Evaluation Study on Speed Control of dc Series Motor Supplied by Photovoltaic System via Bacterial Foraging /
قطاع الدراسات الهندسية / الهندسه الكهربائيه
تخصص البحث : الهندسه الكهربائيه
Engineering Research Journal \ / Vol. 36, No. 3 - July 2013
تاريخ تقديم البحث 27/11/2013
تاريخ قبول البحث 27/11/2013
عدد صفحات البحث 11
A. S. Oshaba
DC Series Motor, Photovoltaic System, Speed Control, PI Controller, Bacteria Foraging Optimization Algorithm.
This paper presents the design and evaluation of a speed control scheme for a DC series motor supplied by Photovoltaic (PV) system. The proposed design problem of speed controller is formulated as an optimization problem. Bacteria Foraging Optimization Algorithm (BFOA) is employed to search for optimal controller parameters by minimizing the time domain objective function. The performance of the proposed technique has been evaluated with respect to load torque variation, ambient temperature and radiation. Simulation results have shown the validity of the proposed technique in controlling the speed of DC series motor under different disturbances.
Five-level Inverter Fed Five-phase Induction Motor Drive /
قطاع الدراسات الهندسية / الهندسه الكهربائيه
تخصص البحث : الهندسه الكهربائيه
Engineering Research Journal \ / Vol. 36, No. 3 - July 2013
تاريخ تقديم البحث 27/11/2013
تاريخ قبول البحث 27/11/2013
عدد صفحات البحث 7
صبري عبد اللطيف محمود( sabry_abdellatif@yahoo.com - 01005681745 )
Multilevel inverter, Fuzzy Logic Control, Multi-phase Induction Motor
This paper presents simulation and experimental implementation of five-level, five-phase cascaded H-bridge inverter. The inverter is controlled by sinusoidal pulse width modulation technique and fed five-phase induction motors. The speed of the motor is controlled by varying stator voltage with frequency, so as to maintain v/f ratio constant at the rated value. A fuzzy logic controller is also considered for controlling the speed. Simulation program using the MATLAB/SIMULINK software, for five-phase induction motors controlled by the proposed system is developed. Experimental results of the 1.5 Hp of five-phase induction motor show the effectiveness of the proposed control scheme.
PERFORMANCE OF CASCADED H-BRIDGE INVERTER INTEGRATED WITH HFT FOR PV SYSTEM APPLICATIONS /
قطاع الدراسات الهندسية / الهندسه الكهربائيه
تخصص البحث : الهندسه الكهربائيه
Engineering Research Journal \ / Vol. 36, No. 3 - July 2013
تاريخ تقديم البحث 27/11/2013
تاريخ قبول البحث 27/11/2013
عدد صفحات البحث 9
محروس أحمد
MLI; PV; HF Transformer; bidirectional converter; Isolated dc sources.
This paper presents a photovoltaic system as a standalone system. The proposed system consists of photovoltaic (PV) module, battery energy storage system (BESS), high frequency transformer, and multilevel inverter (MLI). The MLI consists of two H-bridge single phase inverter per arm (phase) with unequal dc voltages which needs 6 isolated dc sources for the conventional MLI. The relative values between the upper (auxiliary) inverter dc voltage and the lower H-bridge (main) inverter is 1/3 resulting in 9 levels MLI. Each isolated dc source comes from a PV module accompany with a BESS. A high frequency transformer (HFT) is proposed in this paper to generate the dc bus voltage of the auxiliary inverter from the main inverter dc bus voltage. As a result of that the number of isolated dc bus voltages required is reduced by half which is reflected in reducing the number of PV required and thus reducing the cost of the overall system. In addition, a natural balancing between the main and auxiliary inverters dc bus voltages of each arm will be attained due to the HFT turns ratio which result in simplifying the overall control of the whole system. In order to reduce the size of the HFT a judicious modulation index (MI) will be chosen. The proposed system has been simulated using static inductive load. Analyses and simulation have been proposed to validate the proposed control scheme.
Welding of Cylindrical Parts by using Friction Stir Technique /
قطاع الدراسات الهندسية / الهندسه الميكانيكيه
تخصص البحث : الهندسه الميكانيكيه
Engineering Research Journal \ / Vol. 36, No. 3 - July 2013
تاريخ تقديم البحث 27/11/2013
تاريخ قبول البحث 27/11/2013
عدد صفحات البحث 13
طاهر إبراهيم صبري( sabrytaher@hotmail.com - 01001227716 )
investigate the mechanical - metallurgical
The objective of this work was to investigate the mechanical and metallurgical properties in order to demonstrate the feasibility of friction stir welding for joining Al6061 and Al6063 aluminum alloys Welding was performed on cylindrical parts with different thickness 2mm and 3mm,five rotational speeds,485,710,910,1120 and1400 rpm and a traverse speed 4mm/min was applied. The tests were conducted for the study to determine the mechanical properties (maximum stress - the percentage of elongation) and hardness measurement along the welded sections using the Vickers method, was also studying the crystalline structure of welded joints .The FSW welds exhibited many advantages over traditional arc welding techniques.
التوافق بين الهوية وتنمية المجتمعات والتغاير العالمي في المباني الثقافية / مباني المتاحف الحديثة
قطاع الدراسات الهندسية / الهندسه المعماريه
تخصص البحث : الهندسه المعماريه
Engineering Research Journal \ / Vol. 36, No. 3 - July 2013
تاريخ تقديم البحث 27/11/2013
تاريخ قبول البحث 27/11/2013
عدد صفحات البحث 11
ناهد أحمد عمران
تنمية ثقافية –تصميم المتاحف – الهوية –ثقافة العولمة – مدن المعرفة
استوعبت مباني متاحف الكثير من المتغيرات من مجرد الحفاظ على الثقافات الماضية إلى التغيير في الشكل والتشكيل والدمج مع العمران الحاضر بثقافته ،و تعرض الدراسة مفهوم انثروبولوجيا المتاحف وأهمية دور المتاحف في تنمية المجتمع المحلي والسياحة الثقافية لتكون مراكز تعبرعن الثقافات والهوية ونشر وإحياء التراث الأنساني في المحيط العمراني من خلال الفكرة المعمارية التي تعبر عن هوية المجتمع ،ووسائل عرض حديثة التقنية والأنشطة الداعمة لوظيفة المُتحف لتصبح مراكز تعلىمية وسياحية تمهد للحفاظ على الموروث الانساني والتعريف بالهوية الذاتية. كما تتناول الدراسة أهمية الأحساس بالمكان المادي والمعنوي في ظل التصميم والتشكيل المعماري المتوافق مع المتغيرات العالمية. وتهدف الدراسة عرض ومقارنة لبعض المتاحف العالمية من حيث دورها الوظيفي ومواصفات التشكيل المعماري التي اهتمت بالتوفيق بين المفهوم الوظيفي وتأكيد هوية الطابع المعماري لحضارة المكان. والبحث مزيل ببعض النتائج والتوصيات للوصول إلى تغيير في المفهوم الوظيفي للمبنى المُتحفي وعلاقتة بالمكان و الزمان بإعتبارها مراكز إحياء وتنمية الثقافات ودمج المجتمع المحلي والأقليمي في الإحتفاظ بالتراث القومي .
Engineering Research Journal \ / Vol. 36, No. 3 - July 2013
تاريخ تقديم البحث 27/11/2013
تاريخ قبول البحث 27/11/2013
عدد صفحات البحث 17
هشام محمد محمد حسين
الحمامات العامة - الحمامات الشعبية - حمامات حلوان - الحمامات الرومانية
اتخذت الحمامات العامة ( الحمامات الشعبية ) مكانة متميزة في مختلف الحضارات ، غير أن كل حضارة كانت تضع تعديلات في تصميم هذه الحمامات بما يتناسب مع ظروفها و عاداتها ومعتقداتها كما كانت تختلف في المقياس من حضارة إلي أخري – ففي الحضارة الرومانية مثلا كانت تصل إلي مقياس مدن كاملة و في الحضارة الإسلامية كانت متداخلة في النسيج العمراني للمدينة بل و كانت تنتشر بالأحياء السكنية – إلي أن وصل تطوير هذه الحمامات إلي الشكل الحديث الذي هي عليه الآن في هيئة منتجعات استشفائية أو مراكز استشفائية . كما شغلت الحمامات العامة مساحة كبيرة في الجانب الثقافي للعديد من المجتمعات بل انها تعتبر جزء لا يتجزأ من ثقافة هذه المجتمعات فهي تعتبر الملجأ و الملاذ للحصول علي الراحة و النظافة و الاستجمام و الخلاص من ضغوط الحياة وذلك علي كافة مستويات هذه المجتمعات دون تفرقه ، كما يعد الدور الصحي للحمامات العامة من اهم ادواره الفعالة في المجتمعات فهو يعيد للبشرة تألقها ولمعانها الطبيعي ويجعلها أكثر شبابا لمدة أطول كما يساعد في تخفيف بعض الحالات المرضية بدءا من الكآبة وحتى التهاب المفاصل و يخلص الجسم من العديد من السموم والمواد الضارة به . و يعد تدهور حال الحمامات العامة في العديد من الأقطار العربية نتيجة تغيير وجهة نظرة المجتمع تجاه تلك المشروعات , وارتبطت أفكار المجتمع بكونها مكان لتفشي الأمراض أو مخالفة الآداب العامة , وهو ما يجب تصحيحه و تغيره من أذهان المجتمع حتى تستعيد هذه المشروعات مكانتها و تقوم بدورها. الا أن احتفاظ بعض المجتمعات العربية كالمجتمع التونسي بموروثة الحضاري و الثقافي و العمل علي تنميته كان هو السبب الرئيسي وراء محافظة مشروعات الحمامات العامة - بكافة أشكالها – علي مكانتها ( حيث تأصلت عادة الاستحمام ضمن عادات التونسي منذ القدم ) و ارتبط أفراد المجتمع بزيارة تلك الحمامات و ارتيادها بشكل منتظم وأصبحت جزءا لا يتجزأ من ثقافة المجتمع و تقاليده بغض النظر عن المستوي الاجتماعي أو الثقافي أو المادي لأفراده – سواء كبار أم صغار – و ذلك بالرغم من تعاقب العديد من الحضارات المختلفة علي المجتمع التونسي . كما ان الحمامات العامة بالجزائر تختلف عن تلك الموجودة بمصر حيث أن الحمامات الجزائرية تتميز ببرامج معمارية مختلفة، حيث أن الحمام بالجزائر يشمل عناصر خاصة بإقامة النزلاء ، إلي جانب احتواء هذه الحمامات علي قاعات اجتماعية و مكتبات و مطاعم و ملاعب و أماكن للتنزه , وهذا التطور الملحوظ في البرامج المعمارية لتلك الحمامات كان الدافع إلي إقبال الجمهور و الزائرين من المرضي و ذويهم و الأصحاء القادمين للاستمتاع والاسترخاء و الناقهين , حيث أن الحمامات تغطي شريحة كبيرة و تلبي العديد من الاحتياجات المختلفة لزائريها . لذا يجب العمل علي الاستفادة من التجارب العالمية في تنمية الحمامات العامة و خاصة الدول العربية ( تونس – الجزائر – المغرب) حيث انها اقرب في الظروف و المحددات الي مصر .
مؤسسات علاج الإدمان الحكومية في مصر / دراسة تحليلية
قطاع الدراسات الهندسية / الهندسه المعماريه
تخصص البحث : الهندسه المعماريه
Engineering Research Journal \ / Vol. 36, No. 3 - July 2013
تاريخ تقديم البحث 27/11/2013
تاريخ قبول البحث 27/11/2013
عدد صفحات البحث 10
محمود أحمد دسوقي محمد( creation_desouki@hotmail.com - 01003570534 )
علاج الإدمان، مصر، الحكومية، تحليل
يتناول البحث دراسة نموذجين من مباني علاج الإدمان الحكومية في مصر ومشاكلها التصميميمة المختلفة وتأثيرها على نجاح العملية العلاجية ويقوم بتحليلها والمقارنة ما بينها، ومن ثم يستطيع التوصل للنتائج والتوصيات التي من شأنها تحسين هذه الخدمات معماريا.
LARGE SCALE PHYSICAL MODEL TO INVESTIGATE THE MECHANICS OF EMBANKMENT EROSION DURING OVERTOPPING FLOW /
قطاع الدراسات الهندسية / الهندسه الكهربائيه
تخصص البحث : الهندسه الكهربائيه
Engineering Research Journal \ / Vol. 36, No. 3 - July 2013
تاريخ تقديم البحث 27/11/2013
تاريخ قبول البحث 27/11/2013
عدد صفحات البحث 16
Entesar A . S. EL-Ghorab
Flow pattern, Embankment failure, Overtopping, Large scale physical model
This paper presents the results of large scale physical model embankment failure experiments. The model simulates the failure by overtopping of three embankments that are varying in dimensions and soil type. The soil is either homogeneous pure sand or mixture of sand, silt and clay. A new measuring technique consists of the labeled rod bridge; grids lined and captured instantaneous pictures are utilized to monitor the failure. It was used to analyze the morphological evolution during embankment failure. The flow pattern and progressive failure of embankment overtopping were investigated. The results showed four types of phenomenon during embankment failure: erosion; erosion with sliding; erosion with mass failure and head cut migration. The results revealed that the recorded time to reach the full breach failure in case of mixture materials (sand, silt and clay) is seven times that with pure sand. Also, reducing the embankment height to 50% (0.9m), led to increase the time to peak discharge 8.4 times that of large one (1.8m). Adding 15% clay to pure sand changes soil characteristics to (c and ?) soil which makes soil to have a critical vertical cut height. Set of dimensionless regression equations are developed by using the experimental data. In conclusion, types of embankment failure are defined. Adding a percentage of clay (15%) to the pure sand led to the maximum remain vertical cut height of about 50% of the calculated critical vertical cut height (Zo). Bearing in mind the limited number of large scale testes for embankment breach in literatures, the set of data could be used for calibration of mathematical breach models and provides a reference for the flood risk management of embankments.
Reinforced concrete jacketing is one of the widely used repairing techniques for beams and columns. The aim of this research is to evaluate the efficiency of using concrete jackets using different reinforcements and thicknesses. The behavior of repaired reinforced concrete defected beams is investigated under flexural effect. The tested beams are preloaded up to 70 and 90% of their ultimate capacity then, repaired using concrete jackets. The main variables are thickness of concrete jacket (3, 5 cm), diameter of reinforcing steel bars (8, 10 mm) and concrete jacket type. The experimental results showed that, repairing using concrete jackets enhances the load capacity up to 378%. Increasing jacket thickness enhances the structural performance of the tested beams and in the same time increases its weight. It also increases the stiffness compared to the control beam and consequently the repaired concrete beams indicated a brittle manner compared to the ductile failure of the control beams.
Engineering Research Journal \ / Vol. 36, No. 3 - July 2013
تاريخ تقديم البحث 27/11/2013
تاريخ قبول البحث 27/11/2013
عدد صفحات البحث 12
منير محمد كمال( prof_mounir@yahoo.com - 01065641276 )
Self-compacted concrete; Red brick; Ceramic; Recycled materials; Flexural strength
The effect of recycled materials as a recycled aggregate (crushed red brick and crushed ceramic) on the fresh and hardened properties of Recycled Self-Compacting Concrete (RSCC) was investigated. Recycled materials were used to replace coarse aggregate at different ratios of 25%, 50%, 75% and 100% to produce RSCC mixes. Twenty one concrete mixes were cast and test to fulfill the aim of this paper. This paper aimed at studying the properties of RSCC mixes and evaluating the behavior of RSCC beams under flexural loads. Nine tested loading simply supported concrete beams were tested in flexure. The fresh properties of RSCC were evaluated using slump flow, J-ring and V-funnel tests. Compressive strength, splitting tensile strength and flexural strength were performed in order to investigate mechanical properties. The density for different mixes was evaluated. The behavior of the tested beams was investigated with special attention to the deflection under different stages of loadings, initial cracking, cracking pattern, and ultimate load. The average of the compressive strength decreased by 34% and 26% for the mixes with crushed red break and ceramics, respectively compared to that of control mix was observed. In addition, the density for the mixes with crushed red brick decreased by 14 % compared to that of control mix. The obtained results presented the properties of this concrete were expected from a structure point of view, and that the recycled coarse aggregates can successfully be used for making of SCC.
Reduction in environmental pollution using rice-husk ash in concrete /
قطاع الدراسات الهندسية / الهندسه الميدانيه
تخصص البحث : الهندسه الميدانيه
Engineering Research Journal \ / Vol. 36, No. 3 - July 2013
تاريخ تقديم البحث 27/11/2013
تاريخ قبول البحث 27/11/2013
عدد صفحات البحث 10
Turki Mesfer Al-Aboud
Concrete, Rice-husk ash, X-ray diffraction, Scanning electron microscopy, Compressive strength, Flexural strength. Chloride and sulphate resistance
The production of cement as a binding component of concrete is costly, consumes high energy, depletes natural resources and emits huge amounts of greenhouse gases (one ton of cement production emits about one ton of CO2). Consequently, environmental degradation, serious pollution and health hazards associated with cement and concrete industries, have come under intense scrutiny from environmentalists and the governments. Developed and some developing countries, are already using industrial and agricultural wastes in concrete. These wastes also pose several environmental problems. Partial inclusion of waste instead of 100% cement has been found to be environmentally safe, stable, durable as well as economical. Rice husk ash (RHA), rich in silica content, can be produced from rice husk using appropriate combustion technique for use in concrete as a supplementary cementitious material. The present study used rice-husk ash (RHA) as a partial replacement of cement in concrete. X-ray diffraction analysis, scanning electron microscopic examination, compressive strength (without and with superplasticizers), flexural strength, resistance to aggressive chemicals and cost analysis were carried out. Concrete and mortars containing 25% RHA as a replacement of cement, exhibited same or better results compared to conventional concrete. Moreover, it leads to substantial cost savings not to mention benefits to the environment.
HIGH SIDE VOLTAGE CONTROLLER TO IMPROVE PERFORMANCE AND VOLTAGE STABILITY OF A POWER SYSTEM /
قطاع الدراسات الهندسية / الهندسه الكهربائيه
تخصص البحث : الهندسه الكهربائيه
Engineering Research Journal \ / Vol. 36, No. 3 - July 2013
تاريخ تقديم البحث 17/12/2013
تاريخ قبول البحث 17/12/2013
عدد صفحات البحث 8
هبة عبد الحميد متولي خطاب( khatab.heba@yahoo.com - 01004151345 )
Synchronous generator, HSVC, AVR, PSS, Voltage stability, Voltage Droop Rate
This paper describes a high side voltage controller (HSVC) design, implementation and performance study for a synchronous generating unit connected to an infinite bus power system via a transformer and a double-circuit transmission line. In addition to enhance the system performance, the HSVC can improve power system voltage stability by adding supplemental control to conventional generator excitation system. The simulation results using detailed non-linear model for the system with: a conventional automatic voltage regulator (AVR), power system stabilizer (PSS), and applying HSVC, are obtained. These results illustrate the superiority of HSVC to enhance the system performance as well as its voltage stability when subjected to different disturbances.
Optimal Power Flow Control Based Shunt FACTS Devices Using PSO Algorithm /
قطاع الدراسات الهندسية / الهندسه الكهربائيه
تخصص البحث : الهندسه الكهربائيه
Engineering Research Journal \ / Vol. 36, No. 3 - July 2013
تاريخ تقديم البحث 17/12/2013
تاريخ قبول البحث 17/12/2013
عدد صفحات البحث 11
جمال عبد الوهاب مرسي( gamorsy@yahoo.com - 01003099394 )
optimal power flow, particle swarm optimization, FACTS.
In this paper, an efficient and reliable evolutionary-based approach is employed to solve the optimal power flow (OPF) problem. This approach utilizes the global and local exploration capabilities of particle swarm optimization (PSO) to search for optimal setting of control variables for the OPF which is formulated as a nonlinear constrained objective optimization problem with both equality and inequality constraints. To illustrate how the proposed method has an efficient role, the standard IEEE 30-bus power system is studied and the PSO is used to minimize each of the total fuel cost, system power loss and voltage deviations. Two different types of FACTS devices are embedded with the test system, SVC and STATCOM, to achieve the objectives functions under certain constraints. The results show the effectiveness of STATCOM with optimal settings over the SVC with same conditions.
Optimal Power Flow Problem Solution Incorporating FACTS Devices Using PSO Algorithm /
قطاع الدراسات الهندسية / الهندسه الكهربائيه
تخصص البحث : الهندسه الكهربائيه
Engineering Research Journal \ / Vol. 36, No. 3 - July 2013
تاريخ تقديم البحث 17/12/2013
تاريخ قبول البحث 17/12/2013
عدد صفحات البحث 10
جمال عبد الوهاب مرسي( gamorsy@yahoo.com - 01003099394 )
optimal power flow, particle swarm optimization, SVC and UPFC.
This paper presents an efficient and reliable evolutionary-based approach to solve the optimal power flow (OPF) problem. To search the optimal setting of control variables for the OPF, which is formulated as a nonlinear constrained objective optimization problem with both equality and inequality constraints, particle swarm optimization (PSO) algorithm is used. The standard IEEE 30-bus power system is studied to illustrate how the proposed method has an efficient role. The objectives are minimizing the total fuel cost, system power loss, installation cost of FACTS and voltage profile improvement. Two different types of FACTS devices are incorporated with the test system, SVC and UPFC, to achieve the objective functions under certain constraints. Furthermore, the proposed method is used to determine the optimal location of FACTS controller. The results show the effectiveness of UPFC with optimal settings over the SVC under the same conditions. Also, the results illustrate the importance of determination of the best location of FACTS devices.
Fault Tolerant Of Three-Phase Inverter Fed Speed Sensorless Induction Motor Drive System /
قطاع الدراسات الهندسية / الهندسه الكهربائيه
تخصص البحث : الهندسه الكهربائيه
Engineering Research Journal \ / Vol. 36, No. 3 - July 2013
تاريخ تقديم البحث 17/12/2013
تاريخ قبول البحث 17/12/2013
عدد صفحات البحث 8
زكى محمد البربرى
Induction motor drive, Current control Voltage source inverter (CCVSI), Fault tolerant, four-switch three phase inverter (FSTPI).Insulated Gate Bipolar Transistor (IGBT).;
This paper proposes an algorithm for fault tolerance of three-phase inverter fed speed sensorless control of three- phase induction motor drive system. The fault tolerance of inverter when one switch is open or one leg of six-switch inverter is lost is considered. The control of the drive system is based on indirect rotor field oriented control theory. Also, the speed estimator is based on model reference adaptive system (using stator current and rotor flux as state variables for estimating the speed). The fault tolerant algorithm is able to adaptively change-over from six switch inverter to four switch inverter topologies when the fault is occurred; also, it makes a smooth transition of the motor speed, torque and current when changing over from faulty condition to new healthy status which is (Four-Switch Three-Phase Inverter (FSTPI) topology), thus, the Six Switch Three-Phase Inverter (SSTPI) topology (pre-fault status) almostly retained. The proposed algorithm is simulated by using the MATLAB/SIMULINK package. The obtained results from the simulation model demonstrate the performance enhancement and good validity of the fault-tolerance control for speed sensorless induction motor drive system.
Fault Tolerant Of Three-Phase Inverter Fed Speed Sensorless Induction Motor Drive System /
قطاع الدراسات الهندسية / الهندسه الكهربائيه
تخصص البحث : الهندسه الكهربائيه
Engineering Research Journal \ / Vol. 36, No. 3 - July 2013
تاريخ تقديم البحث 17/12/2013
تاريخ قبول البحث 17/12/2013
عدد صفحات البحث 8
زكى محمد البربرى
Induction motor drive, Current control Voltage source inverter (CCVSI), Fault tolerant, four-switch three phase inverter (FSTPI).Insulated Gate Bipolar Transistor (IGBT).;
This paper proposes an algorithm for fault tolerance of three-phase inverter fed speed sensorless control of three- phase induction motor drive system. The fault tolerance of inverter when one switch is open or one leg of six-switch inverter is lost is considered. The control of the drive system is based on indirect rotor field oriented control theory. Also, the speed estimator is based on model reference adaptive system (using stator current and rotor flux as state variables for estimating the speed). The fault tolerant algorithm is able to adaptively change-over from six switch inverter to four switch inverter topologies when the fault is occurred; also, it makes a smooth transition of the motor speed, torque and current when changing over from faulty condition to new healthy status which is (Four-Switch Three-Phase Inverter (FSTPI) topology), thus, the Six Switch Three-Phase Inverter (SSTPI) topology (pre-fault status) almostly retained. The proposed algorithm is simulated by using the MATLAB/SIMULINK package. The obtained results from the simulation model demonstrate the performance enhancement and good validity of the fault-tolerance control for speed sensorless induction motor drive system.
Experimental Investigation of Four Switch Three Phase Inverter Performance Fed Sensorless Speed Control of Induction Motor Drives /
قطاع الدراسات الهندسية / الهندسه الكهربائيه
تخصص البحث : الهندسه الكهربائيه
Engineering Research Journal \ / Vol. 36, No. 3 - July 2013
تاريخ تقديم البحث 17/12/2013
تاريخ قبول البحث 17/12/2013
عدد صفحات البحث 8
هيثم زكي عزازي( h_azazi@yahoo.com - 01066475518 )
Induction motor, Four switch inverter, Six switch inverter, Sensorless control, model reference adaptive system (MRAS) , total harmonic distortion(THD) and digital signal processor (DSP).
This paper presents an experimental investigation of four switch inverter performance fed three phase induction motor drives. The speed estimation based on fundamental wave models using model reference adaptive system as speed estimator technique. The motor is fed from four switch three phase inverter. A comparative study for sensorless speed estimation using four switch three phase inverter and six switch inverter is experimentally investigated. Also a comparison of system performance based on four switch inverter and conventional six switch inverter in terms of speed response and total harmonic distortion of stator currents is presented. Experimental results at different point of operations are presented verifying robustness of sensorless speed estimation at different load levels. Sensorless speed estimation based on four switch three phase inverter is quite acceptable considering its speed response.
Ballizing is a method of burnishing an internal diameter by forcing a precision ground steel or a tungsten carbide ball through a slightly undersized pre-machined hole. This plastic deformation process produces a smooth surface with favorable mechanical properties and negative residual stresses. The objective of this investigation is to determine the optimal setting of the ballizing parameters while ballizing 70/30 cu-zn brass alloy. The parameters considered are interference, wall thickness of the hole, number of passes, ball speed and initial surface roughness of the hole, whereas the responses are surface roughness, residual stresses and microhardness variation of the ballized hole. The optimal setting of the parameters is determined through experimental planning, conducted and analyzed using Taguchi method. It is found that the initial surface roughness of the hole exerted the greatest effect on surface roughness of the ballized hole, followed by interference and wall thickness of the hole. The No. of passes and ball speed were found to have only a slight influence on the surface finish. A critical interference (300 ?m) exists for maximum improvement in roughness. Based on the experimental results, the optimal ballizing for compressive residual stresses were obtained at 4 mm wall thickness, 400 ?m interference and 2 mm/sec ball speed.The initial surface roughness and No. of passes were found to have no significant effect on the residual stresses. The optimum conditions for surface roughness and residual stresses are different. The microhardness just below the ballized surface was improved up to 65%. The maximum depth of the plastically deformed layer was observed at 300 ?m below the ballized surface. Generally, it was observed that the maximum value of the strain hardening increases with the increase in both interference and wall thickness. The results of confirmation experiment agree will with the predicted optimal settings.
Numerical and experimental study of the three-dimensional unsteady flow field around finite cylinders placed on a ground wall is presented. The effects of free-end shape reading flat, hemisphere and cone top of the circular cylinder are examined. The numerical results were obtained using the computational fluid dynamic (CFD) code, Fluent 6.3.26. The three-dimensional unsteady flow filed is investigated using unsteady Reynolds averaged Navier-Stokes (URANS) equation along with the four equations v2-f turbulence model. This turbulence model is implemented in the CFD code using User Defined Function (UDF) and User Defined Scalars (UDS). The measurements of surface pressure distribution around the bodies are presented. The cylinder has an aspect ratio of 1.33 (h/D = 1.33) and faces flow with Reynolds number of 1.7 x 105 based on free stream velocity and cylinder diameter. The results show that the top free surface of the models affects the flow field, such as the development of the wake structure, recirculation zone and the reattachment zone. The results indicate also that the hemispherical free end cylinder is subjected to the larger flow induced vibration while the cone free end is subjected to the lowest flow induced vibration
Study on the parameters affecting the performance of adsorption cooling system /
قطاع الدراسات الهندسية / الهندسه الميكانيكيه
تخصص البحث : الهندسه الميكانيكيه
Engineering Research Journal \ / Vol. 36, No. 3 - July 2013
تاريخ تقديم البحث 17/12/2013
تاريخ قبول البحث 17/12/2013
عدد صفحات البحث 11
علي رحيم السيد الغلبان( aaghalban@yahoo.com - 01069915417 )
Silica gel; Adsorber; COMSOL Multiphysics®; Porous medium; Cooling system
This paper presents numerical simulation of a silica gel/water adsorption refrigeration system. The commercial COMSOL Multiphasics® code is used for simulation which employs the finite element multi-dimensional model for heat and mass transfer processes. The simulation has been carried out for rectangular tube adsorber. The proposed model is validated against available experimental data in the literature. The effects of cycle time, heating temperature, cooling temperature, contact coefficient of heat transfer between grains and heat exchange’s surface, evaporator temperature, grain size and adsorbing/desorbing bed layer thickness on the system performance were investigated. The results show that both3-D and 2-D modeling for section of the bed lead to predicting the performance of the entire bed with a good accuracy. One of the main results of this study is that the layer thickness which gives optimal coefficient of performance (COP) doesn’t depend on grain size. Moreover the results show that both of COP and specific cooling power (SCP) increase by decreasing grain size.
NUMERICAL STUDY OF ENHANCING HEAT TRANSFER USING TWISTED TAPE INSERTS /
قطاع الدراسات الهندسية / الهندسه الميكانيكيه
تخصص البحث : الهندسه الميكانيكيه
Engineering Research Journal \ / Vol. 36, No. 3 - July 2013
تاريخ تقديم البحث 17/12/2013
تاريخ قبول البحث 17/12/2013
عدد صفحات البحث 15
A. Khalil
Heat transfer; Twisted tapes; Pitch ratio.
In the present work, a numerical study of heat transfer for flow inside tube using twisted tapes inserts is presented. Four models have been studied which are plain tube, tube with single twisted tape, tube with double twisted tapes co-swirling flow and tube with double twisted tapes counter swirling flow. The effect of twisted tape pitch and width ratio on heat transfer, Nusselt number, pressure DROP and effectiveness are studied. It is found that Nusselt number, effectiveness and pressure DROP are increased as pitch ratio decreased. Also, the results show that counter swirling tape inserts has Nusselt number higher than co-swirling tapes, single tapes, and plain tube by about 5-9 %, 14-22 %, and 55-80 % respectively. The results indicate also that twisted tapes with clearance ratio are less effective compared to the types of zero clearance (tight fit tapes). Finally, a good agreement has been found between the present numerical results and published experimental results.
ASSESSING THE ROLE OF POINT SAMPLE NEIGHBORHOODS /
قطاع الدراسات الهندسية / الهندسه الميدانيه
تخصص البحث : الهندسه الميدانيه
Engineering Research Journal \ / Vol. 36, No. 3 - July 2013
تاريخ تقديم البحث 17/12/2013
تاريخ قبول البحث 17/12/2013
عدد صفحات البحث 7
رائد محمد كامل حسونة( rd3165@yahoo.com - 01061752756 )
Digital elevation modeling – point samples - neighborhood
In this study, mathematical models for the self and relative neighborhoods of spatial point configurations have been proposed. This was intended for data/check elevation point patterns. These models were based on some realized point patterns within an illustrative rectangular geographical window. This window includes the Nile Valley, Eastern Desert and South Sinai in Egypt. The investigated data and check patterns had point elevation values, which were based on the SRTM30 global elevation model. The trends of the neighborhood models agreed with those of the interpolation quality, as expressed in terms of the standard deviation of discrepancies. Moreover, closed expressions were proposed, which relate the terrain interpolation qualities with the relevant neighborhood models. It is recommended to use such criterion for planning the spatial distributions of elevation point patterns in digital terrain modeling.
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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