Table of content

Basrah Journal for Engineering Science

مجلة البصرة للعلوم الهندسية

ISSN: Print: 18146120; Online: 23118385
Publisher: Basrah University
Faculty: Engineering
Language: English

This journal is Open Access

About

The Basrah Journal for Engineering Science (BJES) is an open access, peer-reviewed bi-annually journal (two issues per year) that aims at the publication of original research papers on the latest developments and techniques in the variety fields of Engineering science and their applications to the real world. The BJES is the Official journal of the Iraqi Ministry of Higher Education and Scientific Research issued by the College of Engineering, University of Basrah, Basrah, Iraq. The Submitted papers should be written in English, and all submissions should be made through the on line EDAS system. Papers may be theoretical (including computational), experimental or both. The contribution should be unpublished before and not consideration for publication elsewhere. BJES maintains a standard double-blind peer review process, which means that the identities of the authors and the reviewers are not known to each other. BJES is an Open Access Journal, which supports the rights of users to read, download, copy, distribute, print, search, or link to the full texts of these articles provided they are properly acknowledged by cited.

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Contact info

Address: Engineering College , University of Basrah ,Basrah, Iraq
P.O.Box: 801
Fax: 0188696
E-mail: bjes_editor@yahoo.com
Mobile No.: 07801419901

Table of content: 2009 volume:9 issue:1

Article
Solar Chimney Power Plant in Basrah

Authors: Salman Hashim Hammadi
Pages: 1-8
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Abstract

The solar chimney is a natural draft device which uses solar radiation to provide upward momentum to the in-flowing air, thereby converting the thermal energy into kinetic energy through an air turbine which in turn can he converted into electrical energy. The main parts of the solar chimney power plant are a large circular solar collector, tall chimney and air turbine. In this paper a theoretical study was performed to evaluate the performance of a solar chimney power plant system in Basrah city where the sunny days and the solar radiation is high. A mathematical model was developed to study the effect of various parameters on the output power of the solar chimney. It was found that the output power depends strongly on the chimney tall and the difference between the collector air temperature and the ambient air temperature as well as the outside heat transfer coefficient which essentially depends on the wind speed.

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Article
Solar Updraft Tower Power Plant with Thermal Storage

Authors: Salman Hashim Hammadi
Pages: 9-16
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Abstract

A mathematic model is presented for solar updraft tower power plant with water-storage system. This model is developed to evaluate the effect of geometrical parameters of the solar tower power plant and thermal storage system as well as the wind velocity on the power production of the plant. The analysis based on variable solar incident radiation along the day. The results show that the tower tall, the tower diameter, the wind velocity, and the collector diameter have a significant effect on the power production while the thickness of the water -storage layer is shifted the peak value of the output power far away from mid-day and more smoothing the output power curve. The results are compared with other model and experimental data. A good agreement is obtained.

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Article
Finite Element Evoluation of Mode I Stress Intensity Factor of Composite Material Under Domain Loading

Authors: HAIDER HADI JASIM --- AMEEN A. NASSER
Pages: 17-24
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Abstract

In this paper, a finite element method program under domain loading and plain strain conditions is developed and applied in evaluation of the stress intensity factor in opening mode (K) in two dimensions crack problems. Two types of crack problems are analyzed and verified: first, cracked rotating disc made from bi-directional fiber reinforced material composite, second crack blade made from bi-directional fiber reinforced metal matrix composite. It is found that the finite clement method under domain loading is a good tool for the analysis of composite material. The simulation is accurate in comparison with that obtained from extrapolation method. The stress intensity factor for fiber reinforced metal matrix composite is larger when obtained from fiber-reinforced material under same condition.

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Article
Effect of Magnetic Field Distribution on the Performance of the Electromagnetic Flow meter ia Partially- Filled Pipes

Authors: Muneer A. Ismael --- Qais A. Rashack --- S.E. Najem
Pages: 25-33
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Abstract

Electromagnetic flowmeters have proven their merit in measuring the flow rate of conducting liquids in fully-filled pipes. In contrast with the most of the published works about the electromagnetic flowmeter. the attentions were focused in this work into the use of these devices in partially-filled pipes. In this application these devices suffer from the problem of different outputs with different liquid level for the same flow rate. We studied whether the process of changing the distribution of the magnetic field through the measuring section improves the flowmeter performance against this drawback or not. An adaptive numerical mesh was used in predicting the flow induced signal and its response to the liquid level. The induced signal was assumed to be picked up by a pair of point electrodes tested for different angular positions. The results showed that the performance of the electromagnetic flowmeter in partially- filled pipes could be appreciably improved by making the magnetic field progressively decreases from top to the bottom of the flowmeter. When the lower magnet coil is excited by a current one- half lower than the upper coil together with two point electrodes placed at 22° below the flowmeter horizontal centerline, the fiowrneter performance offer more stable sensitivity.

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Article
Dynamic Forces and Stress Analysis in the Journal Bearing System

Authors: Azzam D. Hassan
Pages: 34-41
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Abstract

This paper is concerned with a stress analysis in a bearing under unbalanced forces of the journal Some aspects of mathematical modeling of rotating structures were considered. “Finite Element Method” is formulated for modeling rotating structures. As an application, a test rotor mounted on two-lobe hydrodynamic hearings is presented. Unbalance response calculations for various unbalance magnitudes are carried out in the bearing location. The bearing coefficients were found at rotational speed of 4OOO rpm. An accurate identification of bearing force parameters, i.e. stiffness and damping coefficients is presented by a classical linearized model. The bearing support forces in flexible rotor-bearing systems are presented as a function of unbalance response of the journal. The calculation of the bearing stress due to rotor unbalance are carried out using ANSYS. The ANSYS program gives a good aids in understanding the stress analysis in the bearing under the action of journal rotation.

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Article
SIMULATION OF COLD FLAT ROLLING USING FINITF ELEMENTS MODELING

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Abstract

This research makes a two-dimensional model for cold flat rolling process using ANSYS program The Contact pair are used between the contact surfaces using the boundary condition of Surface to Surface Contact. . The process of symmetric rolling is tested for two types of materials (aluminum and mild steel) . The rolling force for (1 %) to(25%) reduction of a slab of dimensions of (200*10)mm using (Avitzur) theoretical equations and ANSYS, The radius of the rolls for aluminum are (75)mm and that for mud steel are (300) mm. The numerical results were compared with (Avitzur) theoretical equations . The comparison shows that the values of forces calculated using (Avitzur) theoretical equations are accurate enough up to (5%) reduction, and the numerical results proved its accuracy up to (25%)reduction. The study shows that forces increases as a results of increasing the rolling metal area at entry rate. The angle of the neutral point was also studied in this work and it is found that it decreases with the increasing of reductions rate, due to an increase in the cohesion area on the sliding one within rolling process while the theoretical results failed to calculate the angle of the neutral point correctly.

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Article
BRAZING OF GRAPHITE/GRAPHITE USING A NEW FILLER TECHNIQUE

Authors: ADNAN S. JABUR
Pages: 54-63
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Abstract

Brazing is one of the best methods of graphite to graphite or lb metals joining. But the major problem associating the graphite brazing is the poor wetting by. the conventional molten fillers. For this reason, scientists have produced a special filler metal based on- active elements which. interacts with graphite to form carbides. Also. Recently another technique to overcome the wetting problem was introduced by H. Ohmura and T. Yoshida. It included inserting an intermediate layer of pure iron foil inside the copper filler. In the present work, another filler combination of Cu/ steel/Cu foils is proposed as new filler technique for graphite brazing. It was found that, it produced a succeeded joint with a good properties consisted of a columnar phase which resulted from the partially dissolution of iron in molten copper. Additionally, the increasing of brazing time caused reducing the thickness of the steel central layer and increasing the thickness of the columnar phase layers. The x-ray diffraction test developed that, the joints contained two carbide types, iron and copper free elements.

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Article
CHARACTERIZATION OF COPPER LELCTRODEPOSITION AS A NEW FILLING TECHNIQUE IN 316L STAINLESS STEEL BRAZING

Authors: ADNAN S.JABUR
Pages: 64-71
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Abstract

The objective of this research is to characterize a new technique of copper filler addition to the brazing joints of 316L stainless steel to overcome the wetting problem between them. This technique includes the electrochemical deposition of copper on the stainless steel joint parts to insure optimum coinciding, minimum oxidation during brazing heating, and consequently good wetting and bonding. An evaluation of the present technique and a comparison with traditional one were performed. The samples were tested to find the shear strength, microhardness, microstructure and x-ray diffractometry. in general, the present new electrodeposited fillers were clearly better than the traditional filler in producing perfect joints with higher shear strength. On the other hand, there was an opportunity of production acceptable joints with electrodeposited fillers under air environment.

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Article
Processing of Near Singular Integrals in 3D Boundary Elements Method

Authors: Jaafar Khalaf All
Pages: 72-83
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Abstract

In this work, the efficiency of double Gauss quadrature method, used to integrate over a rectangular element in 3D BEM, has been investigated. The efficiency of a quadrature or integration scheme is investigated by estimating the critical ratio for which the absolute relative error of the numerical integration is less than 1x106. As small as the critical ratio is, the quadrature is more efficient. Also, special transformation techniques have been introduced and used to increase the accuracy and efficiency of double Gauss quadrature especially for near singular cases, where the source point is very close to the element under consideration. Three types of kernels were considered, weak, strong and hyper singular kernels which can be encountered in the integral equation of 3D elastodynamics BEM problems.

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Article
APPOINTING THE PROPER OPERATING VARIABLES FOR EFFICIENT AIR-COOLED LIBR-WATER ABSORPTION REFRIGERATOR

Authors: ABDULWADOOD SALMAN SHIHAB
Pages: 84-98
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Abstract

The aim of the present study is to perform analytical simulation for the single-effect LiBr- water absorption refrigerating system (ARS) in order to scan for all possibilities of operating the cycle among most available operating variables to obtain the best performance and determine what are the proper parameter needed to be changed so that the refrigerator can operate using ambient air instead of water and cooling tower accessories to dissipate the beat at the condenser and absorber. The COPs of the cycle was obtained as a function of the different temperature of the cycle and solution concentration. The performance characteristics of the cycle were examined by changing the temperature of the heating source supplied at the generator, the temperatures at the condenser, absorber, and evaporator. It can be concluded that the concept of air cooled absorption chiller is feasible with coefficient of performance of 0.43 to 0.79 depending on the evaporator temperature for any cooling capacity in some applications. where the chilled water supply temperature is not necessary to be too cold,

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Article
A New Simulator for Dynamic Local Grid Refinement For Reservoir Simulation

Authors: Ahmed N.Nimir Al-Sabeeh
Pages: 100-120
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Abstract

The ability to predict the performance of a petroleum reservoir is of immense importance for the petroleum industry. Numerical simulation is the most powerful tool that can be used for reservoir performance prediction. In the current study a new simulator has been designed for two phase compressible oil water flow through compressible porous media. The new simulator is able to treat the frontal advancement and the high rate of change region by static and dynamic local grid refinement. A new approach is proposed in this study to trace the frontal advancement. The proposed simulator has been applied to several field reservoir cases and show good performance.

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Article
Performance Evaluation of Reverse Osmosis Process in Al-Dura Power Station

Authors: Hasan Ferhood Makki
Pages: 122-130
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Abstract

The present work aims to study the performance of reverse osmosis process at Al-Dura power station. The selected membrane which is used in this work is made from polyamide (thin film composite membrane (TFC)) constructed as spiral wound module. The basic advantages of this type of membrane are the higher productivity compared with the total volume of the module, and stability of the polymer towards the chemical effect. It was found that recovery percentage (or product rate), rejection percentage (or solute concentration in product), and concentration factor decreases ‘with increasing operating time the reverse osmosis unit, whereas, the operating pressure for reverse osmosis unit increase with time. Maximum salt rejection percentage and Maximum recovery percentage were determined to be 96% and 75% respectively for polyamide membrane.

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Article
A modified fixed phase iterative recovery algorithm for restoration of gray-Scale blurred images

Authors: Jassim M . Abdul-Jabbar
Pages: 131-142
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Abstract

A novel iterative method for the restoration of gray-scale blurred images is presented. The method is an enhanced modification of the Fixed-Phase Iterative Algorithm (FPIA). A blurred image is enhanced by Laplace operator during the FPIA method on each iteration. This modification is originally supported theoretically by a derivation of some iterative deploring methods that are based on the enhanced version of the blurred image instead of the blurred image itself only. The modified fixed phase iterative algorithm (MFPIA) method is examined to restore some Gaussian-and motion-blurred gray-scale images. The restored images via this proposed method are compared with the original FPIA method. From the comparison, it is apparent that the MFPIA method is better from human visual measurements point of view with less number of iterations. In addition to that benefit the restoration by the FPIA method results in images of bad quality even with high number of iterations.

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Article
A New Design for Linear Phase FIR Digital Filter with Efficient Realiztion

Authors: Afaf A.Abood --- jassim M.Abdul Jabbar
Pages: 143-156
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Abstract

In this paper, the design of linear phase FIR digital filter using Frequency Sampling method is presented. Such design is achieved with a reduction in the maximum stop-band ripples utilizing optimal transition- band sample value throughout the use of Golden Section search method for single transition samples, and with aid of Steepest Descent method for double transition samples. The realization requirements of such filters are reduced by the use of a new analytic design. The reduction can be increased to 50% of the whole filter structure. Therefore, the designed FIR filter offers global properties, minimum stop-band, minimum pass-band, average deviation, and reduced structure complexity.

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Table of content: volume:9 issue:1