Print ISSN: 1813-0526

Online ISSN: 2220-1270

Volume 15, Issue 1

Volume 15, Issue 1, Winter and Spring 2007, Page 1-111

Modeling and Simulation of multi-pulse Cycloconvereter-fed AC induction motor and study of output power factor

Maamoon Al-Kababjie; Rezgar Mohammed Khalil

Al-Rafidain Engineering Journal (AREJ), 2007, Volume 15, Issue 1, Pages 1-14
DOI: 10.33899/rengj.2007.44905

The need for use of cycloconverters is in controlling a.c motors at low speed drive especially in high power application. The MATLAB-SIMULINK model for three pulse, six pulse and twelve pulse three phase to three phase cycloconverter has been constructed. The control strategy of supplying the firing pulses is based on the cosine wave crossing method. The SIMULINK model for the control circuits to perform the procedure of this strategy has been constructed. A control circuit for each thyristor to control its firing pulses has been constructed separately to prevent any complexity in the control circuit. An R-L load was used. In additional a three phase induction motor has been connected to test the reliability of the system in controling the output frequency and then the motor speed. The present study includes circulating current and semi-circulating current modes of operation with study of measuring and correction of output power factor of the cycloconverter and output voltage waveform harmonics.

Keywords:Three-phase to Three-phase, Cycloconvereter, Modeling and Simulation, MATLAB-SIMULINK model

Influence of Mutual Coupling due to Zero-Sequence On The Performance of Distance Relay

Dr. Abdul Ghani A. Abdul Ghafoor; Mr. Ahmed Ateya Al-Badrany

Al-Rafidain Engineering Journal (AREJ), 2007, Volume 15, Issue 1, Pages 1-15
DOI: 10.33899/rengj.2007.44935

To get accurate performance of the distance protection function, Must be all influencing quantities and limitations on the measuring accuracy of distance relay that imposed by power system in considered. This research includes study and analysis of the problems which faces the conventional distance relay which was designed for single circuit distance protection when applied double circuit of over head transmission line, due to mutual coupling zero - sequence system in this case, For various operational conditions and fault location,This work had been conducted with (I.N.R.G. 132 kV) transmission lines systems under to ground fault condition, The current and voltage at the relay and fault location were calculated.
The results show that zero sequence mutual coupling may cause the distance relay to seriously over reach under reach for different operational situations and fault locations, Values of short circuit levels ratio and power flow for feed sources which connected to the line ends have major effect in this problem.
This research indicate the possibility of zero sequence coupling compensation by injecting proportion of the zero sequence current flowing in the parallel feeder into the relay to reduce this effect, This method is successful when relay and fault location are in the a same circuit, Also when relay and fault location are in different circuits but with limits .
Keywords: Protection, Distance Relay, Influence of Mutual Coupling.

Towards the Improvement of the Computer Network of Mosul University Using (OPNET) Software

Dr. A.I. A. Jabbar; Mohammed Basheer Abdullah

Al-Rafidain Engineering Journal (AREJ), 2007, Volume 15, Issue 1, Pages 15-26
DOI: 10.33899/rengj.2007.44924


Mosul University network which covers most of its departments and colleges has been implemented in a star topology using fiber optic cables and Cisco switches. In order to participate in optimizing the network performance by minimizing broadcast and collision domains, a proposed network (as an example) for the Engineering College based on VLAN technique has been developed using the network simulator software (OPNET IT GURU). The suggested model could be applied to other colleges. The results being obtained represent the optimum possible improvements in terms of node delay, throughput and minimizing unnecessary traffic to avoid network congestion.

Keywords: Network Simulation, OPNET, VLAN, Switch

obile Phone and Health Hazard

Abed AL-Rahman A.M. Hayawi; Dr. Kaydar M. Quboa

Al-Rafidain Engineering Journal (AREJ), 2007, Volume 15, Issue 1, Pages 16-26
DOI: 10.33899/rengj.2007.44937

Due to unlimited expansion of mobile communication devices,a rapid increase in the exposure of people to radio frequency radiation has occurred which in turn resulted in many questions regarding the possibility of hazardous effects of these fields.
Although mobile phones are low-power transmitters but they are used close to the user’s head.
In this paper, the specific absorption rate of the electromagnetic energy absorbed in human tissues is examined for partial exposure and inter-related to current radiation safety standards. Simulation of specific absorption rate of electromagnetic power absorption in human head is carried out for mobile phones of different antennas using CST-microwave studio package.
The results showed that maximum permissible exposure limits for “Safe Exposure” set by FCC are not reached. However these limits are set on thermal basis and reflect the present understanding of these fields, which are considered to be non-harmful for humans. On the other hand there are complains from using mobile phones which suggests non-thermal effect may exist. Further research in this area is needed to reach clear evidence that existing safety guidelines govering exposure of the public to the radiation employed in mobile telephony are adequate.

Effect of Depth and Location of cracks on the natural

Mohammed Najeeb Abdullah

Al-Rafidain Engineering Journal (AREJ), 2007, Volume 15, Issue 1, Pages 27-36
DOI: 10.33899/rengj.2007.44938


In this work , the influence of the location and depth of transvernce cracks on the natural frequency of cantilever beam was studied. The study of the cracked beam has been carried out theoretically, starting from derivation of equation for the additional strian energy in the presence of a crack .The equation of natural frequency change due to the presence of a crack can also be calculing for cantilever beam . The results showed that the presence of the crack causes a decrease in the values of the natural frequencies of beam as the decrease in the value of natural frequencies of the beam with cracks in the area nearer to the supports, was lesser than in areas away from the supports. Finally, the theroetical results were compared with the experimental results of previous researches, which were in a cloce agreement especially for the behavior of beam curves as function of the crack depth.
Key Word : Beam , Crack , Natural Frequency, Depth , Location

Enhancement Of Spatial Structure Of An Image By Using Texture Feature Extraction

Turkan Ahmed Khaleel

Al-Rafidain Engineering Journal (AREJ), 2007, Volume 15, Issue 1, Pages 27-39
DOI: 10.33899/rengj.2007.44927

In this paper a new algorithm has been developed to enhance spatial structure by using texture feature extraction. Then, this algorithm has been programmed and an integrated program has been prepared by using Microsoft Visual C++ 6.0. In order to ascertain the usefulness of this algorithm, it has been applied in two groups of images, the first group consisted of three images of different feature. The results have been evident enhancement in spatial; structure. The second group of images consisted of multi-spectral images taken by Thematic Mapper (TM) in the city of Mosul. The results of this algorithm have been used in the classification.
The measurement of classification accuracy of the results of this algorithm compared with the original images which have not undergone any spatial structure enhancement revealed that this algorithm executed the process of texture feature extraction excellently. Further, the results were clear in the barren areas, Agricultural fields and the other areas as well.
Keywords: texture feature extraction, Spatial filter , Classification

Evaluation of fluoride concentrations in Mosul city Drinking Water

Suaad A. Abawi; Layth A. Al-Annaz

Al-Rafidain Engineering Journal (AREJ), 2007, Volume 15, Issue 1, Pages 37-45
DOI: 10.33899/rengj.2007.44939

The research evaluated the fluoride concentrations by collecting samples of drinking water twice a month through one full year. Then the fluoride concentrations was measured and compared with the recommended values set by international environmental and health organizations .The results indicate that there is fluctuation in the fluoride concentrations . It ranges from (0.075)mg/l to (0.225)mg/l with an average of (0.147)mg/l . All samples concentrations are lower than the guide values. Thus the water is suitable for drinking as far as this characteristic concerned , with an expectation that dental caries cases may be appearance .
The results also indicated that all fluoride concentrations in Mosul city drinking water were less than the optimum value which is (0.7)mg/l , according to EPA. This value was stabilized according to the mean value of maximum daily temperature for the Mosul city (28.42) ○C over the last (5) years. However, to avoid consumed excessive dosage of fluoride, the fluoridation should not be practiced unless it is advised by the specialists in the nutrition, public health and dentistry. The fluoride may be supplied to the human by sources other than water, also there is a variety in the amount of the fluoride consumed by different persons.

Key words : drinking water / fluoride concentration .

Theoretical Determination of Forming Limit Diagram for Steel ,Brass and Aluminum alloy sheets

Anas O. Edrees; Waleed J. Ali

Al-Rafidain Engineering Journal (AREJ), 2007, Volume 15, Issue 1, Pages 40-55
DOI: 10.33899/rengj.2007.44929

Abstract :
Sheet metal forming is defined as the ability of metal to deform plastically (deformation by Stretching or drawing) or changing the shape of the sheet into a new desirable shape with out necking or crack . To control the operation of sheet metal forming with out failure. A diagram is used in which the range accepted , failure and critical deformation range are shown . This diagram is known as the Forming limit diagram. It is considered as one of the important tool to determine the formability of sheet metals. Every sheet metal has its own forming limit diagram which determines its formability, strain limit and the forming regions. These diagrams can be assessed using theoretical and experimental approaches, In this paper, the FLD is determined using different yield criteria Hill1948, Hosford1979 and modified Hosford 1985. It is shown that the determination of forming limit curve using the modified Hosford 1985 criterion with the (M-K) analysis , gave the best results compared with the other used criteria .Using this criterion gave the closest forming limit curve to that obtained experimentally, but with different criterion index for different alloy . The value of the index (a=6) gave the best results for brass, while (a=8) gave the best results for aluminum alloy and mild steel.

Evaluation of Wady ‘Eqab Wastewater Effluent and its Effect upon Tigris River

Adil A. Bilal; Mus’ab A. Al-Tamir; Mohammad A. Said

Al-Rafidain Engineering Journal (AREJ), 2007, Volume 15, Issue 1, Pages 46-60
DOI: 10.33899/rengj.2007.44940

The study focused on evaluating the Wady ‘Eqab wastewater effluent, which is discharged directly in Tigris river. This effluent represents a mixture of industrial and domestic wastewater, that collected the large portion of the wastewater from industrial district at right bank of river and some residential quarters.
According to Iraqi standard for conservation of water resources, The suspended solid concentration for stream effluent increased by (122%) and other impurities increase by (16%-29%), Where is according to organic load, the stream effluent classified as weak, for its biological oxygen demand (BOD5) is (56)mg/l as an average. As compared with Municipal wastewater for last previous years, Wady ‘Eqab wastewater impurities were with less concentration levels; These impurities increased by different percentage and some exceeds (34) times. However, The river water is still clear and within the Iraqi standards for conservation of water resources, for the region follow the stream discharge point.
Key words: Tigris river, Wady ‘Eqab, Wastewater streams, Water pollution, Mosul city

Method Of Characteristics In Plates And Multi-Material Beams

Dr. Mereen Hassan Fahmi

Al-Rafidain Engineering Journal (AREJ), 2007, Volume 15, Issue 1, Pages 56-71
DOI: 10.33899/rengj.2007.44931

The behaviors of structural waves (axial, shear and bending) are studied in multi-material beams and single material plates using the method of characteristics (MOC). The characteristics equations in one dimensional problems are extended and derived to cover the two dimensional problems and to make the method be applicable to study the wave behavior in plates.
The results showed that the structural waves changed their forms during their propagation in the multi-material beams and some reduction is occurred in the natural frequency of the beam. The propagation of structural waves in plates showed same behavior as in beams, so the propagation in two directions can be separated and each direction can be considered individually as one dimensional problem to simplify the characteristics equations and saving the computing time and solution techniques.

KEYWORDS: Beams, Method of Characteristics, Plates, Structural waves and Vibration.

Rainfall-Discharge Relation for Adhaim and Greater Zab Rivers

Dr. Basil Khether Dawood

Al-Rafidain Engineering Journal (AREJ), 2007, Volume 15, Issue 1, Pages 61-74
DOI: 10.33899/rengj.2007.44941


The Dynamic Regression model (DR) was used for forecasting the discharge of Adhaim and Greater Zab rivers with considering the effect of rainfall on the discharges.
The auto correlation function (ACF) was used to determine the stationary level of the time series, also the partial auto correlation function (PACF) was used to identify a suitable Auto Regression Integrated Moving Average (ARIMA) model for time series of rainfall and discharges for both rivers and the factors of the transfer function models (TF) were determined. The model passed the tests successfully and the dynamic regression model for both rivers became suitable for forecasting the discharges depending upon the historical data of the rainfall and the discharges.
Key words : Rainfall , Adhaim river , Greater Zab river

Behavior Assessment Of Various Filters Configuration In Removing Water Low Turbidity: A Statistical Treatment

Ahlam Z. Ameen; Abdulmuhsin S. Shihab; Sati M. Al-Rawi

Al-Rafidain Engineering Journal (AREJ), 2007, Volume 15, Issue 1, Pages 72-83
DOI: 10.33899/rengj.2007.44933

The research focuses on the behavior of laboratory bench-scale filters that receive low-turbidity raw water. The filters have different configuration in terms of materials type, materials size and thickness. These filters operate under in-line and direct mode of filtration with different doses of alum and coagulant aid.
A total of 200 filter runs were conducted. Statistical methods had been used in the determination of best configurations of tried filters. Analysis of variance (ANOVA) and Duncan multiple range test had been employed for this purpose.
The results showed the superiority of filters operating under direct filtration mode compared to those of in-line filtration mode. It was thought that flocculation played a role in this result. Fine sand media of 0.56 mm E.S appeared to surpass the coarse media due to more trapping of impurities at pore spaces. The effect of coagulant aid addition was detected to act positively only with capping media filters, where an improvement in performance did occur. However, such improvement was low and did not justify importation of anthracite coal and coagulant aids and add an economic burden.
Keywords: Filtration modes, Filtration, Water turbidity, Water treatment.

free flow equation for vertical and inclined sluice gates

Dr. Basil K. Daowd Lect; Ahmed Y. Mohammed; Dr. Moayed S. Khaleel

Al-Rafidain Engineering Journal (AREJ), 2007, Volume 15, Issue 1, Pages 75-80
DOI: 10.33899/rengj.2007.44942

In this paper a hydraulic study on free flow under sluice gate have been carried out in a rectangular flume using six gate cases (vertical gate and inclined with angles (30,45,60)o with a horizon in flow direction and (30&45)o opposite it. Four gate opening (2,3,4,4.5) cm and five different upstream heads (18.9,21,24,26,28.9) cm, were used. The coefficient of discharge (Cd) have been evaluated and shown that the average value of this coefficient increases from (0.645) for vertical gate to (0.832) for inclined gate (60)o with flow direction, while it decreases to (0.576) for inclined gate (45)o opposite flow direction .
A general equation of free flow under vertical and inclined gates, with any angle and with flow or opposite it, was contrived with error percentage not exceed (12.32)%.

The Attributes of Spatial Organisation of Traditional and Contemporary Urban Structures -A Comparative Study of Two Selected Areas in Mosul -

Miqdam A.M.Alkurukchi; Mumtaz H.D.Aldewachi

Al-Rafidain Engineering Journal (AREJ), 2007, Volume 15, Issue 1, Pages 81-95
DOI: 10.33899/rengj.2007.44943

The urban environment represents an expression of the temporal status of its society . Any alterations caused by the development of this society will be followed by changes in the built environment and these will affect the spatial organisation attributes of this environment .
This research explains the similarities and dissimilarities of spatial organisation attributes for both traditional and contemporary urban areas . Two temporally different districts in Mosul are selected as a case study and they are analysed using the space syntax methodology .
The research is ended with a number of findings which explain the attributes of each district , the traditional one has its efficient accessability with high control on any strange traffic while the influence of the designer is obvious in the organization of spaces in the contemporary district.
Keywords : Spatial Organisation , Spatial Configuration , Space Syntax

Areal analysis of the traditional residential unit’s components in Mosul city, its relationship with their design attributes.

Mumtaz H. D. Aldewachi; Miqdam A. M. Alkurukchi; Rabee’a K. T. Haydaran

Al-Rafidain Engineering Journal (AREJ), 2007, Volume 15, Issue 1, Pages 96-111
DOI: 10.33899/rengj.2007.44944

Within the discipline of domestic Architecture, the relationship between areal determinations and design attributes of the traditional residential units represents a variable that lacks adequate research endeavors.
Accordingly, this study hypothesized the existence of a relationship between areal determinations and design attributes, in traditional residential units in Mosul city.
The first stage of solution was to select a purposive sample of 50 units, measuring its variables, and finally a statistical analysis was made.
A number of findings were obtained, explaining the relations between the design attributes of the residential units and their areal components.

Key words : Areal Analysis ,Domestic Architecture , Traditional Residential Units .