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: 2008 volume:11 issue:2

Article
Model Development of U-turn Capacity Using Simulation and Empirical Approaches
تطوير نظام لسعة الإستدارة المرورية للوراء بتطبيق النظرتين التجريبيةِ والمحاكاة

Authors: Hussein Kariem Mohammed
Pages: 189-193
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Abstract

In this study, both empirical and simulation approaches were used to estimate capacity of U-turn movement at median openings of divided arterials. The empirical approach using regression analysis was adopted to estimate the best form of the predictive equation for the U-turn capacity and investigate the effect of different relevant factors that might affect the estimated capacity. Simulation approach was used also to calculate capacity on the basis of the U-SIM model; this model represents the traffic performance at U-turn median openings and calculates the number of turning vehicles with respect to a different conflicting traffic stream. The results of both approaches were compared and presented in this study. A linear model was also recommended as a relationship between the average total delay of the U-turning vehicles and the conflicting traffic flow.


Article
NONLINEAR FINITE ELEMENT ANALYSIS OF PRESTRESSED CONCRETE MEMBERS
التحليل اللاخطي للاعضاء الخرسانية مسبقة الجهد بطريقة العناصر المحددة

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Abstract

A finite element method of analysis is used to study the strength and behavior of prestressed concrete members under short-term and sustained load conditions. The degenerated assumed strain eight-node shell finite element is used with each node having five degrees of freedom. Material nonlinearity has been included in the analysis. Concrete is considered as an elastic-plastic material in compression with strain hardening. prestressing tendons are modeled by a multi-linear five branches stress-strain relationship. The layered approach is used to represent the concrete whereas the prestressing tendons are modeled as axial members embedded within the concrete elements. A computer program is developed and used for the analysis of prestressed concrete members having arbitrary tendon layout in either pretensioned or post-tensioned tendons. The tendon layout is specified and the loading due to prestressing is numerically calculated using the computer program. The validity of the proposed model for embedded bar representation of the prestressing tendons and the developed method of prestressing force inclusion into the entire member is demonstrated. The capabilities of the computer program resulting from the present developments are verified by analyzing experimentally tested prestressed concrete slabs. The computed results are compared with the available experimental data. The comparison verified the accuracy and adequacy of the method and models used utilizing the developed computer program.

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Article
Behavior of Reinforced Concrete Composite Beams with Embedded Prestressed Concrete Prisms Using Nonlinear Finite Element Analysis
سلوك الروافد المركبة الخرسانية المسلحة المتضمنة موشورات خرسانية مسبقة الجهد باستخدام التحليل اللاخطي بالعناصر المحددة

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Abstract

The investigation described herein deals with a theoretical study of the flexural behavior of simply supported composite beams consisting of precast prestressed concrete prisms as tension reinforcement in reinforced concrete, by developing a non-linear three-dimensional finite element model. Eight-node isoparametric brick elements with and without smeared steel reinforcement are used to model the reinforced concrete medium and the precast concrete prism respectively, using the corresponding material properties and considering the appropriate tensile cracking and compressive crushing phenomena for each , while a two-node three-dimensional axial element capable of plastic post-yield deformation is used for modeling the prestressing steel strands. Perfect bond is assumed for all concrete-concrete and steel-concrete contact surfaces. with its qualified brick and axial elements is used to predict the load-deflection behavior of four typical simply supported beams using such composite system and varying in cross-sectional whole dimensions and areas of precast prisms, prestressing strands and nonprestressed rebars. That behavior is compared with behavior of four previously tested corresponding specimens to verify the accuracy of the finite element model in the linear and post-cracking stages. A parametric study comprizing effects of the relative eccentricity of the prestressing strands and the geometric state of precast prestressed prisms on flexural behavior of this composite system is preformed to compute these effects on stiffness and ultimate resistance proving their major role after cracking which depends on the relative quantities of precast prisms and prestressing strands. Accurate results of the present finite element model has proved its effectiveness and reliability in the analysis of such composite systems, hence giving motive to widen its application in that field.

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Article
ASPECTS FOR INCREASING THE EFFECTIVENESS OF THERMO-COMPRESSOR MULTI EFFECT DISTILLATION PLANTS
طرق زيادة فاعلية محطات التحلية المتعددة التأثير ذات الضغط الحراري للبخار

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Abstract

Currently, there is a strong demand for efficient seawater desalination plants, which can meet the tougher environment regulation and energy saving requirements. From this standpoint the present work was undertaken to include the proposed schemes for repowering and modification of grid connected Thermo-Compressor Multi Effect Distillation (TC-MED) plants. The Modified Solar Distillation Plant (MSDP) during sunny periods may be applied to full cogeneration mode of operation with feeding the surplus electricity into Electrical Power Grid (EPG). To investigate the potential effect of the proposed schemes a computational models have been developed and implemented on simulation programs. The study result shows the effectiveness of proposed schemes. For the case study (MSDP with Low backpressure Turbine (LT) and annual share of solar thermal power generation 22.5 %) the economical effect amounts 216.8 ton/year for each MW design thermal power consumption of TC-MED and the corresponding decrease in MSDP exhaust gases emission (carbon dioxides (CO2) 660 ton/year.MW , nitrogen oxides (NOx) 286.3 kg/year.MW). Moreover implementation of MSDP-LT scheme for repowering and modification of conventional six effects TC-MED plant will increase the above sited environmental and thermal effectiveness by 72.5 % due to the 24989.8 ton/year.MW of annual solar distilled water production besides boosting 723.9MW.hr/year.MW of solar electricity in EPG.

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Article
Computing Cutting Time in Turning Operation Based on AutoCAD Drawings
حساب زمن القطع في عملية الخراطة بالاعتماد على رسومات الاوتوكاد

Authors: Dr. May George A. Kassir
Pages: 243-250
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Abstract

In view of importance the cutting time, it is considered one of the most important factors in different machining processes where it affects production time, cycle time, and product cost consequently. This research aims to build up a system for computing cutting time in turning operations from AutoCAD drawings. The proposed system has been built using Visual Basic programming language and interfacing it with AutoCAD by Visual Basic for Application (VBA) Technique. The system is able to compute cutting time from the drawings according to the color of each solid entity; these colors were defined previously in the system. They are related to the type of turning operation (external, internal, and facing turning operations) as well as the rough and finish machining operations. The system was examined with two models, and it was accurate and efficient. It is possible consideration the proposed system step toward the integration between CAPP/CAM systems.


Article
Nonlinear Dynamics of Thick Composite Laminated Plates Including the Effect of Transverse Shear and Rotary Inertia

Authors: Muhsin J. Jweeg
Pages: 251-262
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Abstract

In this work, a suggested analytical solution for nonlinear dynamic analysis of (fiber-reinforced) composite laminated thick plate is developed by using first-order shear deformation theory (FSDT). A computer program was built for this purpose for anti-symmetric cross-ply and angle-ply, simply supported thick laminated plate and the developed equations are solved by using (MATLAB V.7) program. The finite-element solution is also adopted using (ANSYS V.8) package, to confirm the analytical results. The results presented show the effect of plate thickness-to-side ratio (h/a), aspect ratio (a/b), number of layers (N), the degree of orthotropic ratio (E1/E2), fiber orientation, boundary conditions, lamination scheme, and the effect of shear deformation and rotary inertia on the thick laminated plate

Keywords

: Composite --- Plate --- Shear --- Inertia


Article
IMAGE PROCESSING TO DETERMINE MASS TRANSFER COEFFICIENT FOR GAS BUBBLE

Authors: Dr.Naseer A.Al-Habobi
Pages: 263-269
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Abstract

This paper suggests a simple system to study the hydrodynamics in a bubble column reactor and measuring gas-liquid specific interfacial area a, individual mass transfer coefficient kL, gas holdup εG, flow regime, bubble size distribution, coalescence of bubbles, and bubble rising velocity for a single bubble by using image processing techniques. The images were taken by a digital camera and then analyzed with MATLAB 2008 to extract the required data of design parameters for the bubble columns. Experiments of bubble column of (0.081m diameter and 1.03 m height) were carried out with air-water. Gas velocity UG is varied from (0.22×10-4 -0.22×10-3) m/s. This range of values of UG allows the study the homogeneous flow regimes. To study the flow regime in bubble column the gas velocity changes from (0.00967-0.131521 m/s), afford to study and select the Homogeneous, Transition and Heterogeneous regimes. Transition velocity from bubbly to churn turbulent flow for (air-water) system, was about 0.148982 m/s.


Article
MODIFIED HZSM-5 AND H-MORDENITE ZEOLITES AS SUPPORTS FOR PLATINUM CATALYST
تحسين الحفازات Pt/HZSM-5 و Pt/HMOR كحامل للحفاز البلاتيني

Authors: Dr. Jabir Shanshool جابر شنشول
Pages: 270-277
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Abstract

Bifunctional Pt/HZSM-5 and Pt/HMOR catalysts were prepared and applied to the isomerization of n-Hexane. Catalysts containing 0.3wt% Pt on both catalysts with potentially high acidity were prepared by impregnation method. The tested catalysts show that optimum selectivity with maximal isomer yield was obtained for Pt/HZSM-5 catalysts. The nanoparticles were characterized by inductively coupled Plasma (ICP), X-Ray Diffraction (XRD), BET Surface Area, and Transmission Electron Microscopy (TEM). TEM was revealed uniformly dispersed platinum particles on the substrate with average particle size ranging from ~6.893 to 8.847nm. It was demonstrated that the loading content and particle size of the nanoparticles deposited on zeolites could be tuned by changing the weight of precursor and the conditions of loading


Article
Real Time Image Segmentation for Face Detection Based on Fuzzy Logic
منظومة تقطيع الصورة في الزمن الحقيقي لكشف الوجوه باستخدام المنطق المضبب

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The segmentation of objects whose color-composition is not trivial represents a difficult task. In this work we propose a fuzzy algorithm application for the segmentation of such objects. It is chosen; by the characteristics that it represents the face segmentation. A priori knowledge about spectral information for certain face skin region classes is used in order to classify image in fuzzy logic classification procedure. The basic idea was to perform the classification procedure first in the supervised and then in fuzzy logic manner. Some information, needed for membership function definition, was taken from supervised maximum likelihood classification. The system uses three membership functions which are taken as Gaussian distribution curve. For real time needs, the system is implemented on an FPGA.


Article
Performance Evaluation of WirelessLocal Area Network

Authors: Rasha Albert Elia Hallaji
Pages: 288-294
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Abstract

The enormous growth of public mobile communications and the tendency to provide similar wireless services in indoor environment reacts on the activities in the area of wideband wireless local access, and Wireless Local Area Networks (WLAN) architectures and protocols. The IEEE 802.11 WLAN standard has been developed to provide high bandwidth to mobile users in a short-range indoor environment. Apart from mobility, it should provide some QoS guarantees, for certain set of services. In this paper, wireless computer network was constructed and analyzed according to standard IEEE 802.11b with its two channel rates 1Mbps and 11Mbps using OPNET IT Guru Simulator. The physical layer at the radio-interface supports three different coding techniques: Frequency Hopping Spread Spectrum (FHSS), Direct Sequence Spread Spectrum (DSSS) and Infrared (IR). The present model considers DSSS coding. The system utilizes the behavior of the IEEE 802.11b WLAN within single Basic Service Set (BSS). The BSS consists of 5-20 stations, which is a reasonable size of the WLAN. Each station performs access to the network using the Distributed Coordination Functionality only. The observed performance measures are defined as follows: - Throughput is the average number of successfully transmitted bits per second. - Delay is defined to be the elapsed time between the moments of packet arrival at the station queue and positive acknowledgment reception for the corresponding frame, averaged over all successfully transmitted frames. It is concluded that, the simulation’s results show that the model performs as expected and demonstrates the performance of different traffic types under different network configurations for the selected workload

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Article
Testing The Effective Performance Of Ofdm On Digital Video Broadcasting

Authors: Ali Mohammed Hassan Al-Bermani
Pages: 295-302
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Abstract

One of the most exciting areas in telecommunications and networking is wireless technology. The rapid growth of mobile telephone uses various satellite services. So, the present work deals with high data stream applications of Digital Video Broadcasting (DVB), which takes an important place in the studies and development researches due to its direct contacts on the human daily life. In this design the focusing is on the modern types of DVB where modified module of the Terrestrial DVB for Handheld terminals (DVB-H) is used and it was simulated to perform the physical layer of the designed system. Different modes of DVB-H with high bit rate of Orthogonal Frequency Division multiplexing (OFDM) and high number of sub-carriers are considered to show the effect of Coded Orthogonal Frequency Division multiplexing (COFDM) on the system SNR using the convolutional encoding. The modes are tested to show the characteristics of each type involving BER calculation. The obtained results show the effect of OFDM in the designed system by evaluating it using AWGN and mobile multipath channels. These demonstrate the effective of OFDM over single carrier systems where the complexity and cost of implementation are both increaseed by increasing number of carrier. The elimination of ISI is achieved using efficient coding techniques with small guard time. The 4k mode shows good performance in mobile reception, providing satisfactory and reasonable receiver cost/complexity. The Peak Signal to Noise Ratio (PSNR) measurement of the reconstructed received image pixels provides more mentality and good comparing method than the BER measuring. The obtained results are compared between the PSNR of each reconstructed images for different modes with the corresponding transmitting SNR.


Article
Theoretical IR spectroscopic study of Copper Phthalocyanine (CuPc)

Authors: M. T. Hussein
Pages: 303-306
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Abstract

The mobile π electron of Phthalocyanine can serve as current carries and provide the basis for semiconductor properties and to increase the current carries by substituting with Copper metal. The modes of vibration recorded for CuPc were (165) with vibrational frequencies recorded in the region (15- 3080)cm-1,intensity and symmetry for each mode were interpreted on the basis of using HyperChem 6.0 semi-empirical molecular orbital of self consistent field of MNDO method (Modified Neglected of Differential Overlap) of parameterization PM3 involving a quantum mechanical semi-empirical Hamiltonian with restricted and unrestricted Hartree-Fock approximation. The high occupied molecular orbital (HOMO) and low unoccupied molecular orbital (LUMO) were (-4.986 and -2.222)eV respectively. The energy gap calculation (∆E) was (2.764) eV, the ionization potential (I.P.) was (4.986) eV and electron affinity (E.A.) was (2.222)eV . Other characteristic such as dipole moment, the charge density and electrostatic potential were plotted with a contour diagram, using both two and three dimensions. The results suggest that CuPc has anomalous behavior than metal-free phthalocyanine H2Pc. Such behavior was ascribed to the bonding nature of the central Cu ion differing from that of other metal derivatives. We can suggest that CuPc has attracted much attention as a potential candidate for device applications.


Article
Engineering Modeling of Human Cardiovascular System
نـمذجـــــــة هـندسيـــــة للجهــاز القلبــي الوعائـي فـي جسم الإنســــان

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Abstract

Cardiovascular system is primarily considered as the human body's transport system. Oxygen, carbon dioxide, nutrients and other vital substances to the various tissues of human body are carried by the blood which circulates in a closed circulation. The cardiovascular system has been comprised of a combination of several basic compartments, which are structurally connected to and functionally interact with each other. Engineering modeling of such important system has become a useful tool to diagnose the cardiovascular diseases and recommend the appropriate way of their medical treatment. This paper presents a quantified model describing the relationship between the input and output variables of the hemodynamic regulation of the system through implementing a set of first order differential equations that governing this performance and describing its parameters such as pressures, volumes and flows in a closed-loop lumped system. Construction of this model was based on the interaction between the pulsating heart and the vascular circulations of the system through mapping the physiological parameters to the electrical analog elements (resistor, capacitor and inductor and diode) depending upon the close correspondence between the electrical circuits and the cardiovascular system in order to obtain a reasonable investigation for the behavior of the system in normal and pathophysiological conditions.


Article
A Robust Algorithm for Ear Recognition System Based on Self Organization Maps
خوارزميةقوية لنظام تمييزالاذن معتمداً على الخرائط الذاتية التنظيم

Authors: Ali Hussein Ali Al-Timemy
Pages: 315-321
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Abstract

This paper presents a robust algorithm for ear identification based on geometrical features of the ear and Kohnen Self Organization Maps (SOM). Using ears in identifying people has been interesting at least 100 years. The researches still discuss if the ears are unique or unique enough to be used as biometrics. Ear shape applications are not commonly used, yet, but the area is interesting especially in crime investigation. In this paper we present the basics of using ear as biometric for person identification and authentication. High resolution ear images are taken by high resolution digital camera. Six images have been taken for twenty three persons. Four geometrical distances were calculated for each image. These geometrical distances are used as an input to the unsupervised Kohonen self organization maps. The accuracy of identification were found to be equal to 98%, for the proposed system .We conclude that that the proposed model gives faster and more accurate identification of persons based on the ear biometrics and it works as promising tool for person identification of persons from the image of their ear for criminal investigation purposes.

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Article
Estimation of Concentration Polarization Using the Combined Film theory/ Spiegler-Kedem Model and Empirical Correlation

Authors: Taha Yaseen Khalaf
Pages: 322-328
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Abstract

At a given operating pressure and in a given apparatus, concentration polarization results in an increase in the effective osmotic pressure of the feed solution on the membrane surface, a consequent decrease in the effective pressure ( ) for fluid flow across the membrane, and progressive changes in the mass transfer coefficient, product rate, and solute separation along the length of the membrane in the direction of feed flow. The problem then is to predict the effect of concentration polarization on solute separation and on predict rate, under specified experimental condition. In the present work, the reverse osmosis experiments were conducted in a spiral wound model to get separation data using a NaCl-water system up to 2500 ppm and cellulose acetate membrane. The purpose of this paper is to predict and analyze the concentration polarization using a combined film theory model and empirical correlation. Therefore, the results of the experiments show that the concentration polarization affected when using different models.

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