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:first conf./ eng. coll. issue:A

Article
FITTING SEASONAL STOCHASTIC MODELS TO INFLOWS

Authors: Dr. Salah Tawfeek Ali
Pages: 1-12
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Abstract

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Article
Effect of Non – Uniform Permeability on the Operational

Authors: Dr. Basim A. Abass Lekaa' Hameed
Pages: 13-25
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Abstract

Effect of non uniform permeability on the operational characteristics of finite width misaligned self lubricated journal bearing is investigated throughout this work. A modified boundary conditions for the oil film pressure is obtained by applying integral momentum equation to the oil film region in the bearing clearance. The performance characteristics of a misaligned self lubricated journal bearing with slenderness ratio of unity are obtained for various eccentricity ratios and misalignment angle. The bearing permeability is changed in radial and circumferential directions. Using self lubricated bearing with non – uniform permeability enhances the performance of such bearing. An decreases in maximum pressure and load carrying capacity, attitude angle, and coefficient of friction. Oil film extent increases with increasing the oil supply pressure.


Article
BUOYANCY EFFECTS ON OPPOSING LAMINAR FLOW

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Abstract

Experiments have been performed to investigate mixed convection heat transfer in the thermal and hydrodynamic entrance region of a uniformly heated inclined tube. The effects of surface heat flux, Reynolds number, the direction of main flow relative to secondary flow (opposing flow), and angle of tube inclination on the temperature distribution and local Nusselt number along tube were studied. The study covered Reynolds number range (450≤ Re ≤2008), and heat flux range (95 ≤ q ≤898) W/m Rayligt number from 1.1132  10 5 to 3.6982  10 5 and angle of inclination α=0° (Horizontal), α=30°, α=60° (Inclined), α=90° (Vertical).Results show that the heat transfer process improve whenever move angle of inclination from vertical position to horizontal position . The experimental data were correlated for Nu as a function of Ra m &Re m m for each angle of inclination and then superimposed the angle of inclination to give a general equation of average Nusselt number at any α in opposing flow. 2 ,


Article
Study the Effect of Grain Refinement and Modification on

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The present study deals with an investigation of dry sliding wear behaviour of grain refined and or modified (Al–20Si) alloy by using a Pin-On-Disc. The refining was by grain refinements (Ti and B), modification (Sr, Na and P) and combined action of both (Ti, B + P +chilling). Results indicate that combined grain refined and modified Al-20Si alloys have microstructures consisting of uniformly distributed α-Al grains, eutectic Al–silicon and fine primary Si - particles in the interdendritic region. These alloys (5,6) exhibited better wear resistance (13-15 times) than the same alloy subjected to only grain refinement or modification (1, 2 and 3) . The improved wear resistances are related to the refinement of the aluminum grain size, uniform distribution of fine fibrous eutectic Al–silicon and fine primary Si- particles.

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Article
Analysis Sequencing of Manufacturing Processes of the

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The study immediately aims to prepare technical path to manufacture three industrial products because of its unavailable in local markets where two of its use for translating of motion in the lathe machine and one use for translating of motion in an internal combustion engine where introduce the best percentage loading time(exploit) on the productivity machine and an addition to calculate of waiting time on it. This research deals manufacturing that products in the sequencing workshop includes three productivity machine are (lathe, milling, grinding) where for every machine one operator with calculates operating time to those products depending upon scientific rules at any stage of operations machine to arrive the best sequencing which is giving the total of shorter time to executive an industrial sequencing operations upon productivity machine then those products are testing then dealing by heat treatment and cooling with special rates to add limited specifications. An effects appear that (CAB) is an optimal sequencing which finishing productivity cycle with time(129)minutes and the waiting time(0,33,72) minutes upon productivity machine.


Article
Effect of Percentage of Fibers Reinforcement on Thermal and

Authors: Dr. Abbas A. Al-Jeebory
Pages: 70-82
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Abstract

The objective of this research is to study the effect the change of reinforcement percentage by fibers on the thermal conductivity for polymeric composite material consist of conbextra epoxy (EP-10) resin reinforced by biaxial woven roving S–type glass fibers )º٤٥-º٠( with density (550 g/cm 2 ) where we used different percentage of fibers reinforcement to the resin (20%,40%,60%,80%) and studied the influence that on thermal conductivity for composite material due to this change, and we used Fourier equation to calculate the thermal conductivity coefficient (k),and we used reinforcement percentages (20%,40%,60%) to reinforced the mechanical tests specimens to calculated impact strength, tensile strength, flexural strength as illustrated in diagrams which represent the relation between thermal conductivity coefficient (k) with temperature and between mechanical properties and reinforcement percentages.

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Article
دراسة الموصلية الحرارية ومقاومة الصدمة لمادة البولي استر غير المشبع المقواة بدقائق الالمنيوم

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Abstract

This work aims to prepare a polymer – metallic (composite material) reinforced by aluminum particles with different grain size and various volume fraction. Using filing particles from aluminum with a grain size (13 µm), and aluminum dust particles. This work studies the effect of volume fraction for aluminum particles and predicts its effect on thermal conductivity and impact strength of the prepared composite material. The results show that the thermal conductivity of a material reinforced by aluminum particles (filings) increases as the volume - fraction increases, where it reaches (4.85 W/mm.K) at volume – fraction (9.2 %), whereas in composite material reinforced by aluminum dust, the thermal conductivity increases to reach (4.74 W/mm.K) at volume – fraction (2.2 %) and then decrease to (4.38 W/mm.K ) at volume fraction ( 4.7% ) and then stable at limited ratio from volume fraction. Also the results show that the mechanical impact resistance for composite materials by dust particle increases as the volume – fraction – particle increases, where it reaches (81.25 kJ/m 2 ) at volume fraction ( 9.2% ). whereas composite materials reinforced with aluminum particle (filing) also increase as volume – fraction increases, but, as little as the increasing of composite materials reinforced by dust where reachs (63.158 kJ/m ) at volume fraction ( 9.2 % ). 2

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Article
Analysis and Simulation of Narrow Band Digitally

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This paper illustrates the analysis and simulation of narrow band antenna arrays with adapted radiation pattern using digital beamformation. The technique used for the system is the Shifted Sideband Beamformer ( SSB ) . This paper analyzes the stages of the receiver and presents a model for simulation. The SSB was chosen because it exhibits moderate complexity and storage requirement. Different spatial filters such as Uniform weight, Blackman-Harris, Tylor, and Dolph-Chebyshev were used to control the side lobe level of the arrays. This paper also shows how to implement null steering procedure to circumvent the jamming and high interference angles. Only the linear and two dimensional arrays were taken into consideration.


Article
Improved Distance Spectrum of Asymmetric Turbo Codes

Authors: Ahmed Abdul-Kadhim Hamad
Pages: 111-118
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In this work, the performance of a class of asymmetric turbo codes, which are composed of mixed types of non-identical, recursive systematic convolutional codes has been investigated. Internal pilot insertion technique is utilized to further improve the BER performance of turbo code especially at high SNR. The minimum distance of turbo codes and the multiplicity of low weight codewords can be improved by inserting pilot bits within the sequence of information bits entering the turbo encoder. This technique was shown to be useful on the symmetric and asymmetric turbo coded signals.

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Article
THE EFFECT OF MAIN NONLINEARITIES ON SERVO

Authors: Shaima A. Mahdi
Pages: 119-134
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Servo systems are indispensable in modern industry. For example, they are widely used in robotics, electrical vehicles and automated factories. Therefore, the study of the stability of the system and its response to linear and nonlinear elements is an important control system problem. This paper focuses on determination of servo system transfer function and the effect of the main nonlinearities on its stability by developing an algorithm for the system and simulating using MATLAB. The algorithm used is the describing function algorithm and its analysis ,since it is one of the methods used to analyze nonlinear systems stability.


Article
الخلايا الكهروكيميائية كتقنية جديدة لمعاجة المياه

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This paper deals with possibility of using electrochemical cells to produce potable water, where previous studies showed that the traditional treatment by using alum led to increase the residual aluminum concentrations about (11%) in the treated water, which result in negative effects on human, potable water pipes and water type .In addition to that disinfection by using chloride resulted in more problems such as lack of controlling for adding dose and expired chloride. Thus it is necessary to find a new technique for disinfecting water without using chloride, by using laboratory electrochemical cell made up of stainless steel bar (cathode) and two types of cylindrical aluminum and carbon steels (anode). This technique has been tested on samples taken from excavated well from Al- Khatoniya village and samples from Al-Mahaweel river then make physical , chemical and biological tests before and after treatment .The results shows the efficiency of this technique to treat river water without using chloride after comparison with U.S.P.H.S and W.H.O specifications.

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Article
(Architecture and Society)
العمارة والمجتمع

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Abstract

Human as researchable organism of information , collecting it , for the most important thing discerning him , by creating special system in his environment. The research problem appears through two sides, the first relates with the human and his , her existing and institutional belonging as individual and society , the second relates with the degree of relation between the evolutionary nature through life , and the suitable physical evaluation according to life dynamic. In order to cure the research problem for reaching the results , the research depends on a hypothesis , that the evolutionary value of human relates with human thinking’s , his environment through , regionalism, tertian, norms characters and norms, in order to create architectural system according to evolutionary values with parallel to the evolution of the human . The research depend on analytics methodology stands on the theories through that attitude , for the societies the evolutionary condition affects the type of architecture production. The research reaches to the most important results that the evolution of societies affects the type of architecture according to two directions; - , first , relates with human thinking evolution .- second , relates with human and his instructional containing and the demographic growth , that affects the societies and architecture from the other side.

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Article
(The strategy of city development according to the more effected poles)Analytical

Authors: د. حمزة سلمان جاسم
Pages: 173-200
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Town development is one of the major priorities that make societies depend on in order to build suitable environment for human and societies needs.The strategies differ about city developing , some of them relate with natural ingredients , according to its sources , as potential forces , on the other hand there is artificial , can be as attractive poles , for town developing with in hierarchy of levels. The researchproblem appearswithin the mechanism of the city development according to investment policy ,depending on tourism through the researchable sample of Hilla town , as case study, as part of the total development of the country, as part of the international system. The research used a hypothesis, that city development stand on activate more affective poles in order to discover and activate it, for town contains many related poles, every one depends on the other. Investment is one of the major mechanisms for their activation. In order to reach the research results, the analytical methodology, depended on descriptive phrase used to analyze the poles in the case study. The research reached through the case study, that the town development affected by the existence of the poles, the degree of their relation, and their interaction, with a mechanism, make investment as an important side in the poles activation, and the town developing on the other hand.

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Table of content: volume: issue: