Wind energy is one of the most common and natural resources that play a huge role in energy sector, and due to the increasing demand to improve the efficiency of wind turbines and the development of the energy field, improvements have been made to design a suitable wind turbine and obtain the most energy efficiency possible from wind. In this paper, a horizontal wind turbine blade operating under low wind speed was designed using the (BEM) theory, where the design of the turbine rotor blade is a difficult task due to the calculations involved in the design process. To understand the behavior of the turbine blade, the QBlade program was used to design and simulate the turbine rotor blade during working conditions. The design variables such as (chord length and torsion angle) affecting the performance of wind turbines were studied. Aileron (NACA4711) was selected for sixteen different sections of the blade with a length of (155 cm) both (power factor, torque coefficient, lift coefficient, drag coefficient, lift-to-drag coefficient ratio) where high-accuracy results were obtained and it was found that the best performance in which the turbine rotor can operate is when the(tip speed ratio) is equal to (7). In addition, a power factor was obtained (Cp = 0.4742), not exceeding the Betz limit (0.59%). It is good efficiency for a small wind turbine, and it turns out that the design of a small horizontal wind turbine with three blades is suitable for working in areas with low wind speed.
إن استخدام النظم الالكترونية في القطاع المصرفي وبالخصوص نظام مقاصة الصكوك الالكترونية (ACH) في عمليات التحويل الالكتروني للاموال بين المصارف تتضمن تحويلات مالية عالية القيمة بين المصارف المشاركة بهذا النظام, وان اي خلل قد يحدث بالنظام يؤدي الى حالات تلاعب في مقاصة الصكوك الالكترونية في المصارف المشاركة وبالتالي حدوث عملية اختلاس, ومن هذا المنطلق تبرز مشكلة البحث في اهمية توافر برنامج تدقيق مقترح ياخ
... Show Moreقد يشعر الطلبة و الاساتذة بالملل و الروتين وقلة الاهتمام بما يقومون به مما يؤدي تدني الفاعلية الذاتية وتدني احترام الذات و تدني الافكار المسبقة عن الاداء و توقع النجاح في المهمات و هذا الشعور يؤدي الى تدني امكانية تطوير فاعلية ذاتية في اداء التدريسين و في المذاكرة و التحصيل لدى الطلبة , و بما ان طلبة الجامعة هم فئة مهمة في المجتمع تقع عليهم مسؤولية قيادة معظم مفاصل المجتمع و ميادينه و يمثلون طاقة انتاجية ب
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مشكلة البحث وآهميته :
تعد مرحلة ما قبل المدرسة من المراحل شديدة الأهمية في نمو الأطفال في هذه المرحلة تمتد رغبة الطفل في التعرف على العالم المحيط به ثم تتطور أنشطته لتصبح أكثر عمقا وأتساعا فتتضمن البيئة البعيدة عنه ، هذا فضلا على أن 50% من التنمية الذهنية للطفل تتشكل في السنوات الأربع الأولى من العمر وأن القراءة هي إحدى المكونات الأساسية التي تعززهذا الجانب من التنمية .
( أبو
... Show MoreThe old ways of education has not been able to achieve the ultimate goal in the development of the child's personality and prepared for public life , so shall educators to adopt modern methods of learning such as cooperative learning , which takes into account the considerations psychology of children and their level of mental , as the collective learning is important for children mighty and vulnerable children and so by placing the child in front of something significant tangible and choose topics of relevance to the concerns of the child himself . ( Maroni , 2008 : 101-102 ) . Consisted importance of research of the most important goals of community child care and upbringing proper education to create him a good citizen intact,
... Show MoreThis research attempts to investigate narrative structure in oral narrative particularly in Oprah's Show from a sociolinguistic viewpoint. Narrative is said to be universal in the sense that it is found in all times and places. There is no society or culture without narrative. Oral narrative is organized in a specific order. The research aims at studying and analyzing this order. In addition to that, it highlights the importance of narrative in conveying some moral messages to people who are listening to the story. The study is divided into two parts; theoretical and practical. The theoretical part draws on presenting a survey of literature which includes definitions and explanations of some related terms. The practical part is concerned
... Show MoreIn this paper, an Anti-Disturbance Compensator is suggested for the stabilization of a 6-DoF quadrotor Unmanned Aerial vehicle (UAV) system, namely, the Improved Active Disturbance Rejection Control (IADRC). The proposed Control Scheme rejects the disturbances subjected to this system and eliminates the effect of the uncertainties that the quadrotor system exhibits. The complete nonlinear mathematical model of the 6-DoF quadrotor UAV system has been used to design the four ADRCs units for the attitude and altitude stabilization. Stability analysis has been demonstrated for the Linear Extended State Observer (LESO) of each IADRC unit and the overall closed-loop system using Hurwitz stability criterion. A minimization to a
... Show MoreMethylotrophs bacteria are ubiquitous, and they have the ability to consume single carbon (C1) which makes them biological conversion machines. It is the first study to find facultative methylotrophic bacteria in contaminated soils in Iraq. Conventional PCR was employed to amplify MxaF that encodes methanol dehydrogenase enzyme. DNA templates were extracted from bacteria isolated from five contaminated sites in Basra. The gene specific PCR detected Methylorubrum extorquens as the most dominant species in these environments. The ability of M. extorquens to degrade aliphatic hydrocarbons compound was tested at the laboratory. Within 7 days, gas chromatographic (GC) studies of remaining utilize
... Show MoreThis paper presents a vibration suppression control design of cantilever beam using two piezoelectric patches. One patch was used as an actuator element, while the other was used as a sensor. The controller design was designed via the balance realization reduction method to elect the reduced order model that is most controllable and observable. the sliding mode observer was designed to estimate six states from the reduced order model but three states are only used in the control law. Estimating a number of states larger than that used is in order to increase the estimation accuracy. Moreover, the state estimation error is proved bounded. An optimal LQR controller is designed then using the estimated states with the slid
... Show MoreIn present work an investigation for precise hole drilling via continuous wave (CW) CO2 laser at 150 W maximum output power and wavelength 10.6 μm was achieved with the assistance of computerized numerical controlled (CNC) machine and assist gases. The drilling process was done for thin sheets (0.1 – 0.3 mm) of two types of metals; stainless steel (sst) 321H, steel 33 (st). Changing light and process parameters such as laser power, exposure time and gas pressure was important for getting the optimum results. The obtained results were supported with computational results using the COMSOL 3.5a software code.
The purpose of this paper is to find the best multiplier approximation of unbounded functions in –space by using some discrete linear positive operators. Also we will estimate the degree of the best multiplier approximation in term of modulus of continuity and the averaged modulus.