Engineering Research Journal \ / Vol. 35, No. 3 - July 2012
تاريخ تقديم البحث 11/11/2013
تاريخ قبول البحث 11/11/2013
عدد صفحات البحث 9
رجب أحمد السحيمى
Phasor measurement unit (PMU), State Estimation (SE), Network Observability, Power System Analysis Toolbox (PSAT), and Synchronized Measurements
The recent development of phasor measurement units (PMUs), enhancing synchronization and high time-resolution of measurements, allows the creation of dynamic snapshots and makes network real-time observability possible. A proposed analysis of power system observability and the rules of PMUs placement with the aim of linear static state estimation (SE) of power system networks are presented in this paper. According to the Power System Analysis Toolbox (PSAT), MATLAB toolbox, several algorithms of PMUs allocations as well as their differences and relations are introduced such as a graph-theoretic procedure based on Depth First Search, Simulated Annealing Method, Minimum Spanning Tree Method, and others. These different methods are used to benchmark the real networks with different scales, topologies and voltage levels in Egypt besides the standard test systems of IEEE 14-bus and IEEE 30-bus. The obtained results indicate the effectiveness of the applied methods of optimal PMUs placement for power system observability with the aim of linear static SE as well as the further requirements for optimal PMUs placement, which are not provided by any of the different methods for future work. By comparing the studied methods, we found that, it could not be said that there is an algorithm is optimal for all cases.
Direct torque control (DTC) of an induction motor fed by a voltage source inverter is a simple scheme that does not need long computation time. The main advantage of DTC technique is that it is not sensitive to the variation of motor parameters except the stator resistance in its flux observer especially at low speed operation. The stator resistance can be changes during the motor operation due to ambient temperature or frequency. This paper, introduces an additional on Line fuzzy controller used to estimate the stator resistance for the DTC flux observer. The inputs for the proposed fuzzy controller are speed and stator current errors between the traditional DTC flux observer values, which using constant value of the stator resistance equals to the nominal value, and their values using the proposed on line stator resistance estimator values. The induction motor saturated pi model is used which is more practical than the approximate linear model especially in the large motors. The saturation function and the motor parameters are identified experimentally. The proposed technique response is checked at sinusoidal and trapezoidal reference speeds. The results show good improvements of the DTC response using the proposed adaptive fuzzy controller during on line variation in the stator resistance of the induction motor.
This paper presents a simplified mathematical model for proton exchange membrane fuel cell (PEMFC) systems. The system performance is validated through a comparison with experimental datasheet results of a commercial PEMFC stack. The model is then used to study the transient response of a PEMFC when subjected to different load variations. A PI controller is designed to control the fuel cell output voltage during different transient conditions. The results ensure that the model provides an accurate representation of the dynamic and steady state behaviour of the fuel cell. In addition, the results show the fast response capabilities of the PEMFC for following changes in the load. This model will be useful for the optimal design and real-time control of PEMFC systems especially for electric vehicles applications.
IMPROVING THE ACTIVE POWER FILTER PERFORMANCE WITH AN ADAPTIVE LINEAR NEURAL NETWORK BASED ON THE REFERENCE GENERATION /
قطاع الدراسات الهندسية / الهندسه الكهربائيه
تخصص البحث : الهندسه الكهربائيه
Engineering Research Journal \ / Vol. 35, No. 3 - July 2012
تاريخ تقديم البحث 11/11/2013
تاريخ قبول البحث 11/11/2013
عدد صفحات البحث 12
أحمد محمد بدروم
Active power filter, Adaptive Linear Neuron (ADALINE), reference current extraction, Digital Signal Processing (DSP).
The use of artificial neural networks (ANNs) in power system problems is increasing attention due to their ability to learn and handle the nonlinearities and uncertainties of the systems. Since the last decade, different ANNs identi?cation and ?ltering techniques have been applied in power systems and adaptive linear neuron networks (ADALINE) are actually widely used. More recently artificial neural networks have been introduced as a complement or an alternative to traditional control algorithms. The use of neural networks in control applications including process control, robotics, industrial manufacturing and aerospace applications, among others has recently experienced rapid growth. This paper proposes a new control method for shunt active power filter, which is based on ANN. An adaptive linear neuron (ADALINE) will be presented to estimate the reference compensation currents. The resultant compensation currents eliminate harmonics and reactive power compensation with a quick dynamic response. Theortical and expermental results in a good agreement.
EXPERIMENTAL AND NUMERICAL INVESTIGATIONS FOR THE COMBUSTION OF SELECTED COMPOSITE SOLID PROPELLANT /
قطاع الدراسات الهندسية / الهندسه الكهربائيه
تخصص البحث : الهندسه الكهربائيه
Engineering Research Journal \ / Vol. 35, No. 3 - July 2012
تاريخ تقديم البحث 11/11/2013
تاريخ قبول البحث 11/11/2013
عدد صفحات البحث 11
أحمد محمد حجاب
Composite Propellant, Gas/solid Phases, Heterogeneous Propellant, AP/HTPB, Level Set Method.
In this study, numerical and experimental study for the packing and burning of composite solid propellant is presented. A mathematical model which describes the unsteady burning of a heterogeneous propellant by simultaneously solving the combustion fields in the gas phase and the thermal field in the solid phase with appropriate jump condition across the gas/solid interface is developed. The gas-phase kinetics is represented by a two-step reaction mechanism for the primary premixed flame and the primary diffusion flame between the decomposition products of the HTPB and the oxidizer AP. The propagation of the unsteady non-planer regression surface is described, using the Essentially-Non-Oscillatory (ENO) scheme with the aid of the level set strategy. Moreover, an experimental investigation for similar sample of 200 microns AP particles with 50 microns AP particles imbedded in a matrix of HTPB is performed. The results show that the large AP particle diameter has a great effect on the combustion surface deformation and on the burning rate as well. Moreover, the effect of various parameters on the surface propagation speed, flame structure, and the burning surface geometry is obtained.
This paper examines the mixed convection in a square cavity filled with different nanofluids. The lower side is stationary and was equally divided into a pair of heat source–sink; the left and right vertical sides are be insulated and have opposed velocity whilst the upper side is stationary and insulated. Steady state laminar regime is considered, the transport equations for continuity, momentum, energy are solved. The numerical results are reported for the effect of Richardson number, and solid volume fraction on average Nusselt for various parametric conditions. This study was done for 0.01 ? Ri ? 100, and 0 ? ? ? 0.06 while the Prandtl number represent water is kept constant at 6.2 and Grashof number at 104. A comparison is made with the previous published results. The comparison shows good agreements with previous published results.
EFFECT OF CARBON FIBERS ADDITION ON WEAR BEHAVIOR OF AS41 MAGNESIUM ALLOYS /
قطاع الدراسات الهندسية / General
تخصص البحث : General
Engineering Research Journal \ / Vol. 35, No. 3 - July 2012
تاريخ تقديم البحث 11/11/2013
تاريخ قبول البحث 11/11/2013
عدد صفحات البحث 7
ياسر فؤاد
wear; adhesive; magnesium alloys; AS41; AS41+C.
The objective of the present study is to evaluate AS41 alloy in adhesion wear and the effect of carbon addition on that behavior. In the present work, experimental study has been carried out to characterize and evaluate magnesium alloys AS41 and AS41+C. Different techniques have been used to investigate the microstructure, hardness and wear behavior of AS41 and AS41+C. The dominance of a wear regime is discussed in the light of SEM micrographs of worn surfaces. The wear experiments have been carried out under conditions of varying speed as well as varying load. The results of this study have highlighted the wear behavior of the AS41 and AS41+C alloys matrix composites. The results indicate that the AS41+C had the highest wear resistance followed by the AS41 alloy under both conditions, of constant speed and increasing load. Also, the same orders of decreasing wear resistance as that of decreasing hardness. Only the use of cheap materials both the alloy and the reinforcement in relation to cost effective production processes for manufacturing of magnesium based MMCs can introduce this class of low density materials for automotive and light industries.
USE OF PSO ALGORITHM IN DETERMINATION OF THE OPTIMUM OBSERVATION WEIGHTS IN THE DEFORMATION MONITORING NETWORKS /
قطاع الدراسات الهندسية / الهندسه الميدانيه
تخصص البحث : الهندسه الميدانيه
Engineering Research Journal \ / Vol. 35, No. 3 - July 2012
تاريخ تقديم البحث 11/11/2013
تاريخ قبول البحث 11/11/2013
عدد صفحات البحث 8
محمد إسماعيل دومة( zeyad1612002@yahoo.com - 01224416907 )
.Civil Engineering
Geodetic networks are very important tools used to monitor earth and/or structural deformations. However, a geodetic network must be designed to meet sufficiently some network quality requirements such as precision, reliability, or sensitivity. This is the subject of geodetic network optimization. The determination of the observation weights problem in the deformation monitoring networks can be dealt with as an optimization procedure, this problem can performed by solving the second-order design (SOD) problem. Traditional methods have been used for geodetic optimization tasks. On the other hand, some heuristic techniques have been started to be used recently in geodetic science such as the Particle Swarm Optimization (PSO) algorithm. The general purpose optimization method known as Particle Swarm Optimization (PSO) has received much attention in past years, with many attempts to find the variant that performs best on a wide variety of optimization problems. In this paper, the PSO algorithm, a stochastic global optimization method, has been employed for the determination of the optimum observation weights to be measured in the field that will meet the postulated criterion matrix at a reasonable precision. The fundamentals of the method and a numeric example are given.
Engineering Research Journal \ / Vol. 35, No. 3 - July 2012
تاريخ تقديم البحث 11/11/2013
تاريخ قبول البحث 11/11/2013
عدد صفحات البحث 9
زينب فيصل عبدالقادر
: Sacred Architecture, symbolism, number symbolism, Ancient Egyptian, Coptic Architecture and Islamic Architecture.
Numbers have long been seen as expressions of cosmic order, possibly deriving from ancient Babylonian observation of regular cosmic events, such as night and day, the phases of the moon and cycles of the year. Belief architecture Filled with symbolism for the reason of its indirect impact on the spiritual atmosphere of this type of buildings. Symbolism can be found in which symbolic colors, symbolic shapes, number symbolism and other symbolic tools that emphasize on the spatial experience of these buildings. The research deals with number symbolism in religious buildings in Egypt and their meaning. This study extends along three periods of Egyptian architecture; that represent Ancient Egyptian Architecture, Coptic Architecture and Islamic Architecture in Egypt.
In gated residential developments, it was believed that the waning provision of well-landscaped open spaces including man-made lakes, swimming pools and golf courses, have all added to Egypt’s water woes consuming an overwhelming amount of much needed water, a valuable resource highly appreciated in arid zones. ِAlso, lack of peoples’ understanding of ecology remains major obstacles to achieving more sustainable residential landscapes. The purpose of this paper is twofold: firstly, using a hypothetical framework, the present study provides insights about sustainability awareness and residents’ satisfaction in gated residential developments. Secondly, it aims at presenting new evidences; through descriptive and inferential analyses of a Resident Satisfaction Survey, a key principle relating to satisfaction in residential developments has been identified. That is: the need to encourage residents’ participation in management process to ensure maximizing their satisfaction. Here, the study attempted to understand the relationship between residential landscape management and satisfaction, which is a perceptual construct of residents, then using residents’ participation in landscape management in order to enhance the understanding of sustainability concepts and the implementation of sustainability measures. It will conclude with a brief summary of some of the main points highlighted and provide insight for planning and managing of residential landscapes to improve both landscape sustainability and residents’ satisfaction.
التقنيات التقليدية التراثية وكيفية توظيفها فى العمارةالمعاصرة للمناطق الحارة الجافة /
قطاع الدراسات الهندسية / الهندسه المعماريه
تخصص البحث : الهندسه المعماريه
Engineering Research Journal \ / Vol. 35, No. 3 - July 2012
تاريخ تقديم البحث 11/11/2013
تاريخ قبول البحث 11/11/2013
عدد صفحات البحث 13
إيمان محمد عيد عطية( emanprof@hotmail.com - 01223271549 )
التقنيات التقليدية التراثية, تصنيف التقنيات التقليدية, تقليل الكسب و زيادة الفقدان الحرارى.
Humanity faces the problem of climate control and how to create a suitable climate for man life since antiquity, for that when human had built a shelter he took care about two elements: the first was a protection from climate and the second was creating a suitable indoor climate for his convenience. Wherefore, the building form and design through the ages offered so many different solutions which suitable for every historical period, every environment and location for achieving that goal, therefore we find that building in any climate regions often shows the accumulation of ages experiences which may be up to centuries of trying to achieve the ideal environmental form and design, and we observe that clearly in Islamic architecture. Muslim architect was a proficient in invention of many traditional vocabularies which make him achieves the thermal convenience and helps him to overcome the climatic problems he faces in Desert regions, which considered having a special nature due to the different harsh climates they have. No doubt that Arabian world have so many economic and social changes in order to the stormy technological development of west , which makes the contemporary architecture ignores these traditional vocabularies , and replaced it by the mechanical solutions which are not suitable for environmental conditions although it proves its failure and high cost, especially in Desert regions , in addition to use a foreign materials and building construction methods which are not suitable for our society and its environmental , climatic , social , cultural and economic conditions , so we have to research in our traditional storage finding traditional solutions , and specify which of it can be applied , and which can be developed to be suitable for the environmental and social conditions. إن مشكلة التحكم المناخى وخلق جو مناسب لحياة الإنسان قديمة قدم الإنسانية نفسها , فقد حرص الإنسان على أن يتضمن بناؤه للمأوى عنصرين رئيسيين هما : الحماية من المناخ ومحاولة إيجاد جو داخلى ملائم لراحته , لذلك نجد أن المبانى فى أى منطقة مناخية غالباً ما توضح تراكم خبرات سنين عديدة قد تصل إلى قرون من محاولات الوصول إلى المثالية فى التصميم والتشكيل البيئي وبصورة معمارية جميلة أيضاً , وهو ما نلاحظه جلياً واضحاً فى العمارة الإسلامية , ومنذ القدم نجد أن الإنسان تفاعل مع بيئته لتطوير تقنيات لتلبية احتياجاته المختلفة، وتكونت عمارته نتيجة هذا التفاعل، وكان كل ما يصنعه الإنسان طبيعياً لأن المواد التى كان يشيد بها هى المواد المتوفرة فى بيئته الطبيعية. فقدم حلولاً معمارية فريدة وعناصر معمارية مميزة تعتمد على استخدام التقنيات المتوافقة مع البيئة الطبيعية، مما جعل العمارة مستجيبة ومتلائمة مع ظروف البيئة الصحراوية، ونجح فى أن يقدم حصيلة إبداعية زاخرة معبرة عن المكان، تنسجم معه وتتكيف مع ظروفه، وذلك عن طريق تطويع الكتلة والفراغ والمعالجات المعمارية لتتجاوب مع تقلبات الطقس السلبية, وأثبتت الحلول المعمارية التى قدمها قدرتها على تحقيق الراحة الحرارية للإنسان واستجابتها لمتطلباته، إلى جانب خدمتها للوظائف الجمالية والحسية، فاكتسبت المبانى السمات والطابع الذى ميزها بيئياً وجعل لها شخصية بصرية مميزة , ومؤخراً حاول العديد من المعماريون اللجوء إلى هذه التقنيات التقليدية التى أثبتت كفائتها فى التعامل مع الظروف الخاصة للمناطق الحارة الجافة , فبدأت هذه المحاولات على يد المعمارى حسن فتحى منذ منتصف القرن المنصرم , وتزايدت هذه المحاولات بصورة ملحوظة حتى صارت تمثل اتجاهاً بيئياً فرضته أزمتى الطاقة والتغيرات المناخية على الساحة بحيث أصبح لزاماُ على كل المعماريون دراسته وتطويره لاستغلاله فى العمارة المعاصرة .
جميع البيانات التي يتم تسجيلها على النظام هي ملك للجهة صاحبة هذه البيانات
لا يتم الاطلاع على هذه البيانات من قبل مهندسي المركز إلا للضرورة القصوى ولغرض الدعم الفني وبالاتفاق مع الجهة صاحبة البيانات شفوياً أو كتابياً
لا يتم إعطاء أي بيان من بيانات النظام لأي فرد او جهة فرعية تنتمي للجهة صاحبة البيانات او لأي جهة أخرى إلا بموافقة كتابية من الجهة صاحبة البيانات
يمكن استخدام البيانات المسجلة على النظام بهدف عمل إحصائيات يستفاد منها فى قياس اداء النظام وكفاءة استخدامه من قبل مستخدميه
يتم تأمين جميع البيانات الخاصة بالنظام من خلال تأمين الحاسب الخادم الذي يستضيف البيانات ومن خلال تأمين انتقال البيانات بين جهاز المستخدم والحاسب الخادم وكذلك تأمين واجهة النظام التي يستخدمها المستخدم
كل مستخدم للنظام مسئول مسئولية كاملة عن كلمة المرور الخاصة به وعليه اتخاذ كافة الاحتياطات الممكنة حتى لا يستطيع أى شخص آخر الحصول عليها
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