Table of content

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES

مجلة النهرين للعلوم الهندسية

ISSN: 25219154 / eISSN 25219162
Publisher: Al-Nahrain University
Faculty: Engineering
Language: Arabic and English

This journal is Open Access

About

AlNhrain Journal for Engineering Sciences is a refereed scientific engineering journal published by the College of Engineering, Nahrain University two times per year. The journal publishes the scientific output of researchers from Iraq and abroad in the fields of architectural, chemical, civil, computer, electrical, information technology, laser and optoelectronics, mechanical and medical engineering as well as in related fields. Papers written in Arabic and English are accepted and they are subjected to proper evaluation and accordingly classified as follows:
• Original research papers and papers on novel design, analysis or construction methods of great value to the engineers which include basic and practical results.
• Short communications or short discussions on papers which have already appeared in the journal provided that whose text should not exceed 800 words.

The material of the paper should not violate any intellectual property right of any person or entity and should not contain any subject matter that contravenes any laws and should meet ethical standards applicable to the research discipline.

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Contact info

Editor-in-Chief
College of Engineering Journal
Al-Nahrain University
P.O. Box 64040 , Al-Jadyriah
Baghdad-Iraq.
e-mail: journal.engineering@nahrain-eng.org
jourengnah@gmail.com
Phone: +964 (0) 7817 202 662

Table of content: 2010 volume:13 issue:1

Article
Harmonic Phase Shifter for Discrete Amplitude Modulation Technique
معدّل الطور للتوافقيات في نظام التضمين الموجي المتقطع

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Abstract

In discrete amplitude modulation or integral-cycle control, subharmonic and higher order harmonic components are generated in the three phases of a three phase system. These harmonic components are found to be unbalanced in phase displacement. The correction of the unbalanced phase displacement angles of a particular subharmonic or higher order harmonic for this type of triggering is investigated to solve the limitation of use of this important type of control as a drive and many other industrial applications. The multiple of 2 phase shifting technique is used to correct unbalanced phase displacement angles produced in a three-phase system. A computer-based harmonic phase corrector is designed and tested with threephase resistive and induction motor loads. It is found that there is a well agreement between the theoretical and experimental results and it is believed that the major problems associated with the integral-cycle triggering mode with three-phase circuits have been solved in the present work.


Article
The Linear Vibrational Behavior of Thick Plates Including the Effects of Shear and Rotary Inertia
السلوك الاهتزازي المرن للصفائح السميكة بوجود تأثيرات القص والقصور الدوار

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Abstract

In this work, a suggested analytical solution for static and dynamic analysis of (fiber-reinforced) composite laminated thick plate is developed by using the single layer theory and first-order shear deformation theory (FSDT) theory. The dynamic analysis for equations of motion for those theories is presented and solved by using the modal analysis method of forced vibration. A computer program was built for this purpose for anti-symmetric crossply and angle-ply and simply supported thick laminated plate and the developed equations are solved by using (MATLAB V.7) program. The numerical solution by using finite-element technique is also adopted using (ANSYS V5.4) package, to compare the analytical results. Both above approaches use (FSDT) and include the effect of shear deformation and rotary inertia. The results are the deflection, stress in each layer and (through thickness) interlaminar shear stress for thick laminated plates with different boundary conditions subjected to the static and dynamic loading conditions. The results presented show the effect of plate thickness-to-length ratio (h/a), aspect ratio (a/b), number of layers (N), the degree of orthotropy ratio (E1/E2), fiber orientation, boundary conditions, lamination scheme, and the effect of shear deformation and rotary inertia on the thick laminated plate.


Article
Natural Convection Air cooling of Electronic Components in Partially top vented Enclosures
التبريد بالحمل الطبيعى لعناصر الكترونية فى حيز مهوى جزئيا من الأعلى

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Abstract

The study of natural convection from a heat source located at the bottom of partially top vented enclosure is presented. Air cooling for electronic components situated at the bottom of a top vented enclosure is studied theoretically. The flow was assumed to be laminar, steady and of constant physical properties. The process was described by the continuity, momentum and energy partial differential equations, which were expressed in Cartesian coordinates system. Due to the nature of the studied problem and with proper transformation, at the dependent and independent variables, these governing equations were expressed by a set of dimensionless partial differential equations. This set of differential equations is transformed to set of difference equations by the implantation of a finite difference technique. Accordingly, the solutions for this problem were obtained by the application of the well-known Gauss Siedel iteration method. A computer program, by using FORTRAN-90 language, was developed to solve the present proposed mathematical model. According to this solution; the values of Nusselt number, for different values of Rayleigh number are obtained. Comparisons between the present obtained results and those results obtained in previous theoretical results were performed for parametric variations of the vent opening size and shape. Also a correlation for Nusselt number as a function of Rayleigh number and equivalent diameter of the vent is proposed.


Article
Evaluation of Reliability of Rupture and Expected Value of Fracture Speed of Ceramic Turbine Wheel Taking the Effect of Residual Stresses
تقييم احتمالية الانكسار والقيمة المتوقعة لسرعة الانكسار لقرص

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Abstract

In this paper, Weibull uni-axial and multiaxial distribution function including residual stresses is developed and applied to evaluate the reliability of fracture and expected value of fracture rotating speed of turbine rotor wheel having blades manufactured from ceramic material and have inner crack. The residual stress is measured by X-Ray method. Third cases are considered, first taking only the effect of rotational loading (radial and tangential stresses) in ceramic disc, second taking the effect of rotational and thermal stresses in ceramic disc, and third taking the effect of rotational and thermal stresses in ceramic blade. As a result, there is a convergence between results gets from uniaxial and multi-axial distribution function, and the residual stresses will reduce the risk of fracture of wheel and blade. The expected values of rupture strength of ceramic blade is higher than of that of disc material, therefore the failure occurs in blade first than in disc material in service survival


Article
Prediction of Air Flow, Temperature and Humidity Patterns in a Pilot Plant Spray Dryer
حساب أنماط الجريان ودرجة الحرارة والرطوبة للهواء في وحدة المجفف الرذاذ

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Abstract

This paper presents the prediction of air flow, humidity and temperature patterns in a cocurrent pilot plant spray dryer fitted with a pressure nozzle using a three dimensional model. The modeling was done with a Computational Fluid Dynamic package (Fluent 6.3), in which the gas phase is modeled as continuum using the Euler approach and the droplet/ particle phase is modeled by the Discrete Phase model (Lagrange approach).Good agreement was obtained with published experimental data where the CFD simulation correctly predicts a fast downward central flowing core and slow recirculation zones near the walls. In this work, the effects of the air flow pattern on droplets trajectories, residence time distribution of droplets and deposition of the droplets on the wall also were investigated where atomizing of pure water was used.

Keywords


Article
Effect of Salt Content on The Corrosion Rate of Steel Pipe in Turbulently Flowing Solutions
تأثير المحتوى الملحي على معدل التآكل للأنبوب من الفولاذ في ظروف جريان اضطرابي

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Abstract

The effect of salt content on the corrosion rate of carbon steel pipe in aerated water under isothermal turbulent flow conditions (Reynolds number= 15000-110000 and temperature of 30-60oC) is investigated by weight loss method. The test solutions were distilled water (one time distilled) and sea water (0.5N NaCl). Also the results of 0.1N NaCl solution obtained by Hasan [2003] were considered. The effect of Reynolds number temperature on the corrosion rate is also studied and discussed. For each run, nine specimens of carbon steel were placed in the test section and the corrosion rate for each one was determined at every Re and temperature and the average was taken. The variation of friction factor with Re and temperature was determined by measuring pressure drop across the test section. The results revealed that the salt content has considerable effect on the corrosion rate for the whole investigated range of Re and temperature. The highest corrosion rate was encountered in sea water (3.5% NaCl). Also distilled water causes considerable corrosion rate but it is lower than for the whole range of Re and temperature. Also it is found that Reynolds number increases the corrosion rate depending on temperature. Temperature affects the corrosion rate by changing two main parameters, oxygen solubility and diffusivity.


Article
Design A Real Time Fast Fuzzy Filter Using Fpga

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Abstract

A nonlinear filtering is an important part of processing and restoring image sequence. The computation complexity of these filtering algorithms makes them difficult for real-time processing. This paper presents the design and implementation of a pure fuzzy filter, which is effective to remove the impulse noise, and a new method for hardware implementation into single chip FPGA is proposed. The construction of the fuzzy filter is simple and depends on a set of fuzzy rules to well detect and remove noise pulses. Simulation results show that the fuzzy filter exhibits better filtering properties than standard median filters. The basic FPGA implementation of the filter cannot reach the limit for real time processing with good efficiency. The proposed fuzzy filter is implemented by modifying the input data locations and increase the speed of processing seven times without any increase in the cost.


Article
Analysis and Design of Controller for Level Process Control without Sensor
تحليل وتصميم مبسطر للسيطرة على عمليات المستوى بدون استخدام متحسس

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Abstract

This paper deals with process control, generalized definition and modeling design of flow systems and control it based on compare to constant as principle of operation approach. After reviewing the operation of the plant, a compare system between water level and desire level is formulated to control flow rate. The scheme is then designed and tested by Matlab and Simulink Toolbox. Simulation is presented and shown that on/off switch with constraint is better and more versatile compare with conventional approach.

Keywords

Process --- controller --- flow


Article
Hybrid Color Image Compression based DPCM and Slant Transform
ضغط الصورة الملونة اعتمادا علي تضمين الفرو قات وتحويل الانحدار المائل

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Abstract

Nowadays, still images are used everywhere in the digital world. Images take lot of computer space, in many practical situations, all original images cannot be stored, and a compression must be used. Moreover, in many such situations, compression ratio provided by even the best lossless compression is not sufficient, so lossy compression is used. In this paper ,Differential pulse code modulation (DPCM) in slantlet transform and Run Length Code for image compression is used. Apply slantlet transform on each component in the color image(after applying color space conversion from RGB to YCbCr)and encoding Y component by DPCM and encoding Cb and Cr with RLC.The compression ratio and Peak Signal to Noise Ratio (PSNR) are used as measurement tools. When comparing the proposed approach with other compression methods Good result obtained.


Article
Unsupervised Segmentation Method for Brain MRI Based on Fuzzy Techniques
طريقة الانقسام الآلي لصور رنين مغناطيسي للدماغ باستخدام التقنيات الضبابية

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Abstract

In the present research a novel spatially weighted Fuzzy C-Means (FCM) clustering algorithm for image thresholding is presented. The segmentation technique is for magnetic resonance (MR) images of the brain based on fuzzy algorithms for learning vector quantization (FALVQ) by creating of a combined method in utilizing both LVQ (learning vector quantization) and the fuzzy technique. Such a technique is obtaining more efficient method for the process of diagnosis of the human brain tumor without the need for sophisticated steps or human manner. To speed up the FCM algorithm, the iteration is carried out with the statistical gray level histogram of image instead of the conventional whole data of image. Some comparisons with classical thresholding algorithm and fuzzy thresholding algorithm are also considered in this research. Experimental results on real images are given to demonstrate the effectiveness of the proposed algorithm. In addition, due to the neighborhood model, the proposed method is more tolerant to noise.

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Article
Study of Adhesive Wear of Epoxy Reinforced with glass fibers Composite Material
دراسة البلى الالتصاقي الجاف لمادة مركبة من راتنج الايبوكسي المدعم بألياف الزجاج

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Abstract

The dry wear, compression resistance and hardness of a material that consists of Epoxy reinforced with (25%) ratio of Glass fiber have been Studied. A comparison is made between the properties of the composite at temperature ( 20 2 0C) with those of un reinforced Epoxy to find out the effect of reinforcement on the composite. Volume fraction for specimen was (25%) and the reinforcement material were continuous fiber oriented in woven raven. The measurement of wear rate shows a decreases with reinforcement. Compression resistance and Hardness increase with reinforcement. The results of compaction have clearly shown that wear rate and wear rate volume increasing normal applied load, sliding distance, time sliding and hardness of disc. The results also show that wear rate and wear rate volume for all materials increases with normal applied load and running time. The results also show that wear rate and wear rate volume decrease with increasing the applied with increasing the hardness of disc and sliding distance. The topography of some physically tested was studied using optical microscopy

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Article
Designing an Integrated Systematic Excavator for Agricultural Land
تصميم منظومة متكاملة تعمل كحفارة (عازقة)ارض زراعية

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Abstract

In this research a complete design of a plough for agricultural land has been achieved. This is a theoretical study, design and invention, for it is considered like the ones available now. Precisely, it is a borne type which can be carried on a vehicle. The optimal design has been reached through making some primary designs for the research on well excavated land by using spiral digging blades which unearths the earth on both sides. These blades are fixed on a subjacent system raised by a hydraulic tool when the digging process finishes. This hydraulic tool enables to obtain a digging successive course by controlling the process of lowering the lower system gradually to perform the digging process by a control system connected to the hydraulic tool. Throughout observation of the previous researches related to plowing [2, 3], it has been found that loads are put on the most digging blades of the ploughs to increase the digging efficiency and to reach deeper points. This has been taken into account in our presented research by designing springs between the lower system mentioned above and the upper fixed system. From this we get a downward force which will be observed by detailed drawings. Besides, hindering digging blades by solid materials in the earth has been given attention for they penetrate the earth to a depth of (30 cm) by our designing the springs to raise the lower system when hindered and later to reach a system design as a whole

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