@article { author = {Dahab, A. A.}, title = {MAGNETIC BEHAVIOR OF COMPACT AND CONVENTIONAL SINGLE TOWER TRANSMISSION LINE}, journal = {ERJ. Engineering Research Journal}, volume = {28}, number = {4}, pages = {329-334}, year = {2005}, publisher = {Menoufia University, Faculty of Engineering}, issn = {1110-1180}, eissn = {}, doi = {10.21608/erjm.2005.69994}, abstract = {The paper investigates the magnetic flux density levels under and around a single tower transmission line. The single tower is a tower carrying transmission circuits with negligible mutual effect from any other circuits. Three cases for a single tower carrying a single circuit are considered. The first is a conventional delta which exhibits the highest level patterns. The second is a compact inverted delta which exhibits the optimal level patterns. The third is a compact delta which falls in between. A single tower carrying a conventional double 3- phase circuit is compared with a 6-phase converted circuit having the same configuration. These two cases are compared with a compact design 6-phase single tower transmission line. The 6-phase compact circuit exhibits the optimal performance. The conventional converted 6-phase circuit exhibits the highest density level patterns. The conventional double three phase circuit falls in between.}, keywords = {Compact transmission lines,Double three-phase circuit lines,Single towers,Six phase Circuits}, url = {https://erjm.journals.ekb.eg/article_69994.html}, eprint = {https://erjm.journals.ekb.eg/article_69994_8aef187503ae161c69618c7c0ca9651c.pdf} } @article { author = {Tweig, N.T. and Mahmoud, S.A. and Shokralla, S.S.}, title = {D.C. MOTOR CONTROLLED BY CUK CONVERTER FED FROM A PHOTOVOLTAIC SYSTEM}, journal = {ERJ. Engineering Research Journal}, volume = {28}, number = {4}, pages = {335-341}, year = {2005}, publisher = {Menoufia University, Faculty of Engineering}, issn = {1110-1180}, eissn = {}, doi = {10.21608/erjm.2005.69999}, abstract = {In this paper the theoretical and experimental investigations for both steady-state and dynamic operation of dc-dc Cuk converter powered a separately excited dc motor are presented. The analysis is extended to the photovoltaic generator supply. The effect of duty ratio for different irradiation levels on the motor performance is obtained. The relation between solar irradiation level and converter duty ratio to ensure maximum energy utilization is given. The maximum photovoltaic generator can be obtained by adjusting the converter duty ratio for certain irradiation levels with a pump load. The proposed system can be utilized in spray irrigation and green house water supply management.}, keywords = {Solar cells .dc-dc converter,Cuk converters,Photovoltaic generators,dc- motor}, url = {https://erjm.journals.ekb.eg/article_69999.html}, eprint = {https://erjm.journals.ekb.eg/article_69999_2e400dac07382630a11126730a9be321.pdf} } @article { author = {El-Khouly, Fahmy M.}, title = {A SIMPLE FUZZY LOGIC SPEED CONTROLLER FOR A DC MOTOR FED BY SEPIC CONVERTER}, journal = {ERJ. Engineering Research Journal}, volume = {28}, number = {4}, pages = {343-351}, year = {2005}, publisher = {Menoufia University, Faculty of Engineering}, issn = {1110-1180}, eissn = {}, doi = {10.21608/erjm.2005.70000}, abstract = {This paper presents a closed loop speed controi of a separately excited DC motor. A cascade combination of a diode bridge rectifier and single-ended primary inductor converter (SEPIC) is used to feed the DC motor from an AC supply. This circuit combination offers both step-up and step-down characteristics of the motor terminal voltage as well as an approximately sinusoidal supply current with an improved power factor. A fuzzy logic speed controller is used to overcome any system nonlinearity and parameter changes. Also. a wide range of both speed and load changes with satisfactory response is obtained. Two fuzzy membership functions are used reflecting few and simple control rules. Moreover. a genetic algorithm (GA) is used to optimally tune the fuzzy controller parameters. Simulation results of the system are obtained by solving the differential equations in different modes of operation. The system is laboratory implemented and the controller is investigated using a digital signal processing board (DSPI 104). The experimental and simulation results are verified and a correlation between both has been found. The results confirm the relevance of the proposed configuration a- a useful rectifier that achieves sinusoidal supply current, high power factor and motor speed regulator.}, keywords = {SEPIC converter. DC motor,Speed control. Fuzzy logic control}, url = {https://erjm.journals.ekb.eg/article_70000.html}, eprint = {https://erjm.journals.ekb.eg/article_70000_62abafb43d684c70c63ee5bfa4d98c62.pdf} } @article { author = {Abdel-Fattah, A. and Abou-Taleb, F.Sh and Moustafa, Gamal H.}, title = {INVESTIGATIONS OF A TWO DIMENSIONAL JET IMPINGING ON TWO FLAT PLATES WITH AN ANGLE BETWEEN THEM}, journal = {ERJ. Engineering Research Journal}, volume = {28}, number = {4}, pages = {353-365}, year = {2005}, publisher = {Menoufia University, Faculty of Engineering}, issn = {1110-1180}, eissn = {}, doi = {10.21608/erjm.2005.70003}, abstract = {Jet Impingement on two flat plates with an angle between them has been experimentally and Numerically studied at different flow and geometrical conditions. The numerical simulations were performed by the solution of Navier-Stokes equations with a k- E model. The stagnation pressure ratio (p, I p.) was varied from 1.2 to 3. Thus, the Reynolds number based on the nozzle width (b) was ranged from 4.5 x lo4 to 8.3 x 10' . The distance between the center of the two plates and nozzle exit plane (hlb) was changed from 5 to 60. The angle between the two plates (0) was varied from 50" to 180' . Pressure distributions along the two plates were compared with those of a free jet. Also, results have been compared with those obtained from the numerical solution. It is concluded that the jet flow behavior and pressure distributions are more sensitive to the initial stagnation pressure, the impingement distance than those obtained with varying the angle between the two impingement plates. Comparison of the predicted behavior of the jet with those obtained from experimental results gives a good agreement.}, keywords = {jet,impingement surface,Navier Stokes,K- E model,Pitot tube}, url = {https://erjm.journals.ekb.eg/article_70003.html}, eprint = {https://erjm.journals.ekb.eg/article_70003_5773c1498d303e516c8c818e33296e27.pdf} } @article { author = {El-Haroun, A. A.}, title = {THEORETICAL AND EXPERIMENTAL HEAT TRANSFER ANALYSIS OF A FLAT PLATE COLLECTOR FOR A SOLAR THERMAL WATER PUMP}, journal = {ERJ. Engineering Research Journal}, volume = {28}, number = {4}, pages = {367-373}, year = {2005}, publisher = {Menoufia University, Faculty of Engineering}, issn = {1110-1180}, eissn = {}, doi = {10.21608/erjm.2005.70007}, abstract = {}, keywords = {}, url = {https://erjm.journals.ekb.eg/article_70007.html}, eprint = {https://erjm.journals.ekb.eg/article_70007_37376c342edc2869f0265909f7b00858.pdf} } @article { author = {Mahfouz, F. M.}, title = {FORCED CONVECTION FROM AN ISOTHERMAL CIRCULAR CYLINDER PLACED IN A CROSS STREAM OF MICROPOLAR FLUID}, journal = {ERJ. Engineering Research Journal}, volume = {28}, number = {4}, pages = {375-384}, year = {2005}, publisher = {Menoufia University, Faculty of Engineering}, issn = {1110-1180}, eissn = {}, doi = {10.21608/erjm.2005.70248}, abstract = {This paper investigates forced convection associated with the cross-flow of micropolar fluids over a horizontal heated circular cylinder. The full conservation equations of mass, linear momentum, angular momentum and energy are solved to give the details of flow and thermal fields. Heat convection process are mainly influenced by Reynolds number, Prandtl number and material parameters of micropolar fluid. The Reynolds number is considered up to 200 while the Prandtl number is fixed at 0.7. The vortex viscosity is the only material parameter considered in this study and is selected in the range from 0 to 5. The study has shown that generally the mean heat transfer decreases as the vortex viscosity increases. The results have also shown that both the natural frequency of vortex shedding and the amplitude of oscillating lift force experience clear reduction as the vortex viscosity increases}, keywords = {Micropolar fluid-cylinder-forced convection-vortex viscosity-vortex shedding}, url = {https://erjm.journals.ekb.eg/article_70248.html}, eprint = {https://erjm.journals.ekb.eg/article_70248_d8bea104004dff7a3df4a3a35996ef72.pdf} } @article { author = {Moustafa, A.A. and Abo El-Nasr, A. and Jadi, A. S.}, title = {WEAR AND FRICTION BEHAVIOR OF AN Sic PARTICULATE REINFORCED 2124A1 COMPOSITE}, journal = {ERJ. Engineering Research Journal}, volume = {28}, number = {4}, pages = {385-393}, year = {2005}, publisher = {Menoufia University, Faculty of Engineering}, issn = {1110-1180}, eissn = {}, doi = {10.21608/erjm.2005.70252}, abstract = {The present paper deals with the investigation of wear and friction characteristics of 10 vol.% Sic particulate reinforced 2124A1 composite in addition to its unreinforced 2124Al alloy. A pin-on￾ring apparatus has been employed. The effects of the normal load, sliding speed, and sliding time on mass loss and coefficient of friction were examined. The specific wear energy and the activation energy were also estimated in order to gain more understanding of the mechanisms that control wear in these materials. The present results show, for both materials, that mass loss linearly increases with increasing normal load and sliding time. It is also observed that increasing sliding speed leads to a complicated wear manner. The unreinforced alloy has the greater mass loss when compared with the reinforced composite, but when increasing sliding speed, the unreinforced alloy exhibits minimum values of mass loss. In all cases, the coefficient of friction is greater, for the present composite, than that for the unreinforced alloy. Furthermore, wear mechanisms were investigated and discussed in the light of microscopic observations.}, keywords = {}, url = {https://erjm.journals.ekb.eg/article_70252.html}, eprint = {https://erjm.journals.ekb.eg/article_70252_15220f05153427182240b0588462d784.pdf} } @article { author = {Asseala, S.A. and Gomaa, F.R.}, title = {FATIGUE LIFE ESTIMATION OF 6061 ALUMINIUM ALLOY BASED ON MODAL DAMPING MEASUREMENTS}, journal = {ERJ. Engineering Research Journal}, volume = {28}, number = {4}, pages = {395-406}, year = {2005}, publisher = {Menoufia University, Faculty of Engineering}, issn = {1110-1180}, eissn = {}, doi = {10.21608/erjm.2005.70255}, abstract = {The damping property of 6061 aluminium alloys, fabricated by hot isostatic pressing (HIP), has been studied for different ratios of fatigue on the base of modal damping analysis. The effects of age hardening on hardness, fatigue strength and damping loss factor of the material are discussed. On the other hand, the interrelations of fatigue life ratios and the damping loss factor are examined using modal analysis of free-free standard fatigue specimens within a wide range of resonance frequencies (2000 Hz-25 kHz). Methodologies used to generate data and extract the characteristics of damping phenomenon have been illustrated. Numerical analysis of values of damping loss factor has been evaluated and compared with experimental measurements. A rotating bending fatigue test is performed to correlate the modal damping to fatigue damage. The results show that, age hardening process increases the fatigue strength by 15% and the damping loss factor by 160 %. The underlying mechanisms are analyzed and discussed. The results seem to be a useful guide that may help in estimating the lifetime or at least the remaining life of a member loaded under fatigue through measuring damping loss factor.}, keywords = {Modal Testing,Fatigue-Aging-Dislocation-6061Alumirlum Alloy-Modal Damping}, url = {https://erjm.journals.ekb.eg/article_70255.html}, eprint = {https://erjm.journals.ekb.eg/article_70255_a6a0400cdbb8abff4a36b7bdd6f0078d.pdf} } @article { author = {Matthana, Mohamed H.}, title = {BEAHAVIOUR OF REINFORCED CONCRETE BEAMS MADE OUT OF RECYCLED CONCRETE}, journal = {ERJ. Engineering Research Journal}, volume = {28}, number = {4}, pages = {407-423}, year = {2005}, publisher = {Menoufia University, Faculty of Engineering}, issn = {1110-1180}, eissn = {}, doi = {10.21608/erjm.2005.70261}, abstract = {Concrete is the most widely used construction material. Waste concrete represents an unavoidable product of concrete industry. It is produced because of the dentolition of concrete structures, rejected concrete, leftover fresh batches, unwanted elements in pre-cast factories, etc. Waste concrete is usually discarded in landfills causing very serious euvironmental problems. As the interest in recycling waste materials is, nowadays, getting an increasing worldwide attention, there is an environmental incentive for recycling waste concrete with the other types of recycling. In a previous paper by the author et. al., the properties of recycled concrete have been given a detailed study. The present investigation is aimed at understanding the effect of using recycled concrete on the behaviour of reinforced concrete beams. Waste concrete with no information about its previous mix properties and original strength and quality is used. The waste concrete is manually crushed and then tested for grading, bulk unit weight, and water absorption. Concrete specimens; cubes, beams, and cylinders from mixes made out of crushed concrete as a part of coarse aggregate are prepared and then tested for the uniaxial compression, splitting tension, and flexural strengths. The uni-axial stress-strain behaviour and the modulus of elasticity are also obtained. A total of eighteen reinforced concrete beams have been casted and tested to study the behaviour of beams made out of recycled concrete. This number of beam specimens is divided into six groups. Three groups of beams are tested for shear loading while the other three groups were aimed for flexural loading. Both of the flexural and shear groups of beams consisted of three categories each of three beams. The first category of beams was made out of normal concrete with normal coarse aggregate from gravel while the other two categories are made out of recycled concrete with coarse aggregate from crushed concrete. The latter two categories had two various ratios of crushed concrete as a part of the coarse aggregate. The study brings out the important results that; the use of recycled concrete reduces both the load carrying capacity and the stiffness of beams while the design equations, given by various codes, for normal concretemay be iipplicable for reinforced beams made out of recycled concrete without great loss of accuracy.}, keywords = {Reinforced concrete,Beams,Crushed Concrete,Recycled Beams & Recycled Concrete}, url = {https://erjm.journals.ekb.eg/article_70261.html}, eprint = {https://erjm.journals.ekb.eg/article_70261_b6010a9b148a5a2333905ff2c6478692.pdf} } @article { author = {El-Shanawany, Ramadan A and Higazy, Mahmoud Sh.}, title = {ORTHOGONAL DOUBLE COVERS OF COMPLETE BIPARTITE GRAPH BY THE UNION OF CERTAIN STARS}, journal = {ERJ. Engineering Research Journal}, volume = {28}, number = {4}, pages = {425-429}, year = {2005}, publisher = {Menoufia University, Faculty of Engineering}, issn = {1110-1180}, eissn = {}, doi = {10.21608/erjm.2005.70265}, abstract = {An Orthogonal Double Cover (ODC) of the complete graph is a set of graphs such that every two of them share exactly one edge and every edge of the complete graph belongs to exactly two of the graphs. We consider the case where the graph to be covered twice is the complete bipartite graphs, and all graphs in the collection are isomorphic to the spanning subgraph G (union of certain stars).}, keywords = {Orthogonal double cover,ODC, Graph decompositions}, url = {https://erjm.journals.ekb.eg/article_70265.html}, eprint = {https://erjm.journals.ekb.eg/article_70265_8b41bea4ffd0022fa4d0481b204e1f23.pdf} }