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.
Background: Penetrating neck injuries are common problem in our country due to increasing violence, terrorist bombing and military operations.
These injuries are potentially life threating and need great attention and proper management.
Objective: The aim of this study is to focus on the importance of anatomical zonal classification of the neck in the management of penetrating injuries of the visceral compartment of the Neck.
Methods :70 patients with various injuries who were managed at causality unit and Otolaryngology department in Al-Kindy Teaching Hospital during aperiod from January 1st 2015 to October 31st 2015.
The study carried on those patient depending on proper clinical examination and their urgent management.
This paper concerns with openness concept in contemporary learning environment, which ranges from physical characters to its relation with learning efficiency and its output. Previous literatures differ to clear the effect of openness on the engagement between learner within themselves, and with this kind of spaces. Engagement means: active participation, the ability of making dialogue, self-reflection and the ability to explore and communicate with them and
within learning space. Research roblem was: The lack of knowledge about the effect of Openness on learner engagement with learning spaces. The two concepts were applied on three types of learning spaces in the Department of the Architectu
This paper aims to review the intellectual to the most important thought leaders administrative and strategic They both (Henry Fayol and Michelle Porter), who forward a lot of ideas that have helped countries in the advancement and progress their economies , has been drawing literature theoretical common border in Contributions ( Fayol ) philosophical and between applications ( Porter ), which reversed strategies of the three ( the leadership of the cost, differentiation, and focus ), so browse search how to apply and use the principles of Fayol in the implementation of strategies competitiveness of Porter, and stems from a problem ( ( to what extent a reflection of the principles ( Fayol) fourteen strategies (Porter ) competitiv
... Show MoreSteel fiber aluminum matrix composites were prepared by atomization technique. Different air atomization conditions were considered; which were atomization pressure and distance between sample and nozzle. Tensile stress properties were studied. XRF and XRD techniques were used to study the primary compositions and the structure of the raw materials and the atomized products. The tensile results showed that the best reported tensile strength observed for an atomization pressure equal to 4 mbar and sample to nozzle distance equal to 12 cm. Young modulus results showed that the best result occurred with an air atomization pressure equal to 8 mbar and sample to nozzle distance equal to 16cm
In this paper an estimator of reliability function for the pareto dist. Of the first kind has been derived and then a simulation approach by Monte-Calro method was made to compare the Bayers estimator of reliability function and the maximum likelihood estimator for this function. It has been found that the Bayes. estimator was better than maximum likelihood estimator for all sample sizes using Integral mean square error(IMSE).
Media, especially press plays an important role in fighting corruption and tackling this phenomenon, which has become widespread in our society, through its effective role in raising awareness of the seriousness of spreading of corruption of all its forms in society.
All international conventions and agreements stress the necessity of the role of media and its importance in the light of corruption. All countries also commit themselves to the necessity of guaranteeing the freedom of media and the circulation of information and preparing it as a prerequisite for activating the People’s Control Mechanism and supporting measures and means to prevent and combat financial and administrative corruption more actively and effectively.
Co
Education is a process of learning and education at the same time. As the conditions of modern life necessitate every person to keep learning, education has become a necessity to meet life needs. The society today is concerned with the educational process and aims to live up the expectations. Since education is an integral part of education and its means, it has become as a mean to achieve its purposes. The educational environment was a traditional environment limited to specific inputs, possibilities and stimulus of both teacher and student. Due to the latest advancement, the educational environment has been expanded to become a rich, with strong connections. It has expanded to encompass the entire global environment. The current
... Show MoreAcute appendicitis is one of the commonest causes of acute abdomen. There is a wide discussion and controversy on the surgical and nonsurgical treatment of acute uncomplicated appendicitis. The aim of this study was to evaluate the efficacy and outcomes of the conservative management of selected cases of acute appendicitis with an antibiotic first plan.
This was a single hospital-based prospective study with a durat
The liver protective effects of pentoxifylline were studied through pre-treatment of rats with various intraperitoneal (IP) doses (25, 50 and 100mg/kg/day) 14 days before induction of liver toxicity by carbon tetrachloride (CCl4). The parameters of oxidative stress, malondialdehyde (MDA) and reduced glutathione (GSH) were measured in liver homogenate in addition to histopathological examinations. Analysis of data revealed significant amelioration of oxidative stress in groups of animals pre-treated with different doses of pentoxifylline (PTX) compared to group of animals intoxicated by CCl4 as evidenced by lowering MDA contents and elevation of GSH levels in liver tissue homogenate but the levels still signifi
... Show MoreThe phenomenon of advertising In the poetry of Ali bin Abdul Rahman Balnopi Sicilian