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:1

Article
NUMERICAL STUDY OF THE TRANSIENT HEAT TRANSFER ERMAL ENERGY STORAGE SYSTEM BASED PCM
الدراسة العددية للحالة غير المستقرة لنظام خزن الطاقة الحرارية

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Abstract

In this paper, the unsteady state heat transfer through the thermal energy storage system is investigated numerically by using finite difference method in order to study the optimum thermal design of the latent heat thermal storage. The present analysis takes into account the heat transfer in two dimensions for fluid, tube and the PCM. The conical shape of the PCM is examined here for different diameters depending on the cone angle (ψ). The results of the present study are compared with other study to confirm the accuracy. Results of a numerical case study are presented and discussed. The results show that the decreasing the value of (ψ) will increase the hot and cold fluids effectivenesses and the difference between the effectiveness (hot and parallel cold and counter cold) increased with decreased value of (ψ) in the negative range (ψ = -0.13 deg). The counter flow for the cold fluid produce higher effectiveness than the parallel flow for the cold fluid especially for the negative value of (ψ = - 0.13 - 0 deg).


Article
TRANSIENT THERMAL BEHAVIOR OF FLUIDIZED BED COLUMN

Authors: Dr. Riyadh S. Al-Turaihi
Pages: 23-37
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Abstract

The effect of the particle size (d p ) and the fluidized velocity investigated Experimentally and theoretically for different values of heat flux thermal behavior in gas-solid fluidized bed was done with time. In this work three different particle size was employed (450,650 and 850 mµ ). The fluidizing agent was air at different velocities in the range of (2-2.8 m/s). The rig provided with a horizontal heating tube with outer diameter of (3.175cm) was heated eclectically with different power supplies (80,240,350 Watt). Presented mathematical model one dimensional unsteady includes energy, continuity, and momentum equations for each of two phases. In order to solve the foregoing equations in a numerical way, the discretization method based on control volume procedure has been used the computer code (FLBD) which is written with mathlab 2008. The results show that the temperature distribution along the packing height decreases with increase particle size and the heat flux represents as the temperature increases as the air velocities increase with time. Compared the experimental and theoretical results and the comparison is a good agreement.


Article
COATED CARBIDE CUTTING TOOLS PERFORMANCE IN HIGH SPEED MACHINING PROCESSES
اداء عدد القطع الكاربيدية المطلية في عمليات التشغيل غند السرع العالية

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Abstract

High-speed machining (HSM) has emerged as a key technology in rapid tooling and manufacturing applications. The present work studies the effect of cutting parameters (cutting speed, feed and depth of cut) in turning process applied on C-60 steel using multi- coated carbide cutting tools at high cutting speeds. The influence of cutting parameters on a cutting forces, tool wear and surface roughness are analyzed. The importance of orthogonal force components to surface finish and tool wear are explored. The results show that cutting forces has a very strong correlation with surface finish and that increased spindle speeds lead to far superior surface finish .Tool wear measurements demonstrated the capability of such coated carbide tools in turning steel with reasonable low tool wear (i.e. high tool life). Forces measured resulted in relatively low values. The cutting component (F c ) is the largest of all. For the different cutting conditions studied, the feed rate has the greatest influence on force and tool wear.


Article
THE EFFECT OF REST PERIODS ON THE FATIGUE LIFE OF MEDIUM CARBON STEEL UNDER DIFFERENT FATIGUE LOADING

Authors: Dr. Hussain J.M.Alalkawi
Pages: 48-62
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Abstract

The fatigue crack growth ( FGG ) behaviour of medium carbon steel alloy under different rest periods is investigated under room temperature and stress ratio R= -1 using replication technique . This work examines the constant and variable amplitude torsional fatigue under different time of rest periods . The short and long fatigue crack growth equations are obtained experimentally . The average grain size diameter is 0.277 mm which separates between short and long crack region. The main remarks can be drawn from this work are : The fatigue life of specimens is increase by rest periods under constant amplitude tests . The factor of increasing is about 1-12 . While this factor becomes 1.75 – 8.7 times the predicted life for variable amplitude tests . Rest periods generate strain ageing which in terms increase the total fatigue life .

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Article
SOME OF DIELECTRIC PROPERTIES OF POLYMER/FERROELECTRIC COMPOSITES

Authors: Inaan M. Abdulmajeed
Pages: 63-72
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Abstract

BaTiO 3 , synthesized in polycrystalline form, using stoichiometric mixture of oxide with traditional ceramic technique and characterized by X-ray diffraction, tetragonal structure of prepared powder were found. Moreover, particle size of ceramic powder determined using laser particle size analyzer. The particle size distribution was found in the range (0.427-3.195)µm. The epoxy ceramic composite system was prepared. BaTiO 3 with content 10%, 20%, 30%, 40%, 50% wt and 60% wt. respectively used as filler. Permittivity of the composites was investigated at frequencies from 2KHz to 5 MHz The dielectric loss tangent (tanδ) was determined as a function of frequency, compositions. It was found that the weight percent of BaTiO composite effect on the dielectric properties. At low frequencies, BaTiO 3 3 filler in ceramic/epoxy /Epoxy composites have much higher dielectric constant. Dielectric constant increases considerly with the addition of BaTiO 3 fillers, however, the higher conductivity of BaTiO conductivity with increases BaTiO 3 3 than epoxy lead to an increase in ac content, the increase in both properties was attributed to the presence of the high permittivity ferroelectric phase


Article
ESTIMATION OF FATIGUE PROPERTIES OF 35NCDV12 ALLOY STEEL UNDER CHROMIUM COATING USING THE STAIRCASE METHOD
( تخمين خصائص الكلل لسبيكة الفولاذ OF 35NCDV12 تحت التغطية الكرومية بأستخدام طريقة السلم )

Authors: Dr. Nabil N. Swadi *
Pages: 73-88
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Abstract

In this paper, the experimental estimation of the fatigue strength and the standard deviation for the 35NCDV12 alloy steel have been found using the Staircase (up and down) method. The specimens divided into two groups. The first group contains 15 non-chromium specimens and the second group contains 15 hard chromium specimens. The thickness of the chrome is about (100 to 120 microns). The fatigue or endurance limit has been determined for each group and then compared with that estimated from S-N (Whler) curve for the 35NCDV12 alloy steel. The results show that the endurance limit of the chromium specimens is decreased to a ratio about 60 % from those non-chromium specimens. This proves that the chromium plating increases the wear and corrosion resistance of the metals and decreases the fatigue strength and endurance limit of those metals. In addition, the results show that the staircase method is very useful testing compared with S-N curve for estimation the endurance limit without a large number of specimens.

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Article
STUDYING THE EFFECT OF TEMPERATURE ON THE BUCKLING LOAD OF LAMINATED COMPOSITE PLATE UNDER DIFFERENT BOUNDARY CONDITIONS
دراسة تأثير درجة الحرارة على حمل الانبعاج للصفائح المصنوعة من مواد مركبة تحت ظروف حدية مختلفة

Authors: Nessren H. Ahmed
Pages: 89-106
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Abstract

ABSTRACT In this study, effect of temperature, aspect ratio, number of layers and boundary conditions on critical buckling load of composite laminated plate was investigated numerically. Six different boundary conditions: (SSSS, SSFC, SSFS, SSFF, SSCC and CCFF), three temperatures (40C, 60C and 80C) and four aspect ratios (1, 1.3, 1.5 and 2) would consider. These variables were analyzed with different types of laminated plate (unidirectional, cross - ply and angle - ply). The thickness of the plate was changed by increasing the number of layers. The results showed that in the case of (a/b = 1 and θ = 0), and the temperature changed from (40C) to (80C), the maximum value of critical buckling load dropped by about (53 %) for (CCFF), while the minimum value of critical buckling load dropped by about (63 %) for (SSCC). Also, it was found that the maximum value of critical buckling load dropped by about (60 %) at the ply orientation (0/0) and (20/-20) at a/b = 1 and CCFF, while the minimum value drops by about (64 %) at the ply orientation (0/0), a/b = 1 and SSCC as the temperature changed from 40C to 80C.


Article
Effect of Heat Treatment on Mechanical Properties for Grey Cast IRON
تأثير اوساط التبريد على الخواص الميكانيكية لملحومات حديد الزهر الرمادي

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Abstract

In this study grey cast iron welded by arc carbon method for two state: first the sample welded immediately, second the sample preheating to 500 o C for samples of weld Region and heat affect zone HAZ then cooling in different media ( air , dry sand and furnace) after test we found that decreasing in hardness and tensile strength, when the cooling rate decrease than that of cooling in the air, microstructure located on the surface of the weld sample convert to Martinsite Phase ( M ), For the sample which cooling in dry sand and furnace, the hardness was less because of decreasing cooling rate that made less changing in microstructure. It was also found that the decreasing in hardness when preheating for sample and increasing in tensile strength led to obviation growth in grain size resultant partial decomposing for perlite that lead to improving toughness and Impact strength .

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Article
THE EXPERIMENTAL STUDY FOR HEAT TRANSFERRED FROM BUILDING ROOFS AND ROOF FINISHING SYSTEM USAGE .
الحرارة المنتقلة من سقف المبنى ونظام التسطيح المستخدم (دراسة تجريبية)

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Abstract

The object of this work is study the thermal behavior for building roofs which made from 150 mm concrete and cover with different materials instead of concrete roofing tiles ( gray color ) at Baghdad city ( 33.2° N) ,its found that the concrete roofing tiles which painted by white color gave 35 % saving value when compared with that energy consumed ordinary tiles ( before painted) while put the plastic tiles over that tiles gaves %28 saving value , and used the concrete roofing tiles which contained 8 mm insulated materials with fiber glass screen gives %27saving value and that tiles is less weight .


Article
TREATMENT OF SOOT MASS EMITTED FROM DIESEL ENGINE
معالجة كتلة السناج المنبعث من محرك ديزل

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Abstract

Soot particles emitted from diesel engines to atmosphere pollute the environment air because many hydrocarbons known for their cancerous properties adsorb on its surfaces during the combustion processes of diesel fuel. These soot particles have very small diameters (less than 2.5 µm) and easy enter with air to the human respiratory system during the inhalation process. In order to control of soot emitted from four stroke, direct injection, air cooled and single cylinder diesel engine we executed two important parts; (1) Rate of soot mass emitted from this engine was measured inside the passageway of exhaust gases. One of the gravimetric methods for soot mass measurement in combustion systems was developed to measure the rate of soot emitted from diesel engine. (2) The rate of soot emitted from the engine was treated in a laboratory scale. Different diesel soot mass patterns were prepared according soot mass measured in limited time interval at different engine loads, and then the soot oxidation rates were studied using linear heating and isothermal heating inside the electrical furnace. The results of soot emitted measurements show that the rate of soot emitted significantly increases and reaches, at high engine loads, to 0.4533 mg/min because of highly reduced in A/F ratio. Then large amounts of diesel fuel inside the cylinder suffer from pyrolysis heating. The results of soot mass treatment with linear heating show that the rate of soot mass oxidation is significant at mid and high loads between the temperatures (500- 800 C o ). It can be concluded, from the results of soot mass oxidation at isothermal heating with different temperatures (600 C , 800 C o ), that the rates of soot mass oxidation at different soot masses (i.e. different engine loads) is approximately equal 25 mg/min. o , 700 C o


Article
النظام الامثل لمتطلبات برامج الصيانة في المنشآت الصناعية ( الايدي العاملة - المواد - الجهد - الكلف )

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Abstract

Field research confirmed that the maintenance activity equal to the importance of productive activity At the same time not be seen as purely a work of engineering, but among the activities of administrative and engineering, economic, because it aims to achieve a better exploitation of factors of production of basic materials, machinery and work Production Elements in order to reduce production costs next to maintain the specified quality standards for the finished products. That the calculated requirements best Perfects the elements of major maintenance (labor - raw materials - labor - costs) will be reflected certain to increase the amount of production per unit time and improve product quality by reducing the rates of damage during production and reduce the cost of manufacturing, from here it is clear that interest in conservation and the adoption of systems and advanced studies for planning effectiveness factor of the key factors for achieving the goals of industrialization and improve the indicators of profit on the whole level of productive activity for any manufacturing facility, and therefore we can through this research to achieve the following advantages : - Utilization of production capacity available to the most efficient. -Managementof maintenance efficiency target. - Improve the indicators of profits through control of the cost elements of the search. - Find elements are indicators of the operational efficiency of the facility. - Reduce accidents and injuries during the implementation stages of production for the manufacture of specific goods.

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Article
STUDY THE EFFECT OF SILICON ADDITION ON THE CORROSION BEHAVIOR AND DRY SLIDING WEAR OF CU AL NI SHAPE MEMORY ALLOY
دراسة تأثير اضافة السليكون في السلوك التآكلي والبلي الانزلاقي الجاف لسبيكة ( نحاس - المنيوم - نيكل ) التي تتذكر شكلها

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Abstract

In this search the effect of silicon additions on the corrosion and dry sliding wear behavior of (Cu+13wt%Al+3.8wt%Ni) shape memory alloy have been studies, alloys prepared by powder metallurgy in two case based alloy after sintering treatment at temperature 850 for 6hr and alloys after addition silicon as (0.4 , 0.8 wt%Si).Corrosion test based up electrochemical by drawing the polarization curves method (Tafel) in salt solution (3.5wt%NaCl).A Dry sliding wear has been studies based on pin on disk at a constant load, constant velocity and constant distance of sliding with various sliding time. The result shows when the silicon content increase the corrosion resistance of alloy increases also the dry sliding wear resistance of an alloy increases .

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