إنّ زاويةَ سقوط أشعةِ الشمس على سطحِ اللوح الشمسي ودرجة حرارته يُؤثّرانِ سلبياً على الطاقة الكهربائية للوح وكفاءته. أن مشكلة زاويةِ السقوط عادةً ما يتم حلها بإستخدام منظومة التتبع (المقتفي) الشمسي ذات المحورِين والذي يُبقي اللوح بشكل مستمر متعامد مع أشعةِ الشمس طِوال اليوم. هذا يُؤدّي إلى أقصى إمتصاصِ للإشعاعِ الشمسيِ والضروريِ لإنتاج الكميةِ القصوى مِن الطاقةِ وعند مستوىات عالية مِن الكفاءة الكهربائية. لحَلّ مشكلةَ الحرارة فقد تمّ استخدام تقنية الغرفة الزجاجية (المزججة) والتي يتدفقِ خلالها الماء بوصفها طريقة تبريد جديدةِ لتخفيض درجة حرارة اللوح. في هذه البحث، تمّ تصميم منظومِة التزجيج المقترحة بالتكامل مَع منظومة التتبع ثنائية المحاور واجريت التجارب المختبرية عليها لغرض تحسين كفاءةَ اللوح الشمسي، لاسيما في المناخِ الحارِ. نظام التزجيج المُقتَرَحِ يُمْكِنُ أَنْ يُؤدّي وظيفتين بشكل آني، أولاً، يعَمَل أداة تبريد لتقليل الحرارةِ المَخْزُونة في داخل اللوح أثناء عَملها وثانياً مرشِحا بصريا للطيفِ الضوئي. تمّ حساب معاملات التصميمُ الأمثل وبمستويات مختلفة لقيم نظامِ التزجيج وفقاّ...

Neural networks are complex nonlinear models;this characteristic enables them to be used in nonlinear system modeling and prediction applications.The estimation and prediction are importantroles in the communication system.The proposed approach based onthe Wavelet Neural Networks (WNNs)usesmorlet as an activation function in thehidden layer of the wavelet neural network,while the Radial Basis Function Neural Networks (RBFNNs)usebasis functionthat can be calculated as a Gaussian function. In this paper,a comparisonbetween the performance ofWavelet Neural Networksand Radial Basis Functionfor GPS prediction is presented.The comparison results(usingMATLAB programming)presentthat the Wavelet Neural Networks method has a great approximation ability, suitability and more stable in Global Positioning System (GPS)prediction than the Radial Basis Function Neural Networks,were highly effective predictions for accurate positioning and RMS errors are 0.05meter after using of Wavelet Neural Networks prediction.

Linear motor offers several features in many applications that require linear motion. Nevertheless, the presence of cogging force can deteriorate the thrust of a permanent magnet linear motor. Using several methodologies, a design of synchronous single sided linear iron-core motor was proposed. According to exact formulas with surface-mounted magnets and concentrated winding specification, which are relying on geometrical parameters. Two-dimensional performance analysis of the designed model and its multi-objective optimization were accomplished as a method to reduce the motor cogging force using MAXWELL ANSYS. The optimum model design results showed that the maximum force ripple was approximatrly reduced by 81.24%compared to the original model with a smaller ripple coefficient of 0.22. Likewise, the model was redesigned taking into consideration two cases; laminated core and solid core. It was found that the error between the analytical and numerical results of the output force did not exceed 0.0967%.

The efficiency of the solar PV panel decreases significantly as the PV panel’s operating temperature increases. There are many cooling techniques might be suitably deal with this problem to enhance the solar panel efficiency. The presented cooling technique used for solving the PV panel’s temperature elevation is an active close loop cooling system, accomplished using two water glazing chambers made from acrylic glass placed at the PV panel surfaces (rear and front). These champers are utilized for cooling down the PV cell’s temperature, as well as filtering the useful sunlight spectrum. The results show that the PV cell’s temperature reduction by 50.06% with using the cooling system, this leads to an average increase in the maximum output power and consequently electrical efficiency of the PV panel by about 12.69% and 14.2%, respectively.

Experimental investigations had been done in this work to demonstrate the effect of graphite filler contents on the mechanical and tribological behavior of (30% volume fraction) glass-polyester composite system. The stress-strain relations, modulus of elasticity, yield stress, ultimate tensile strength and ultimate compression strength were studied according to ASTM-D 638-87and ASTM-D 695 to present the composite mechanical behavior. The wear rate and wear resistance were investigated according to ASTM-D 5963 using pin on disc machine to present the composite tribological behavior. The results showed that the mechanical and tribological properties behavior was improved when the graphite filler content was increased up to 7.5% and then decreased after that. At 7.5% filler content the modulus of elasticity, yield stress, ultimate tensile strength, ultimate compression strength and wear resistance increased by (41%, 64%, 24%, 60% and 38%) greater than unfilled composite, while the wear rate was decreased by 27% less than the unfilled one.

The main objective of this research is to design and select a composite plate to be used in fabricating wing skins of light unman air vehicle (UAV). The mechanical properties, weight and cost are the basis criteria of this selection. The fiber volume fraction, fillers and type of fiber with three levels for each were considered to optimize the composite plate selection. Finite element method was used to investigate the stress distribution on the wing at cruise flight condition in addition to estimate the maximum stress. An experiments plan has been designed to get the data on the basis of Taguchi technique. The most effective parameters at the process to be find out by employing L9 (33) orthogonal array, signal to noise ratio (S/N), main effect and analysis of variance (ANOVA). The results show that, the experimental and the predicted results are very close. It was found that the type of fiber is the most effective parameter on the plate selection, followed by filler content and then the fiber volume fraction. The best parameters combinations are ((E-glass woven roving + unidirectional carbon) fiber, 7.5% graphite filler and 30% fiber volume fraction). This combination provides good mechanical properties, high safety factor, acceptable cost, and offers weight savings on average by 40% percent as compared to aluminum alloy.