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
Mobile:
Email: joengbag@uobaghdad.edu.iq

Table of content: 2010 volume:16 issue:2

Article
Using Programming Application To Solution The Difficult Award Of Contracts (Supplied- Construction)
استخدام التطبيقات البرمجية فى حل صعوبة إرساء العطاءات في المقاولات (الإنشائية, التجهيز).

Authors: صدى عبد الخالق حسن
Pages: 849-870
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Abstract

The research aims to use the computer and it's potential to identify and choose the best offers submitted by companies contracting with the third-expected increases in the wages of labor and prices of building materials and the large variability in the impact of the inability of many of the construction to complete the implementation of the specific time or the estimated cost and thus create a lot of problems executive, which affected the speed and quality of works. A good management and good planning through implementation to reflect the realities and possibilities of each of the contracting companies to tender for any contract so a knowledge of possibilities of each company and compare it with the other , according to the mechanism in the desired implementation , depending on the nature of each project if we were able to optimize( cost , duration , quality ) the selection of the presentations developed by the companies and thus the achievement of the project , including and appraiser of the cost , quality and needed time . The research has dealt with the items and factors of success of the trade-off between the companies to choose the best offer depending on the factors instrumental to the selection and identification of a percentage and in accordance with the increases Field of personal interviews with many of the professionals and the process of opening and analysis of tenders and the number of software made in the hands of the user the best way to differentiate between companies on the basis of cost or duration , or the quality and efficiency of the company , calculated in accordance with the factors previously or by including the budget allocated according to percentage of each individual of items ( cost , duration , quality ) and by political department raised the auction and the type of project , as well as to identify the type of auction is it a construction or the establishment.


Article
Effect Of Using Iron Slag On Foundry- Molding Mixture Properties
تأثير استخدام خبث الحديد على خواص مزيج رمال السباكة

Authors: خضير جاسم محمد
Pages: 871-884
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Abstract

This work deals with slags produced from melting processes of cast iron and steel .as an industrial solid by product with investiga effect environment in general .Huge quantities of slag are produced from foundries and steel work complexes , as (10-30)% of iron alloys produced .In order to use those quantities at the same foundries , this work investigates the using of slag in sand moulding mixtures 10,20,30 and 40 % of milled slag to the same size of silica sand , instead of silica , and prepared standard speciemens to test grean compression strength and gas permeability in green and dry cases.Results showed improvement in comp.strength in green tests, by using slag. While in dry tests, however, that comp. strength increased by using slag.But we couldn´t break dry speciemens to have given results over 10% slag because their values were over the rang of tester(6.5kg/cm²). Accordingly we can state that slag can be used in moulding mixture at the same foundries to improve properties and to get rid from its pollution effect and transport costs.

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Article
Sustainable House Between Environment Determiners and Design Considerations
المسكن المستدام بين محددات البيئة واعتبارات التصميم

Authors: عمر حازم خروفة
Pages: 885-908
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Abstract

The aim of sustainability represents one of the most important aims that most architects sought for achieving it. Thus, the economical factor appears to have the priority within the set of factors leading to this aim, where the effect of this factor appears much clearly in housing projects in comparison to other types of buildings. Therefore, many attempts and experiments were adopted in the field of economical low cost housing in different places of world. These attempts were associated with many aspects concerning the subject of achieving the possible economy of house of all levels. In spite of the numerous attempts that were adopted on the local level for putting general lines for the economical housing directions; the results were not in the desired level especially if we look at the subject within the determiners of local environment and their hard climatic considerations. This research deals with the conditions of sustainable house within two pivots; the first is environmental that looks after the conditions of local environment and the second is constructive where it is related to determine the modes, devices and constructional material. The second pivot represents the considerations concerning the design regarding the methods and devices of construction. Thus, the two pivots together throughout their subdividing give important stages for achieving the aim of sustainability of house. The research depends on the analytical descriptive technique for several economical executive housing samples in different places of world and gives and evaluation of the possibility of getting benefit of them locally.

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Article
The effect of architecture staff in activate the technology of digital education in the Iraqi school of architecture
دور التدريسي في تفعيل تقنية التعليم الرقمي في المدرسة المعمارية العراقية

Authors: لينا غانم --- وحدة شكر
Pages: 909-929
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Abstract

Many researches assigned the importents of enhance the architectural education movement. It is obvious that these studies have elaborated in their interest in architectural curriculum and teaching methodm in addition to the important of qualifying the staff to cover these changes. Most of these studies couldn't define a specific solutions to improve teachers method to lead the digital education According to this the research problem was defined as: "There is no comprehensive study clear the real attitude of the architectural teachers in Iraqi schools of architecture from the digital teaching…within the vocabulary of (digital knowledge– desire for more information about digital knowledge - the attitude of digitalizing architectural curriculum between accepting and denying – employing this technology on selected sample)". Thus the research goal is defined as: "Give a clear vision about architectural teacher attitude in Iraqi schools of architecture in relating to to discover his real preparation to employ his knowledge using the digital technology in developing the architectural education in general, and applying their concepts in department of architecture in particular. In order to "built the propitiate mechanism in which may be used to activate this technique in Iraqi schools of architecture ". Reviewing architectural teaching curriculum and the degree which it may send for the digital education vocabulary, and define the most important ways to employ them , reviewing the studies about the reality of digital learning in Iraqi schools of architectural and analyzing the results and compare them between the architectural schools attitude the conclusions and recommendations in order to qualify them in activating the digital education technique in these schools .

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Article
Taguchi Experimental Design and Artificial Neural Network Solution of Stud Arc Welding Process

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Stud arc welding has become one of the most important unit operations in the mechanical industries. The need to reduce the time from product discovery to market introduction is inevitable. Reducing of standard deviation of tensile strength with desirable tensile strength joint as a performance character was use to illustrate the design procedure. The effects of (welding time, welding current, stud material, stud design, sheet material, sheet thickness, sheet cleaning and preheating) were studied. Design of Experiment (DOE) is a structured and organized method to determine relationships between factors affecting a process and output of the process itself. In order to design the best formulation it is of course possible to use a trial and error approach but this is not an effective way. Systematic optimization techniques are always preferable. Tensile strength quality is one of the key factors in achieving good stud welding process performance. 225 samples of stud welding was tested. Computer aided design of experiment for the stud welding process based on the neural network artificial intelligence by Matlab V6.5 software was also explain. The ANN was designed to create precise relation between process parameters and response. The proposed ANN was a supervised multi-layer feed forward one hidden layer with 8 input (control process parameters), 16 hidden and 2 output (response variables) neurons. The learning rule was based on the Levenberg-Marquardt learning algorithm. The work of stud welding was performed at the engineering college laboratory, Baghdad University by using the DABOTEKSTUD welding machine, for 6 mm diameter stud. The sheet materials are (K14358 and K52355) according to (USN standards, and stud materials are (54NiCrMoS6 and 4OCrMnMoS8-6) according to (DIN standards). The eight control parameters (welding time, sheet thickness, sheet coating, welding current, stud design, stud material, preheat sheet and surface condition) were studied in the mixed L16 experiments Taguchi experimental orthogonal array, to determine the optimum solution conditions. The optimum condition was reached for the stud welding process tensile strength, where the researcher develops a special fixture for this purpose. The analysis of results contains testing sample under optimum condition, chemical composition of usage materials and micro structure of optimal condition sample. According to that: Practicality: the influence parameters that affect the stud welding process are welding time, which have a major effect on stud welding process, followed by sheet material and stud material. The reduction in standard deviation was approximately (30.06 per cent) and for the range was as approximately (29.39per cent). In the other side the increase in the tensile strength mean was as approximately (30.84 per cent). The influence parameters that affect the tensile strength stud welding process are: the factor welding time has a major effect on stud welding process, followed by factor C (sheet coating) and factor F(stud material).


Article
Bending Moment Influence Surfaces For Rectangular Concrete Plates Simply Supported At Three Edges And Built-In At The Fourth Edge

Authors: Zena R. Al-Ani --- Sabah S. Razouki
Pages: 4795-4821
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Abstract

Presented in this paper is a series of bending moment influence surfaces for concrete rectangular plates simply supported at three edges and built-in at the fourth edge. The solutions are obtained analytically on the basis of thin plate's theory with small deflection using double Fourier series. The influence surfaces are presented for two observation points namely the center of the plate as well as the midpoint of the built-in edge. A computer program was written in FORTRAN language to generate the influence surfaces making use of the developed analytical solutions of this work. The validity of the computer solution was confirmed by comparing its results with published results for zero Poisson's ratio and excellent agreement was obtained. An application of the influence surfaces for the case of a line load as well as a strip load is also presented. The paper reveals that the bending moment influence surfaces depend on the actual value of Poisson's ratio, aspect ratio of the plate, and position of the observation point.


Article
Implementation Of R-Technique In Production Planning And Control

Authors: Fadhil Nassrallah Mahan --- Zuhair Issa Ahmed
Pages: 4822-4841
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Abstract

The planning engineering is considered a vital part in the industrial operations series that leads to achieve the proposed production plan. Because of scientific advancement and technical development in the industrial field, the managements of the companies and job shops start to automate the engineering and management activities for the aim of quickness and accuracy in making proper decisions for the production process in order to get final product in a better quality and minimum cost. This is achieved by the future estimation of production plan. The research concern with evaluating the size of work arrival to the manufacturing shops and determining the amount of capacity that is required to perform these evaluated job volume in a manner that warrant decreasing the cost of orders and machines waiting. To achieve this aim, a constructation of simulation system by using Visual Basic computer program that helps the user in future estimation of job volume and determination of the best process capacity of the job shop which through it the job can be accomplished. Actual and realistic data that are collected from the documents of Electrical Industrial Company (EICO) factories is in random orders arriving to factories in one man-day and also the actual time to perform number of these orders. Through the designed software which is used as a tool for simulating of the target production system in this research, the best simulation daily process capacity was obtained for the job shop to be 130 hr per day where as, it achieved the minimum value of the total cost. There is a great effect for this increment of job shop daily process capacity in decrement of waiting of orders and this lead to optimal exploitation for these presented capacities. To verify simulation results and obtain the optimum selection for these results, the researcher used a modern technique called R-Technique or Response Surface Methodology (RSM), which the desirability function which is used as a dual-purpose standard to obtain the optimum value of job shop process capacity.


Article
Numerical Study Of Two-Dimensional Transient Natural Convection In An Inclined Shallow Porous Cavity Exposed To A Constant Heat Flux

Authors: Ayad K. Hassan --- Jasim M. A. Al-lateef
Pages: 4842-4857
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Abstract

Numerical models are used to solve the two-dimensional transient natural convection heat transfer problem in an inclined shallow porous cavity. A constant heat flux is applied for heating and cooling all opposing walls. Solutions for laminar case are obtained within Rayleigh number varied from 20 to 500 and aspect ratio for porous cavity varied from 2 to 4. A finite difference method is used to obtain numerical solutions of full governing equations. Both vorticity and energy equation are solved using alternating direct implicit (ADI) method and stream function equation by successive over relaxation (SOR) method. The results are presented for the flow filed, temperature distributions, and average Nusselt number in terms of the Rayleigh number, aspect ratio, and the inclination angle of cavity. the convection becomes more and more vigorous as thr orientation angle of the cavity is increased and for high Rayligh number no steady unicellular flow could be maintained in side the cavity. The effect of inclination angle on Nasselt number is more pronounced as the Rayleigh number is increased. When the inclination angle increased the Nusselt number increased and sudden transition appears and flow becomes unicellular and Nusselt number increased clearly. The value of mean Nusselt number strong function with the value of Rayleigh number, aspect ratio and the orientation of porous cavity.


Article
Hydrodynamic And Thermal Two Dimensional Boundary Layers Development Between Rotating Turbine Blades

Authors: Taif H. Sali --- Ihsan Y. Hussain
Pages: 4858 -4876
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Abstract

The hydrodynamic and thermal boundary layers have great effect on the fluid flow and heat transfer between rotating turbine blade. In the present work, the flow and heat transfer is analyzed numerically by solving two dimensional incompressible boundary layer equations.A(k – ε) turbulence modeling is used to obtain the eddy viscosity. The finite volume method is introduced to carryout all computational solution with staggered grid arrangement. Due to complex physical domain the original coordinate system is transferred to non orthogonal coordinate system. The calculation of present work done for rotating two dimensional turbine cascade with different rotating speeds (1500 rad/s, 1800 rad/s, 1900 rad/s), and for different Reynolds number (5000, 10000, 100000), in subsonic flow (M<1). The two dimension fluid flow is described by presenting plots of vector and contour mapping for the velocity; pressure and heat transfer fields as well as Nusselt number variation. The results were verified through a comparison with published duct results, good agreement was obtained. The final results were then compared with published results for turbine blades and good agreement was also obtained, the overall comparison show good agreement.

Keywords

Turbine Blades --- Rotating --- Flow --- Heat transfer


Article
Flow Separation Of Axial Compressor Cascade Blades

Authors: Sabah Faleh Habeeb --- Arkan Kh. Al-Taie
Pages: 4877 -4896
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Abstract

An experimental and theoretical investigation of the effect of flow separation on the performance of a cascade NACA 65_(12)10 axial compressor blade has been carried out. The experimental work includes the fabrication of three blades from wood, each having a chord (100mm) but one of these blades having a span of (90mm) for smoke tunnel testing and the other two blades having a span of (380mm) for wind tunnel testing.The two blades were connected by suitable mechanism in order to be fixed in the wind tunnel protractor and rotated in the required stagger angle. The cascade was tested in an open type low-speed subsonic (Mach number=0.117) wind tunnel, for Reynolds number (Re=239605) based on maximum velocity (35 m/s) and airfoil chord length. The total and static pressures were measured in selected points between the two blades for stagger angles of (4 , 0 ,-4 ,-8 and -120) by using a multi-tube manometer and a pitot static tube. The small blade (90mm span) is tested in the smoke tunnel to visualize the real behavior of flow separation. The theoretical work includes using the software FLUENT (V6.2) to simulate the flow between the two blades. The study shows that the flow separation begins when the cascade are inclined at a stagger angle of (-4) on the suction side of the lower blade at a position (96%chord experimentally and 98%chord theoretically). Then, the separation zone increases with increased stagger angle (in clockwise direction) and reach to the position (61%chord experimentally and 63%chord theoretically) at a stagger angle (-12 ).These results are validated by a smoke tunnel tests.This separation affects the performance of the compressor, where the static pressure ratio (pse /psi ) decreases as the separation zone gets bigger. The range of working stagger angle is then calculated. It was found in the range (-18 to 36 ). The flow behavior between the two blades shows that the blade-to-blade configuration works as nozzle-diffuser. The theoretical results were compared with the experimental results and good agreement was obtained.


Article
Analysis Of Fuel Longterm Effects Using Subchannel Codes

Authors: M.Y. ABDUL – AHAD --- E.A. AMIN
Pages: 4897-4909
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Abstract

Thermohydraulic computer codes such as COBRA3C are now becoming in practical use as part of power plant licensing process. One of the areas of interest to reactor designer is the effect due to longterm operations and the changes that might occur either due to irradiation (burnup) effects or thermal stresses in the reactor. The present study is an attempt to predict coolant channel temperature profiles at the core End Of Life. In addition deeper insight is given to the individual single partial contribution to the changes in Begin Of Life and End Of Life profiles. The effects due to fuel swelling, rod bowing, and changes in physical properties are studied in details using COBRA3C code. The codes COBRA3C and the kinetic code AIREKMOD together a structure routine are joined in a modular system. As a result coupling between the different transient parameters in normal and abnormal operation conditions could be performed. Results of such coupling are shown to improve the prediction of DNBR.

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Article
Simulation Of Two Dimensional Flow And Conjugate Heat Transfer Problem In Cooled Gas Turbine Nozzle Guide Vane

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Abstract

The coupled treatment (conjugate numerical methodology) allows the simultaneous solution of the external flow (steady, two dimensional, compressible and turbulent flow) and conduction within the metal (steady, two dimensional) of gas turbine nozzle guide vane (with and without internal convection cooling). Validation of the developed conjugate capability is investigated in the present work. The numerical results were compared with experimental results for steady, two dimensional, compressible and turbulent flow through the gas turbine nozzle cooling guide vane type (NASA-C3X), and the results were found to be in good agreement with experiments by(Hylton 1983). The study shows that the (conjugate numerical methodology) gives good and more accurate results than the un-coupled treatment. It also shows that the cooling of the vane reduced the thermal stresses which are focused in the trailing edge of the vane for being thin. Moreover, the cooling flow inside the passages of the vane reduced the temperature of vane body and that gives longer life to the vane for the same Turbine Inlet Temperature (TIT) and efficiency. Otherwise, it gives higher Turbine Inlet Temperature and high efficiency if one chose to keep same life of the vane. Finally, the present study shows that the conjugate heat transfer simulation is a good tool in gas turbine design, and it serves as base future work with more complex geometries and cooling schemes for turbine blade.

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Article
Comparative Analysis For Link Cross-Section Of Manipulator Arms

Authors: Dler Obed Ramadhan --- Ahmed Abdul Hussain Ali
Pages: 4930-4953
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The stresses and deflections in robot arm was analyzed using ANSYS software package. Industrial robot analyzed in this work consists of three arms that have 2-DOF. The analysis of each arm had been made separately. The maximum stress and deflection have been analyzed for a static applied at one end of the arm while has the other end fixed. Links of various cross-sections having same masses, length, and material properties to make a choice of the shape that gives a high stiffness to weight ratio have been examined. After specifying the best section for the arms of the robot an optimization process began to determine the dimensions of the arms sections which give the least deformation this had been done by the aid of a program build up by using the MATHCAD software package. In the beginning the program finds the optimum section in which the stress in the members not exceeds the allowable stress and finds the total weight of the robot after that the program begins to change the dimensions to satisfy the condition of minimum deflection of the whole robot after that the program estimates the best choices of the dimension for each section that gives the minimum weight and deflection. The dynamic behavior of the best chosen structure of industrial robot was studied to find the natural frequencies(Wn) and mode shapes. The result shows that the hollow circular section is the best section for the first link while a square section is the best section for the other two links.


Article
Antiseizure Characteristics Of Leaded Aluminum Alloys Under Dry Sliding Conditions
خصائص مقاومة الالتصاق لسبائك الالمنيوم المحتوية على الرصاص تحت ظروف الانزلاق الجاف

Authors: Akeel D. Subhi
Pages: 4954-4959
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Aluminum-Silicon alloys, with soft lubricant metal, are considered to be one of the important tribological alloys which resist seizure. The effect of different lead percentages (1-20%Pb) that added to the modified eutectic Al-12%Si alloy on the wear rate and resistance was studied by sliding these alloys under dry sliding conditions on a carbon steel disc at different sliding distances (2.24-40.37 km). The results showed that the wear rate was decreased and wear resistance increased with increasing lead percentage of Al-12%Si alloy. Furthermore, wear rate was increased linearly with increasing sliding distance.

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Article
Dependable Discharges Of The Upper And Middle Diyala Basins

Authors: Haitham A. Hussein
Pages: 4960 -4969
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The Diyala river is a major tributary of the Tigris river that runs through Iran and Iraq which drains an area of 32600 km2. The catchment area consist of four parts which are the area of the basin above Derbendi-Khan, Upper Diyala, Middle Diyala and lower Diyala. Through the last two decade the water coming to the upstream Derbendi-Khan reduced and this reduction reach to about 35%. This research focusing on the water dependable discharges reached to upper and middle Diyala river basin as compared with Russian study(water balance). The water balance mention that the discharge can be supplied the above basins with probability of 95%for the year (1947-1948). In this research consider the mean discharge down stream Derbendi-Khan dam for the period (1989-2007) in order to find the dependable probability for discharge which can be satisfied and equivalent to the water balance study . In this research considered different probabilities (95%,80% and 50%) of each months (Oct-Sep) water year for the period (1989-2007) by using the empirical Wei Bull probability equation, and it was conclude that the probability of 50% can be considered the suitable probability for the water requirement to upper and middle basins.


Article
Parallel Fuzzy Logic Controller Implementation Using MPICH2

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In this work FLC program is implemented using C++ codes. Two implementations are presented one with the rules stored inside the program, the other with rules in a rulebase file. The execution times of these two implementations, along with MATLAB FLC implementation, are compared using different simulated FLCs. Furthermore, to reduce the rulebase searching time, a parallel FLC is implemented using C++ and MPI (Message Passing Interface). The MPICH2 package is used to run the parallel FLC. A cluster of four computers is used as the parallel environment. The execution time of this FLC program is evaluated using servomotor, Anti Skid System, and other simulated applications. The speedup and efficiency are studied using different number of computers. The results show that decomposing the rulebase searching operation to more than a computer reduce the execution time significantly.


Article
Bearing Capacity of Square Footing on Geogrid-Reinforced Loose Sand to Resist Eccentric Load

Authors: Faris W.Jawad --- A'amal A. Al-Saidi --- Mosa J. Al-Mosawe
Pages: 4990 -4999
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This research presents and discuss the results of experimental investigation carried out on geogrids model to study the behavior of geogrid in the loose sandy soil. The effect of location eccentricity, depth of first layer of reinforcement, vertical spacing, number and type of reinforcement layers have been investigated. The results indicated that the percentage of bearing improvement a bout (22%) at number of reinforced layers N=1 and about (47.5%) at number of reinforced layers N=2 for different Eccentricity values when depth ratio and vertical spacing between layers are (0.5B and 0.75B) respectively.

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Article
Theoretical Simulation of Stress-Strain Relations for Some Iraqi Clays Using the Endochronic Model
التمثيل النظري لعلاقات الإجهاد – الانفعال لبعض الأطيان العراقية باستعمال نموذج الزمن الضمني

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A constitutive law can be defined as a mathematical functional relation between physical quantities such as stress and strain and may take other factors like time ,temperature and additional material properties into account. In this paper , the endochronic model is used to predict the stress-strain relations of two Iraqi clays. This model is a viscoplastic one but without introducing a yield surface. It encompasses material behaviour such that the current stress state is a function of strain history through a time scale called “intrinsic time” which is not the absolute time but a material property. The simulation showed that the model overestimates the strains for all cases studied. This may be attributed to the material parameters which require a parametric study to determine their actual values for Iraqi clays


Article
Building of an Expert System for WWTP Operation and Management: Rustimiyah South WWTP as a case-study

Authors: Bashar J. Khalaf Al-Daami --- Rafa H. Al-Suhaili
Pages: 5021 -5032
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This paper presents the building of expert system to enable the inexperience plants operators to application of better of wastewater treatment plant. This methodology consists of three steps: (i) creation of a decision trees (algorithms) for the diagnosis operational problems; (ii) implementation into a real-based system; and (iii) verification. This system called expert system for Rustimiyah south wastewater treatment plant operation (ES-RS-WWTPO). The knowledge acquisitions to build this system ware extracted from literature. Moreover local experience ware also incorporated using the results of a well designed questionnaire. The results obtained in the application three operational states showed that the system was able to diagnosis (correctly) state of plant with reasonable accuracy. The programmer language for built this system id Visual Basic 6.0.

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Article
The Effect Of Variation Of Nonlinear Load On Power Factor Of The Ac Supply Network

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The aim of this paper is to evaluate the effect of the converter system on the power factor of the supply network .Therefore a 3-phase, 6-pulse , bridge converter is assembled and connected to a power supply through a 3-phase ac voltage regulator .The theoretical analysis is simulated using Fourier series analysis and Fast Fourier Transform ( FFT ) algorithm . The experimental measurements of distortion factor , displacement factor and total power factor are recorded . The experimental results are shown to be coincident with the theoretical results. The consideration of power factor improvement relative to distortion and displacement factors is discussed.


Article
Influence of Lens on Migration of Dense Non-Aqueous Phase Liquid in Saturated Zon
تأثير وجود حاجز على حركة السوائل العضوية الاثقل من الماء في الطبقة مشبعة من التربة

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This study concerns the control of movement of Dense Non-Aqueous Phase Liquid (DNAPL) in saturated zone in the presence of relatively low permeability lens. A two-dimensional, finite-difference numerical model for the simultaneous movement of the DNAPL and water through the saturated zone of the soil is developed. The system is, actually, a three fluid phase system (water, DNAPL and air) but in the derivation of the model, air was treated as an immobile phase at constant atmospheric pressure. The flow equations for Dense Non-Aqueous Phase Liquid and water are cast in terms of the wetting and non-wetting fluid pressure heads respectively. The finite- difference equations are solved fully implicitly using Newton-Raphson iteration scheme with a Taylor series expansion to treat the nonlinearity. The present numerical results are compared with results of Kueper and Frind (1991b). The results of all tests showed that the presence of lens controls the vertical movement of Dense Non-Aqueous Phase Liquid (DNAPL) in heterogeneous porous medium.

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Article
Drag Force Of Two Spheres In Power Law Fluids

Authors: Abeer Ibrahim Alwared --- Abbas H. Sulaymon
Pages: 5061-5073
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The present research is concerned with studying of the drag force on two spheres moving side by side and in line in non-Newtonian liquid. Polyacryamide (PAA) solution with different concentrations (0.01, 0.03, 0.05 and 0.07)% by weight and water is used for comparison for obtaining the effect of fluid properties on the drag force. Different types of spheres stainless steel, glass and plastic with different sizes and densities were used. Within the considered range of power law index (0.6 - 1), and generated Reynolds number (1.1 -75) in power law fluid and Reynolds number (100 - 1000) for water it was found the drag coefficient increases with increasing the power law index for constant generated Reynolds number and the drag force increases with fluid density increases but it decreases with the sphere density increases.


Article
Removal Of Methyl Tertiary Butyl Ether Fromsynthetic Wastewater

Authors: Suondos K. A. Barno
Pages: 5074 -5083
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Methyle tertiary-butyl ether (MTBE) is the most fuel additive used through the world.Thus, it has been reported that MTBE is the second high concentration contamination found in ground water. Study of the effect of reaction time and reaction temperature of 25 to 55° C on the kinetic of chemical oxidation has been done with 3000 ppm MTBE in water at pH range 3 to 7 and 1:1 hydrogen peroxide to Fenton’s reagent ratio. Also, Kinetic analysis was carried out to determine reaction order and activation energy for the reaction of MTBE disappearance during the reaction with Fenton’s reagent.


Article
Shear Capacity Of Concrete Prisms With Interface Joints
مقاومة القص للمواشير الخرسانية التي تحوي على مفاصل إنشائية

Authors: Riyadh Jawad Aziz
Pages: 5084 - 5097
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Construction joints are frequently used in engineering structures for various reasons. When the size of the structure is relatively large stoppage of concrete casting at certain locations is necessary. Stoppage of casting may also occurs due to sudden failure of mixing machines, or when the concrete stock ingredients runs out of materials, or when weather conditions do not permit casting operations to continue. If stoppage of concreting occurs, a joint between old and new concrete forms, it is then necessary to evaluate the horizontal shear capacity at the interface between old and new concretes to prevent progressive slip from taking place and to insure satisfactory performance of the structure. A total of 16 push-off tests were performed to quantify the shear strength capacity at the interface between old and new concretes and to recommend the necessary practice for such circumstances. Test parameters include different interface surfaces smooth and rough with and without shear keys. The variables also include presence of shear reinforcement across the interface surfaces. Test results have indicated that leaving concrete surface at the end of casting rough with shear keys is essential to restore part of shear resistance between old and new concretes. Presence of shear reinforcement further improves the shear resistance at the interfaces. It was found that the average nominal shear capacity of concrete at the interface relative to the nominal shear capacity of control specimens cast monolithically is about 43% for rough surfaces having amplitude of 6mm and 55% for rough surfaces with shear keys. When 3-Φ10 shear reinforcement is used along rough interface, shear resistance increased to 62% relative to the shear capacity of control specimens cast monolithically.

Keywords

shear --- capacity --- concrete --- prism --- interface joints --- rough --- smooth --- surface


Article
Investigation Of The Effect Of The Wake Generated By Rotor Blades On The Flow Through Stator Passage For Low Pressure Turbine

Authors: Ahmed W. Mustafa --- Ihsan Y. Hussain
Pages: 5098-5115
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Abstract

The effects of incoming wakes of upstream rotor on the flow field in a low pressure turbine cascade are investigated. The flow field is studied numerically with and without inlet wake. The rotor effect is represented by moving bars that produce passing wakes at the entrance of the stator. The flow field is analyzed numerically by solving the steady and unsteady forms of the two-dimensional compressible Reynolds-averaged Navier-Stokes equations. Steady flow is performed without wake while the unsteady flow is performed with periodic inlet wake for Reynolds number of order 105. A k- turbulence model is used to obtain the eddy viscosity. The Cartesian velocity components and pressure on a collocated (non-staggered) grid are used as dependent variables in the momentum equations, which discretized by finite volume method, body fitted coordinates are used to represent the complex blade geometry accurately, and grid generation technique based on elliptic partial differential equations is employed. SIMPLE algorithm is used to adjust the velocity field to satisfy the conservation of mass. The results show that the wake passing produces unsteady pressure field in the direction of the rotor traverse. The comparison with the experimental data is acceptable and there is similar trend between the prediction and experimental data, except at the separation flow region due to the limitation of the turbulence model.


Article
Crack Detection in a Rotor Dynamic System by Vibration Monitoring

Authors: Jawad K.Z --- Nabil H. H
Pages: 5116-5128
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Abstract

Vibration monitoring is one of the most important techniques which are used to detect the cracks or defects in rotating mechanical systems. To distinguish characteristics of the system response that may lead to the transverse crack in rotating shaft, local asymmetry crack model is used where crack simulated by increasing the flexibility of the shaft and transverse crack in the shaft is introduced. The obtained results showed a decreasing in the resonance shaft speed with increasing the crack depth ratio. The feature is used for diagnostics the crack in the shaft by using the graphed results between the natural frequency and shaft speed. The method of detecting was applied for several crack depth ratios (uncracked, %10, %20 and %30) in a clamped-free rotor. Also for investigating the effect of position of crack and effect of mass location, a crack and mass with different locations are introduced in the shaft. Although, the presence of a transverse shaft crack has also been shown to induce an unstable response for some shaft speeds and the behavior of the 2x harmonic component of the system response is effective target observation for a monitoring system.


Article
Using Personal Computer For Vibration Measurements And Rotor Balancing

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Abstract

Most prime movers have vibrational problems due to the inherent unbalance in the engines. The unbalance may be due to faulty design or poor manufacture. Naturally, the structures designed to support heavy centrifugal machines, like motors, turbines and reciprocating pumps, are also subjected to vibration. In all these situations, the structure or machine component subject to vibration can fail because of material fatigue resulting from the cyclic variation of the induced stress. Furthermore, the vibration causes more rapid wear of machine parts such as bearings and gears and also creates excessive noise. This research is an example in the field of reducing as much as possible the vibration. To accomplish this, a digital instrument, based on an industrial computer, designed to measure the vibration level and rotor speed. Thereafter, displaying the required amount of weight that must be added or removed from blade in order to reduce the unbalance, which cause vibration


Article
Design and Implementation of Information System For general Diagnostic and Remedy Of Casting Defects

Authors: Ban Bakir Jawad --- Kasim M. Daws
Pages: 5150- 5168
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Abstract

Casting defects are ones of the important problems occurring in the casting process .The large number of the defects make the diagnosis of them difficult and depend on the inspector experience and his information of the defects property. This diagnostic perhaps being wrong and not accurate. Therefore in this research an inclusive program through information system was designed to diagnose the defects and its causes then put the suggested remedy, this program contains four methods to recognize the defects in castings .The methods are 1.Use selection of the listed property of the defects 2.Benefit from the pictures of defects to diagnose the defect. 3. The questions and answers method .4.Combo box that contains all the defects name .The last method was designed only for the workers having a great experience in this field. It is found after verification that the method of picture is the simplest and rapidly one because the user needs to see the picture that is given to him and compare them with the castings defect. The program was designed by the use of Visual Basic language, which allows making dealing with the methods easy. The arrangement of this number of defects was done by use general classification that classify them to seven groups and these were divided to subdivision groups .The verification was done to check the effectiveness of the program and it gave good results.

Keywords

Defects --- remedy --- diagnostic --- casting --- information


Article
A Study Of Free Vibration And Fatigue For Cross-Ply Closed Cylindrical Shells Using General Third Shell Theory (GTT)

Authors: Wedad I. Alazzawy --- Muhsen J. Jweeg
Pages: 5170-5184
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Abstract

Free vibration solution will be developed for laminated simply supported closed cylindrical shells. This solution is obtained using General Third Shell Theory (G.T.T.). Also the critical in-plane fatigue load is studied and the required equilibrium equations are developed, the effects of tension or compression in-plane load on the natural frequencies are discussed also. The natural frequencies and in-plane fatigue load results are very close to those obtained by other researchers.


Article
Experimental Study Of Fatigue Characteristics Of Laminated Composite Plates
دراسة عملية لخواص الكلال للصفائح المركبة الطباقية

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Abstract

The fatigue damage is a dangerous and could be considered as the most unwanted failure in the materials that are used to construct the engineering components. As composites take an advanced position in the industry of aircraft, marine and many other high performance components, because of their high ability and their light weight and for their strength, this forces us to find the deformation and data to give a good expectation for the composite behavior under fatigue and other types of damage. In this study the material used is the glass fiber with a polyester resin; the experiment used a device to force the composite to be under a bending fatigue through specified deflection and then the force is measured. The results for different values of imposed deflection and different thicknesses are presented, as S-N curves and in a logarithmic way. Fractography has been used to characterize the fatigue damage in the composite, it is shown that the fatigue damage in the composite is a complex, interactive damage process and combines between several damage mechanisms such as delamination, fiber breakage, matrix cracking and fiber matrix debounding.


Article
Parametric Study Of Laminar Free Convection In Horizontal Annulus With And Without Fins On The Inner Cylinder

Authors: Jasim Mohammed Mehdi --- Saad M. Saleh
Pages: 5199-5213
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Abstract

An experimental and numerical study has been carried out to investigate the heat transfer by natural convection in air-filled annulus between two horizontal isothermal concentric cylinders with and without annular fins under steady state conditions; the inner cylinder surface is maintained at a higher temperature and the outer cylinder surface at a lower one. In the experimental study, the annulus inner surface is maintained at high temperature by applying uniform heat flux to the inner cylinder while the annulus outer surface is subjected to ambient temperature and maintained at low temperature. The experiments were curried out at a range of Rayleigh number (1.81×103 – 4.03×104) for case without fins and (1.08×103 – 2.94×104) for case with fins, at different diameter ratios (η = 2.0, 2.6 and 3.0). The results showed that: (1) increasing the diameter ratio(η) strongly increases the heat transfer rate, (2) increasing Rayleigh number increases the heat transfer rate for any η and (3) attaching annular fins to the inner cylinder surface of (No. of fins/cm) of 1.25 and (fin height/gap width) of 0.143, 0.186 and 0.286 reduced the mean Nusselt number ( ) within (16.3 - 29.7) percent of that for the case without fins at the same Rayleigh number. In the numerical study, only the case without fins was investigated. The buoyancy driven fluid flow resulting from the temperature difference between the cylinders, is assumed to be steady, laminar, two dimensional and symmetric about the vertical center-line. Only half of the domain needs to be modeled from symmetry considerations. Navier-Stokes and energy equations are expressed in vorticity-stream function form and discretized via finite difference method. The Rayleigh number (based on gap width) varied from l02 to l05 with the influence of diameter ratio obtained near a Rayleigh number of 104. Results for the local and mean Nusselt number, the contour maps of the streamlines and isotherms are presented, to show some of the flow and heat transfer characteristics. The results numerically obtained showed a good agreement with the present experimental data.


Article
Fault Tree Analysis as a Modern Technique for Investigating Causes of Some Construction Project Problems

Authors: Abbas M. Burhan
Pages: 5214 -5224
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Abstract

Construction projects contain many problems that can occur during the execution. Each problem results from many causes. Fault tree analysis (FTA) technique is a graphical model for analyzing causes of a problem (or undesired event) using logic gates to describe combinations of individual faults that can create an undesired event. Each level of the tree lists the lower level events that are necessary to cause the event shown in the level above it. The assessment process of a problem with FTA technique can be divided into two types: qualitative and quantitative assessment. As a case study to apply FTA technique in construction field, the researcher studied a building in Baghdad that had punching shear problem to analyze the causes lead to this problem. This research aims to introduce the main principles of FTA technique and how to use in identifying and analyzing the causes of problems that can occur in the construction projects. Also, it aims to compute the probability of occurrence of any problem or undesired event.


Article
Optimization of DEM Interpolation

Authors: Ahmed Kasim Hameed AL- Akaby --- Hussain Zaydan Ali
Pages: 5225 -5238
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Abstract

Digital Elevation Models (DEMs) are simply regular grids of elevation measurements over the land surface. DEMs are mainly extracted by applying the technique of stereo measurements on images available from photogrammetry and remote sensing. DEMs play a vital role in many scientific, environmental, engineering as well as military applications which need accurate and dense DEMs. However, generating a dense and accurate DEM comes with the price of spending both time and money on the field measurements. Fortunately, advanced space technology has provided much single (if not stereo) high resolution satellite imageries almost worldwide with the available global or local DEMs. This study included evaluating both DEM produced from topographic map and raster DEM after resolution enhancement by using single satellite image. According to the results of these experiments, a strategy was proposed for using the reflectance data to enhance the accuracy of DEM interpolation. The proposed the reflectance data models were implemented in a software package and successfully tested.


Article
Image Segmentation Using Multiwavelet Transform

Authors: Manal Fadel Younis
Pages: 5240-5248
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Abstract

This paper presents region growing image segmentation method which unifies region and boundary information. Several studies shown that segmentation based on image features can improve the accuracy of the interpretation. The goal of segmentation is to simplify and/or change the representation of an image into something that is more meaningful and easier to analyze. Image segmentation is typically used to locate objects and boundaries (lines, curves, etc.) in images. More precisely, image segmentation is the process of assigning a label to every pixel in an image such that pixels with the same label share certain visual characteristics. A problem that frequently arises when an image is segmented is that the number of feature variables or dimensionality is often quite large. It becomes necessary to decrease the number of the variables to manageable size. The other main difficulty of traditional image segmentation is the lack of adequate tools to characterize different scales of image effective. In this paper it proposed three dimension multiwavelet algorithm to overcome this difficulty and then the region growing method is applied to segment this image.


Article
Removal Of Dyes From Textile Effluent By Adsorption Onto Oven Dried Alum Sludge

Authors: Rasha H. Salman
Pages: 5249-5262
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Abstract

The present study deals with the removal of dyes from the effluent of the state company for cotton textile industries located at Al-Khadmya by using oven dried alum sludge (ODS) as adsorbent. Two different dyes; Direct black and solar brown are studied. Alum sludge was collected from Al-Qadisiya water treatment plant; it was heated in an oven at 105°C for 24 hours, then cooled at room temperature and crushed to produce particle sizes of 1.18-2.36 and 4-4.75 mm. Batch and fixed bed mode were used. In batch experiments the effect of oven dried alum sludge weight on adsorption process and equilibrium isotherm were studied by using 15-125 g/l of oven dried alum sludge for direct black and 15-175 g/l for solar brown, with constant initial dyes concentration of 10 mg/l and constant particle size of 4-4.75 mm. Batch kinetics experiments showed that equilibrium time was about 12-14 days. The three models Freundlich, Langmuir and Freundlich-Langmuir gave good fitting for the adsorption capacity. In the fixed bed isothermal adsorption column, the effect of initial dye concentration (Co), particle size, influent flow rate (Q) and bed depth (H) were studied. The results showed that the oven dried alum sludge was effective in adsorbing dyes with removal efficiency ranged between 90% to 92%.


Article
Coupled Vertical – Torsional And Lateral Free Vibration Of Thin-Walled Curved Beam

Authors: Shatha Dhia Al Khazraji
Pages: 5263-5282
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Abstract

This study is concerned with the derivation of differential equation of motion for the free coupled vertical – torsional and lateral vibration of opened thin-walled curved beams. The curved beam to be considered in this study is of isotropic opened thin – walled (I) section with equal top and bottom flanges. The derivation depends on Hamilton's principle which required finding the potential and kinetic energy of the curved beam section due to internal stresses and all types of movements (Vertical,Torsional and Lateral) .The effect of restrained warping displacement is also considered in this study. Three differential equations are derived for vertical, torsional and lateral movement .and approximate solutions are developed by using the method of multiple scale via a perturbation technique. The resulting natural frequencies and modes for vertical , torsional and lateral movements are compared with those calculated by using finite element approach (STAAD Pro. 2007) and with the results other studies.

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