Table of content

Iraqi journal of mechanical and material engineering

المجلة العراقية للهندسة الميكانيكية وهندسة المواد

ISSN: 20761819
Publisher: Babylon University
Faculty: Engineering
Language: Arabic and English

This journal is Open Access

About

Iraqi journal for mechanical and material engineering is a refereed scientific journal published quarterly by the engineering college/ university of Babylon. It deals with high quality researches in fields of mechanical and material engineering.

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Contact info

Journal E-mail:
j.mec_mat_eng@yahoo.com
Babylon university/Babylon/Iraq P.O.Box(4)
Tel:++96430245387.(1155)

Table of content: 2012 volume:12 issue:2

Article
Electrocoagulation of Textile Wastewater with Fe Sacrificial Anode

Authors: Ajjam, S.K. and Ghanim, A.N
Pages: 192 - -201
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Abstract

Electrocoagulation is an electrochemical technique used to treat a high polluted effluent whereby sacrificial anodes corrode to release active coagulant precursors into the solution. This research focuses on the performance of EC technique to treat a high strength wastewater textile industry located in Al-Hilla-Iraq using a batchwise mode. Several working parameters such as current density, total suspension solid removal percent, chemical oxygen demand removal percent, turbidity removal percent and the operating time were studied. It was found that the application of 12mA/cm provided 69.2%, 62.5% and 54.3% removal in turbidity, COD and TSS, respectively, while the application of 20mA/cm 2 current density provided 90.1%, 85.2% and 83.1% removal in turbidity, COD and TSS, respectively, within 60 min. of EC treatment and with an inter-electrode spacing of 5cm. Also it was found that the contaminants of treated textile wastewater such as BOD, COD, TDS, TSS, turbidity, nitrates, chloride, total hardness, sulfate, total phosphates, electrical conductivity, oil and grease and the total phenols were within allowable limits for wastewater reuse. The loss of particles due to electrocoagulation after treatment as a function of operation time was expressed as a first order kinetic model and the kinetic constant for each contaminant removal was predicted for each current density. 2


Article
NUMERICAL SIMULATION LAMINAR NATURAL CONVECTION HEAT TRANSFER IN A RECTANGULAR ENCLOSURE WHEN ONE OF ITS VERTICAL WALLS IS HEATED PARTIALLY
دراسة عددية لانتقال الحرارة بالحمل الحر الطباقي في حيز مغلق مستطيل عندما احد جداره العمودية يسخن جزئيا

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Abstract

Two-dimensional natural convection heat transfer with a rectangular enclosure is examined numerically. The left vertical wall is partially heated, the reminder of the wall and the right wall is cooled to uniform temperature distribution, the top and bottom walls are adiabatic. The theoretical study involved the numerical solution of the Navier-Stokes and energy equations by using finite difference method. The stream function– formulation is used in the mathematical model. The numerical solution is capable of calculating the stream function, vortices and temperature fields of the computational domain. A computer program in (FORTRAN 90) is used to carry out the numerical solution. Problem has been analyzed and the non-dimensional governing equations are solved using finite difference method. Enclosure is assumed to be filled with an air with a Prandtl number of 0.71. The problem is analyzed for different values of the Rayleigh number in the range (10 3 ≤ Ra ≤ 5×10 5 ) and aspect ratio (0.5≤ AR ≤ 2). It is found that for small Rayleigh, the heat transfer is dominated by conduction and begins to be dominated by convection with increasing Rayleigh. In order to validate the numerical model, the results of variation local Nusselt number and a relation between average Nusselt number and Ra number, are compared with previous works, for square enclosure filled by air (Pr=0.71). There are excellent agreements which validate the present computational model.


Article
INSTABILITY OF ANGLED PIPELINE ARISING FROM INTERNAL FLUIDS FLOW
عدم الاستقرارية في خط الانابيب ذات الزاوية والناشئة عن تدفق الموائع الداخلية

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Abstract

In this study, the instability behavior of angled pipelines conveying fluid is investigated by using three-dimensional finite element method. Several parameters that affect the dynamic characteristic have been studied extensively such as pipe lengths ratio, diameters ratio, frame angle, inlet fluid velocity, inlet fluid pressure, and pipe thickness. Taking into account the Coriolis force, force that conforms fluid to the curvature, and axial tension forces; the natural frequency of an angled pipeline fixed in both ends is studied. The derived element matrices include the mass, stiffness, contradictory and damping. The study found that increasing the obtuse angle leads to decrease the frame critical fluid velocity. For each formed pipeline angle, there was an optimal frame diameters ratio that gives maximum inlet critical velocity of flowing fluid. A relatively small increase in frame frequency is obtained when increasing the inlet fluid pressure. Besides that, there was a perfect pipe thickness for each fluid flow velocity that gives rise to get the extremely dynamic characteristic.


Article
The Ovality Problem in Cement Kilns (A Numerical and Experimental Study)

Authors: Montadher A. Muhammed
Pages: 238-265
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Abstract

The Ovality phenomena which occurs in cement kilns was studied by using a numerical method based on F.E. techniques with the help of software (Pro-Engineer 4),the theoretical results was compared with practical one, the temperature distribution for kiln shell was measured by kiln shell scanner. The results showed that the dangerous value of Ovality which cause bricks cracking and falling was 7 cm and up, as well as, the maximum axial stresses was concentrated on the last hot quarter at 14 cm distance of brick. The largest Ovality was found in the burning zone at tire No.1 which was responsible for coating come off and in turn brick damages. The research include suggestions in order to reduce the Ovality phenomena.


Article
SOCKET'S FAILURE OF PARTIAL FOOT PROSTHESIS TYPE CHOPART
فشل الوقب للطرف الاصطناعي للبتر الجزئي للقدم نوع جوبارت

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Abstract

The research was achieved in the center of prosthesis manufacturing ( Sadr Al– Qanat Factory for Prosthesis and Orthoses), and Baghdad Factory/Ministry of Health and Prosthesis and Orthoses workshop (Belong to Technical Medical Institute). The research made a study on a sample of (60) handicapped in the kind of partial foot amputation for the foot kind (Chopart).The material used in manufacturing the socket was plastic or leather or the two materials together. It was found that the maximum percentage of failure was (55%) for the socket made from plastic and the cause of failure was fracture where as the minimum percentage was (15%) for the socket that made from leather and the cause of failure was fracture. Either for the height of the socket It was found that the maximum percentage was (50%) for the socket of height with knee level and the cause of failure was fracture, where as the minimum percentage was (15%) for the socket of 1/3 distance between the knee and ankle joint and the cause of failure was fracture also. Either for the motion of ankle joint it was found that the maximum percentage was (60%) for the socket of no motion and the cause of failure was fracture where as the minimum value was (15%) for the socket of no motion but the cause of failure was the shape change of the socket.

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Article
Studying the Effect of Thermal Shock on Stress Intensity Factor Using FEM
دراسة تأثير الصدمة الحرارية على معامل شدة الاجهاد بأستعمال طريقة العناصر المحددة

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Abstract

This research concerns with studying the effect of sudden increment in temperature or thermal shock effect on Stress Intensity Factor generated at crack region. The Mechanical Stress Intensity Factor (MSIF) was computed using Finite Element Method technique with the aid of ANSYS software as well as a theoretical methods. The percent of error as a comparison between these results was about (3.18%). Elements used for thermal analysis were plane77, then by using switch element technique from thermal to structural so, elements would be plane82 for structural analysis. A comparison between this value and the values of Thermal Stress Intensity Factor (TSIF) which is generated due to thermal stresses in case of applying a thermal load (thermal shock) had been adopted to know the importance of this effect. So, a coupled field method with the same program, had been used to calculate these values with estimation effect of heat transfer method. The results proved that for an instant temperature difference the effect of steady-state heat transfer method was more than the transient method. Also TSIF for low temperature difference, may exceed the value of MSIF in case of (100 MPa) statical structural applied load without considering the temperature effects.


Article
Studying The Effect of Polymer Powders on some Mechanical Properties of Epoxy

Authors: لينا فاضل كاظم
Pages: 289-297
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Abstract

To determine the possibility of using polymer powders as reinforcing materials in the thermoset polymer matrix composite , epoxy as the matrix and carboxy methyl cellulose (CMC) and polyethylene glycol (PEG 4000) as the reinforcing powders were used to prepare a particle reinforced composite. In the sample preparation, seven weight fractions of each powder (0.02, 0.04, 0.06, 0.08, 0.1, 0.12, 0.14) wt% were designed to determine the mechanical properties of composites that represented by hardness and compression strength. The results of this research were: for epoxy reinforced with CMC, the hardness increases with increasing the weight fractions reaching to (78.2 ) at 0.1 wt % and decreases in other weight fractions while maximum compressive load (7.324kN ) was obtained at 0.12wt %, for epoxy reinforced with PEG4000 the hardness increases with increasing the weight fractions reaching to (71.1) at 0.06wt % and decreases in other weight fractions while maximum compressive load (10.449 kN) was obtained at 0.08wt%.

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Article
Effect of Addition SiC Particles on the Hardness and Dry Sliding Wear of the Copper-Graphite Composite

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Abstract

This research have been devoted to copper-graphite particulate composites which have high thermal/electrical conductivities and excellent dry lubrication for solid contacts and sliding that arise from a synergetic composite effect between copper and graphite. They have been widely used in their engineering application for sliding components, such as electrical brushes and bearing .This research is devoted to study the effect of addition of SiC particles at different weight percentage(1%, 1.5% , 2% and 2.5% ), to the copper graphite composite as matrix, which consist of (90 wt% copper – 10 wt% graphite), on the resistance wear under dry sliding condition by using pin-on-disk technique and hardness, the structure produced by powder metallurgy methods (P/M). The results showed that the composite material reinforced with SiC particles has wear rate lower than that of the base composite where, the wear rate of the base composite is (2.58 × 10 -7 ), which is become (0.6×10 -7 ) after addition of SiC at (2.5 wt% SiC), and the results of hardness for the base composite are (25, 7.61) in Vickers test and Brinell test which respectively become (60, 44) after addition of (2.5 wt% SiC).


Article
Numerical Study of the Influence of Vortex Generator on Flow Structure and Heat Transfer Around a Cube Mounted in Channel

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Numerical Investigation of the influence of vortex generator on the enhancement of heat transfer from a wall mounted cube which placed in the middle of a rectangular channel have been conducted using finite – volume method . The momentum and convective heat transfer equations were discretized and solve using large – eddy simulation (LES). In order to study the influence of vortex generator on the flow structures and heat transfer coefficient, the flow which considered a fully developed turbulent flow and the convective heat transfer equations were solved around two cube configurations: a smooth cube and a cube with vortex generator attached to its surface . The vortex generator used in this paper is a simple rib attached to the top and the side walls of the cube, in the steam wise middle of the cube . The flow Reynolds number based on the bulk velocity and the height of the channel was 13000 . The LES results were compared with the experimental data of [6],a good agreement was obtained . Also the results showed that the flow in the boundary layer around the cube with vortex generator is more turbulent and unsteady than the flow around the smooth cube without the vortex generator. More turbulent structures are generated close to the surface of the cube resulting in a good mixing of heat and hence high heat transfer coefficient and this investigation is a efficient way to enhance the heat transfer from the cube with vortex generator .


Article
STEAM CONDENER PERFOMANCE EVALIATION BYUSING NEURAL NETWORK
تقييم اداء مكثف بخاري بأستخدام الشبكة العصبية

Authors: Hisham Hassan Jasim
Pages: 319-333
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Abstract

This work applied Artificial Neural Network (ANN) for performance evaluation of steam condensers which are widely used in power plants and refineries. Two condensers were experimentally investigated. Experimental data was obtained by use unit steam power from G.U.N.T Company and industrial condenser operates in Dura refinery. The commonly used Back Propagation (BP) algorithm was used to train and test network. Input of neural network include inlet water temperature, water flow rate, steam temperature and enthalpy difference. The exit water temperature represented output of the neural network. The maximum deviation between the predicted results and experimental data was less than 1%. It is recommended the (ANN) can be used to predicate the performance of thermal system in engineering applications, such as modeling condenser for heat transfer analysis. Afterwards, ANN resulted used to find thermal parameters (convection heat transfer coefficient of water side and steam flow rate ) based on software program built by Matlab language. Comparing the resulted from modeling with experimental data reveals a good agreement (-3% to 3%).  s m h w


Article
Comparison of Applied Pressure Effect on ImprovingDensity, Hardness, and Microstructure by Both SqueezeCasting Process and Pressure Die Casting Process for 380-Al Alloy

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The present study includes the effect of applied pressure on elimination the porosities that formed during both squeeze casting process and pressure die casting. For pressure die casting the pressure was applied on the full liquid molten alloy (750 o C) where the pressure was applied on molten alloy at (650 o C) i.e. the molten was fifty liquid fifty solid (mushy zone). The tests and measurements of density, hardness, and microstructure show the improvement in density and hardness for the samples of both techniques but the increasing in hardness and density values in squeeze casting were higher than the values of pressure die casting samples also the test of microstructure shows the decreasing in (DAS) for the squeeze sample more than the (DAS) of pressure casting samples. The above improvement in microstructure, hardness, density belongs to the behavior of applied pressure in both cases which means that the mushy zone of molten alloy represents the optimum region to improve the mechanical properties by applied pressure


Article
Inhibitive Action of Ellagic Acid on Corrosion Behavior of ( 316 L SS ) in Simulated Body Fluid
التأثير التثبيطي للأجك أسيد على سلوك التآكل للحديد المقاوم للصدأ في اللعاب الصناعي

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Abstract

Potentiodynamic polarization measurements were used to study the effect of Ellagic acid on biocorrosion of ( 316 L SS ) in Simulated body fluid (Ringer Solution) was used as the electrolyte .The temperature of the polarization test cell was maintained at 37±1 O C by thermo stated water bath to simulate the human body .The result from corrosion behavior investigated by electrochemical measurements appear the corrosion current density of ( 316 L SS ) specimens in Ringer solution containing Ellagic acid was much lower than the values obtained in Ringer solution without Ellagic acid .


Article
FINITE ELEMENT ANALYSIS OF CONNECTING ROD USING NASTRAN SOFTWARE

Authors: Wisam Abdul-Lateef
Pages: 357-374
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Abstract

Connecting rods , are widely used in automotive internal combustion engines .In this paper, the connecting rod model based on finite element analysis (FEA)is proposed. Critical location of maximum stress and suitable materials for the connecting rod has been identified and the contact stress analysis and dynamic behavior of it has been investigated.The structural model of the connecting rod was utilizing the ( Solid works) and Steel alloy (C-70) materials. The linear static stress distribution and dynamic analysis are investigated using Finite Element software package (NASTRAN).For TET10 mesh the linear static stress analysis and the critical location was located at node (174743) and the critical location for TET4 was at node (110703).Then it can find that TET10 is able to capture the higher stresses than TET4 for the same global length and size.


Article
MODELING and SIMULATION of ELECTROPATING PROCESS
نمذجة ومحاكاة عمليات الطلاء الكهروكيمياوي

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In this study, it is acquainted with the kinetics of the chemical and electrochemical reactions by modeling and understanding of the essential and secondary (conjugate) chemical and electrochemical reactions during plating process . In addition , the effects of various conditions on the speed and kinetic of those reactions is also considered . In order to apply this manner , the mean-field kinetic equations and Poisson equation for charged lattice model are adopted using two types of one-dimensional cells for theoretical part of this study , namely (half and full cell) e/2 ) . Provided that the cell should contain two identical electrodes of thickness ( of size ( 100 ) with an applied potential of ( 10 ) .A computer program in visual basic is specially constructed to show the results of this study as it should be . Through this program the concentrations are determined including (metallic atoms, cations, anions, solvents, vacancies and electrons) , the charges distribution and electrical potential across the sites. the results , during the three periods ( 10)5,3,1( t ) , showed that under potential application across the cell , the deposition continues for long time then it is suppressed when the anode reaches 5 failure limit , and it is observed that the deposition increases with the extension of space charges at the cathode , from the other hand , the ionic evolution (cation) will take a peak shape at the cathode , then it has a certain gradient between anode and cathode. A reversed situation occurs for the anions evolution . At the same time, electric potential distribution across the sites becomes higher resulting in deposition increasing .


Article
NUMERICAL INVESTIGATION OF FREE VIBRATION ON NEW STEPPED WING MODEL

Authors: Ahmad Saddy Mohamad
Pages: 389-410
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Free vibration study represents one of the most important studies for complex structure such as wing structure. In this search, a new model for wing structure was created including changing in the airfoil shape. The wing of airfoil Naca 2414 of aluminum 2024 alloy was used to construct the wing. Four case studies were accomplished for different airfoil shape so that the location of the airfoil is change from location to other at the chord. Free vibration analysis for five modes was performed to obtain the vibration characteristics such as natural frequency and mode shapes. From the results, it was found that, in general the change in the airfoil leads to (keeping same weight so the thickness and wing length remain constant) increase the vibration characteristics. A numerical program include the analysis was achieved and added to ANSYS milieu as a new motivation.

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Article
EXPERIMETAL INVESTIGATION OF TEMPEARTURE DISTIRBUTION IN ARC FUSION WELDING

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Experimental study of Heat transfer phenomena in welding process has been carried out in the present work. The experimental study was carried out on six groups (each consists of two plates) of low carbon steel material. Each plate is rectangular in shape with dimensions of (150mm x 200mm) with different thickness, (11mm) for groups (1) and (2) from A285 grade (B), ((16mm) for groups (3) and (4) from A 285 grade (C), and (19mm) for sets (5) and (6) from A285 grade (A) using single V-Butt edge design of joint welding for each group. Data Acquisition System (DAS) was manufactured and used in order to measure the transient temperature distribution of the models at the selected positions (channel (1) to channel (10)). The experimental measurements showed that the maximum temperature occurs close to the fusion region and starting to decrease a way from fusion region which is called unaffected base metal passing through the region of heat affected zone. The agreement of the results are good a comparison with present experimental work. Confirm results that were carried out experimentally. The agreement of the results is good capability and reliability the experimental steps of calculating heat transfer in Manual Metal Arc welding (MMAW).


Article
Effect of filler materials on the dry sliding wear behavior of unsaturated polyester resin
تأثير المواد المالئة على سلوك البى الانزلاقي الجاف لراتنج البولي أستر غير المشبع

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In this paper, several specimens from unsaturated poly ester resin with different filler materials such as (Fe2O3, CaCO3, CaO, Cement, Ca(OH)2( have been prepared. Three weight percent have been used as (10%,20%, and 30% wt)from each filler materials. Casting samples are grinded by 800 grit using SiC grinding paper and then washed by distilled water. Dry sliding wear has been done using pin on desk test in different period of wear time as (5,10,15,20,25,30 min). it has been shown that addition of cement with percent (10 % wt) get lower wear rate for unsaturated polyester resin.

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