@article { author = {Elsayed, Aly abdel-Zaher and Aly, Aly G and Ahmed, Mahmoud Hussien and Omran, Omran Abd Elfadil}, title = {REPAIR AND STRENGTHENING OF THE WATER PIERS BARRAGES BY INJECTION TECHNIQUE AND ITS EVALUATION}, journal = {JES. Journal of Engineering Sciences}, volume = {40}, number = {No 1}, pages = {1-19}, year = {2012}, publisher = {Assiut University, Faculty of Engineering}, issn = {1687-0530}, eissn = {2356-8550}, doi = {10.21608/jesaun.2012.112330}, abstract = {The water structures (hydro techniques) dames, reservoirs, barrages ..etc., are complicated engineering structures and may have the demand properties not only hardness and stability but also have the most important property as impermeability [1]. The construction of water structures is highly expensive because they are critical structures and have many purposes. The grand barrages on the Nile are the most important for their many benefits (either in irrigation or industrial …etc). Continuous tests are needed to keep them long time working in effective condition with high efficiency in addition, to repair and strengthen every components. The concrete is the mainly material of the most water structures body and may be subjected to corrosion abrasion and the effect forst may be destroyed by physico-chemical mechanism such as carbonation and phenomena of alkali-aggregate reactions. All of these different modes of deterioration can cause debonding between cement and gravel by the propagation of cracks and loss of material properties [11, 12]. This study concerns with the experimental investigation of injection of barrage body. The main purpose refers to piers completely full of the voids and cracks inside the body material [1], where the cracks are not available to be seen. The disappeared cracks need special operation to get the main characters to perform the suitable operation, in field by the specific discharge, and grout mixing performance should be known to determine the suitable mixing. In the field which the samples of piers are taken (samples are used in this research), the mixing is from ordinary cement with percentage from bentonite (1-2%) from cement weight [1]. The diameter of the core samples which be taken from pier body is (38, 44, 48, 52, 64, 76 and 84 mms.) and after preparing with ratio between the length to the diameter varied from 1 to 2. A 42 samples from Assiut barrage and 43 samples from Naga-Hammadi barrage were taken to perform the required tests [2, 3, 4]. The main objectives of this research are to study the effect of injection to improve the compressive strength and impermeability of the pier body and comparing the results before and after the injection operation [1]. The study concluded that the injection influenced by clear effect on compressive strength. The average compressive strength was increased by (112.63%) from the average strength before injection for Assiut barrage and increased by (81.75%) before injection for Naga-Hammadi barrage. Also the density was improved, to increase the structure solidity and stability.}, keywords = {}, url = {https://jesaun.journals.ekb.eg/article_112330.html}, eprint = {https://jesaun.journals.ekb.eg/article_112330_e93e4d86f193eab8f2f145069f5c0677.pdf} } @article { author = {Bahobail, Mohammed Ali}, title = {THE MUD ADDITIVES AND THEIR EFFECT ON THERMAL CONDUCTIVITY OF ADOBE BRICKS}, journal = {JES. Journal of Engineering Sciences}, volume = {40}, number = {No 1}, pages = {21-34}, year = {2012}, publisher = {Assiut University, Faculty of Engineering}, issn = {1687-0530}, eissn = {2356-8550}, doi = {10.21608/jesaun.2012.112711}, abstract = {Adobe is one of the oldest building materials in use and abundantly found everywhere with affordable and reasonable cost. It is basically just dirt that has been moistened with water, sometimes with chopped straw or other fibers added for strength, and then allowed to dry in the desired shape. In addition to being simple and economic, adobe bricks are fireproof, durable, non-toxic, possess low sound transmission levels through walls and provide sufficient thermal mass to buildings. Adobe brick walls are load bearing structures, which can be used to build up to several stories high. Also, adobe bricks have ability to build vaults and domes. In addition to this, adobe bricks afford great flexibility in the design and construction process. They can be simply cut, reshaped and can easily be subjected to opening to be use for building’s services. Besides having, these advantages; they have some disadvantages too which can be summarized as follows; moderately low compressive strength, low tensile strength, low scratch resistance and low water resistance. To overcome these defects, additives should be added to the soil to improve its quality and increase its capability to stand against these defects. This paper provides an overview of the mud’s additives that are used in different regions of the world, and their enhancement to improve the soil stability, including mineral, Synthetic, vegetable and animal additives. The paper also includes an experimental study that examines the thermal conductivity of mud brick mixed with some additives (plant oil, ash, soap, and cow dung).}, keywords = {}, url = {https://jesaun.journals.ekb.eg/article_112711.html}, eprint = {https://jesaun.journals.ekb.eg/article_112711_583c58f2d6b4e9d023d14d3b16d86873.pdf} } @article { author = {Musmar, M. A.}, title = {EFFECT OF LINK ON ECCENTRICALLY BRACED FRAMES}, journal = {JES. Journal of Engineering Sciences}, volume = {40}, number = {No 1}, pages = {35-43}, year = {2012}, publisher = {Assiut University, Faculty of Engineering}, issn = {1687-0530}, eissn = {2356-8550}, doi = {10.21608/jesaun.2012.112712}, abstract = {The study deals with the eccentrically braced steel frames (EBF). EBF configuration is similar to traditional braced frames with the exception that at least one end of each brace must be eccentrically connected to the frame. The energy dissipation is achieved through the yielding of a beam segment called the link, while the other frame members, including outer beam segments, braces, and columns, should remain essentially elastic. The study incorporates applying lateral loading to several types of eccentrically loaded frames, in addition to a concentrically braced frame and a moment frames to compare the structural response. The paper includes analyzing the effect of link length on the ductility of the frame and the amount of drift.}, keywords = {Steel frames,eccentrically braced frames}, url = {https://jesaun.journals.ekb.eg/article_112712.html}, eprint = {https://jesaun.journals.ekb.eg/article_112712_cf8efd1b0c086ea9f9ff9be98c8bfa9f.pdf} } @article { author = {Mohamad, Randa and Al-Samara, Mohammad and Sandvol, Eric}, title = {SEISMIC TOMOGRAPHY AND ITS IMPLICATION STRUCTURES USING REGIONAL SEISMIC PHASE RECORDED IN SYRIAN NATIONAL SEISMIC NETWORK AND SURROUNDING NETWORKS}, journal = {JES. Journal of Engineering Sciences}, volume = {40}, number = {No 1}, pages = {45-65}, year = {2012}, publisher = {Assiut University, Faculty of Engineering}, issn = {1687-0530}, eissn = {2356-8550}, doi = {10.21608/jesaun.2012.112713}, abstract = {Tomography or production of earth image using seismic waves similar to CAT scan stands for medicine computerized axial tomography using ultrasound, gama rays, or X-rays to produce a focused image of the structures across a specific depth within the body by sending signals through an object in different directions and add the signals to construct a cross section of the object. In this study we focused on Lg attenuation in Syria using the waveforms data recorded at 57 stations for 340 events in Syria and surrounding areas to determine values of Lg Q0 (Q at 1 Hz and its frequency dependence) by using the standard two-station method. These values are used to derive a tomographic model of laterally varying Q0 for Syria and surrounding areas. The Lg Q0 calculated values varies between 60 and 400. The lowest Q values are located in northwestern Syria beneath the triple junction of the Arabian, African, and Eurasian plates. We also observe high Lg attenuation along the northern segments of the Dead Sea fault system, Aleppo plateau, southwestern of Palmyra fold-and-thrust belt, and in eastern region of Syria beneath Rawda and Qamichli Uplifts. We found moderately high Q values along the North-South trending zone that cross the Palmyride fold and thrust belt through central Syria. There are two distinct high Q anomalies: one concentrated beneath Rutbah uplift, and the other in northwestern portion of the Palmyra fold-and-thrust belt and north Euphrates basin. We found that the Lg Q0 tomographic model and its power-law frequency dependence Lg η correlate well with regional tectonic trends within Syria and the surrounding regions. Furthermore, we observe that Lg attenuation is sensitive to the upper crustal structure. As well as in this study we used the Pn Seismic phases velocity for all the enter two stations paths located in Syria and we divided the velocities into two groups of Pn velocity (6.65-7.7), (7.7-8.5) km/sec, and we determined the cross points represents the anisotropic boundaries. The alignments of those anisotropic boundaries in the uppermost part of the mantle showed well correlation with the main tectonic and main structures known in Syria as Palmyra fold-and-thrust belt and we found it limited with the higher group velocity boundaries while the cross points with lower boundaries distributed alignment along Dead Sea fault system. Low velocity zone found trending north west-south east crossing the central Palmyra fold-and-thrust belt and dividing it into two parts the northeastern and the west southern part.}, keywords = {tomography,LgQ}, url = {https://jesaun.journals.ekb.eg/article_112713.html}, eprint = {https://jesaun.journals.ekb.eg/article_112713_b61862820ef1505a251f2ae02b11f311.pdf} } @article { author = {Abdelkareem, Khairy Hassan and Abdelseed, Fayez Kaiser and Sayed, Mohamed Omar}, title = {THEORETICAL INVESTIGATION ON FLEXURAL PERFORMANCE OF RC BEAMS STRENGTHENED EXTERNALLY BY CFRP}, journal = {JES. Journal of Engineering Sciences}, volume = {40}, number = {No 1}, pages = {67-91}, year = {2012}, publisher = {Assiut University, Faculty of Engineering}, issn = {1687-0530}, eissn = {2356-8550}, doi = {10.21608/jesaun.2012.112714}, abstract = {In this paper an analytical model is presented for reinforced concrete beams externally reinforced with carbon fiber reinforced polymer (CFRP) laminates using finite element method adopted by ANSYS. The finite element models are developed using a smeared cracking approach for concrete and three dimensional layered elements for the CFRP composites. In particular, attaching unidirectional CFRP to the tension face of RC beams has provided an increase in the stiffness and load capacity of the structure. However, due to the brittle nature of unidirectional CFRP, the ductility of the beam decreases. Consequently, the safety of the structure is compromised, due to the reduction in ductility. The purpose of this research is to investigate the behavior of normal and high strength reinforced concrete beams strengthened with CFRP sheets. The major test parameters included the grade of concrete, the different dimensions of the beam and the tensile reinforcement ratio. Furthermore, change in the strength, ductility and toughness of the beams, as the grade of concrete, the dimensions of the beam and tensile reinforcement bar ratios are altered, are investigated. Fifty-four reinforced concrete beams were modeled and analyzed up to failure.}, keywords = {Finite Element Model,CFRP,High strength concrete,Ductility,Strength,Toughness}, url = {https://jesaun.journals.ekb.eg/article_112714.html}, eprint = {https://jesaun.journals.ekb.eg/article_112714_cd461262f617f9a6392393a550236ef3.pdf} } @article { author = {Abdel Hafez, Atif M. and Ahmed, M.M. and Alamary, A.S. and Mohmoud, A.M.}, title = {BEHAVIOR OF SIMPLY SUPPORTED COMPOSITE CONCRETE-STEEL BEAM WITH CORRUGATED WEB UNDER VERTICAL LOADS}, journal = {JES. Journal of Engineering Sciences}, volume = {40}, number = {No 1}, pages = {93-108}, year = {2012}, publisher = {Assiut University, Faculty of Engineering}, issn = {1687-0530}, eissn = {2356-8550}, doi = {10.21608/jesaun.2012.112715}, abstract = {This paper presents the behavior of simply supported concrete-steel composite beams with corrugated web under vertical loads using the commercial finite element (FE) software ANSYS. The three-dimensional (FE) model is used to simulate the overall flexural and shear behavior of simply supported composite beams with corrugated web subjected to vertical loads. This study covers: load deflection behavior and load strain curve. The reliability of the model is demonstrated by comparison with experimental results test carried out by author and others. Two identical composite beams with corrugated web were tested to failure under vertical loads. The comparison shows good agreement. A parametric study was undertaken using the validated model performed using finite element program. The parametric analysis was executed to study the effect of web thickness on the behavior of concrete-steel composite beam under vertical loads. The comparison between concrete-steel composite beam with corrugated and flat web was introduced in this paper. From this study, it can be concluded that, the corrugation in web increases the stiffness and ductility for composite beam. The increasing of corrugated web thickness increases the ultimate load and enhances the shear behavior of concrete-steel composite beam.}, keywords = {Experimental tests,Finite Element Analysis,composite beam,corrugated steel web,Nonlinear Analysis}, url = {https://jesaun.journals.ekb.eg/article_112715.html}, eprint = {https://jesaun.journals.ekb.eg/article_112715_4bb42c81162e80ea980b885ffd9242ee.pdf} } @article { author = {Ali, Nashat A. and Abozeid, Gamal and Elshamandy, Mohammed G.}, title = {ANALYSIS OF SOME PARAMETERS AFFECTING THE CHARACTERISTICS OF POLLUTED WATER – JET IN OPEN CHANNEL}, journal = {JES. Journal of Engineering Sciences}, volume = {40}, number = {No 1}, pages = {109-120}, year = {2012}, publisher = {Assiut University, Faculty of Engineering}, issn = {1687-0530}, eissn = {2356-8550}, doi = {10.21608/jesaun.2012.112716}, abstract = {Experiments were conducted to investigate the effect of jet shape, inclination, velocity ratio and initial concentration on the characteristics of side polluted surface water jet in open channel with two different angles of inclination to mainstream direction. The polluted water is prepared by adding sodium chloride with different concentrations to fresh water. The initial jet velocity is varied to cover a range of velocity ratio R from 3.30 to 10.30. For each velocity ratio, the solute concentration is changed to take values of 800, 1050, 1440, 1780 and 2320 ppm Centerline jet trajectory, velocity decay and dilution of polluted water are measured. Velocity is measured by a calibrated current meter while the jet coordinates and water depths are measured using point gages. Samples are taken from the jet centerline to measure the jet concentrations. The concentrations are measured using 4510 conductivity meter. The factors influencing the problem are normalized with the help of dimensional analysis principle. The analysis of the results revealed that the geometrical characteristics of a polluted water jet in cross-flow, the decay of velocity and dilution of pollution concentration are mainly depending on the studied parameters. Equations have been developed from the correlation of the experimental results.}, keywords = {Open channels,Surface discharging jets,Pollutant concentration}, url = {https://jesaun.journals.ekb.eg/article_112716.html}, eprint = {https://jesaun.journals.ekb.eg/article_112716_12c07f5fa0f8f767ac8977fa2350af1a.pdf} } @article { author = {Khafaga, Mohamed A.}, title = {SHEAR BEHAVIOR OF REDUCED-WEIGHT REINFORCED CONCRETE BEAMS}, journal = {JES. Journal of Engineering Sciences}, volume = {40}, number = {No 1}, pages = {121-146}, year = {2012}, publisher = {Assiut University, Faculty of Engineering}, issn = {1687-0530}, eissn = {2356-8550}, doi = {10.21608/jesaun.2012.112718}, abstract = {This paper presents an investigation to improve the understanding of the shear behavior of reinforced reduced-weight concrete beams made of light-weight expanded clay aggregate (LECA) as a partial replacement (by volume) to the normal-weight aggregates. Eleven reinforced concrete beams divided into two groups were fabricated and tested using the symmetrical two-point loads test. The tested beams consisted of seven reinforced reduced-weight concrete beams and four reinforced normal-weight control beams. The effects of several variables such as type of concrete according to its weight, shear span to depth ratio (a/d), concrete grade and the amount of stirrups were experimentally investigated. The behavior of the tested beams was analyzed in terms of mode of failure, load-deflection response, load-strains response, shear stress- shear strain relationships, first shear cracking loads, ultimate carrying capacity, stiffness and ductility. Furthermore, the test results were compared with the predictions using the Egyptian Code for Concrete Structures, (ECP 203). Despite the experimental results illustrated that the reduced-concrete beams were shown less load carrying capacity, stiffness and ductility than those of the comparative normal-weight concrete beams, the theoretical predictions using the Egyptian Code were quite conservative. This could be attributed to that the effect of arch action is still underestimated in the Egyptian Code.}, keywords = {reduced-weight concrete beam,Shear behavior,failure mode,first shear cracking load,Ultimate Load}, url = {https://jesaun.journals.ekb.eg/article_112718.html}, eprint = {https://jesaun.journals.ekb.eg/article_112718_76b0c603a15aa191af0356699a39ba10.pdf} } @article { author = {Sharkawy, Abdel Badie}, title = {A COMPUTATIONALLY EFFICIENT FUZZY CONTROL SCHEME FOR A CLASS OF MIMO SYSTEMS: THE EXAMPLE OF ROBOT MANIPULATORS}, journal = {JES. Journal of Engineering Sciences}, volume = {40}, number = {No 1}, pages = {147-171}, year = {2012}, publisher = {Assiut University, Faculty of Engineering}, issn = {1687-0530}, eissn = {2356-8550}, doi = {10.21608/jesaun.2012.112723}, abstract = {This paper develops a decentralized fuzzy control scheme for MIMO nonlinear second order systems with application to robot manipulators via a combination of genetic algorithm and fuzzy systems. The controller for each joint consists of a feedforward fuzzy torque-computing system and a feedback fuzzy PD system. The feedforward fuzzy system is trained and optimized off-line by an improved genetic algorithm, that is to say, not only the parameters but also the structure of the fuzzy system is self-organized. The feedback fuzzy PD system, on the other hand, is used to keep the closed-loop stable. The rule base consists of only four rules per each degree of freedom (DOF). Furthermore, the fuzzy feedback system is decentralized and simplified leading to a computationally efficient control scheme. The proposed control scheme has the following merits: 1) it needs no exact dynamics of the system and the computation is time-saving because of the simple structure of the fuzzy systems; and 2) the controller is insensitive to various parameters and payload uncertainties. These are demonstrated by analysis of the computational complexity and various computer simulations.}, keywords = {Robot manipulators,Genetic Algorithm,Feedforward fuzzy torque computing,Fuzzy PD feedback control,Closed-loop stability,Computational complexity,Parametric and payload uncertainties}, url = {https://jesaun.journals.ekb.eg/article_112723.html}, eprint = {https://jesaun.journals.ekb.eg/article_112723_40a5b82d81367a33181cbf66755d8063.pdf} } @article { author = {Sharkawy, Abdel Badie and Salman, Shaaban A.}, title = {AN ADAPTIVE FUZZY SLIDING MODE CONTROL SCHEME FOR ROBOTIC SYSTEMS}, journal = {JES. Journal of Engineering Sciences}, volume = {40}, number = {No 1}, pages = {173-189}, year = {2012}, publisher = {Assiut University, Faculty of Engineering}, issn = {1687-0530}, eissn = {2356-8550}, doi = {10.21608/jesaun.2012.112724}, abstract = {In this article, an adaptive fuzzy sliding mode control (AFSMC) scheme is derived for robotic systems. In the AFSMC design, the sliding mode control (SMC) concept is combined with fuzzy control strategy to obtain a model-free fuzzy sliding mode control. The equivalent controller has been replaced by a fuzzy system and the uncertainties are estimated on-line. The approach of the AFSMC has the learning ability to generate the fuzzy control actions and adaptively compensates for the uncertainties. Despite the high nonlinearity and coupling effects, the control input of the proposed control algorithm has been decoupled leading to a simplified control mechanism for robotic systems. Simulations have been carried out on a two link planar robot. Results show the effectiveness of the proposed control system.}, keywords = {Sliding mode control (SMC),Adaptive fuzzy sliding mode control (AFSMC),Fuzzy logic control (FLC),Adaptive laws,Robotic control}, url = {https://jesaun.journals.ekb.eg/article_112724.html}, eprint = {https://jesaun.journals.ekb.eg/article_112724_3ffc66f526e0632f57f1fcc3ed105318.pdf} } @article { author = {Thabet, A.}, title = {EFFECT OF NANOPARTICLES ON WATER TREEING CHARACTERISTICS IN XLPE INDUSTRIAL I NSULATING MATERIALS}, journal = {JES. Journal of Engineering Sciences}, volume = {40}, number = {No 1}, pages = {191-208}, year = {2012}, publisher = {Assiut University, Faculty of Engineering}, issn = {1687-0530}, eissn = {2356-8550}, doi = {10.21608/jesaun.2012.112719}, abstract = {Water treeing is still now one of the main causes of cable deterioration and so, it is widely known that water treeing is the responsible for the reduction of the service life of polymeric cables. This paper has been studied the effects of adding various amounts of nanoparticles as ZnO, and Al2O3 on water treeing characteristics in XLPE industrial materials. This research has focused on studying development of the nano-composite materials performance with water tree growth resistance superior to the unfilled matrix, and has stressed particularly the effect of filler volume fraction on the water tree length and via various frequencies. Finally, this research aims to present a systematic and comparative study about the effect of adding nanoparticles to change dielectric insulation properties, and to understand the role effect of these nanoparticles in the industrial insulation materials which can make significant improvement in water tree resistance, life-time of insulation and decreasing the water tree length in the industrial insulation materials.}, keywords = {water treeing,Water void,Nanoparticles,Nanocomposite materials}, url = {https://jesaun.journals.ekb.eg/article_112719.html}, eprint = {https://jesaun.journals.ekb.eg/article_112719_67a498c1aa16c89b125663ff83a388a4.pdf} } @article { author = {Kassem, Ahmed M.}, title = {NONLINEAR AUTOREGRESSIVE MOVING AVERAGE CONTROLLER FOR ISOLATED WIND GENERATION SYSTEM CONTROL}, journal = {JES. Journal of Engineering Sciences}, volume = {40}, number = {No 1}, pages = {209-222}, year = {2012}, publisher = {Assiut University, Faculty of Engineering}, issn = {1687-0530}, eissn = {2356-8550}, doi = {10.21608/jesaun.2012.112720}, abstract = {In this paper, the voltage and frequency control of an isolated self-excited induction generator, driven by wind turbine, is developed with emphasis on nonlinear auto regressive moving average (NARMA-L2) based on neural networks approach. This has the advantage of maintaining constant terminal voltage and frequency irrespective of wind speed and load variations. Two NARMA L2 controllers are used. The first one is dedicated for regulating the terminal voltage of the induction generator to a set point by controlling the thyristor firing angle of a static reactive power compensator (SVAR). The second one is designed to control the mechanical input power to the generator via adjusting the blade pitch angle of the wind turbine. In this application, an indirect data-based technique is taken, where a model of the plant is identified on the basis of input-output data and then used in the model-based design of a neural network controller. The proposed system has the advantages of robustness against model uncertainties and external disturbances. The robustness of the wind-energy scheme has been certified through step change in wind speed. Moreover, the system is tested also during a step change in load impedance. Simulation results show that high dynamic performance of the proposed wind energy scheme has been achieved.}, keywords = {Wind turbine,Induction Generator,NARNA-L2 controller,Neural Networks}, url = {https://jesaun.journals.ekb.eg/article_112720.html}, eprint = {https://jesaun.journals.ekb.eg/article_112720_438c122530d6b3dca38282f796e4b835.pdf} } @article { author = {Zahra, Mohamed M.}, title = {A NEW DYNAMIC INTEGRATED SATELLITE /TERRESTRIAL MODELS FOR HANDOFF PRIORITIZATION IN HIGHWAYS WIRELESS MOBILE SYSTEMS}, journal = {JES. Journal of Engineering Sciences}, volume = {40}, number = {No 1}, pages = {223-234}, year = {2012}, publisher = {Assiut University, Faculty of Engineering}, issn = {1687-0530}, eissn = {2356-8550}, doi = {10.21608/jesaun.2012.112721}, abstract = {In Highways wireless mobile networks, in order to ensure that ongoing calls are not dropped while the users roam among cells, handoff calls may be admitted with a higher priority as compared to new calls. One way to improve system performance of cellular networks is to use efficient handoff models when users move between cells. In this paper, Non-priority Model (NPM) and Guard Channel Model (GCM) are presented and evaluated to improve the utilization of wireless network resources. However, Simulation results show that the required Grade of Service (GoS) of handoff calls is guaranteed at low and medium traffic loads only regardless that improvement of handoff calls blocking probability is at the expense of blocking probability of new calls. So, we reveal how to overlay highway microcells by macrocells to improve many teletraffic parameters. The new proposed models are called integrated Satellite/Terrestrial (Sat/Terr) models. Teletraffic performance of the proposed models is investigated using simulation technique. Simulation results are accumulated to evaluate the system performance.}, keywords = {wireless mobile networks,handoff,Simulation,guard channel model,non-priority model,integrated satellite/terrestrial models}, url = {https://jesaun.journals.ekb.eg/article_112721.html}, eprint = {https://jesaun.journals.ekb.eg/article_112721_1f05c55c7cf423bdecec234c10c95906.pdf} } @article { author = {Mohamed, Yehia S. and El-Sawy, A. M. and Mossa, Mahmoud A.}, title = {FIELD ORIENTATION CONTROL OF A WIND DRIVEN DFIG CONNECTED TO THE GRID}, journal = {JES. Journal of Engineering Sciences}, volume = {40}, number = {No 1}, pages = {235-253}, year = {2012}, publisher = {Assiut University, Faculty of Engineering}, issn = {1687-0530}, eissn = {2356-8550}, doi = {10.21608/jesaun.2012.112722}, abstract = {This paper aims to develop a method of field orientation scheme for controlling both active and reactive powers of a DFIG (double fed induction generator) driven by a wind turbine. The controlled system consists of a wind turbine that drives a DFIG connected to the utility grid through AC-DC-AC link. The control method is based on the theory of controlling the de and qe axes components of voltage and current for both rotor side and line side converters using PI controllers. The main control objective is to regulate the dc link voltage for operating at the maximum available wind power. A mathematical dynamic model of a DFIG driven by a wind turbine system is presented. Digital simulation has been carried out in order to evaluate the effectiveness of the proposed system. The results confirm that good steady state and dynamic performances of the proposed system has been achieved under different types of wind speed variations.}, keywords = {Wind turbine,DFIG,reactive power control of induction machines,PI controller}, url = {https://jesaun.journals.ekb.eg/article_112722.html}, eprint = {https://jesaun.journals.ekb.eg/article_112722_a20ca480f54b9e2991776ddc8e437aa4.pdf} } @article { author = {Kandil, A.}, title = {MICROSTRUCTURE AND MECHANICAL PROPERTIES OF SICP/AZ91 MAGNESIUM MATRIX COMPOSITES PROCESSED BY STIR CASTING}, journal = {JES. Journal of Engineering Sciences}, volume = {40}, number = {No 1}, pages = {255-270}, year = {2012}, publisher = {Assiut University, Faculty of Engineering}, issn = {1687-0530}, eissn = {2356-8550}, doi = {10.21608/jesaun.2012.112726}, abstract = {Magnesium alloy (AZ91) matrix composites reinforced with various volume fractions of SiC-particulates were processed. A Stir casting process has been employed under an inert atmosphere to produce magnesium matrix composites. This process leads to a complete wetting of SiC particles in the molten magnesium. Microstructural feature, such as SiC particles distribution, and the interface between the magnesium matrix and SiC was characterized by scanning electron microscopy (SEM) and energy dispersion X-ray analysis (EDX). The results show a refined matrix structure of the composite compared to the matrix alloy, a uniform SiC distribution in the matrix and that no reaction takes place during the synthesis of the magnesium alloy matrix composites between the oxidized SiC and the molten magnesium. However, AZ91 matrix composite showed a massive formation of ternary intermetallic compound of Mg17 (ZnAl)12 at the SiC interface. The mechanical properties of AZ91 and AZ91-SiC composites have been evaluated and the results are compared with the unreinforced AZ91 alloy. Results of the mechanical properties revealed an increase in hardness value, maximum tensile strength and 0.2 % yielding strength. It was proposed that the strength increase due to SiC addition to AZ91 alloy was a result of a change in the matrix strength, i.e. an increase in dislocation density and a reduction of matrix grain size. However, it is also evident that the strain to failure significantly decreased as the volume fraction of the particulate increased. Examinations of the fracture surface show good bonding between SiC/matrix, extent of fine dimples, matrix cracking and particle cracking.}, keywords = {}, url = {https://jesaun.journals.ekb.eg/article_112726.html}, eprint = {https://jesaun.journals.ekb.eg/article_112726_926b0cdd33ea26e73afc40433831d37d.pdf} } @article { author = {Abdel Haffez, Gamal S.}, title = {CORRELATION BETWEEN BOND WORK INDEX AND MECHANICAL PROPERTIES OF SOME SAUDI ORES}, journal = {JES. Journal of Engineering Sciences}, volume = {40}, number = {No 1}, pages = {271-280}, year = {2012}, publisher = {Assiut University, Faculty of Engineering}, issn = {1687-0530}, eissn = {2356-8550}, doi = {10.21608/jesaun.2012.112727}, abstract = {The crushing energy in mineral processing industry is usually determined by empirical Bond index, regardless of the mechanical properties of a rock. Although several attempts have been made to obtain the comminution energy based on theoretical approaches, it would be beneficial to examine this relation based on physical concept. In this paper, some Saudi samples of bauxite, kaolinite, granodiorite, magnetite, granite, feldspar and quartz were tested for hardness, abrasion, compressive strength and modulus of elasticity and the bond work index of these samples were estimated. The value of Bond work index of the above samples has shown a variation from 10.8 kwh ton-1 for bauxite (high abrasion value and low compressive strength) to 20.4 kwh ton-1 for granite (low abrasion value and high modulus of elasticity). The correlation between the abrasion value(X2) and work index (Wi) is found to be Wi = -1.8 Ln (X2) + 11.5 with correlation coefficient of 0.80.}, keywords = {Bond work index,Mechanical properties of rocks,Grinding energy- Crushing resistance}, url = {https://jesaun.journals.ekb.eg/article_112727.html}, eprint = {https://jesaun.journals.ekb.eg/article_112727_e54b6bf5dac844a12bd12a5f5c11da0f.pdf} } @article { author = {Moussa, Mohamed Mohamed Azmy Ahmed and EL-Za'farany, Mohamed Abbas}, title = {UPGRADING OF THE REGIONAL URBAN PATTERN IN UPPER EGYPT (NILE VALLEY IN ASSIUT REGION – AS A CASE STUDY)}, journal = {JES. Journal of Engineering Sciences}, volume = {40}, number = {No 1}, pages = {281-294}, year = {2012}, publisher = {Assiut University, Faculty of Engineering}, issn = {1687-0530}, eissn = {2356-8550}, doi = {10.21608/jesaun.2012.112729}, abstract = {Upper Egypt suffers from many physical problems at the regional level, and which the most important is there is a break in the urban pattern (spatial and functional relationships) for the urban communities of all sizes and patterns, leading to disruption in the relationship between these communities. We find that a limited number of cities suffering from stress and increased demand for services which provided while most other cities suffer from marginalization and absence of its role in at the regional level. Accordingly, the study focuses on the upgrading of the regional urban pattern in Upper Egypt, which suffers from random urban growth. and that application on Nile Valley in Assiut Region as a case study. The study concluded to develop a proposal that could help to solve the urban problem in Upper Egypt as well as their different implications, and to achieve a balance between the current urban pattern, and resettlement of new urban communities.}, keywords = {}, url = {https://jesaun.journals.ekb.eg/article_112729.html}, eprint = {https://jesaun.journals.ekb.eg/article_112729_e69e55b25ba2bae5f2eae50ed2f3e970.pdf} } @article { author = {Moussa, Mohamed Mohamed Azmy Ahmed and EL-Za'farany, Mohamed Abbas}, title = {TOWARDS A FUTURE VISION FOR THE REGIONAL URBAN NETWORK FOR UPPER EGYPT "NILE VALLEY IN ASSIUT REGION - AS A CASE STUDY"}, journal = {JES. Journal of Engineering Sciences}, volume = {40}, number = {No 1}, pages = {295-310}, year = {2012}, publisher = {Assiut University, Faculty of Engineering}, issn = {1687-0530}, eissn = {2356-8550}, doi = {10.21608/jesaun.2012.112731}, abstract = {The study concludes a trial to gain access for a future regional urban planning in Upper Egypt, stemming from a comprehensive analysis of available capabilities, limitations, problems, and future needs, with regard to the circumstances of different environmental and regional linkage among them. Accordingly, the research suggests a future vision for the regional urban network. This vision is represented in the classification of city sizes, and its distribution according to its influence circles. The research aims to transfer the traditional villages to urban villages, and neglect hamlets, and ranches which are scattered heavily on agricultural land.}, keywords = {}, url = {https://jesaun.journals.ekb.eg/article_112731.html}, eprint = {https://jesaun.journals.ekb.eg/article_112731_c1ccee0de5bbdfebe202e5e200ff3db2.pdf} }