Table of content

Journal of Engineering

مجلة الهندسة

ISSN: 17264073
Publisher: Baghdad University
Faculty: Engineering
Language: Arabic and English

This journal is Open Access

About

The Journal Engineering was issued in 1986. It was Stopped from 1990 – 1997 because of the economic blockade. It restarted publication after the fourth scientific engineering conference for it published the papers that were accepted in the conference.
It is a scientific engineering journal refereed by specialized and qualified professors in most of the engineering fields and those Specialists in the issued by the college of Engineering university of Baghdad .It was serenely publibued , but from 2011 it has issued of monthly for the numerous papers submitted to the journal to publish their papers in this scientific journal in addition to some of the Arabs professors because the journal is considered one of the valued journals in the Arabic homelan .
Many professions were the head editor of the journal from its first issue. The first one was prof.dr. Laith Ismail Namiq then prof.dr. Mohammed A.Alawis ,prof.dr.Ali A Al – kilidar prof.dr. Abdul-Ilah Younis and currently Prof.dr.Qais S. Ismail.

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Jadriyah, Baghdad
Iraq
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Email: joengbag@uobaghdad.edu.iq

Table of content: 2006 volume:12 issue:2

Article
Some Factors Affecting the Ultrasonic Pulse Velocity Test Results of High Strength Concret
بعض العوامل المؤثرة على نتائج فحص سرعة الذبذبات فوق الصوتية للخرسانة عالية المقاومة

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Abstract

The high strength concrete is characterized by its high strength, low porosity and good performance under aggressive environmental conditions. The paper presents some factors affecting the Ultrasonic Pulse Velocity test results for high strength concrete such as water/ cement ratio, type of aggregate, frequency level of transducers, dimension of the specimens and path length. An experimental equation has been derived for the prediction of compressive strength of high strength concrete from pulse velocity, which can be used for the estimation of strength. It provides more reliable prediction and can be used in precast concrete factories manufacturing precast concrete girders for bridges.

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Article
Developing of Concrete Tiles
تطوير إنتاج البلاطات الخرسانية (الشتايكر)

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Abstract

A case study had been made to investigate the reasons of the repetitive failure during concrete tiles testing. Cubes, cylinders, and prisms in addition to full-scale concrete tiles had been prepared. Half of these samples were made using the same popular concrete mix. Test results indicated that, these samples were below standard requirements. The second half of the test samples was prepared using a newly designed concrete mix. Based upon the recommended breaking load, the required flexural strength of the tiles was calculated. This mix was designed to comply a flexural strength that was recommended by specifications. Care had been also concentrated on aggregate grading and concrete curing. Tests showed positive results. In spite of this success it is still believed that there is a possibility of some failures may be due to mass production or due to bad quality control. A new proposed model had been prepared and tested. Finally these newly proposed tiles had shown that it was more resistant to breaking loads by +21% in comparison with the previous samples. This result might insure the production of safe concrete tiles.


Article
A Study Effect of Some Variables in Tig Spot Welding for (Aluminum - Magnesium ) Alloy
دراسة تأثير بعض المتغيرات في لحام TIG SPOT لسبيكة (المنيوم-مغنيسيوم)

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Abstract

The present work investigates the effect of some of the variables in spot tungsten inert gas shielded welding (TIG Spot) for (Aluminum-Magnesium) alloy type (5052-O) which is non–heat treatable alloy for its wide industrial uses and applications in field of welding technology. TIG Spot welding was performed by using tungsten electrode (EWTh2)of diameter (3.2mm) and DC current with direct polarity (DCSP) at constant shielded gas flow rate (15litre/min). The welded specimens were tested by using the Instron machine to determine the maximum shear force (shear strength ) of spot welded and to define the optimum conditions of spot welding variables in relation to the weld current, weld time and arc length of welding to produce an acceptable weld. The metallurgical changes of the weld zone and heat affected zone were studied under optimum conditions of welding. It has been shown that the increase in the welding current and welding time tends to increase the maximum shear force and it reaches maximum value and then decreases with high currents and long times. The maximum shear force was 2.4KN at welding current of (90) Amp , welding time ( 7)sec and arc length (1.6mm ) for 1mm thickness. It was also found that the highest value of hardness ( 53.5 Hv) was at the center of the spot welded and decreases gradually from the center of the weld spot towards the base metal.

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Article
Possibility Study of Kerosene Fraction Produced from Yemen Crude Oil as Jet Fuel with High Quality Specification
دراسة إمكانية إنتاج قطفة كيروسين من نفط اليمن كوقود نفاث عالي الجودة

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Abstract

Laboratory investigation and many comparisons between laboratory and commercial samples of Yemeni kerosene distillates were carried out .The physico-chemical properties of the kerosene distillates were determined . The possibility of their utilization as an aviation turbine fuel with high quality specification " assisting the increase of flight height and velocity " was confirmed . At the first look to obtained results , it is shown that the physicochemical properties for all samples are in the international permissible limits. The carbon content is distributed as the following: 15% normal paraffin ; 50% branched paraffin ; 2% mono-cycloalkanes ; 16% bicycloalkanes ; 16% branched mono-cycloaromat with branches prevailing ; 1% bicycloaromat . The samples are not hygroscopic for long period of time . The smoke point is in higher limits standard . Where the freezing point is in lower limits standard .These points prove that the Yemeni kerosene might be prepared for a spectra of jet aircrafts. This Kerosen permit high flying height because it has lower density and freezing point and it permit high velocity of aviation because it has high percentage of branshed and cyclparaffins with high specific energy without needed for addition of chemical additives, but may be need for portion of isomers of paraffin.

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Article
A Fully Automatic Approach for Grayscale Image Colorization

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Abstract

Colorization is a computer assisted process of adding color to a monochrome (grayscale) image or movie. The early published methods to perform the image colorizing rely on heuristic techniques for choosing RGB colors from a global palette and applying them to regions of the target gray-scaled image. The main improvement of the proposed technique is the adoption in a fully automatic way the genetic algorithm as an efficient search method to find best match for each pixel in the target image. The proposed genetic algorithm evolves a population of randomly selected individuals (that represents a possible color setting for target image using a reference colored source image toward solution that could resemble natural or real colors to the objects of the target scene). Moreover this study proposes new crossover operator, called Spread out Uniform Crossover (SUX) that turns the recombination scheme of uniform crossover over spreading vital genes at the expense of lethal genes rather than exchanging genes between mating parents to the generated offspring. The results of the proposed colorization techniques are good and plausible.


Article
Aerotriangulation by Coplanarity

Authors: Fanar Mansour
Pages: 247-258
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Abstract

Before corresponding points in photos taken with two cameras can be used to recover distances to objects in a scene, one has to determine the position and orientation of one camera relative to the other. This is the classic photogrammetric problem of aerotriangulation. Iterative methods for determining X,Y,Z ground positions for unknown points using aerotriangulation process, were developed long ago; without them we would not have most of the topographic maps we do today. Described here in this research a simple iterative scheme for recovering relative orientation process then applying intersection problem (vector method) using the condition of coplanarity, out of the usual for photogrammetrists in using the familiar condition of collinearity. The data required is a pair of bundles of corresponding rays from the two projection centers to points in the scene. It is well known that at least five pairs of rays are needed, because, each object point gives only one equation. The results were amazing according to the variances that have been obtained for the angular orientation elements. The programs have been written using Matlab software ver. 5.3.


Article
Evaluation of Thermal Stresses in Continuous Concrete Bridges

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Abstract

This search is mainly concerned with making a comparison between three methods for analyzing continuous concrete bridges, Priestly, Abdul-Ahad and finite elements. Three standard Design temperature distribution, New Zealand, AASHTO and British (5400) were used to analyze the concrete bridges in Baghdad. The analysis of two continues precast prestressed concrete bridges in Baghdad are presented. Another comparison as made between the thermal stresses and the stress associated with dead and live loads. Analytical results indicated that stresses and curvature values are very sensitive to the type of temperature distribution assumed. The suggested analytical models for the bridge can be used to be predict thermal movement and stresses due to any shape of temperature distribution.


Article
Water Pressure Equalization in Pipe Network Case Study : Al- Karada Area in Baghdad

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Abstract

In order to make a balance between the increasing of potable water demand and the available quantity, a pipe network should be managed in an optimal hydraulic operation state. The optimal operation of a water supply network leads to minimize the effect of the variance in pressure between the available and minimum required pressure head. It simulates the hydraulic model and puts the optimized project with the constraints (minimum design head=20 m, and the available commercial pipe diameter, (1600> D> 250 mm). The objective function is to minimize the cost for the suggested hydraulic solution to a minimum value. Pressure uniformity coefficient (UC), Standard deviation (σ) and coefficient of variance (Cv) are used to show that the pressure head at the nodes of the network is uniformly distributed. The optimal design of the case study (R9 water supply network) has an actual cost of 561,169,310 ID and the uniformity indices of UC=99.565, σ=3.6508 and Cv=0.1543 while the existing design has cost of 856,617,170 ID with the uniformity indices of UC=97.909, σ=3.5977 and Cv=0.7906. Hence there is a benefit of 34.5% in the cost of the optimal design used in this study, with high uniformity coefficient. The effect of Hazen-William coefficient (C) on total cost showed an inversely linear effect. For the value of C=130, the actual cost was 600,898,300 ID, i.e., the penalty cost approached to zero and has no effect on the total cost.


Article
The Selection of Optimum Road Oath using Geographic Information System (GIS)

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Abstract

In this research a modern scientific procedure was used utilizing geographic information system GIS in selecting the optimum road path between two cities . All the programming facilities offered by ArcView GIS software with its extensions of spatial analysis and 3D analysis to solve the problem .The solution take a form of geographic map graduated in colors from best to bad portion of land that the suggested road could pass through. The proposed procedure was checked by conventional mathematical solution used in such problems and the results were both agreed.


Article
Development of Statistical Model for the Prediction of Permanent Deformation in Paving Materials

Authors: Abbas F. Jassim --- Namir G. Ahmad --- Hamed M. Alani
Pages: 305-316
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Abstract

Permanent deformations (rutting) of asphalt pavement which appear in many roads in Iraq have caused a major impact of pavement performance by reducing the useful service life of pavement and creating services hazards for highway users. Therefore, it is important to analyze and investigate this type of distress. The objectives of the present paper include; the analysis of the main contributory factors influencing rutting and development of statistical model for the prediction of permanent deformation this type of distress. To achieved these objective for requirements of data collection, five type of gradation.(40-50) asphalt cement and different types filler are used to prepare three hundred sixty asphalt concrete specimens throughout the work using Marshall method and Superpave system. Most of these specimens are tested by applying diametric creep under different temperatures and stress levels. A statistical model has been developed for prediction of rut depth in local asphalt paving materials as influencing by the factors of asphalt cement, mineral filler type , air voids and environmental temperature.


Article
Static Analysis of Thin - Walled Curved Beam Element Including Watping Effects

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Abstract

A new mathematical model for three-dimensional thin-wall curved beam element of closed section with seven degree of freedom per node is derived using the finite element procedure. The seventh degree of freedom is to account for warping restraint effects in thin-walled closed section. These effects may become significant and should be fully considered in such sections for which warping deformations are relatively large. This model considers the coupled action due to the curved geometry of the element using its exact static behavior in the derivation of the displacement field. Also, the model considers the non- uniform torsional behavior of closed thin–walled sections in cases where additional axial direct stresses and complementary shear stresses are formed. The developed warping function of this model considers the interaction between the normal warping stresses and the accompanying warping shear stresses as well as coupled action between the torsion and bending. In addition to the ordinary axial and flexural deformations, the strain energy , which is used to obtain the stiffness matrix of the developed curved beam element fully, considers the additional axial , primary and secondary shear deformations due to warping restraint . The validity of this element is investigated by comparing the developed program analysis results with some available analytical solutions.


Article
Optimization of the Operation of A Complex Water Resources System ; Part -I : Analysis of the Convergence Criterrion in A Solution by the Discrete Differential Dynamic Programming

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Abstract

An iterative - solution procedure necessarily involved pre- specified convergence criteria to stop iteration . The Discrete Differential dynamic Programming procedure to solve optimization problems formulated by the Dynamic Programming is an iterative - solution procedure which , in its traditional form , involves two convergence criteria , namely , (α) and (β). The research used the optimum operation of an existing complex water - resources system as a case study . The objective function was formulated as the maximum real monetary return . The formulated optimization model was run for a total of (194) different operation cases . Beside the traditional (α) and (β), seven new styles for a unique convergence criterion were examined in the solution. Considering the monetary return and the number of performed iterations as the bases of comparison , the research showed that the new (ɣ) convergence criterion was the favorite among the tested convergence criteria.

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Article
Physical Adsorption of Reforming Catalyst by Nitrogen

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Abstract

Physical adsorption by nitrogen gas was studied on seven commercial platinum reforming catalysts (RG-402, RG-412, RG-432, RG-451, RG 422,RG-482, PS-10), four prepared platinum catalysts (0.1%Pt/alumina, 0.2 %Pt/alumina, 0.45 %Pt/alumina and 0.55% Pt/alumina), and γ-alumina support. Physical adsorption was carried out by using Accelerated Surface Area and Porosimetry (ASAP 2400 device) at 77 K . The results indicate that the surface area in general decreases with increasing platinum percentage,high platinum loaded (0.45% and 0.55%) it was found that the percent increasing in surface area was lower than those obtained for low platinum loaded catalysts , and at very higher platinum loading 0.6 %Pt , some reduction in surface area was observed . The precipitation of Re and Ir metals with 0.35 % and 0.6 % platinum increases the surface area , while precipitation of 0.57% Sn with 0.375% Pt/ γ-alumina deceases the surface area catalyst .


Article
Effect of Starvation on Thermo-Elastohydrodynamic Lubrication of Rolling / Sliding Contact

Authors: Somer M. Nacy --- Basim A. Abbas
Pages: 361-372
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Abstract

A complete numerical solution of thermal compressible elastohydrodynamic lubrication of rolling / sliding contact was achieved to determine the effect of inlet boundary condition on the film shape, film pressure, and film temperature in an elastohydrodynamic line contact problem. The direct iterative technique is used to solve the simultaneous system of Reynolds, ,elasticity , and energy equations for different locations of inlet oil fed . The effect of various load, speed , and slip conditions have been investigated . the results indicate that the effects of starvation are an increase of oil film temperature and decrease in oil film thickness so that the temperature effect are significant and can not be neglected.


Article
Construction Risk Management

Authors: Abbas M. Burhan --- Zuhair M. Saco
Pages: 373-387
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Abstract

In most of the construction projects, there are many events or risks may occur during the execution of project. These risks (e.g. the excess of project cost or the expected time, increasing the prices of material and labor, accidents, changes, engineering errors or omissions, bad quality, delay in reaching the facilities to the site, etc.) may effect negatively on the project and the parties. Therefore, these risks must be identified and assessed accurately to avoid or reduce the negative effects for these risks. The concept of risk is used to assess and evaluate uncertainties associated with an event or a process. A construction process includes many uncertainties, therefore, the construction project’s parties are becoming aware of the construction process and thus the risks within this process are seeking more and more clarification that all is being done to remove foreseeable risk and minimize unforeseeable risk. It is also becoming clear that generic approaches to the management of risk are maturing and becoming easier to apply.


Article
Prediction of Aerodynamic Coefficients of Missile using Panel Method

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Abstract

The low order panel method with Neumann boundary condition have been used to predict the normal force curve slope, the pitching moment curve slope, the center of pressure location and the aerodynamic load distribution for missile in compressible, steady flow. The wing-body-canard interference problem have been solved using two schemes (iterative method and internal singularity method) both are based on the panel method. The normal force curve slope, the pitching moment curve slope and the center of pressure location for a given missile has been predicted using the present numerical method and the DATCOM technique.


Article
Hardness Removal from Drinking Water

Authors: Ahmed A. M. Ali --- Nawar O. A. Nasser
Pages: 405-413
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Abstract

This study included three trials that were made during December 2003 by using lime, of 98% w/w calcium hydroxide to find the relation between lime doses to be added and the hardness removed .The trials were performed by adding various doses of lime and measuring the hardness, electrical conductivity and pH in water produce by three plants, Nissan in the north of Baghdad, Al-Karama and Al-Wathba water treatment plant in Baghdad center. The objective of this study is to find the optimum lime dose that gives the minimum hardness content. The results indicate a non linear relation between lime dose added and the hardness removed . The results represented a 36% removal in hardness when using an optimum dose of lime 200 ppm in Nissan water treatment plant, while a percentage removal of 34% was obtained in both Al-Karama and Wathba water treatment plants with 300 ppm dose of lime. The low percentage removal indicates the presence of non-carbonate hardness which could not be removed by lime alone.


Article
Design & Implementation of Fractional - N Frequency Synthesizer

Authors: Ali M. N. Hassan
Pages: 415-427
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Abstract

This research involves design & implementation of fractional – N frequency synthesizer with the following specifications: Frequency range (2350– 2750) MHz, Step size (1 kHz), Switching time 8.9 µs, & phase noise @10 kHz = -115dBc & spurious -69 dBc The third order Fractional –N technique was chosen to satisfy the design requirements. In this system the Σ∆modulator placed on digital phase-locked loop to control the fractional value of the frequency division ratio thereby eliminating spurious and allowing good phase noise performance. The development in I.C. technology provides the simplicity in the design of fractional –N frequency synthesizer because it implements the phase frequency detector(PFD) , prescalar, Σ∆modulator & reference divider in single chip. Therefore our system consists of a single chip contains (low phase noise PFD, charge pump, prescalar, Σ∆modulator & reference divider), voltage controlled oscillator , loop filter & reference oscillator. The application of this synthesizer in frequency hopping systems, wireless transceivers ,GSM & radar because it has high switching speed ,low phase noise & low spurious level.


Article
Stiffness and Damping Properties of Embedded Machine Foundations

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In this study, a dynamic analysis of machine foundations under vertical excitations is carried out. The effect of embedment and foundation geometry has been taken into account. The stiffness and damping of soil are considered as frequency dependents. A computer program (CPESP) in FORTRAN POWER STATION has been coded to evaluate the stiffness and damping coefficients depending on excitation frequency and embedment depth. Results have shown that increasing the embedment depth leads to increasing the resonant frequency and decreasing the amplitude of vibration.


Article
Influence of Variability in Flexible Pavement Parameters on Backcalculation Moduli

Authors: Namir G.Ahmed
Pages: 445-457
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Abstract

Many researchers recommended Falling Weight Deflectometer (FWD) to be use for the purpose of stiffness profile determination of existing pavement. Several sources of uncertainties contribute to the inaccuracies in moduli obtained in this manner. these include: 1) the measured parameters (deflection basin and FWD load), 2) the back calculation model, and 3) the pavement parameters, such as Poisson's ratio and thickness of each pavement layer . In the present study the influence of the variation in the thickness and other pavement parameters on the backcalculate moduli are investigated .Theoretical deflection basins were generated for different pavement structure using program Mich-pave. Mich-back program was then utilized to backcalculate the moduli from these theoretical basins. To assess the influence of the variability in thickness, Poisson's ratio, FWD load and deflection, a Monte Carlo simulation process was employed. Results show that the backcalculation of the layer moduli is greatly influence by the variability of the combined pavement. A sensitivity analysis showed that the uncertainties in thicknesses are the major contributor to variations of the backcalculated Moduli.

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