in some newly constructed roads within Baghdad, the capital of Iraq, and some suburban areas. The use of excessive amount of natural sand in asphalt concrete mixes which is attractive to local contractors could be one of the possible causes to the lack of strength properties of the mixes resulting in frustration in the pavement performance. In this study, the performance properties of asphalt concrete mixes with two natural sand types, desert and river sands, were evaluated. Moreover, five replacement rates of 0, 25, 50, 75, and 100% by weight of the fine aggregate finer than 4.75 were used. The performance properties including moisture susc

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