2024-03-29T17:51:53Z
https://erjm.journals.ekb.eg/?_action=export&rf=summon&issue=10847
ERJ. Engineering Research Journal
1110-1180
1110-1180
2000
23
3
Quality Control in Service Industry: A Telephone Service Center at a Bank
Khalid A.
Aldakhilallah
Quality control initially focusedmanufacturingorganizations and service organizations were largely ignored.However, service industry has become a crucial player in theglobal economy in the past few decades. This requires a shift inquality control research which represented a challenge to TQMpractitioners in the 80's and 90's. Service organizations mustconsistently deliver servicelevels that meet or exceedcustomers' needs and expectations. In order to enhance theircompetitiveness, service firms need to develop and implement aquality system that ensures continual quality and productivityimprovement Also, a service organization that is seeking tomaintain or improve its competitiveness must focus on itscustomers and emphasize customers as the driven force behindquality outcomes. In this paper, a telephone service center at amajor bank in the United States is evaluated. The banktelephone service center employs 60 full-time and part-timerepresentatives. Each representative is responsible for--- Austmare' inquiries
2000
07
01
1
33
https://erjm.journals.ekb.eg/article_71303_62314c24811cdcc25706446450b1e4fb.pdf
ERJ. Engineering Research Journal
1110-1180
1110-1180
2000
23
3
PERFORMANCE ANALYSIS OF A SUPERCONDUCTING GENERATOR USING DAMPING AND SYNCHRONIZING TORQUES
G.A.
Morsy
H.
Khattab
A.M.
Kinawy
In this paper the performance of a superconducting generator (SCG) is analysed using damping and synchronizing torques. A numerical algorithm has been applied to obtain these torque components using a time response analysis of the SCG unit with-a different suggested controllers. Speed governor, phase advance and proportional integral controllers have been considered and the damping contribution by each of them are shown.
2000
07
01
35
50
https://erjm.journals.ekb.eg/article_71304_24ef6afa30b7e29aa0c925f9067a4e7f.pdf
ERJ. Engineering Research Journal
1110-1180
1110-1180
2000
23
3
A WIND TURBINE SIMULATOR USING ANN CONTROLLED DC DRIVE
M. E.
Abdel- Karim
This paper presents a new simulator using a dc motor drive to simulate the characteristics of a vertical-axis wind turbine in steady-state operation. The drive system consists of a separately excited dc motor fed via a thyristor converter. This drive is controlled by its Artificial Neural Network (ANN) inverse model using the wind turbine model as a reference. The controller is implemented by a LabView software program which provides a great flexibility and gives the possibility to simulate any wind turbine characteristics. The proposed simulator is tested for both dynamic and steady state modes at different wind velocities and loads. It is shown that the steady-state characteristics of the proposed simulator follow, satisfactorily, those of the actual wind turbine.
2000
07
01
51
61
https://erjm.journals.ekb.eg/article_71305_cd147fce3ce53eda63c6269a3097276e.pdf
ERJ. Engineering Research Journal
1110-1180
1110-1180
2000
23
3
STUDY OF THE INCIPIENT MOTION 03 BED PARTICLES FOR GRAVEL BED CHANNELS
Kassem Salah Abd EL-Wahab
El- Alfy
For rivers in flood, the shear stress at the top of the stationary gravel bed can set up a sheared layer of contact-load (bed-load). As is well known, movement of solid particles does not initiate until the shear stress exceeds some critical value ( Tc ) The main objective of this research is the laboratory prediction of the conditions at which the incipient motion occurs in the gravel bed channels through fifteen grading of gravel bed. The laboratory critical shear stress for every bed grading is computed and compared with that resulted from formulae used in calculating the critical shear stress on channel bed. The experimental analysis is used to obtain the relations describing the boundary of the initiation of motion of the gravel bed particles. Also the flow velocity adjacent to bed and the mean flow velocity are measured at the critical conditions (case of incipient motion). The influence of the value of the downward angle of the bed on the critical shear stress is also examined. From the laboratory experiments, it was concluded that the values of the critical shear stress are similar to the values from the existingformulae, especially Shields diagram, and Shulits and Hill formula. From the measurements of the bed velocity at the incipient motion conditions, a relationship between the dimensionless critical bed velocity (VbdV,,) and the ratio (Re/Fnd) is predicted. It is also noticed that there is aninverse proportionality between the downward bed angle and the critical shear stress required to initiate motion of the gravel bed
shear stress
incipient motion
critical conditions: bed particles
2000
07
01
63
76
https://erjm.journals.ekb.eg/article_71306_52a2c52b753d3569bbe05a2358127e88.pdf
ERJ. Engineering Research Journal
1110-1180
1110-1180
2000
23
3
Effect of Preheat on Tensile and Corrosion Properties of Steel Welded Joints
Ad A.
BAYOUMI
M. T.
ELMESTEKAWI
Steels of high carbon content,. in general, have high strength, that makes them needed in many engineering applications. However, the repair of components made of such steels through maintenance by welding presents a major problem. Therefore. in the present investigation a trial is made to find out a way to facilitate the welding or such high carbon, high strength steel with the objective to improve its mechanical properties. Preheating to different temperatures was carried out on different carbon content steels before butt weld joints were made. The joints were subjected to tension and corrosion tests. The results showed that there.is a relation between the preheating temperature and the carbon content of the steel of interest.~he~ showed that preheating in the range of 100-150°C improved the tensile strength of the tested steel of carbon content of 0.6, 0.9 and 1.55 wt.%.,Little improvement of ductility has been noted. Also, the results showed that, little effect for preheat on the comosion resistance.
2000
07
01
77
94
https://erjm.journals.ekb.eg/article_71307_73ecf396f2b328b616848b36283114d1.pdf
ERJ. Engineering Research Journal
1110-1180
1110-1180
2000
23
3
THE PREDICTION OF SOME MECHANICAL PROPERTIES OF AL-7Si% ALLOY REINFORCED WITH PARTICULATE ALUMINA WITH THE AID OF IMPERICAL FORMULAE
O.M
Khedre
J.M.A
Dandachi
S.
Algahtany
Nowadays, it is well known that Aluminum and its alloys, when reinforced with different particulate materials, can provide designers with a group of composites of some valuable mechanical properties such as elastic modulus, poi$son'<ratio, ultimate strength, ductility, internal friction, and wear characterization. Such mechanical properties are important aspects in the design procedure for many moving and rotating parts ie the mechanicalfield. Fiding them through an experimental way is a hard and long way as the designer needs to prepare~many,composites al1oys:with different contents in order to find the best fit for his,'desig". . .. I Finding imperical formulae, which describe these mechanical properties, gives the chance to choose the contents of the composites materials very near to the desired contents and hence reducing the nuhber of specimens needed in the experimental work. In the present work, the authors suggesting some imperical formulae based on statistical approach for thk ixpeiimental results oh the composite material AL-7Wt% SiIAI,Op As &example, the.wear-: rite can be predicted on different .! i..ii. loads and fbr'many sliding distiirices as bell:! Also, a percentage error, e"$iiation was. done for the curve fiteing b'etween ,the experimental reshlts an'd . . .the theoretical values drawn'fiom the impi'ical I
2000
07
01
95
107
https://erjm.journals.ekb.eg/article_71308_c77b8f3d200302a0e3b82e253b2c88e1.pdf
ERJ. Engineering Research Journal
1110-1180
1110-1180
2000
23
3
PLC BASED CONTROL FOR WIND-POWERED GENERATION
Azzam, Attia
El-sbaie
In spite of many advantages of an asynchronous generator, its use in isolated systems has been very limited due to the difficulties involving in conholling the variation of its generated voltage and frequency due to variation of load current. This paper gives the possibility to minimize the variation of the output voltage and frequency. The technique utilize an algorithmis implemented using PLC devices. PLC has the resposibility of the system sequence control for output voltage and frequency. The system functions were analized and implemented in PLC based hardware and software. The control system was tested systematically in the laboratory and shows excellent performance.
2000
07
01
109
120
https://erjm.journals.ekb.eg/article_71309_60ba8de6968c5ee6fdb39dfe543cc6bd.pdf
ERJ. Engineering Research Journal
1110-1180
1110-1180
2000
23
3
NEW TYPE OF TRANSPORTATION ELECTRIC VEHICLES
Moustafa EL-Sayed
EL-Shebiny
An electric vehicle is one of the most promising technologies for the 21St century, it is one of the solutions to. energy problems in the future. For electric car propulsion, the wheel motor is an application that requires the electrical machines to have flexibility, compactness, robustness, high efficiency, and high torque. This paper describes an on-line control technique for ac drive system composed of two single phase induction motor to be employed in a special electric vehicle used in big factories to transport objects between places with radial or curvature trajectory. An experimental simulator of the proposed system is implemented. The simulation results agree with the experimental results.
2000
07
01
121
135
https://erjm.journals.ekb.eg/article_71311_e2eb9bde1bfc8498774c90d02efabe3b.pdf
ERJ. Engineering Research Journal
1110-1180
1110-1180
2000
23
3
A MODIFIED POWER FLOW METHOD FOR NON SYNCHRONOUS NETWORKS INTERCONNECTION
K.M.
Shebl
M. E.
El-Said
H.
El-Desouki
I.
Bedir
This paper presents an .efficient method for AC-DC power flow used in non- synchronous intercoihection. The proposed method treats the converter as voltage dependent loads and the variables are eliminated from the power flow equations. The method is successfully implemented to IEEE 5-bus test system interconnected with IEEE 14-bus test system. The technical conditions for interconnecting power systems, the short circuit capacity of AC connected b&, the geometrical topology of the land in DC link path, and location of AC bus from the generating stations, are considercd.
2000
07
01
137
145
https://erjm.journals.ekb.eg/article_71312_62df7f05ae2070e35461a4e43599214a.pdf
ERJ. Engineering Research Journal
1110-1180
1110-1180
2000
23
3
A NOVEL SSR-COUNTERMEASURE THROUGH APPROPRIATE DESIGN OF THE SHAFTDYNAMIC PARAMETERS
A. S.
Abdel-Ghaffar
A. H.
Morsi
A. M.
Abdel-Hamid
M. A.
Elmashad
hls paper presents a novel trend toward retirement of the strong oscillations which may exist if the power system is exposed to Subsynchronous Resonance(SSR) phenomenon. Since these harmful oscillations are mainly due to the oscillatory modes of the turbo-generator shaft, the idea of this trend is to suggest an approp~iate design of the shaft-parameters such that the SSR phenomenon may be fundamentally avoided. The effect of shaft parameters like the spring constant and the inertia constant on the shape and location of these oscillatory modes is extensively studied. Modal analysis, eigenvalue analysis, and nonlinear time simulation are used as tools to design a turbo-generator shak which achieve minimum oscillations. Practical constraints are raken In consideration in a way that the proposed design can be agreeably manufactured
SSR
Excitation System
IEEE-SSR Benchmark model
Oscillatory modes
mode shapes
Eigenvalues
SSR countermeasures
Torsionai oscillations
2000
07
01
147
162
https://erjm.journals.ekb.eg/article_71313_286dfd4f95a4c9c2a0d88a07854d1277.pdf
ERJ. Engineering Research Journal
1110-1180
1110-1180
2000
23
3
AN ALTERNATIVE APPROACH FOR SOLVING THE SPACE INTERSECTIONS PROBLEM IN CLOSE RANGE PHOTOGRAMMETRY
Abo El- Hassan M.
Rahil
There are different techniques, that can be used for monitoring building deformations, each is designed for a certain purpose and also depending on many parameters, such as the shape of the construction, the quantity of the deformation , the needed time to collect the necessary measurement and the required accuracy .These techniques can be generally classified into surveying and non surveying techniques .The surveying techniques include conventional geodetic techniques and close range photogrammetry. This paper proposes and discuses a more simple alternative approach for the problem ofthe space intersection in close range photogrammetly, as applied to structure deformation measuring. In this research, a test field was used, for experimental determination of the accuracy of the results obtained from the proposed approach, and of the conventional techniques frequently used in close range photogrammetry The accuracy obtained in this study, was determined by comparing the coordinates in each technique with the original check points coordinate of tk test field
2000
07
01
163
177
https://erjm.journals.ekb.eg/article_71315_5a1600404882c084d04105a584905eee.pdf
ERJ. Engineering Research Journal
1110-1180
1110-1180
2000
23
3
CRACK INITIATION IN PLAIN CARBON STEELS DURING STATIC TENSION AND FATIGUE
A.M.
ABO El-AINENE
In this work, the effect of carbon content on static tensile and fatigue crack initiation behaviour was investigated on four different types of carbon steels with nearly equal ferrite grain sizes by the plastic replica method. Static tests and fatigue tests had been performed using the universal testing machine and the rotating bending fatigue testing machine, respectively. Fatigue tests were mainly performed under the stress level larger than the fatigue limit of each material by the same magnitude. Experimental results show that. for tensile tests, the cracks of materials with low carbon content exist in the boundaries beiween pearlite block and ferrite grain or in their neighborhood. On the other hand, those of materials with medium carbon content cracks also exist in pearlite. For fatigue tests, the carbon content of each material affects the crack initiation behaviour under the same stress amplitude for four types of carbon steels, comparing with that under the stress level larger than the fatigue limit of each material by the same magnitude. In addition, the carbon content of steel hardly affec~s the crack propagation behaviour .
2000
07
01
193
203
https://erjm.journals.ekb.eg/article_71316_1f83ebef8be68611c10831076d920f0f.pdf
ERJ. Engineering Research Journal
1110-1180
1110-1180
2000
23
3
BEHAVIOR OF CAPACITOR-RUN SINGLE - PUASE INDUCTION MOTORS DRIVEN FROM A VARIABLE FREQUENCY SUPPLY
A. H.
Morsi
The capacitor - run single-phase induction motor ispreferred than the other types of single-phase induction motors,due to lower current , higher eficiency and power factor. Speedcontrol of these motors can be achieved through a wide range bythe variable frequency controller Frequency variation needs avoltage variation by the same ratio (V/F = constant) during theconstant torque region. If the capacitor is kept constant, themaximun torque will be decreased by the frequency decreasing.The main object of this work is to keep the maximun torque andthus full load torque, at higher values through thedecreasing. The capacitance value should be increased, byfrequency decreasing, to a value which keeps the winding Cuiruntat its rated value and the motor performance analysis is alsoachievedThe computed and the measured performance characteristics arecompared and found to be in a good agreement
2000
07
01
205
215
https://erjm.journals.ekb.eg/article_71319_c3c86f1b0fef142aa3d8fcf19fa7c62c.pdf