About Journal

Al-Rafidain Engineering Journal (AREJ) is a global, scientific and open access journal. Publishing under the license of Creative Commons Attribution 4.0 International (CC-BY), The first issue of Al-Rafidain Engineering Journal (AREJ) was published in 1993 by the college of engineering – University of Mosul. The journal publishes Engineering Science articles at an average rate of six issues/year (Bi-Monthly). AREJ publishes original and valuable engineering research papers aiming at developing the knowledge in the fields of applied engineering science.  Al-Rafidain Engineering...
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Journal Information

Publisher: College of Engineering, Mosul University

Email:  drjssm@uomosul.edu.iq

Editor-in-chief: Prof. Dr. Jassim M. Abdul-Jabbar

Print ISSN: 1813-0526

Online ISSN: 2220-1270

Simulation of Two Phase Natural Convective Heat Transfer in a Loop Thermosyphon

Raqeeb Hummadi Rajab

AL-Rafdain Engineering Journal (AREJ), Volume 24, Issue 1, Pages 1-6
DOI: 10.33899/rengj.2019.163108

This research includes experimental investigation and theoretical simulation which is manufactured locally in a laboratory to assess the characteristics of the two-phase convective heat transfer and performance of a loop thermosiphon. Practical experiments were performed using pure water, hydrocarbon fluid (acetone) and a mixture of both fluids with determined weight ratios used as working fluids. The experimental results of average heat transfer coefficient that were theoretically simulated under the same boundary conditions in both cases to study the effect of the kind of working fluid on the period required to reach the steady state condition and to achieve high performance within the best design conditions of the experimental rig. A comparison was made between the simulation and experimental results and an acceptable agreement was shown. It is worth mentioning that the Computational Fluid Dynamic analysis (CFD) with Engineering Equations Solver (EES) were used in the theoretical simulation.

Stress Analysis of Different Types of Gas Turbine Blades in AL Mansour Gas Station

Sabah Mohammed Ali; Suha Hashim Ahmed

AL-Rafdain Engineering Journal (AREJ), Volume 24, Issue 1, Pages 7-17
DOI: 10.33899/rengj.2019.163117

Gas turbine blades are suffering from failure, most of the studies indicate that 50% of the failure and breakage due to its complexity circumstances, The aim of this work is to analyze stresses at the first stages in AL Mansourgas power station in Mousl city, (AUTOCAD) which is computer program has been used to draw the blade at the exact measurement, where three kinds of different shapes of blades have taken, The real blade solid and hollow airfoil at the root, hollow airfoil at the root, Solid Airfoil at the root
(AUTOCAD) program has been used to obtain the cross section area at any height along the blade lengths, (MATLAB) program has been used to obtain equations between cross section area and the height  along the blade then determine the centrifugal force for a three blades used in this research. The study concluded that the real blades,solid and hollow is best because it garantee a minimum normal stress.

Laboratory Study of Flow Characteristics Through three Baffle – Sluice Gates.

Duaha A. Al-mallah; Hana A. Hayawi

AL-Rafdain Engineering Journal (AREJ), Volume 24, Issue 1, Pages 1-9
DOI: 10.33899/rengj.2019.163195

The main objective of this study is to investigate the experimentally the coefficient of discharge for three baffle sluice gates and compared with single gate. The channel slope was changed tow times (0, 0.0075). For this purpose three baffle sluice gates were made from fibber class with (1cm) thick, (30cm) wide and (15,25,30)cm height for first, second and third gate respectively. The three gates have been sharp edge from the top and bottom with 2mm thick .The distance between the three parallel baffle gates were changed three times (2, 3.5, 5) cm. The analysis of results showed that discharge coefficient Cd in horizontal channel is larger than its value in inclined channel with direction of flow and the change in space between gates didn't cause an important difference between values of discharge coefficient Cd. The values of Cd were between          (0.561 -0.736) for horizontal channel and three gates, while when the channel inclined the values of Cd were between (0.523-0.662) for three gates.

Experimental Study of the Scour Depth at Downstream Weirs Has Different Holes

Mariam Khder Mohammad Alhealy; Ghania Abd Al Majeed Hayawi

AL-Rafdain Engineering Journal (AREJ), Volume 24, Issue 1, Pages 18-23
DOI: 10.33899/rengj.2019.163111

An experimental study was carried out  to deal with using a weir with circular holes to control the scour occurs behind it. The holes are located near the bed of the channel, their geometric details had been changed in its size, number and their distance from the bed of the channel. The channel bed was lined by crushed gravel with average diameter 11.1 cm. The thickness of the crushed gravel layer was 22 cm and its length was 4 m. There is 18 cases were conducted. Which the diameter of the holes were 1.6, 2.3, 3 cm, and for each size of them, the distance of the holes was 0, 0.25 or 0.5 cm, their number was one or three. These cases were compared with the case of using weir with no hole. The main hydraulic variable was the discharge, which five different discharges were  flowed for each case. The total number of the experiments was 95. The dimensions of the scour hole behind the weir was measured as well as the water surface elevation in the upstream of the weir.
The analysis indicated that the discharge plays the main role to increase the size of the scour hole. Using the weir with holes helps to decrease the scour occurs behind it, because the flow from holes interrupted the flow fallen from over the weir then some of its energy was dissipated. The diameter of the weir's hole that caused the smallest scour was 0.115 cm, while the most effective distance of the this hole to cause the same effect was 0.5 cm, among all the studied cases. Due to its height increases the dissipation of the energy of the falling flow.

Improvement Water Productivity for Wheat Crop at Mosul Area

Rand Saadi Huseen; Dr. Younis Mohamed Hassan; Dr.Eman H. Sheet

AL-Rafdain Engineering Journal (AREJ), Volume 24, Issue 1, Pages 24-30
DOI: 10.33899/rengj.2019.163112

This study aimed to optimize the yield of wheat crop under rainfed Agriculture at Mosul zone in Iraq . this can be reached by the selection of proper time of seeding time which gives the best crop yield for rainfed Agriculture or by adding one supplementary irrigation of selected depth and time which gives the maximum yield or best economical return.
In this study we generated data base using program (Aquacrop) for wheat yield with rainfall depth during the season for rainfall agriculture with rainfall depth +supplementary irrigation by using one irrigation during the season with depth (25,50,100)mm adding to one week of the season which is 23 week with initial water content between field capacity and wilting point with three date to begin the agriculture season the results showed that the optimal seeding time for the rainfed Agriculture is 15 December which gives 257.5 kg/ha yield and the next is 15 November 250.5 kg/ha and 15 January 89 kg/ha, For supplementary Agriculture the best time of the irrigation is the first week of the season with a depth change inversely with rain depth and the best seeding time is 15 November.

Effect of Roughened Flood Plain of Symmetrical Compound Channel on The Resistance of Flow

Aws Younes Hamed; Mwafaq Younes Mhammad

AL-Rafdain Engineering Journal (AREJ), Volume 24, Issue 1, Pages 31-38
DOI: 10.33899/rengj.2019.163113

This research deals with the experimental study of the effect of roughened the flood plain of symmetrical compound channel (having 18 cm main channel and 29 cm flood plain width from both sides) on the resistance of flow using different size of gravel roughness (D50=6.8 ,16.8, 24,47) mm, as well as the flood plain is smooth.
 Five discharges (34,27.8,19.35,12,7.87)L/sec were carried out for each case, The compound channel was divided to 3 sections  perpendicular to the direction of flow  and each of them divided to 7 sections , 4 in flood plain and 3 in main channel . Pitot static tube used for velocity measurements and point gage for water surfacelevel measurement as well as the temperature of water was measurement, From the measurements it can be concluded that  the velocity over the flood plain was reduced clearly up to 40 – 70 % when the flood plain roughened by course roughness compare with that of smooth one  , while the velocity in the main channel increased to satisfy the continuity equation . Empirical equations were developed to combine the resistance coefficient n with other variables include the flow and geometry characteristics

Deriving Equation to Estimate Movement of Water in Soil for Subsurface Drip Irrigation

Dheyaa Mohamed Taha; Dr. Younis Mohamed Hassan

AL-Rafdain Engineering Journal (AREJ), Volume 24, Issue 1, Pages 39-45
DOI: 10.33899/rengj.2019.163114

Subsurface drip irrigation is an efficient irrigation method because it applies water directly to the crop root zone, but one of the disadvantages of this method is the positive pressure which is formed in the soil at dripopening especially in fine soils where the drip discharge is larger than the soil infiltration capacity which leads to decrease the discharge rate because the positive pressure will reduce the operation pressure of the drip. In this study, water was applied to ahole surface which filled with gravel to a needed depth,than distributed from the holebottom to all direction through the soil. Wetting front  was observed during water supply and redistribution periods .
Eighteen laboratory experiments for watching advance of wetting front at different times, by using cuboid-shaped container, dimensions (50*50*70) cm. two side of this container are plastic sheets, soil was compacted in the container to achieve bulk density. Two soils were used in the experiments, sandy loam with initial water content (3% and 6%), discharge (0.5, 1.04 and 2.14) L/hr, and silty clay with initial water content (5% and 8.5%), discharge (0.54 and 1.08) L/hr. For the both soils (5 and 10)cm radius of gravel container  with 20cm depth was used, the container have holes from bottom and side at 5cm high to water exit. The volume of water applied was 4.5 L.
The study presents equation to estimate fully shape of wetting pattern,by using dimensional analysis techniques, the effective variables on wetting front movement had been transfered to dimensionless groups, and by using the (SPSS)software  a relationship was found between distance from center of hole to wetting front and time for all direction.

Theoretical Stress Analysis of Gas Turbine Blade Made From Different Alloys

Suha Hashim Ahmed; Ghaidaa Husain; Majeed Ali Abdulrazaq

AL-Rafdain Engineering Journal (AREJ), Volume 24, Issue 1, Pages 10-18
DOI: 10.33899/rengj.2019.163122

Blades may be considered to be the heart of turbine without blade there would be no power and the slightest fault in blade would mean a reduction in efficiency and costly repairs.
The centrifugal force is one of the problems faced by the designer of blades especially at the first stages. The designer aims at reducing the stresses with in the allowed limit.
The ANSYS 15 software was used as far as it is the most effective in analyzing the different numerous cases of stresses, the blades with limited root in all direction (X,Y,Z) were taken into consideration . The centrifugal forces were applied on the rotor blades at running speed of 6000 r.p.m., The finite element models of the blade were constructed using D3-10-noded Tetrahedron elements shape, SOLID 187,  mesh of the entire blade 23406 Node,136575element. The average of normal stress, Von misses, Maximum principle stress, Minimum principle stress were calculated according to ANSYS 15  program,  these stresses are as the result of the effect of centrifugal force for all planes along the blades and then values of stresses were compared to the curves for each  alloy.The current research concluded that the Titanium alloy is the best alloy used in terms of reducing stresses due to centrifugal force, that is because density of Titanium alloy used is less than that of other used alloys, leading a reduction in centrifugal forcess that are directly proportional to mass.

Similarity Between Inside and Outside in Architecture A Comparative Study Between Mies Van der Roh& Robert Venturi Trends

Shaimaa AL-Dabbagh; Dr. Asma AL-Dabbagh

AL-Rafdain Engineering Journal (AREJ), Volume 24, Issue 1, Pages 46-55
DOI: 10.33899/rengj.2019.163115

The relationship between inside and outside is considered as the principal one in architecture as it is one of its most important relationships in architecture’s history. Human had tended, from the very creation of being, to withhold a part of the outside space in order to form a special inside space of the building.
This is done through containment as in making the cave as a refuge or through designation as in setting a space by using vertical or horizontal elements. This process is called “inside and outside” which might be the leading generated term of building construction. Human firstly and the architect secondly aim at finding, unceasingly, a relationship between interior and exterior spaces. And, as they do so; they manipulate the outer mass, inner space and mutual boundaries in-between through shaping them in a way yielding a relationship between both interior and exterior spaces; thus, to find similarity or dissimilarity between the shapes of the outer mass and the inner mass of the interior space. The present study attempts to study the similarity characteristic by studying its contrast as a characteristic of the relationship between interior and exterior to determine the differences between the architects' trends (Mies and Venturi) regarding to the relation of inside and outside. this relationship will be having a big role in determining the patterns of buildings, their trends, and intellectual and spatial affiliations.
In order to achieve the objectives of the research, in the practical side, three (3) single residential houses were chosen for each architect, and After applying difference variables to the selected sample, throughout the study  a vision had been put into words expressed in that: the difference between inside and outside is what is known as the (In between), Which is the resultant of, basically, pro forma purposes, which are adapted to perform particular functions later as in Mies Architecture, or any strict functional purposes as in Venturi Architecture.

Buckling Analysis of Hybrid Laminated Composite Beam Analytically and Numerically

Omar A. Mohamed

AL-Rafdain Engineering Journal (AREJ), Volume 24, Issue 1, Pages 19-25
DOI: 10.33899/rengj.2019.163123

Composite materials become more attractive for researches because of higher strength to weight ratio. As a result, many papers have recently published in this field. The current study deals with improving the resistance of hybrid laminated composite beam under critical buckling load. A number of carbon layers under various orientation angle and positions of hybrid fiber coupled with glass epoxy layers have been studied analytically and numerically. Firstly, an analytical model is presented by using Euler's theory to determine critical buckling load. Then, a 3D finite element models for the composite beams have been simulated by using ANSYS commercial program. The results show a very good agreement between theoretical and FEM (finite volume method). The critical buckling load, shows a proportional with increase the carbon layers number as same time the critical buckling load value shows a valuable decrease when the position of carbon layer insert towards the mid-plane more ever, this value various with orientation angle changing.

Neighborhood Sustainability Evaluation Based on UN-Habitat … Principles: Case Study Masike and Avro city in Duhok

Layla M. Raswol

AL-Rafdain Engineering Journal (AREJ), Volume 24, Issue 1, Pages 26-34
DOI: 10.33899/rengj.2019.163124

The aim of this research is to introduce guidelines and concepts to optimize the urban Design and planning for residential area and to contribute to the sustainable housing development in Kurdistan cities. The Housing Sector as one of the most important sectors in the city development has facing a lot of challenges in terms of sustainability due to the rapid population growth in cities of Iraqi Kurdistan. The city of Duhok as an example of other cities in the region has experienced dynamic urban growth in the last decades as a result of the unstable political and economic conditions in the Region. The local government has tried to cover housing shortage by many strategies such as plot distribution as well as supporting investors to provide housing units to meet people 's housing need. The main research objective is to evaluate the urban sustainability of the selected neighborhoods in the new developed area of Duhok city. The research used the principles of UN- Habitat for analyzing neighborhood sustainability by quantitative measurement of: efficient streets network, high density, mix use, social mix and limited land use specialization. The research outcomes indicate that there is an urgent need to direct the urban growth to more walkable mixed land use neighborhoods rather than car-oriented development by integrating the urban sustainability principles in the new housing projects to create healthier living environment for the residents.

Effect of Adding Steel Filings Aggregates on The Properties of Hot Mix Asphalt

N. I. Hasan

AL-Rafdain Engineering Journal (AREJ), Volume 24, Issue 1, Pages 35-45
DOI: 10.33899/rengj.2019.163131

Hot Mix Asphalt (HMA), which are used in road's courses and flexible pavement structures, consisting of fine and coarse aggregates, filler, and binder(asphalt) ,mixed together in percent's according to a specific specifications.
The main objective of this study is to investigate experimentally the effect of adding Steel Filing Aggregate (SFA) on the properties of Hot Mixtures Asphalt for surface layers. 
Steel filing Aggregate is a product of filing, drilling, and cutting of steel industry which, can be used as a partial replacement for fine aggregate in the creating Hot Asphalt Mixtures, for economical , environmental, and improvement purposes.
 The proposed mix designs specimens test of HMA for surface layer were prepared using : obtained Optimum Asphalt Content (OAC)  (where  the asphalt of  penetration grade 40 was provided from Begi Oil Refinery, which was determined to be equaled 5.07 % (of the total weight mix) , ordinary portland cement as the mineral filler by 5 % (of the total weight of aggregates) and locally aggregates, and then tested according to Marshall test method (ASTM- D-1559&MS-2).
Steel Filling Aggregates (SFA), which were passing through the sieve No.4 (4.75 mm) were added to the  above HMA samples in three different percentages which were 5 % , 10 %  and 20 % (of the total weight of mix) in order to evaluate their effects on some of the Marshall test properties of HMA .
The experimental results and calculations for Marshall Tests on mix designs specimens test of HMA showed that adding SFA by above percentages on HMA, satisfy the requirements of the Iraqi General Specification for Roads & Bridges (SORB/2003) and has given significant improvement .The results  also showed that 10% of SFA (of the total weight of mix) is the optimum percent .

Wetting Pattern for A Two-Line Trickle Source

Qamar Moayad Bakir; Haqqi Yasin

AL-Rafdain Engineering Journal (AREJ), Volume 24, Issue 1, Pages 56-65
DOI: 10.33899/rengj.2019.163116

The laboratory tests carried out 12 tests to follow the advance of wetting front at appropriate times during the wetting and redistribution phases as a resulting of water application from a single linear trickle source or two linear trickle sources with a certain spacing to soil profile. These data are used to express with an estimating relationships for the wetting pattern produced by single linear trickle source and two linear trickle sources during wetting and redistribution phases. The study showed that there is a significant correspond between the wetting pattern of the measured and the estimated by the experimental equations. The wetting pattern increases with the decreasing of spacing between the two linear trickle sources, and this increase is regular along the wetting front or the surrounding of the wetting pattern, and this increase in the vertical direction of the wetting pattern is more in sandy loam soil than in silty clay soil and vice versa in the horizontal direction, when compare among the wetting patterns at the end of the wetting phase and the redistribution phase at a total time of 72 hours.

Impedance Force / Position Control for Planar 3DOF Robot Manipulator by Fuzzy Neural Network Combination

Saad Z. S. Al-khayyt

AL-Rafdain Engineering Journal (AREJ), Volume 24, Issue 1, Pages 46-54
DOI: 10.33899/rengj.2019.163196

As the demands for more robot's complex tasks were increased, force and torque control had become necessary. When contact forces are present, the performance of the trajectory tracking controller is degraded. Impedance force / position controller is proposed in this paper. The impedance force at the tip is controlled by fuzzy PID controller. PID controller tuned by adaptive linear network is used for trajectory tracking. A combination of fuzzy PID controller and PID controller tuned by neural network is used to generate the required torque at the robot manipulator's joints. The Jacobian matrix is derived for planar 3-DOF to transform the forces into joints' torque. Simulations are presented for robot manipulator with force contact at the tip. The trajectory tracking is improved by using fuzzy PID controller for impedance force of the environment.

Modal Analysis of Quill Shaft in Turbo-generator Unit Based on SolidWorks

Dr. Fares. Q. Yahya

AL-Rafdain Engineering Journal (AREJ), Volume 24, Issue 1, Pages 55-66
DOI: 10.33899/rengj.2019.163197

The main goal of this work is to carry out a numerical modal analysis of a Quill shaft of turbo-generator unitaffiliate to Mosul gas turbine station, using a trail version of popular finite element analysis software SolidWorks. The main function of Quill shaft is to protect the turbo-generator unit against overloads due to electrical network faults. The high flexibility of this shaft makes it capable of absorbing high displacements of resonance phenomena. This analysis is essentially needed to study the effect of transient loads applied to Quill shaft of turbo-generator unit under severe loading conditions such as electric network disturbances. The first five values of critical  frequencies and mode shapes of axial, bending, and torsional vibrations were studied and analyzed. Each mode has been isolated separately by applying a special type of boundary conditions (restraints) available in program. The three types of natural frequencies have been found and reported. It was observed that the fundamental values of each three types of natural frequencies are relatively high and out of the range of Quill shaft operating speed. Finally, it has been concluded from all analyses that Quill shaft under consideration is safe from the stand point of modal analysis. The results show that the Quill shaft is not running at any of each three types critical speeds. Therefore, the resonance phenomenon for all three types of vibrations can not be happened no matter how high the amount of transient load applied.   

Experimental Study of the Behavior of Fiber Reinforced Concrete Beams under Repeated Loads

Dr.Bayar J. Al Sulayfani; Muna M .Abdullah; Samier S. Shmas

AL-Rafdain Engineering Journal (AREJ), Volume 18, Issue 4, Pages 1-9
DOI: 10.33899/rengj.2010.31560

Concrete behavior subjected to repeated loads is differs than the one subjected to static loads. Repeated loads caused crushing in some part of concrete due to loading and unloading process. Concrete behavior under static loads is affected by adding steel fibers, which improved many properties especially concrete tensile strength. These improvements are studied in this research under the effect of repeated loads, by testing simply supported fibrous reinforced concrete beams with dimensions (1000x150x160) mm, reinforced with different percentages of steel fibers (0.0, 0.5, 0.75, and 1.0%). Repeated loads were applied to the beams through two points and for many cycles up to failure. The physical properties and compressive strength of the concrete used was found by casting standard cylinders (150x300) mm for the different percentages of fibers. All the results show improvements in beams behavior due to fiber addition to the concrete under repeated loads, by increasing the deflection, strain, ductility and energy dissipation due to increasing of added fibers percentages.

Keywords : Repeated load, Reinforced Concrete, Beams, Steel fiber

Use Of Bentonite Clay As A Coagulant Or A Coagulant Aid With Ferrous Sulfate For Synthetic Turbidity Removal

Mohammad S. Hassan; Musa’b A. Al- Tamir

AL-Rafdain Engineering Journal (AREJ), Volume 14, Issue 4, Pages 46-58
DOI: 10.33899/rengj.2006.45374

In this study the bentonite clay has been used as a coagulant and coagulant aid with ferrous sulfate in turbidity removal for different initial synthetic turbidity of Tigris River samples of (10- 500) ntu, The study revealed the efficiency of using bentonite clay as a coagulant alone in removing turbidity with a dose not more than 30 mg/l, Also the study reveled the improvement of ferrous sulfate efficiency for removing water turbidity when bentonite clay used with it in a dose of 7.5 mg/l of bentonite and 5 mg/l of ferrous sulfate. The regression analysis showed that the most important variables affecting on turbidity removal were initial turbidity followed by settling time and bentonite clay dose then finally ferrous sulfate dose.
Key Words: Ferrous Sulfate, Iron Salts, Bentonite Clay, Coagulation, flocculation, Coagulant aids, Turbidity removal, Water Supply

The Effect Of Adding Ethanol To leaded Gasoline on The Performance of Spark Ignition Engine

Dr. A.R Habbo; Mr.H.S Hammodi

AL-Rafdain Engineering Journal (AREJ), Volume 18, Issue 4, Pages 33-43
DOI: 10.33899/rengj.2010.31631

أُجريت هذه الدراسة لمعرفة تأثير إضافة مادة الايثانول بنقاوة 99.2% إلى الكازولين المرصص على أداء محرك احتراق داخلي يعمل بشمعة القدح متمثلاً بعزم المحرك والاستهلاك النوعي للوقود وكذلك كمية الملوثات المنبعثة منه عند ظروف تشغيلية مختلفة شملت كل من نسبة الانضغاط وتوقيت إعطاء قدحة الاشتعال. أُجريت التجارب العملية باستخدام الوقود الجديد (الايثانول + الكازولين المرصص) وبنسب حجمية مختلفة لمادة الايثانول ابتداءً من نسبة 10% وانتهاءً بنسبة 50% وبزيادة مقدارها 10% في كل مرة لبيان تأثير إضافة مادة الايثانول إلى الكازولين المرصص على أداء المحرك وكمية الملوثات المنبعثة منه.
تم إجراء التجارب العملية عند نسب انضغاط مختلفة وهي11:1, 10:1, 9:1 بينما تم تغيير وقت إعطاء القدحة بواقع 5 درجة من درجات عمود المرفق. وتم تثبيت سرعة المحرك ((2000 دورة لكل دقيقة وعند النسبة المكافئة ( ) .
بينت النتائج إن إضافة الايثانول إلى الكازولين المرصص أدى إلى زيادة عزم المحرك والاستهلاك النوعي للوقود مع حصول زيادة طفيفة في درجة حرارة غازات العادم وخصوصاً عند إضافة الايثانول إلى الكازولين المرصص بنسب 30% فما فوق، وصاحب هذا الأداء انخفاض في نسب الملوثات الناتجة من المحرك. كما بينت النتائج أيضاً أن زيادة نسبة الايثانول المضافة إلى الكازولين المرصص عملت على رفع نسبة الانضغاط التي يمكن للمحرك أن يعمل عندها مع غياب ظاهرة الصفع (knock) المعروفة آثارها السلبية على المحرك.

Settlement Analysis of a Piled Raft- E

Raid R. Al-Omari; Ahmed F. Hassan

AL-Rafdain Engineering Journal (AREJ), Volume 22, Issue 4, Pages 1-11
DOI: 10.33899/rengj.2014.89962

Recently the concept of settlement piles has been introduced in which the spacing could be large when the purpose of using piles is to mitigate the settlement rather than resisting the load. For large spacing the effect of cap soil contact on the bearing capacity may increase therefore the new system is usually referred to as piled raft. It is yet not clearly indicated what number of piles or spacing is enough to maintain tolerable settlements. This ambiguity is the main problem of the present research besides some other relations. The software ANSYS version 11 has been used to model and analyze the piled raft. The raft and piles are represented using the 8-node isoparametric brick element SOLID 65 while the surrounding soil is represented using the 8-node brick element SOLID 45. The raft dimensions are kept constants, as well as the cohesion and the angle of friction of the soil. The Drucker-Prager soil yield model has been employed.The results indicate that there is a limiting number of piles represented by the total piles area relative to the group area which in general amounts to 3 to 4% after which there will be no significant advantage of increasing the number of piles to reduce settlement. This relative piles area is slightly affected by the stress level relative to the bearing capacity so that the factor of safety. Accordingly the pile spacing may significantly be increased if the settlement is the major concern.The ultimate bearing capacity was found to moderately increase with increasing the relative pile area up to the narrowest spacing used of 3D which is in agreement with the conventional knowledge.For the conditions investigated the effect of raft-soil contact was found to be not very significant.

Flexural Behavior Of Flat And Folded Ferrocement Panels

Sura A. Majeed; Mohamad N. Mahmood

AL-Rafdain Engineering Journal (AREJ), Volume 17, Issue 4, Pages 1-11
DOI: 10.33899/rengj.2009.43268

The present paper describes the results of testing folded and flat ferrocement panels reinforced with different number of wire mesh layers. The main objective of these experimental tests is to study the effect of using different numbers of wire mesh layers on the flexural strength of folded and flat ferrocement panels and to compare the effect of varying the number of wire mesh layers on the ductility and the ultimate strength of these types of ferrocement structure. Seven ferrocement elements were constructed and tested each having (600x380mm) horizontal projection and 20mm thick, consisting of four flat panels and three folded panels. The used number of wire mesh layers is one, two and three layers. The experimental results show that flexural strength of the folded panels increased by 37% and 90% for panels having 2 and 3 wire mesh layers respectively, compared with that having single layer, while for flat panel the increase in flexural strength compared with panel of plan mortar is 4.5%, 65% and 68% for panels having 1, 2 and 3 wire mesh layers respectively. The strength capacity of the folded panels, having the particular geometry used in the present study, is in the order of 3.5 to 5 times that of the corresponding flat panels having the same number of wire mesh layers. Both types are also analyzed using finite element method to check the flexural stresses in these panels under self weight and cracking load.

Keywords: Ferrocement, Flat Panel, Folded panel, Mortar, Wire Mesh.

The Formal Composition of Khans in Islamic Architecture (An Analytical Study)

Assda A. H. Al-Tuhafi; Talaat I. M. Al-Aane; Khawla F. M. Al-Daudi

AL-Rafdain Engineering Journal (AREJ), Volume 17, Issue 4, Pages 80-96
DOI: 10.33899/rengj.2009.43312

Islamic architecture is considered to be a unique example that reflects the impact of structural formation systems in establishing its form; the structural relations represent the most important items and bases of architectural structures, especially at the abstract level. The structural relations form the basic foundation which represent the most important aspect in producing the formal structure of any building thus they are considered to be the most important method in describing the physical reality of architectural production . Stemming from the above fact, the study focuses on the structural relations that form the plans. The problem of the study is that structural relations which form the plans of Khans buildings in Islamic architecture are not clear. The aim of the present study is to clarify the specialty of Muslim architect intellectuality in the formation of a particular mechanism or method to form and design studied plans with specific functions like khans. To achieve the aim of the study a theoretical framework of structural relations is built depending on modern studies on formation of those relations on the bases of the statistical analytical method. The results arrived at show that the structural relations which form and construct the plans of Khans buildings are characterized by uniqueness as a distinguishing character of Islamic architecture some of these types of building are the khans, though they differ in their architectural design, their date and ever their geographical location. This in turn gives an indication and proof of the Muslim architect creative role in determine the distinguished identity of his architecture with the incentive of Islamic cultural intellect held by that architect all over the places of his civilization whenever and wherever he exists.
Key Word : Formal Composition , Relationships Formative , Khan , Islamic architecture

Optimal Neuro-Fuzzy D.C. Motor Speed Control

Assist lecture. Hameed A; Assist lecture. Hameed A

AL-Rafdain Engineering Journal (AREJ), Volume 21, Issue 2, Pages 73-86
DOI: 10.33899/rengj.2013.72801

This work deals with investigating of d.c. motor speed controlled by a buck-boost converter. Open loop system is tested. Aneuro-Fuzzy controller with random number and type of membership function is designed to control the speed of the d.c. motor as a closed loop system. Because of the lack of a clear and a known way for selecting the type and number of membership function in case of fuzzy control, An Adaptive Neuro-Fuzzy Inference System which comprises a fuzzy inference structure and neural network learning ability is modified to control the speed of the motor. The technique is used to select the optimal number and the best type of membership function for the fuzzy system. The process is carried out through testing four types of membership functions with different numbers (3,5,…etc) for each type and computing the absolute error for each case comparing their results to choose the smallest among them. Then the chosen root is applied to control the system for the rest time of control. The technique is applied to two loads (motors).

The Effect of Filler Type and Content on Hot Asphalt Concrete Mixtures Properties

Nathem A .H. AL- Saffar

AL-Rafdain Engineering Journal (AREJ), Volume 21, Issue 6, Pages 88-100
DOI: 10.33899/rengj.2013.82394

Asphalt concrete consists of coarse aggregates, fine aggregates, filler, and asphalt cement(used as a binder)mixed together in proportions according to a specified specifications.
Mineral filler is the inert material passing the No.200 sieve , occupies the void space between coarse aggregates particles and pores within the aggregates particles .There were many types of local waste materials that can be used successfully used as a mineral filler in hot asphalt concrete mixtures instead of ordinary portland cement and limestone powder.
The main objective of this research is to investigate experimentally the effect of using different types of fillers, and content, on hot asphalt concrete mixtures. Several specimens of hot asphalt mixtures were prepared according to (SORB/R9) using the obtained Optimum Asphalt Content (O.A.C.) with three percentages of the fillers of ordinary portland cement, lime stone powder, and waste glass powder at 4%, 6% and 8% by weight of total aggregates, respectively.
The results of Marshall tests on mix design of hot asphalt concrete mixtures, for the wearing course were concluded that, using the waste glass powder as a filler, with its optimum content of 8% (by the weight of total aggregates), leading to produce asphalt concrete mixtures with higher Marshall Stability, lower Flow, and lower voids in total mix comparing with ordinary portland cement and lime stone powder fillers.

Corrosion Protection of Steel Pipe Samples Buried in Soil

Haitham M. Wadullah

AL-Rafdain Engineering Journal (AREJ), Volume 18, Issue 5, Pages 1-10
DOI: 10.33899/rengj.2010.32798

The types of corrosion protection on corrosion resistance of steel pipe samples buried in soil have been studied in this research. Samples of unprotected carbon steel are used with other protected by different corrosion protection such as galvanic coating, rubber coating and two types of cathodic protection (impressed current and sacrificial anodes). The weight loss technique is used as a function of the corrosion rate (mdd).
The results, which have been obtained, show that the corrosion rates in the unprotected samples are high compared with the corrosion protected samples, and the maximum corrosion resistance is found to be at the cathodic protection systems.

Key words: Corrosion protection, Samples of steel pipe, Buried in soil

Study the Transverse Vibration of a Beam With Different Length

Ziad Shakeeb Al-Sarraf; Sabah Mohammed Jamel Ali

AL-Rafdain Engineering Journal (AREJ), Volume 17, Issue 1, Pages 83-91
DOI: 10.33899/rengj.2009.38471

A numerical solution to the frequency equation for the transverse vibration of a beam (Simply Supported with symmetric overhang) is done. It is proposed two limiting cases of a beam with no overhang, and no span. This agrees with the cases in which the supports are at the nodal Points of a freely vibrating beam. Also the numerical results compared with the analytical solutions for this study are coincident.
An approximation to the solution of the frequency equation for beams with small overhang is presented and compared with the numerical solution. This approximation is quite useful to determine a beam’s flexural stiffness (EI), or modulus of elasticity (E), by free vibrating of a simply supported beam.

Key word : Transverse vibration, beam, frequency

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