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
Mobile:
Email: joengbag@uobaghdad.edu.iq

Table of content: 2014 volume:20 issue:2

Article
Optimal Dimensions of Small Hydraulic Structure Cutoffs Using Coupled Genetic Algorithm and ANN Model
الأبعاد المثالية لحواجب منشأ هيدروليكي صغير بأستخدام مدمج خوارزميةً وراثيةً ونموذجَ شبكة عصبية اصطناعية

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Abstract

A genetic algorithm model coupled with artificial neural network model was developed to find the optimal values of upstream, downstream cutoff lengths, length of floor and length of downstream protection required for a hydraulic structure. These were obtained for a given maximum difference head, depth of impervious layer and degree of anisotropy. The objective function to be minimized was the cost function with relative cost coefficients for the different dimensions obtained. Constraints used were those that satisfy a factor of safety of 2 against uplift pressure failure and 3 against piping failure. Different cases reaching 1200 were modeled and analyzed using geo-studio modeling, with different values of input variables. The soil was considered homogeneous anisotropic. For each case, the length of protection (L) and the volume of the superstructure (V) required to satisfy the factors of safety mentioned above were calculated. These data were used to obtain an artificial neural network model for estimating (L) and (V) for a given length of upstream cutoff (S1), length of downstream cutoff (S2), head difference (H), length of floor (B), depth of impervious layer (D) and degree of anisotropy (kx/ky). A MatLAB code was written to perform a genetic algorithm optimization modeling using the obtained ANN model .The obtained optimum solution for some selected cases were compared with the Geo-studio modeling to find the length of protection required in the downstream side and volume required for superstructure. Values estimated were found comparable to the obtained values from the Genetic Algorithm model.


Article
Visual Continuity of Traditional Vocabulary in contemporary urban Development Projects
الاستمرارية البصرية للمفردات التراثية في مشاريع التطوير الحضري المعاصر

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Abstract

The sustainability of the individual and society get great interest in contemporary studies, Considering the rebuilding of the society cultural values as the most important goals, which prompted many researchers to explore ways and social elements of sustainability and the most important urban and architectural vocabulary achieving it, thus, the search will be directed towards the human being within the social dimensions of sustainability, his belonging and awareness of identity through the employment of local heritage in the contemporary product. The literatures confirmed the continuity of heritage vocabulary in the contemporary product, accordingly the research problem was defined as: "The visual continuity of the heritage vocabulary in achieving social sustainability". To deal with the research problem a theoretical framework was built for the concept of continuity in general, and visual continuity, in particular, and the application of concluded theoretical framework in a contemporary urban projects adopted the heritage vocabulary and expressed sustainable social identity, the results of the analysis showed that the visual continuity of traditional vocabulary achieved At highest level in the continuity of the surfaces organization in terms of optical properties and elevations treatments, and the continuity of formal relations in terms of scale and proportion, when ever the continuity of the local architectural style appears in the heritage formal elements.


Article
Assessment Efficiency Evaluation of Al-Diwaniya Sewage Treatment Plant in Iraq
تقييم كفاءة الاداء لمحطة معالجة مياه الصرف الصحي في الديوانية، العراق

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Abstract

This study aims to evaluate the performance of the sewage treatment plant in Al-Diwaniya, one of cities in the southern part in Iraq. This evaluation could be used to facilitate effluent quality assessment or optimal process control of the plant. The influent reaching the plant is considered a medium to strong in strength with BOD5/COD ratio in the range 0.23 and 0.69 which can be considered an easily degradable sewage by the biological processes performed by the activated sludge unit. The quality of the effluent was found to be higher than the Iraqi standards for disposal to water bodies. The BOD5/COD ratios of the treated sewage varied over a wide range as low of 0.13 to 1.48 indicating operational problems in the plant. Regression analysis was performed to estimate the removal percentages of BOD5, COD, TSS and NO3 that the plant should perform by to reach the disposal limitations.


Article
Prediction of Coefficient of Permeability of Unsaturated Soil
ايجاد معامل النفاذية للترب غير المشبعة

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Abstract

A simple technique is proposed in this paper for estimating the coefficient of permeability of an unsaturated soil based on physical properties of soils that include grain size analysis, degree of saturation or water content, and porosity of the soil. The proposed method requires the soil-water characteristic curve for the prediction of the coefficient of permeability as most of the conventional methods. A procedure is proposed to define the hydraulic conductivity function from the soil water characteristic curve which is measured by the filter paper method. Fitting methods are applied through the program (SoilVision), after indentifying the basic properties of the soil such as Attereberg limits, specific gravity, void ratio, porosity, degree of saturation and wet and dry unit weights.


Article
A Comparative Study of Single-Constraint Routing in Wireless Mesh Networks Using Different Dynamic Programming Algorithms
مقارنة دراسية لتحديد المسار بمحدد واحد في الشبكات اللاسلكية المعشقة باستخدام مختلف خوارزميات البرمجة الديناميكية

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Abstract

Finding the shortest route in wireless mesh networks is an important aspect. Many techniques are used to solve this problem like dynamic programming, evolutionary algorithms, weighted-sum techniques, and others. In this paper, we use dynamic programming techniques to find the shortest path in wireless mesh networks due to their generality, reduction of complexity and facilitation of numerical computation, simplicity in incorporating constraints, and their conformity to the stochastic nature of some problems. The routing problem is a multi-objective optimization problem with some constraints such as path capacity and end-to-end delay. Single-constraint routing problems and solutions using Dijkstra, Bellman-Ford, and Floyd-Warshall algorithms are proposed in this work with a discussion on the difference between them. These algorithms find the shortest route through finding the optimal rate between two nodes in the wireless networks but with bounded end-to-end delay. The Dijkstra-based algorithm is especially favorable in terms of processing time. We also present a comparison between our proposed single-constraint Dijkstra-based routing algorithm and the mesh routing algorithm (MRA) existing in the literature to clarify the merits of the former.


Article
Experimental Investigation for TiO2 nanoparticles as a Lubricant-Additive for a Compressor of Window Type Air-Conditioner System
تحقيق تجريبي للدقائق النانوية لاوكسيد التيتانيوم المضاف لمزيّت ضاغط مكيّفِ هواء نوعِ شباكي

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Abstract

The coefficient of performance of a window type Air-Conditioner system can be improved if a reduction in the work of compressor can be achieved by a suitable technique. The present study investigates the effect of dispersing a low concentration of TiO2 nanoparticles in the mineral oil based lubricant, as well as on the overall performance of a window type Air-Conditioner system using R22 as the working fluid. An enhancement in the COP of the refrigeration system has been observed and the existence of an optimum volume fraction noticed, with low concentrations of nanoparticles suspended in the mineral oil. Results showed that the average compressor work reduced by 13.3%, which ultimately resulted in an increase of 11.99% in the COP due to the addition of nanoparticles in the lubricating oil.


Article
Experimental and Numerical Study on Cavitation Effects in Centrifugal Pumps
دراسـة عملية و عددية حـول تـأثيـر ظاهرة التكهف فـي المضخات النابذة

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Abstract

Experimental and numerical investigations of the centrifugal pump performance at non-cavitating and cavitating flow conditions were carried out in the present study. Experiments were performed by applying a vacuum to a closed-loop system to investigate the effects of the net positive suction head available (NPSHa), flow rate, water temperature and pump speed on the centrifugal pump performance. Accordingly, many of the important parameters concerning cavitation phenomenon were calculated. Also, the noise which is accompanied by cavitation was measured. Numerical analysis was implemented for two phase flow (the water and its vapor) using a 2-D simulation by ANSYS FLUENT software to investigate the internal flow of centrifugal pump under cavitating conditions. It was observed that with decreasing NPSHa, the values of the pump head, flow rate and efficiency initially remain constant, but with further reduction in NPSHa these parameters will decrease. Also, it was found that at 3% head drop the percentage drop of the flow rate is less than 2% whereas the percentage drop of the efficiency is greater than 3%. Numerically, it was noticed that the cavitation regions appear at the leading edge of suction side of the impeller blades which represents the lowest pressure area inside the computational domain of the centrifugal pump.


Article
Experimental and Theoretical Investigation of Noise Effect in Centrifugal Fan Impeller
دراسة عملية ونظرية لدراسة ظاهرة الضوضاء في منفاخ الطرد المركزي

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Abstract

In this work a study was made in centrifugal fan blower to investigate the effect of impeller blade design on sound pressure level (SPL). Shroud and unshroud impeller of nine blades are used. The sound generation from flow inside the test rig at different positions was displayed by using spectral analyzer. The experiments were carried out in anechoic chamber with small holes in its walls, under ambient condition about (25-27) C ° to avoid the effect of temperature on the sound pressure level. The results showed that (SPL) decreased with the increase of distance from the source about (3-4)dB when distance varied about (0.8-1.06)m, and the (SPL) decreased with the decrease of velocity about (8-12)dB when velocity varied between (13000-2600) r.p.m., and when the velocity remain constant (SPL) increased with the increased of pressure about (7-15)dB when the pressure varied between (36-8)mbar. For the purpose of comparison, two types of impellers were tested under same conditions, the results showed that (SPL) increased when shroud used on the impeller. The mathematical results show good agreement with the experimental results. The study also concluded a spectral analysis of the noise generated using 1/3 octave band filter. The analysis showed that (SPL) increased with frequency range of (0.8-400) Hz. The maximum sound pressure level was appeared clearly in the frequency range between 200 – 400 Hz .


Article
Theoritical and Experimental Investigation of the Dynamical Behaviour of Complex Configuration Rotors
مبحث نظري وتجريبي للتصرفات الديناميكية لدوارات معقدة الاشكال

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Abstract

The present work considers an alternative solution for a complex configuration of rotor discs by applying Galerkin Method. The theoretical model consists of elastic shaft carrying number of discs and supported on number of journal bearings. The equation of motion was discretized to finite degree of freedom in terms of the system generalized coordinates. The various effects of the dynamical forces and moments arising from the bearing, discs and shaft were included. Rayleigh beam model is used for analyzing the shaft while the discs are considered rigid . The validity and convergence of the present analysis was carefully checked by comparing with the Finite Element solution. An example of rotor consists of three different size discs and supported by two journal bearing was considered for the numerical solution .The results shows good agreements between the two methods ,where the maximum error not exceeds 5%. The convergence test showed that using few modes (not more than 6) are sufficient for the accurate analysis. The forward and backward whirl was investigated experimentally .The experimental results of a two discs rotor ,show a reasonable agreement where the maximum error not exceeds 11%. The unbalance response, Cambpell diagram, orbit response were plotted .The effects of geometry, disc sizes , location and arrangement on the unbalance response and natural frequencies of three discs rotor were further investigated .


Article
Vibration Analysis of Laminated Composite Plate under Thermo-Mechanical Loading
تحليل الاهتزازات للصفائح المركبة تحت تأثير احمال ميكانيكية حرارية

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Abstract

The present study focused mainly on the vibration analysis of composite laminated plates subjected to thermal and mechanical loads or without any load (free vibration). Natural frequency and dynamic response are analyzed by analytical, numerical and experimental analysis (by using impact hammer) for different cases. The experimental investigation is to manufacture the laminates and to find mechanical and thermal properties of glass-polyester such as longitudinal, transverse young modulus, shear modulus, longitudinal and transverse thermal expansion and thermal conductivity. The vibration test carried to find the three natural frequencies of plate. The design parameters of the laminates such as aspect ratio, thickness ratio, boundary conditions and lamination angle were investigated using classical laminated plate theory (CLPT) and Finite element coded by ANSYS, in addition to the design parameters of dynamic response such as load type with respect to time, x and y dimension and temperature value for simply supported symmetric cross ply. The main conclusion was the natural frequency could increase and decrease depending on the boundary conditions, thickness ratio, and lamination angle, the aspect ratio of the plate. Present of temperature could increase dynamic response of plate also depending on lamination angle, type of mechanical load and the value of temperature.


Article
Vibration Measurement and Analysis of knee-Ankle-Foot Orthosis (KAFO) Metal-Metal type
قياس وتحليل الاهتزازات لمسند نوع قدم كاحل ركبة

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Abstract

This paper deals with calculate stresses in Knee-Ankle-Foot-Orthosis as a result of the effect vibration during gait cycle for patient wearing KAFO .Experimental part included measurement interface pressure between KAFO and leg due to action muscles and body weigh on Orthosis. also measurement acceleration result from motion of defected leg by accelerometer .Results of Experimental part used input in theoretical part so as to calculate stresses result from applying pressure and acceleration on KAFO by engineering analysis program ANSYS 14.Resultes show stresses values in upper KAFO greater than lower KAFO that is back to muscles more effective in thigh part lead to recoding pressure higher than pressure in shank part.


Article
Place Identity in Defining Urban Space of Border Rivers in Historical City Centres
هوية المكان في تعريف الفضاء الحضري لحافات الأنهر في مراكز المدينة التاريخية

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Abstract

In the city, building space could transform to be as place, because architecture does not include only traditional values such as housing, human protection, stability, etc, but could carry other dimensions beyond the housing or building occupancy or develop urban design. Rivers had vision in motion as a way to show dynamic processes in its flowing slowly, which are simply measured in time and the life of citizens. The research consider the river path in traditional cities as Alley connecting the spaces of the city ... old Baghdad was characterized by this property and it is look like Venice in the past, while traditional European cities were able to preserve this property till now, and capable to take transformation of the city with development projects inside it. These cities was distinguished by development of river edge as creating place along the river corridor and try to attract peoples who lived in, protect the natural environment along the river, as well as reflect the characteristics of the city along of the elevation of the river, and conserve the river banks as alley connected between urban spaces. Baghdad which penetrates by Tigris River has maintained this feature until the middle of twentieth century. So now, the research can see the absence of specialized local studies, including The comprehensive development plan of the Baghdad city 2030 to study and Re design the spaces and places along river edge, this led to emerge research problem, in the absence of specific knowledge about identity of river space characteristics for identification of urban space in place of the Tigris River in downtown of Baghdad historical city center, in the urban development plans since the mid-twentieth century until now, and study design factors that contributed with disintegration of the space syntax relations in river elevation. Turning to the experience of historical European cities and how to deal with urban space to the edge of the river and created the identity of the place, especially the interface development experience the (Seine river in Paris, Thames River in London, Tiber River in Rome, Danube River in Vienna & Budapest, Vltava river in Prague) and study urban style in dealing with the river edge, in order to reach the elements which define the identity of each city. In order to reach the aim of research in redefining the identity of places for urban spaces overlooking to integrate the banks of Tigris River in the historical city centre of Baghdad, and the methods of linking the development of river front with the comprehensive development plan of the Baghdad city 2030.

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