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: 2009 volume:B issue:first conf./ eng. coll.

Article
OPTIMUM DESIGN OF REINFORCED CONCRETE

Authors: Dr. Alaa Chaseb Galeb
Pages: 201-210
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Abstract

This paper presents the application of Simulated Annealing optimization method (SA) for solving the problem of the optimum design of reinforced concrete beams based on the recommendations of American Building Code Requirements for structural concrete (ACI 318-05) and the ultimate strength design method. Cost of concrete, cost of steel reinforcement and cost of formworks are considered. The constraints of the problem included the concrete beam strength, width-height ratio, minimum width, and deflection constraints. This optimization problem is implemented by constructing a computer program using Matlab. A number of examples are solved using the developed program and proved that the produced design is economical; also it is proved that the developed program is efficient and versatile.


Article
Flexural Behavior of Reinforced Concrete Partially

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Abstract

This research deals with the flexural behavior of partially end restrained slabs subjected to burning by fire flame. The investigation is based on casting and testing 16 reduced scale (600×600×40mm) reinforced concrete slab specimens. Two concrete mixes with design 28 days compressive strengths of (30 and 38 MPa) were adopted. Two steel ratios of (0.005, 0.009) were used. The specimens were exposed to fire flame temperature levels of (400,500 and 600 211 ° C) at the lower surface of the slab specimens with exposure duration of one hour, then after 24 hours; they were tested in flexure to failure under uniformly distributed load while they are partially edge restrained against lateral and rotational movements. It was found from the results that the values of ultimate load capacity, decreased for all specimens after exposing to fire flame. The residual ultimate load capacity for specimens burnt at temperatures of (400 and 500 °C) was higher than that for specimens burnt at 600 ° C. At temperature around 600 ° C and for steel ratios of (0.005 and 0.009), the percentages of residual ultimate load ranged between (85 and 87%) respectively. The residual compressive strength at 600°C was about (63 %). However the residual modulus of rupture was in the range of (47 and 51 %) and the residual modulus of elasticity ranged between (29 and 26%) at 600ºC.

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Article
Effect of Fire Flame Exposure on Flexural Behavior and

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In this study flexural behavior and shear strength of reinforced concrete beams made of normal strength concrete (NSC) and high performance concrete (HPC) with compressive strength (30,78) MPa respectively at (28) days age, and assessing the residual flexural and shear strengths after exposure to fire flame. The concrete specimens were subjected to fire flame at temperature levels of (400 º C) and (700 º C) at two periods of exposure (1, 1.5) hour then cooled either by air and water. Firing and testing the beam specimens were conducted at age of (60) days. Results indicate remarkable reduction in flexural and shear strengths after exposure to fire flame. The residual flexural strength is (84- 88%), (70- 72%) for HPC, and (86- 91%), (84- 88%) for NSC with (1.0) and (1.5) hour exposure periods respectively at fire temperature (400 º C), while the residual at fire temperature (700 C) is (50-58%), (37-38%) for HPC, and (53-60%), (26-41%) for NSC with (1.0) and (1.5) hour exposure periods 93%), (75- 77%) for NSC with (1.0) and (1.5) hour exposure periods respectively at fire temperature (400 º C), while the residual at fire temperature (700 º C) is (50-55%), (40-45%) for HPC, and (54-57%), (38-46%) for NSC with (1.0) and (1.5) hour exposure periods respectively. º

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Article
THERMAL IMPROVEMENT OF SOLAR HOT WATER

Pages: 244-257
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Abstract

This study includes a comparison between the performances of two locally fabricated similar flat plate solar collectors. One of these collectors is a new design of accelerated absorber, its risers are of converging ducts (the exit area is half that at the entrance). The other collector is of conventional absorber (its risers have the same cross sectional area along its length). Each collector is the major part of an indirect thermosyphon circulation solar hot water system facing the south with a fixed tilt angle of 33.3 o from the horizontal. A side by side experiments are conducted for three months 1,2,&3 of 2009 for different water withdrawal profiles, continuous, interrupted and no load, also for horizontal and vertical storage tank orientations. Two types of storage tanks are investigated (two concentric cylinders and helically coiled tube in cylinder). Results show that a considerable enhancement of thermal performance approximately (60%) of absorbed heat (useful gain) at solar noon is obtained for the new design in comparison with the conventional type. The instantaneous efficiency was 31.5% for the accelerated absorbed flat plate at solar noon, while that of conventional absorber was (16.5%). The longitudinal water temperature variations in the risers of accelerated absorber were larger than that belong to the conventional absorber. The stratification in the storage tank is considerably improved for the solar hot water system with the new absorber design in which the maximum temperature indicated was 50 C (vertical storage tank) while that for conventional absorber was 37 o C. The stratification obtained for coiled tube in cylinder storage tank indicates a good thermal performance with less space requirements. Also the circulation rate in the accelerated absorber was higher when it is connected to coiled tube than that when it is connected to the concentric cylinders. o


Article
EFFECT OF PARTICLE SIZE,FLOW VELOCITY AND

Authors: Dr. Tahseen Al-Hattb
Pages: 258-268
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Abstract

An experimental study to investigate the effect of the particle size (d ) and Reynolds number (Re) for different values of heat flux on the heat transfer coefficient (h) in gas-solid fluidized bed was done. In this work three different sizes of sand particles were employed (525,725 and 925 mµ ). The fluidizing medium was air at different velocities in the range of (1.9-2.9 m/s). The rig provided with a horizontal heating tube with outer diameter of (3.175cm) was heated eclectically with different power supplies (69,90,120 and 150 W) . The fluidized bed temperature profiles were evaluated axially in the fluidized bed for different positions. The recording and the monitoring of these measurements were done by an interface system connected with PC computer. The results show that the temperature distribution decreases with increase particle size and the heat flux represents as the temperature increases as the air velocities increase . A new empirical correlation was suggested in this study .The correlation predicts the value of (Nu p ) as a function of both (Re p ) and (Fr ). All the dimensionless groups are determined based on particle diameter . 48.057.0 Re0042.023.5 Re0738.0 pp p + = p p << << 1675406 168Re61 Fr Fr Nu p p p


Article
دراسة تأثير الكاؤولين في تصميم عجنه مطاطية لاطارات الطائرا ت

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Abstract

This research aims to use the Kaolin material (which is available, cheap, and can undergoes high temperatures) in the design of the rubber master batch which is able to satisfy the special requirements those related with the applications of tires used in land and take off of the airplanes, such as: High Abrasion Resistance, Superior Adhesion between rubber and metals, Suitable Damping Properties, and Resistance to Swelling and High Temperatures. This research has been carried out by using Hard Air Floated Kaolin with 3 µm particle size (DIXIE CLAY) in the laboratory of Babylon Tires Company, and the properties have been measured according to the standards specifications (ASTM). The results showed that: the Adhesion Force has improved when adding Kaolin to the master batch of Natural Rubber (NR) from 33 N to 190 N, Abrasion Resistance (by using the weight difference method) has improved from 0.0096 g to 0.0173 g, Rebound Resilience has improved (decreased) from 45% to 68% (i.e. the damping or the hysterises has increased from 55% to 68%), and at last Resistances to Swelling and Ageing have been improved greatly.


Article
Effect of Heat Treatment on Microstructure and Corrosion

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This work aims to study the effect of the heat treatment (precipitation hardening) on microstructure and corrosion parameters of two alloys (Al- 4%Cu) and (Al- 4.1%Cu- 0.9%Mg). They were prepared by melting and casting in a metallic mold. Hot rolling at 450C° was carried out on ingots by 50% deformation of two alloys to get sheets. Many tests were conducted on these prepared alloys of cast and wrought conditions, including microstructure and hardness and corrosion test. Precipitation heat treatment was carried out which included solution heat treatment at 515C° and aging. Two types of aging, artificial aging at 190C° for 3hr and natural aging at 25C° for 7 days were carried out on prepared alloys in order to indicate the effect of these heat treatments on the microstructure and hardness. Electrochemical corrosion test by Tafel extrapolation method was carried out on all prepared samples of alloys in sodium chloride solution of 3.5% NaCl (PH=8.2) to determine corrosion parameters. such as corrosion potential ( Ecorr. ),corrosion current ( Icorr.) and corrosion rate (mpy). The results show that the corrosion rate of cast samples and homogenized treated was lower than that of wrought samples of two alloys (Al- 4%Cu) and (Al- 4.1%Cu- 0.9%Mg) in salt solution at room temperature. Precipitation heat treatment and artificial aging at 190C° for both cast and wrought conditions lead to increase corrosion rate. The results also show that the addition of Mg to (Al-4%Cu) alloys reduce corrosion current density( I corr .) and corrosion potential (E ) shifts to more noble direction in 3.5% NaCl solution for two alloys in cast and wrought conditions. corr

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Article
A Modified Approach for Reactive Power Compensation in

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This paper presents an attempt to introduce a modified approach for an optimization technique, where the automatic and controlling problems will be analyzing and formulated aiming to improve voltage regulation and reducing power losses. An optimal control of capacitor banks in distribution power systems will be discussed also, using intelligent control. The focus will be on the capacitor placement problem to determine the locations and sizes of the capacitors so that the power loss is minimized and annual economic savings are maximized to achieve the reactive power compensation, in addition to the power factor enhancement.

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Article
A comparative study of final projects of architectural engineering of

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The architectural studies consider as part of cognitive studies in most of worldly universities .The investigation includes six final projects from both countries. The comparative study is made between these two samples which are artistic presentation point of view and the scientific point of view. The former includes the efficiency of presentation, colours and writings. While the latter includes the type of design whether it is urban design or single buildings, way of thinking i:e input, output, diagrams, analysis, human and visual scales, details about the used materials and drawings, type of structure land scapins.) Which consider as determiners in architecture engineering on the basisis that architecture is a mixture of since and art. The researcher propose that there are many differences in the syllabuses , customs , circumstances and other technical materials of the two countries. The study has got by using the analysis on the description of the samples results which denote that there are differences in comparative elements. Then we have got different conclusions with respect of two groups of samples.


Article
Updating the urban plan of the status holy city center of karbala

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Abstract

Cinter of karbala damaged during the demolition of the events in 1991 especially areas near the Imam Hussein ,peace be upon him and his brother Abbas . Demolition has been left unused space and lack of visual and organic link with the rest of the city near or far from it … The removal of a link between Almrkadin surrounding them has led to the removal of many services ,disturbing the movement of vehicles and pedestrians in the city . The mayor of karbala ,the implementation of the directorates of concrete fence to cover these areas ,dilapidated and led to distor the appearance of the city urban and the negative visual impact and Almrkadin and their surrounding in . Addition to isolate them from the city which the free space that have emerged between Almrkadin and their axes ,some of the main streets led to the loss of the human standered for urban design to address the realities,so there was aneed for the preparation of city.

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Article
RESIDENTIAL WATER DEMAND ANALYSIS IN HILLA

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This paper investigates the analysis of residential water demand for the city of Hilla which is the main town in Babylon government in Iraq( Population of about 258568 person , living in an area of 55 Km 2 according to Central Committee of Statistics – Babylon Census Directorate -1997) along with determining the factors that affect such demand for the period from the 1 st of January to the end of August -2004. The cross-section data which was weekly observed was collected by a survey made on a sample of randomly chosen dwellings from different districts of the city. A questionnaire survey was also made to collect all necessary information seemed useful in estimating the daily consumption of domestic water. Demand relations are estimated for total residential, winter, summer, and Sprinkling demands. Stepwise multiple regression analysis was employed to find the structural relationship between water demand per household per day and household characteristics (factors) for each type of demand. All demand models were fitted in log-linear form. In this survey, the average daily water demand for the city of Hilla was estimated to be 1721 L/h/d (273.2L/c/d) for total model, 586.13 L/h/d ( 93L/c/d) for winter model , 2453 L/h/d( 389.4L/c/d) for summer model and 490 L/h/d(77.8L/c/d) for sprinkling model. The most significant factors affecting the demand appear in the fitted equation. Of these factors, household size was found to be significant variable in all demand models, while number of washbasins variable was found to be the significant variable in the total, winter, and summer model. The total built –up area of the house and number of showers was found to be the significant variables in the total and summer models.

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Article
دراسة تأثير مقدار وتركيز الملوثات في نهر الديوانية

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That the reduction of environmental pollutants in the river is one of the most important priorities for the production of drinking water. In this study were selected river known as the Shatt al-Diwaniyah , to demonstrate the potential environmental impacts of various pollutants in the area from the Sunni, is north of the city, even in southern city of Diwaniyah, about (15 km) inside the city at (15) stations selected for the period from March 2008, until the end of October 2008. Study included the measurement of suspended solids (TDS) to the waters of the Diwaniyah, with a measure of directional acid , electrical conductivity measurement, a measurement of dissolved oxygen. The measurement of the concentration (nitrate, the need for chemical oxygen (COD), phosphate). Showed the results of the study during the examination of the statistical analysis that there are weaknesses in the relations between the concentrations of pollutants in the plant (1), with the change in water temperature at all stations ranging between (25.95-31.78) m, respectively. PH values with a range of constraints in all the stations ranged between (7.50-8.17). Also recorded the electrical connectivity values ranged between (1333-1516) Maekerosemnz / cm, total dissolved solids (TDS) values ranging from high (774-875) mg / L, dissolved oxygen values ranging between (7.55-9.51) mg / L , the study recorded a high concentration of vital oxygen requirement beyond the parameters allowed in most of the stations studied. Nutrients were also observed, which fluctuated in a narrow band and a clear concentration especially nitrate, which ranged between (8.01-16.10) Maekerowerem / liter. The effective rate of the phosphate concentration is higher than the permissible limits according to the maintenance of river-1976 rate, in most stations. Has also been observed through the statistical analysis that there is a small decline in the concentration of pollutants to the station with the same time. Why all of this is due to the presence of rubber and textile factory, which put toxic chemicals as well as the presence Al-mbazl in addition to a fever hospital, and kidney of industrial waste into the river, raised, as well as abuses of the networks in the rain by the citizens living on both sides of river. And most of the inefficiency of the main treatment plant as the existing amount of water entering the plant exceeds design capacity to the plant, this water is not in conformity with the emerging environmental determinants of sewage discharged to rivers, the river level in the study period was less from previous years. ﻪﻣﺪﻘﻤﻟا) Introduction.(

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