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: 2010 volume:16 issue:1

Article
Chaos theory and the Generation Of the Architectural for
نظرية الفوضى وتوليد الشكل المعماري

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Abstract

The modern era features the incredible production knowledge by quantum and qualities and with quick changes in theories, interesting practices and even knowledgeُs view points. In the last years new thinking methods boomed in the mathematical field that refers to chaos theory, this field which continues in growth and evolution quickly in different directions, with all the practical potentiality that carried in large and variety phenomena's. The tools and the concepts of the theory is considered as a radical cutting with the known mathematical manners that based the modern science since Galileo, Descartes and Newton , and let us see the world in different and radical views, and with the best understanding for its movement powers, its self organization and its evolution. The different concepts of the chaos theory effected in all the knowledge fields and led to unpredictional results in many areas one of them is architecture. Many architectural studies discussed chaos theory and focused on its effects in architectural field through theoretical studying to the theory and its concepts, but the most of these studying didn't exploit the theory concepts in the formal Generation of the architectural deriving, therefore the research importance came from its trying to answer the important question that the research begins with :( How could new tools be adopted to the Generation of the Architectural forms?), and according to the scientific knowledge that came from the specialized study (architectural & scientific) formulating of the researchُs problem was:( the lack of knowledge concerning the generating ability of the chaos theory in architecture to generate new forms), therefore the researchُs aim was to expose the generation ability for chaos theory in architecture to generate new forms. The research tried to build theoretical framework about the vocabularies of the formal Generation according to chaos theory the research reached to formulate three main Generation vocabularies(dynamics- complexity- flexibility) , according to that the research hypothesis was: (could be generate new forms in architectural field through employing chaos theory concepts), the research started reaching its aim through the practical part which reached to formulate special programming with the computer program (Form( to employing the vocabularies of the formal Generation according to chaos theory to generate new architectural forms And finally reached to a group of conclusions that refer to chaos theory and its formal Generation to create new forms in architecture

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Article
The Space in the Age of Information
الفضاء في عصر المعلوماتية

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Abstract

Three revolutions characterize the age of information: Information Revolution, Technology Revolution and Media Revolution. These revolutions developed and interacted with each other in an amazing way. Way to an extent that it becomes a title to our contemporary architecture. These revolutions changed people’s thoughts, behaviors, and traditions. The effect of technology on the urban structure generally and the urban space specifically changed the physical structure of these spaces as a necessary result to the change of intellectual structure in community. The information revolution changed a lot of the common urban space‘s characteristics and concepts as well as an extreme change in concepts related to the space. The new thought concentrated on the fact that information represents the tools for the interaction between man and his environment. The new electronic information and the improved digital media split the reality out of the realm of body, convert the experiments to the form of event and create a control of the virtual reality. The new space of this kind is called “Virtual Space”. This new space lies between the physical space and the mental space as it presents to the designers not only infinity image to the mental space but the sense of being in the physical space. The physicality of space is no more an important concept in architecture as a result to the emergence of new concepts of space with the effect of information technology. The new digital tools (computers) set free the dual concepts of space in human civilizations. The power of structure and the imitation of the digital media released all types of unlimited imagination. The research aims to explain the concept of (space) in the language of today (the technological language) and clarify the meaning of intelligent space as a result of the change in the concept of space in the age of Informational Technology Revolution .


Article
THE HOLLY QURAN ENCOURAGE RESEARCH IN ARCHITECTURAL HISTORY
القران الكريم يدعو للبحث في تاريخ العمارة

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Abstract

The science of architectural history is considered one of the basic fields of the architectural studies because it reflects civilization, intelligence and creation .The present research problem takes to account the confusion image of the importance of studying architectural history in Islamic architectural theory . Research hypothesis is '' The holly quran encourage research history''. The research contain Ayat al quran that in sure the importance of studying history and explain examples from historical buildings the research in sure the importance of studying historical civilization and buildings, and draw some conclusions from al quran miracles.

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Article
Effect Of Initial Pressure Upon Laminar Burning Velocity Of Methane-Air Mixtures
تأثير الضغط الابتدائي على سرعة انتشار اللهب لخليط هواء- ميثان

Authors: د. محمد ناصر حميد
Pages: 867- 876
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Abstract

The effect of the initial pressure upon the laminar flame speed, for a methane-air mixtures, has been detected paractically, for a wide range of equivalence ratio. In this work, a measurement system is designed in order to measure the laminar flame speed using a constant volume method with a thermocouples technique. The laminar burning velocity is measured, by using the density ratio method. The comparison of the present work results and the previous ones show good agreement between them. This indicates that the measurements and the calculations employed in the present work are successful and precise.

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Article
STUDY OF IMPORTANT VARIABLES OF AERODYNAMICS FOR SUBSONIC AIRCRAFT USING ADVANCED AIRCRAFT ANALYSIS SOFTWARE
دراسة أهم المتغيرات الأيرودينامية لطائرة ذات سرعة تحت صوتية باستخدام برنامج AAA

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This study presents the important variables of aerodynamics of subsonic aircraft using AAA software, moreover to comprehensive preview of some imperical and mathematical equations where needs in this analysis process. Cruise mission chose for this study comparing with another mission of flight such as Take-off, Climb, Dive & Descent, and Landing according to important of the mission and cruise mission has large rung during the flight mission. These analyses of process submit to more and complex iteration process until we access to correct solution. Lift, drag, and moment coefficients along the lift surfaces such as wing, and horizontal tail were showed. Also this paper explain the effect of flight level, aircraft speed, aspect ratio of lift surfaces on lift curve. Results show that, increase the value of altitude, load factor, aspect ratio leads to increase the value of lift coofficent and decrease the airplane velocity.


Article
RELIABILITY - BASED DESIGN PROCEDURE OF AXIALLY LOADED PILESes
طريقة تصميم للركائز المحملة محوريا مبنية على أساس مبدأ الاعتماد

Authors: Mohammed Yousif Fattah
Pages: 4462-4477
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Abstract

Geotechnical engineering involves many different and complex materials and many different mechanisms of behaviour. The direct use of experience as a guide to the prediction and design is effective, provided these are understood. Geotechnical engineering is a relatively new science. Its successful application to prediction requires realistic assumptions to be made, and predictions must be tested against reality. Methods of prediction need then to be refined. An example of the importance of making realistic assumptions is examined in this paper. It includes the effects of soil properties on the ultimate capacity of axially loaded piles. Better analysis offers better prediction and better understanding. Both are only possible when reality is modelled. There are occasions when mechanisms are too complex for predictive analysis. Prediction must then be based directly on experience, applied with an understanding of the mechanisms involved. Moreover, methods of analysis may become too sophisticated for everyday use. However, pseudo-analysis, involving standardized methods based on oversimplified and unrealistic mechanisms of behaviour and material properties, is dangerous. The use of engineering experience as a guide to prediction and design may offer a more effective alternative, provided it is based on a realistic understanding of mechanisms and materials. In this paper, a procedure is recommended to estimate the bearing capacity of axially loaded piles based on reliability calculations. The procedure is an extension of the point estimate method in which the expected values of the standard deviation of the capacity and demand functions are calculated. The probability of failure, the reliability, central factor of safety and reliability index are calculated as appropriate. The procedure is then applied to two cases where the pile in the first case is driven in sand while in the second, it is driven in clay.

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Article
STUDY THE PERFORMANCE OF SULFAMIC ACID AND CITRIC ACID IN REMOVAL THE SCALE DEPOSITED ON THE DURA REFINERY HEAT EXCHANGE PIPING SYSTEM
دراسة ادائية حامضي السلفامك والستريك في ازالة التكلسات المترسبة على انابيب اجهزة المبادلات الحرارية في مصفى الدورة

Authors: Najwa S. Majeed
Pages: 4478-4487
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Abstract

This paper describes an experimental study on the performance of sulfamic acid and citric acid in scale removal of Dura refinery heat exchange piping systems. Experiments were carried out using sulfamic acid and citric acid inhibited by hexamine as cleaning solutions at different time, temperature and concentrations. A dynamic flow system was designed for this state. A scaled copper alloy pipes from the main hot water lines (heat exchanger) was used. Hexamine was used as corrosion inhibitor.The research involved a study of effect of the time ,temperature and acid concentration of each acid on the scale removal, and a comparison of the performance of the two used acids were investigated.

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Article
APPLING ADAPTIVE FUZZY NEURAL ALGORITHM FOR INTRUSION DETECTION

Authors: Noor Adnan Ibraheem --- Mokhtar Mohammed Hasan
Pages: 4488 -4509
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Abstract

Many Network applications used as remote login have some ways for detecting the intruders which are classical ways applied by comparison of operations between login user interface and system stored information. The proposed system tried to detect the intrusions happened by the network intruders using new technique called Adaptive Fuzzy Neural Network which have the ability to detect the intrusions at the same time even if the number of users is large. The proposed system consists of two stages, the first stage is for monitoring all events that happen and analyzing them, and the second stage is to detect intrusions. The detection operation combines anomaly intrusion detection and misuse intrusion detection using the Adaptive Fuzzy Neural Network system, which is a suggested method in our paper used to learn the normal network traffic and detect the abnormal traffic.

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Article
ECG CLASSIFICATION USING SLANTLET TRANSFORM AND ARTIFICIAl NEURAL ARTIFICIAL NETWORK

Authors: Rasha Thabit --- Tarik Zeyad --- Sadiq J. Abou-Loukh
Pages: 4510 -4526
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Automatic detection and classification of cardiac arrhythmias is important for diagnosis of cardiac abnormality. This paper shows a method to accurately classify ECG arrhythmias through a combination of slantlet transform and artificial neural network (ANN). The ability of the slantlet transform to decompose signal at various resolutions allows accurate extraction of features from non-stationary signals like ECG. The low frequency coefficients, which contain the maximum information about the arrhythmia, were selected from the slantlet decomposition. These coefficients are fed to a Multi-Layer Perceptron (MLP) artificial neural network which classifies the arrhythmias. In the present work the ECG data is taken from standard MIT-BIH database. The proposed system is capable of distinguishing the normal sinus rhythm and nine different arrhythmias. The overall accuracy of classification of the proposed approach is 98.40 %. Three other transformation methods are used and the accuracy of the classification of each was compared with the slantlet system accuracy. These transformation methods are: the Fourier transform which gives 67.80% accuracy, the discrete cosine transform which gives 92.72% accuracy, and the wavelet transform (using Haar and Daubechies-4 scaling function coefficients, which give an accuracies of 96.02% and 96.25% respectively).


Article
MEASURMENT THE FLUORESCENCE PARAMETERS OF THE OLIVE OIL AND COMPARING IT WITH SOME LASER DYE MATERIALS

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Abstract

The verse (35) in SURA (AL- Nur) in the HOLY QURAN has inspired the author to look into the possibility of using Olive Oil as active dye laser material. Olive Oil which is classified as organic compound, having a good properties candidate it to be used as active dye laser material. The emission spectrum diagrams at some of absorption peaks (414, 536, 632 and 670) nm will be measured. These diagrams have been used to determine the Fluorescence quantum yield, Oscillator strength, Einstein coefficients for the spontaneous emission, Radiative and Fluorescence lifetime and absorption and cross sections. It has been found that fluorescence occurs at 669 nm for the entire absorption spectrum. Fluorescence of Olive Oil has been experimented using 30mW, 532nm semiconductor laser, with a beam diameter of 1.3mm. Red fluorescence has been noticed over a distance of 7cm in a glass container.

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olive oil --- Fluorescence --- dye laser.


Article
EFFECT OF EXISTING FLANGE OPENINGS AND COLD JOINTS ON STRENGTH OF RC T-BEAMS

Authors: Awadh E. Ajeel --- Ali H. Aziz
Pages: 4535 -4546
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Abstract

In the construction of modern buildings, a network of pipes and ducts is necessary to accommodate essential services like water supply, sewage, air-conditioning, electricity, telephone, and computer network. Passing these services vertically required creating openings in slab (Flanges of T-Beams) after or before construction. New researches show that the concrete flanges provide a certain level of shear resistance above a certain width. Therefore, due to existing of these openings or cold joints in slab (Flange) and abrupt changes in the sectional configuration, opening corners are subject to high stress concentration that may lead to reduction in stiffness of the T-Beam and produced cracking and excessive deflection. In the present research, shear behavior of reinforced concrete T-Beams which contains vertical opening (Flange openings) or cold joints at the flanges are studied as well as the effect of openings or cold joints locations. Eight beams were tested, one of which were constructed without any openings or cold joints (reference beam), while, the others were constructed with openings or cold joints in different locations. Experimental results show that the presence of flange openings reduce the shear capacity about (22% to 32%) for beams containing one opening and about (17%-39%) for beams containing two openings. For beams containing cold joints, the shear capacity decreased about (27%) in comparison with reference beam.

Keywords

T-Beam --- Flange --- Opening --- Cold joints --- Shear --- Slab --- Concrete


Article
EXPERIMENTAL STUDY FOR OXIDATION OF PHENOL BY FENTONS REAGENT

Authors: Sama Mohammed Abdullah
Pages: 4547-4556
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Abstract

The oxidation of phenol in aqueous solution was studied at atmospheric pressure in a batch reactor. Fenton reaction was used to degrade this component. Phenol (50 - 100 ppm) oxidation was carried out in the acidic medium range of (pH=2.7 - 5.8) under mild conditions of temperature (28 - 48°C), stochiometric excess percentage of H2O2 (S.EH2O2%) of (0 - 100%), and Fe(II) to phenol concentrations ratio of (0 - 0.63). The results indicate that the oxidation by Fenton reaction was an efficient method to eliminate phenol, also the amount of catalyst and temperature had the large effect on the phenol degradation. Finally the simple kinetic model for the reaction was established.

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Article
COMBINED ADJUSTED STEP SIZE LMS ALGORITHM AND ACTIVE TAP DETECTION TECHNIQUE FOR ADAPTIVE NOISE CANCELLATION
دمج خوارزمية اقل معدل للتربيع ذات معامل الخطوة المتغير زمنيا مع تقنية كشف الاوزان الفعالة لمنظومة الغاء الضوضاء المتكيفة

Authors: Thamer M. Jamel
Pages: 4557-4568
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In this paper ,a new idea to combine Adjusted Step Size Least Mean Square (ASSLMS) algorithm with standard LMS active tap detection technique is presented .Then the combined method is used for estimating unknown time-invariant (stationary) and time varying (non- stationary) Finite Impulse Response (FIR) channel for adaptive noise cancellation (ANC) application. The focus of this paper is to improve the convergence rate and low level of the error in the steady state for the popular LMS adaptive filter. The simulation results have shown improvement on the convergence rate using the combined technique over both the ASSLMS algorithm and standard LMS active tap detection technique if they are used alone.


Article
Calculation Of Soil Water Diffusivity Using A Model For Soil Moisture Profile Under Different Salinity Conditions
حساب الانتشارية المائية للتربة باستخدام انموذج لمنحنى المقد الرطوبي تحت ظروف ملحية مختلف

Authors: Taghreed F. Younan --- Mahdi I. Aoda
Pages: 4569 -4579
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A closed formed model modified from that of van Genuchten (1980) was used to fit the data of soil moisture profile ( θ vs. λ ) from which the slope dλ/dθ can be evaluated and then the soil water diffusivity [D(θ)] can be calculated. Diffusivity was calculated for three soil textures under different salinity conditions. The results showed that the model fitted the data very well with 1% confidence level (R2 > 0.93). D(θ) increased sharply with soil moisture for all soils but its values were lower when the texture got finer. At a certain sodium adsorption ratio (SAR), D(θ) increase with the increase of salt concentration (C) of the water infiltrating. Increasing SAR of water caused a decrease in D(θ) at any level of C. Same trends were obtained for the values of weighted mean diffusivity(D) .

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Article
Demulsification Of Cutting Fluid Before Disposal To The Environment

Authors: Laith Hamzah Thuaban --- Abbas Hamid Sulaymon
Pages: 4580 -4592
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In this research the treatment of 7201 cutting fluid was carried out to decrease its environmental impact on water resources after being used and being less effective due to the action of contaminants. The breaking of emulsion was carried out using two methods: The first method was by using acid and/or heat. 1 molar sulfuric acid was used to decrease pH to 1.5 whth heating the emulsion to 90 ºC. It was found that the acid is the dominating factor in emulsion breaking and the maximum efficiency achieved was 85% after one day using (10335 ppm) sulfuric acid. The second method was by using two different types of coagulants calcium chloride (CaCl2) and ferric chloride (FeCl3) at different emulsified oil concentrations (2, 4, 6, 8, 10% by volume.), and the residual oil concentration in water layer was measured for each experiment. It was found that using ferric chloride (FeCl3) gave the best emulsion breaking and least residual oil concentration in water layer for all emulsified oil concentrations.


Article
Adding Perfect Forward Secrecy To Kerberos

Authors: Wameedh Nazar Flayyih
Pages: 4593-4605
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Kerberos system is a powerful and widely implemented authentication system. Despite this fact it has several problems such as the vulnerability to dictionary attacks which is solved with the use of public key cryptography. Also an important security feature that is not found in Kerberos is perfect forward secrecy. In this work the lack of this feature is investigated in Kerberos in its original version. Also a public key based modification to Kerberos is presented and it is shown that it lacks the prefect forward secrecy too. Then some extensions are proposed to achieve this feature. The extensions are based on public key concepts (Diffie-Hellman) with the condition of keeping the password based authentication; this requires little modifications to the original Kerberos. Four extensions are proposed; two of them modify the (Client-Authentication Server) exchange achieving conditional perfect forward secrecy, while the remaining two modify the Client-Server exchange achieving perfect forward secrecy but with increased overhead and delay.


Article
Study Of CO And NOx Emissions Of S.I.E Fueled With Supplemented Hydrogen To Gasoline
دراسة ملوثات CO و NOxلمحرك اشتعال بالشرارة يعمل بإضافة الهيدروجين للجازولين

Authors: Miqdam T. Chaichan
Pages: 4606 -4617
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This paper include study of CO and NOx emissions exhausted from single cylinder, 4-stroke S.I. engine, Ricardo E6, with variable compression ratio, spark timing and equivalence ratio, worked by supplementary hydrogen to gasoline. The speed of 25 rps and higher useful compression ratio (HUCR) were chosen in studying the effect of wide range of equivalence ratios and spark timing on CO and NOx emissions submitted from engine. The study showed that exhaust gas emissions depend mainly on equivalence ratio. The higher value of NOx concentrations was in lean side near the stoichiometric equivalence ratio, and reduced when getting far from this ratio. CO concentrations were too small in the lean side, and the effect of equivalence ratio on it was too small in this side also, it increased in the rich side. It was observed that retarding spark timing reduces the NOx concentrations by a large percentage; there was no effect of spark timing on CO concentrations. The effect of speed on NOx concentrations was studied, and it was observed that these emissions became higher at medium speeds and reduced in higher and low speeds, CO concentrations increased with increasing speed also. NOx concentrations increased with increasing hydrogen volumetric ratio in mixture while CO concentrations reduced by this increase.


Article
Residual Stress Distribution For A Single Pass Weld In Pipe

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Heat input due to the welding of mild steel pipe causes a temperature gradient in the parent metal. After welding and temperature cooling down, residual stresses appear around welding zone which reduces the weld strength. Residual stresses are a result of the temperature gradient and the dependency of material properties on the temperature, such as yield strength, elasticity modulus, and thermal expansion coefficient. In this study, a typical flat joint of a single pass weld in a thin pipe was studied analytically and numerically. Analytical approach is performed by exploring a simple method to calculate the magnitude of residual stress in terms of the weld shrinkage behavior. Numerical analysis is performed by applying non-linear transient heat transfer analysis using welding parameters, such as heat generation, free or force convection with ambient, are performed using a general purpose FE package ANSYS 8.0 in order to obtain the temperature distribution in the welded parts. A non-linear thermal-elastic-plastic stress analysis is then performed using the same package to predict the stress fields during and after welding.


Article
Short Term Deflection Of Ordinary, Partially Prestressed And GFRP Bars Reinforced Concrete Beams
الهطول قصير الأمد للعتبات الخرسانية المسلحة العادية والمسبقة الجهد جزئيا ً و المسلحة بقضبان ألياف الزجاج

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The behavior of structural concrete beams is studied under short-term loading. A computer program developed originally by Oukaili to evaluate curvature is modified to evaluate the deflection for flexural structural concrete members. The program deals with actual stress-strain relationships of concrete and steel. The analysis is based on requirements of equilibrium and compatibility of strain in concrete and reinforcement. The proposed model is used in conjunction with the step by step analysis for small loading increments that allows the determination of the history of strain and stress in concrete with prestressing steel or non-prestressing reinforcement only or prestressing and non-prestressing reinforcement together. The evaluation of curvatures for the structural member involves iterations for computing the strains vectors at each analysis step. Newmark's numerical integration is used to evaluate the deflection of the member depending on the curvature values. The stress-strain model that was proposed by (Korpenko et al. 1986) is used and compared with experimental data and other analytical models for each of concrete and steel. The comparison showed good agreement between the model used and the experimental data. This relationship is used in SECTION program and presented in this study. The analytical results for load-deflection diagram are compared with available experimental data. The comparison has shown good agreement.


Article
An Investigation Into Three Dimensional Turbulent Flow Of Newtonian Liquid In Stirred Tanks Mixer

Authors: Nizar Jawad Hadi --- Ihsan Y. Hussian
Pages: 4653-4672
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The present work is concerned with the theoretical and experimental investigation of flow pattern of Newtonian fluid in liquid mixing process in stirred tank with flat blade impeller. A three-dimensional model for mixing process was simulated. The effected parameters are rotation speed and impeller diameter. Continuity, momentum, and turbulent equations were solved by ANSYS package software 5.4 code with FLOTRAN/CFD based on Finite Element method. In the experimental work, two visualization methods are used in this work, the first method is the acid-base reaction visualization method and the second is the particle distribution visualization method. Different chemical materials were used in the first method,H2SO4 as a base,NaOH .Different chemical materials were used in the first method, Methyl red as indicator, while polymer particles were used in the second method. The results of 3D model showed that the speed rotation directly affected the mixing zones, where the speed reduction by half decreasing the mixing zones approximately by half. Also the impeller diameter increasing clearly affected the mixing process where the mixing zones concentrated directly above and below the impeller. In the experimental work, the acid-base reaction visualization method showed that the mixing zones decreased due to the rotation speed reduction depend on the red and yellow colors, which describe the good mixing and poor mixing zones respectively. The mixing zones were concentrated directly above and below the impeller due to the impeller diameter increasing,. The particles distribution method showed that the mixing zones decreased due to the speed reduction, while the mixing zones concentrated directly above and below the impeller due to the impeller diameter increasing. The results showed a good agreement between the theoretical and experimental works in studying the effect of rotating speed, and impeller diameter .


Article
Correction Procedure for the Determination of Soil Specific Surface

Authors: Maysm Th. Al-Hadidy
Pages: 4673-4690
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Specific surface has a very important role in geotacnic especially with that home dell with gypseous soils or other types of salty soils. Because its calculation need for high accuracy, a procedure is presented to calculate a correction factor for Specific surface determination. In a previous work, grain size distribution curves of many soil samples are collected. A value for the specific surface of each soil is determined summing the surface area of subintervals in the distribution curve. In this work, the values of specific surface are obtained from these gradation curves and compared to those calculated using the values of the equivalent diameter for each soil. Fitting has been made and gets the best equation representing these points. From this equation, new values for specific surface are obtained by interning the specific surface calculated from the equivalent diameter and again the point is draw with the origin point (specific surface obtained from these gradation curves). Fitting is made again and the new equation is obtained. Finally, the equation of the calculated corrected specific surface is written. The results showed a very good agreement when using the corrected procedure.


Article
Numerical Analysis Of Thin Beams Resting On Nonlinear Elastic Foundations
التحليل العددي للعتبات النحيفة المسندة على اساس غير خطي مرن

Authors: Adel A. Al-Azzawi
Pages: 4695-4706
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The finite difference method is used for solving the basic differential equation for the elastic deformation of a thin beam supported on a nonlinear elastic foundation. A tangent approach is used to determine the modulus of subgrade reaction after constructing a second degree equation for load-deflection diagram. Results of plate loading test of soil obtained in Iraq were used in the analysis. An iterative approach is used for solving the nonlinear problem until the convergence of the solution. The method of analysis, as programmed for a computer solution, considers the continuous elastic, nonlinear foundation to be active only when the beam is pressing against the foundation. Two examples of with simply supported beams are presented to illustrate the application of the method of analysis.


Article
Calculation Of Volumeteric And Thermodynamic Properties For Pure Hydrocarbons And Their Mixtures Using Cubic Equations Of State

Authors: Munqith N. Reshag --- Sameera M. Hamad-Allah
Pages: 4707-4725
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The objective of this study was to develop a complete package for prediction of volumetric and thermodynamic properties of pure hydrocarbons fluids and their mixtures in one and two phase regions. Two cubic equations of state that are Peng-Robinson and Soave-Redlich-Kwong were used with volatile and black oils respectively to calculate the desired properties in addition to bubble point and dew point pressures and temperatures. Different values of binary interaction parameter were used for each equation and effects of this parameter values on the prediction are examined. Also values of this parameter between the plus-fraction and other component have been evaluated for first time. In calculation of heat capacity, four different mixing rules have been proposed to evaluate the temperature derivatives in case of the mixtures. Wide comparisons with the literature experimental data were made which indicated that both equations of state predict accurately different properties and marked improvements are achieved by use binary interaction parameter other than zero. Also both equations predict bubble point pressure of a certain mixture approximately with same accuracies using the recommended values of binary interaction parameter. Among the proposed mixing rules, Kay’s one appeared the best one to determine temperature derivatives.

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Article
Boundary Elements Modelling For Small/Large Strain Analysis Of Elastomeric Materials

Authors: Muhsin N. Hamza --- Muhsin J. Jweeg --- Imad A. Hussain
Pages: 4726 -4747
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In this paper the boundary elements method is used as numerical techniques for solving elastomeric materials (rubber or rubber-like materials) under small and large strains analysis. Under small deformations, the formulations are based on assuming that the elastomer is linear elastic isotropic incompressible solid. While for the large deformation, the formulation is based on decomposing the 1st Piola-Kirchhoff stresses into linear and nonlinear parts. Thereafter, the final derived equations are composed of both boundary integral and non-linear domain integrals. The non-linear analyses were performed using an incremental procedure with an iterative algorithm. Solving some numerical examples and comparing the results with that obtained from some available results and ANSYS 10.0 showed that the boundary elements method is a good numerical technique for solving incompressible elastomeric materials. And the formulation used for the boundary elements derivations for large strain analysis gave satisfactory results as compared with that of ANSYS ver. 10.0.


Article
The Application of a Step by Step Technique for the Performance Prediction of Thermal Power Plant Surface Condensers
استخدام تقنية الخطوة - خطوة للتنبؤ بأداء المكثفات المستخدمة في محطات الطاقة الحرارية

Authors: Laith Mouayyad Majeed --- Ali Hussain Tarrad
Pages: 4748-4770
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In the present work, the step by step technique is used to predict the performance of the power plant condenser. The procedure includes the calculation of pressure distribution, condensation temperature, water inlet and outlet temperature, condensation load distribution and single phase heat transfer sub-cooling. A quasi two dimensions model is applied, one in the tube water direction and the other in the vapor direction. It is applied with different operating conditions of the condenser such as operating pressure, air percentage mixed with steam, cooling water temperature and fouling factor on tube side for summer and winter seasons. The present model revealed that the fouling resistance has a great effect and plays the major part of the decline in the condenser performance. This is because it decreases the overall heat transfer coefficient and condensation rate. The performance of the condenser when the cooling water enters at the lower pass is better than the upper pass, due to the balance in the distribution of the heat transfer and the condensation rate between tube passes. The model is verified with field operating conditions of Southern Baghdad thermal power station. It has revealed that there is a good agreement between the field data and the present technique. The accuracy fell within (98) % and (89) % for the cooling water temperature prediction for summer and winter respectively, while it showed accuracy of (98) % and (99) % for the condensate exit temperature prediction for summer and winter respectively.

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