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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Contact info

Jadriyah, Baghdad
Iraq
Mobile:
Email: joengbag@uobaghdad.edu.iq

Table of content: 2016 volume:22 issue:5

Article
Prediction of Ryznar Stability Index for Treated Water of WTPs Located on Al-Karakh Side of Baghdad City using Artificial Neural Network (ANN) Technique
التنبؤ بمؤشر الاستقرار(RI) للمياه المعالجة من محطات تصفية الماء على جانب الكرخ من مدينة بغداد باستخدام تقنية الشبكات العصبية الاصطناعية (ANN)

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Abstract

In this research an Artificial Neural Network (ANN) technique was applied for the prediction of Ryznar Index (RI) of the flowing water from WTPs in Al-Karakh side (left side) in Baghdad city for year 2013. Three models (ANN1, ANN2 and ANN3) have been developed and tested using data from Baghdad Mayoralty (Amanat Baghdad) including drinking water quality for the period 2004 to 2013. The results indicate that it is quite possible to use an artificial neural networks in predicting the stability index (RI) with a good degree of accuracy. Where ANN 2 model could be used to predict RI for the effluents from Al-Karakh, Al-Qadisiya and Al-Karama WTPs as the highest correlation coefficient were obtained 92.4, 82.9 and 79.1% respectively. For Al-Dora WTP, ANN 3 model could be used as R was 92.8%.


Article
Field Observation of Soil Displacements Resulting Due Unsupported Excavation and Its Effects on Proposed Adjacent Piles
الملاحظات الموقعية عن الازاحات في التربة الناتجة عن الحفريات غير المسندة وتاثيرها على ركيزة مجاورة افتراضية

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Abstract

Soil movement resulting due unsupported excavation nearby axially loaded piles imposes significant structural troubles on geotechnical engineers especially for piles that are not designed to account for loss of lateral confinement. In this study the field excavation works of 7.0 m deep open tunnel was continuously followed up by the authors. The work is related to the project of developing the Army canal in the east of Baghdad city in Iraq. A number of selected points around the field excavation are installed on the ground surface at different horizontal distance. The elevation and coordinates of points are recorded during 23 days with excavation progress period. The field excavation process was numerically simulated by using the finite element package PLAXIS 3D foundation. The obtained analysis results regarding the displacements of the selected points are compared with the field observation for verification purpose. Moreover, finite element analysis of axially loaded piles that are presumed to be existed at the locations of the observation points is carried out to study the effect of excavation on full scale piles behaviors. The field observation monitored an upward movement and positive lateral ground movement for shallow excavation depth. Later on and as the excavation process went deeper, a downward movement and negative lateral ground movement are noticed. The analyses results are in general well agreed with the monitored values of soil displacements at the selected points. It is found also that there are obvious effects of the nearby excavation on the presumed piles in terms of displacements and bending moments.


Article
Assessing Asphalt and Concrete Pavement Surface Texture in the Field
تقييم نسجة السطح الاسفلتي والخرساني للرصفة موقعيا

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Abstract

The incorporation of safety characteristics into the traditional pavement structural design or in the functional evaluation of pavement condition has not been established yet. The design has focused on the structural capacity of the roadway so that the pavement can withstand specific level of repetitive loading over the design life. On the other hand, the surface texture condition was neither included in the AASHTO design procedure nor in the present serviceability index measurements. The pavement surface course should provide adequate levels of friction and ride quality and maintain low levels of noise and roughness. Many transportation departments perform routine skid resistant testing, the type of equipment used for testing varies depending on the preference of each transportation department. It was felt that modeling of the surface texture condition using different methods of testing may assist in solving such problem. In this work, Macro texture and Micro texture of asphalt and cement concrete pavement surface have been investigated in the field using four different methods (The Sand Patch Method, Outflow Time Method, British Pendulum Tester and Photogrammetry Technique). Two different grain sizes of sand have been utilized in conducting the Sand Patch while the Micro texture was investigated using the British Pendulum tester method at wet pavement surface conditions. The test results of the four methods were correlated to the skid number. It was concluded that such modeling could provide instant data in the field for pavement condition which may help in pavement maintenance management.


Article
Experimental Behavior of Laced Reinforced Concrete One Way Slab under Static Load
تصرف البلاطات الاحادية الاتجاه والحاوية على حديد متعرج تحت تأثير الاحمال الساكنة

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Abstract

Test results of eight reinforced concrete one way slab with lacing reinforcement are reported. The tests were designed to study the effect of the lacing reinforcement on the flexural behavior of one way slabs. The test parameters were the lacing steel ratio, flexural steel ratio and span to the effective depth ratio. One specimen had no lacing reinforcement and the remaining seven had various percentages of lacing and flexural steel ratios. All specimens were cast with normal density concrete of approximately 30 MPa compressive strength. The specimens were tested under two equal line loads applied statically at a thirds part (four point bending test) up to failure. Three percentage of lacing and flexural steel ratios were used: (0.0025, 0.0045 and 0.0065). Three values of span to effective depth ratio by (11, 13, and 16) were considered, the specimens showed an enhanced in ultimate load capacity ranged between (56.52% and 103.57%) as a result of increasing the lacing steel ratio to (0.0065) and decreasing the span to effective depth ratio by (31.25%) respectively with respect to the control specimen. Additionally the using of lacing steel reinforcement leads to significant improvements in ductility by about (91.34%) with increasing the lacing steel ratio to (0.0025) with respect to the specimen without lacing reinforcement.


Article
Three-Dimensional Finite Element Simulation of the Buried Pipe Problem in Geogrid Reinforced Soil
تمثيل ثلاثي الابعاد لمسألة الانابيب المدفونة في تربة مسلحة بشبكة بطريقة العناصر المحددة

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Abstract

Buried pipeline systems are commonly used to transport water, sewage, natural oil/gas and other materials. The benefit of using geogrid reinforcement is to increase the bearing capacity of the soil and decrease the load transfer to the underground structures. This paper deals with simulation of the buried pipe problem numerically by finite elements method using the latest version of PLAXIS-3D software. Rajkumar and Ilamaruthi's study, 2008 has been selected to be reanalyzed as 3D problem because it contain all the properties needed by the program such as the modulus of elasticity, Poisson's ratio and angle of internal friction. It was found that the results of vertical crown deflection for the model without geogrid obtained from PLAXIS-3D are higher than those obtained by two-dimensional plane strain by about 21.4% while this percent becomes 12.1 for the model with geogrid, but in general, both have the same trend. The two dimensional finite elements analysis predictions of pipe-soil system behavior indicate an almost linear variation of pipe deflection with applied pressure while 3-D analysis exhibited non-linear behavior especially at higher loads.


Article
Production of Methyl Ester (Biodiesel) from Used Cooking Oils via Trans-esterification process
انتاج الميثل استر (الديزل الحيوي) من زيوت الطهي المستخدمة بواسطة عملية الاسترة التبادلية

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Abstract

Used cooking oil was undergoing trans-esterification reaction to produce biodiesel fuel. Method of production consisted of pretreatment steps, trans-esterification, separation, washing and drying. Trans-esterification of treated oils was studied at different operation conditions, the methanol to oil mole ratio were 6:1, 8:1, 10:1, and 12:1, at different temperature 30, 40, 50, and 60 º C, reaction time 40, 60, 80, and 120 minutes, amount of catalyst 0.5, 1, 1.5, and 2 wt.% based on oil and mixing speed 400 rpm. The maximum yield of biodiesel was 91.68 wt.% for treated oils obtained by trans-esterification reaction with 10:1 methanol to oil mole ratio, 60 º C reaction temperature, 80 minute reaction time and 0.5 wt.% of NaOH catalyst. The physical properties such as specific gravity, kinematic viscosity, acid number, flash point, pour point, and water content, were measured and compared them with American Standard Test Methods (ASTM D6751). The results of these properties for biodiesel product at (6:1, 8:1, 10:1, and 12:1 of methanol to oil mole ratio) were within the range of American Standard Test Methods (ASTM D6751).


Article
Encoding of QC-LDPC Codes of Rank Deficient Parity Matrix
ترميز QC-LDPC ذات مصفوفة التطابق ناقصة الرتبة

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Abstract

The encoding of long low density parity check (LDPC) codes presents a challenge compared to its decoding. The Quasi Cyclic (QC) LDPC codes offer the advantage for reducing the complexity for both encoding and decoding due to its QC structure. Most QC-LDPC codes have rank deficient parity matrix and this introduces extra complexity over the codes with full rank parity matrix. In this paper an encoding scheme of QC-LDPC codes is presented that is suitable for codes with full rank parity matrix and rank deficient parity matrx. The extra effort required by the codes with rank deficient parity matrix over the codes of full rank parity matrix is investigated.


Article
Numerical Investigation Using Harmonic and Transient Analysis To Rotor Dynamics
دراسة عددية للتحليل الحركي المتناسق والوقتي للمحور الدوار

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Abstract

The rotor dynamics generally deals with vibration of rotating structures. For designing rotors of a high speeds, basically its important to take into account the rotor dynamics characteristics. The modeling features for rotor and bearings support flexibility are described in this paper, by taking these characteristics of rotor dynamics features into standard Finite Element Approach (FEA) model. Transient and harmonic analysis procedures have been found by ANSYS, the idea has been presented to deal with critical speed calculation. This papers shows how elements BEAM188 and COMBI214 are used to represent the shaft and bearings, the dynamic stiffness and damping coefficients of journal bearings as a matrices have been found with the variation of rotation speed of the rotor which are vary with eccentricity of journal with bearings and this eccentricity is a function of Sommerfeld number, the first critical speed analysis has been done from Campbell diagram, the critical speed it is the speed at which resonance case happen, the unbalance response analysis has been done with changing the unbalance mass then finding the maximum response of the rotor for each unbalance mass case, by Campbell diagram plot recognizing the stability of the system and find the line of un stability, above and down this line the system is stable and if speed lies on this line the system is unstable, the main reason of analysis of rotor dynamics is to help Engineers to characterize the lateral dynamics characteristics of a given design with Campbell diagram plot, can find the critical speed, the unbalance response and the system stability .


Article
Temperature Effect on Power Drop of Different Photovoltaic Modules
تأثير درجة الحرارة على انخفاض القدرة لأنواع مختلفة من الالواح الفوتوفولتائية

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Abstract

Solar module operating temperature is the second major factor affects the performance of solar photovoltaic panels after the amount of solar radiation. This paper presents a performance comparison of mono-crystalline Silicon (mc-Si), poly-crystalline Silicon (pc-Si), amorphous Silicon (a-Si) and Cupper Indium Gallium di-selenide (CIGS) photovoltaic technologies under Climate Conditions of Baghdad city. Temperature influence on the solar modules electric output parameters was investigated experimentally and their temperature coefficients was calculated. These temperature coefficients are important for all systems design and sizing. The experimental results revealed that the pc-Si module showed a decrease in open circuit voltage by -0.0912V/ºC while mc-Si and a-Si had nearly -0.07V/ºC and the CIGS has -0.0123V/ºC. The results showed a slightly increase in short circuit current with temperature increasing about 0.3mA/ºC ,4.4mA/ºC and 0.9mA/ºC for mc-Si , pc-Si and both a-Si and CIGS. The mc-Si had the largest drop in output power about -0.1353W/ºC while -0.0915, -0.0114 and -0.0276 W/ºC for pc-Si, a-Si and CIGS respectively. The amorphous silicon is the more suitable module for high operation temperature but it has the lowest conversion efficiency between the tested modules.


Article
Experimental Investigation of Convection Heat Transfer Enhancement in Horizontal Channel Provided with Metal Foam Blocks
دراسة عملية لتحسين انتقال الحرارة بالحمل في قناة أفقية مزودة بكتل من رغوة معدنية

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Abstract

Convection heat transfer in a horizontal channel provided with metal foam blocks of two numbers of pores per unit of length (10 and 40 PPI) and partially heated at a constant heat flux is experimentally investigated with air as the working fluid. A series of experiments have been carried out under steady state condition. The experimental investigations cover the Reynolds number range from 638 to 2168, heat fluxes varied from 453 to 4462 W/m2, and Darcy number 1.77x10-5, 3.95x10-6. The measured data were collected and analyzed. Results show that the wall temperatures at each heated section are affected by the imposed heat flux variation, Darcy number, and Reynolds number variation. The variations of the local heat transfer coefficient and the mean Nusselt number are presented and analyzed. The mean Nusselt number enhancement was found to be more than 80% for all the studied cases.


Article
Improving the Accuracy of Handheld GPS Receivers Based on NMEA File Generating and Least Squares Adjustment
تحسين دقة مواقع اجهزةالـ GPS المحمولة القائمة على توليد ملف NMEA وتقنية التصحيح بأقل المربعات

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Abstract

This study aims to improve the quality of satellites signals in addition to increase accuracy level delivered from handheld GPS data by building up a program to read and decode data of handheld GPS. Where, the NMEA protocol file, which stands for the National Marine Electronics Association, was generated from handheld GPS receivers in real time using in-house design program. The NMEA protocol file provides ability to choose points positions with best status level of satellites such as number of visible satellite, satellite geometry, and GPS mode, which are defined as accuracy factors. In addition to fix signal quality, least squares technique was adopted in this study to minimize the residuals of GPS observations and enhance its accuracy. Moreover, one hundred reference control points were established using geodetic GPS receiver (GR5 receiver), and fixing them in a specified sites of the University of Baghdad, Al Jadriya campus, which selected as a study area, to evaluate positioning accuracy of handheld GPS before and after adjustment. The study findings showed significant decrease in root mean square error (RMSE) in both horizontal and vertical directions from 9.4 m to 3.2 m and 6.8 m to 2.4 m respectively.

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