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 two issues/year (Bi-annually). 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, University of Mosul

Email:  drjssm@uomosul.edu.iq

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

Print ISSN: 1813-0526

Online ISSN: 2220-1270

Numerical Investigation the Failure Mechanism of Left Slope of Darbandikhan Dam

Tareq H. AL-Rahal; Suhail I. Khattab; Bayar J. Al- Sulayfani

Al-Rafidain Engineering Journal (AREJ), 2020, Volume 25, Issue 2, Pages 1-11
DOI: 10.33899/rengj.2020.126573.1013

The aim of this research is to analyze the stability of the left shoulder slope of the Derbandikhan Dam failure due to rainfall and earthquake. This slope consists of unsaturated low plasticity clayey soil. All analyses were conducted by using the Geo-Studio program. The field survey was carried out for the study site and the soil samples were taken to perform the necessary laboratory tests to obtain the required soil properties. The field conditions (Rainfall and earthquake) were simulated, where the slope was exposed to rainfall at (24) mm / day intensity to various periods (10, 20, 30, 40, 50 and 60) days. A slope stability analysis was performed at end of each period. Moreover, another analyses were performed by exposed slope to an earthquake at end of each rainfall period.  Safety factor reached to critical value (1) when slope was exposed to the earthquake after (20) days of rain. 

A Review on Mix Design of Self-Compacting Concrete

Nuha H. Al_jubory; Tuqa Waleed Ahmed; Roua Suhail Zidan

Al-Rafidain Engineering Journal (AREJ), 2020, Volume 25, Issue 2, Pages 12-21
DOI: 10.33899/rengj.2020.126727.1017

In recent years, the use of self-compacting concrete in structures has increased significantly around the world
Many studies have been carried out on the characteristics of this type of concrete with the urgent need to design concrete mix and to find the material ratios used in this type of concrete so far there are no standard mix design self-compacting concrete methods, but there are many types of research to design mixes. Hence the need to review and compare these methods is of considered interest. The review of these studies helps researchers to choose the appropriate method of designing the mixtures of self-compacting concrete and their requirements, whether the strength or workability requirements.

Effect of Water Content and Dry Density on the Shear Strength Parameters for Expansive Soil

Ali Nazal Mohammed; Amina A. Khalil

Al-Rafidain Engineering Journal (AREJ), 2020, Volume 25, Issue 2, Pages 22-29
DOI: 10.33899/rengj.2020.126901.1033

The decrease in shear strength to soil is the cause of many geotechnical problems, especially in clay soils, which may occur due to changes in some soil properties, such as moisture content. Changing the values ​​of moisture content and dry density are important factors that have a clear impact on the shear strength of the soil due to the sensitivity of the soil to such changes, especially expansive clay soils, which requires the study of these factors and their impact on shear strength. The present research aims to study the effect of changes in compaction properties (moisture content and dry density) on the values ​​of shear strength parameters (cohesion and internal friction angle) using direct shear test of expansive soil. Clay soils were selected from the city of Mosul with high expansive properties, and within two sets of tests with a total of thirty compact models. Five percentages of moisture content range between(%32–% 17)  With five percentages of dry density, which ranged between(13.7- 17.7 ).
                The results showed that the shear strength values ​​decrease with increasing moisture content and increasing with increasing dry density at each vertical load . From the results obtained, the cohesion values ​​decreased by increasing the moisture content when dry density was constant and at its lowest value (12.75 ) at moisture content 32%. As for the values ​​of the internal friction angle, they decrease by increasing the moisture content when the dry density is constant and by the lowest value for the angle of internal friction (23.30) at the moisture content 32% and the dry density 13.7 . It is noted that the values ​​of both cohesion and the angle of internal friction increase with increasing dry density and with the highest value of cohesion ( 117.01 ) and the internal friction angle (450), respectively, at a dry density of 17.7 and a moisture content of 17%. 

Robust Power System Stabilizer Design Based on H∞/μ

Firas Ahmed Aldurze

Al-Rafidain Engineering Journal (AREJ), 2020, Volume 25, Issue 2, Pages 30-36
DOI: 10.33899/rengj.2020.127577.1045

In this article,  H∞ /μ controller is relied on to control the power system stabilizer(PSS) using state space approach for a single machine infinite bus (SMIB) system. Design a robust feedback controller for the system using the H∞/μ technology supported by the Matlab / Simulink. The H∞/μ design method leads to a robust controller with a fixed structure and fixed parameters. The uncertainties of the model are taken into account when specifying the weights. The controller demeanor obtained was analyzed through the input represented by the step response and the output response of the power system (PS) in the case of normal operation and then the system with changed parameters. The suggested controller proved its effectiveness by maintaining the stability of the system with acceptable limits of disturbances.

Improving the Performance of A Flat Plate Solar Collector Using Nanofluid as Working Fluid

Omar Mohammed Hamdoon

Al-Rafidain Engineering Journal (AREJ), 2020, Volume 25, Issue 2, Pages 37-45
DOI: 10.33899/rengj.2020.127218.1041

Solar energy is the best alternative to limited fossil fuels. The foremost important means of utilizing solar energy are solar collectors. The most common types of solar collectors are flat plate solar collectors. A great deal of theoretical research has been conducted to enhance the flat plate solar collector efficiency. One effective way to increase the efficiency is by using an improved thermal properties fluid as nanofluid. In this paper, a numerical study has been made to enhance the efficiency and improve the performance of solar collector via the use of (Multi-Wall Carbon Nano Tube-water) MWCNT-H2O nanofluid instead of traditional fluid like water as working fluid under the weather of Mosul city / Iraq (36.3489° N, 43.1577° E). One dimensional dynamic model using implicit finite difference method was used. Solving energy conservation equations through the various layers of the solar system is the basis upon which the current model was based. Effects of nanoparticle volume fraction and mass flow rate on the working fluid stream temperature differences, and the thermal efficiency were studied. The mass flow rate was varied from 0.004 kg/s to 0.03 kg/s, while the volume fraction was varied from 0% to 6%. The results of "Nanofluid Based Flat Plate Solar Collector" were compared with the experimental results presented by [1]. The comparison established a good match between the current results and experimental results. The results showed an increase in the working fluid outlet and inlet temperature difference and collector thermal efficiency due to the addition of MWCNT nanoparticles. The temperature difference of "Nanofluid Based Flat Plate Solar Collector" was found 28.8⁰C at 0.014 kg/s and 6% in April, while it was 25 ⁰C at the same condition in the "Water Based Flat Plate Solar Collector case". Also, the thermal efficiency of "Nanofluid Based Flat Plate Solar Collector" was found 2.41% to 6.68% more than the "Water Based Flat Plate Solar Collector case".

A Review of Solar Air Heaters: Techniques for Thermal Performance Enhancement

Omar Mohammad Hamdoon

Al-Rafidain Engineering Journal (AREJ), 2020, Volume 25, Issue 2, Pages 46-59
DOI: 10.33899/rengj.2020.128374.1065

The solar air heater is a simple device which captures solar energy. Producing hot air by using a solar air heater is a renewable energy heating technology used to process heat generation for space heating. Such systems produce heat at a minimum initial and running cost. Minimum maintenance like cleaning of collectors only is required. Many studies have studied the possibility of improving the performance of solar collectors and raising their thermal efficiency through additions and improvements that were added to the solar heater. Among these improvements are: Adding the extended surfaces to the upper or lower  channels, or both,  attaching baffles to the absorber plate surface, using corrugated absorber plate, and storing the extra thermal energy and releasing it during sunset. The objective of the present paper is to review the various studies dealing with previous improvements, to present the design modifications, in addition to summarizing their most important results. Based on the review, it is found that: Adding the fins and baffles together to the absorber plate surface of the single or double pass solar air heater has a great effect on improving the thermal efficiency. The use of a corrugated absorber plate leads to a significant increase in the efficiency of the solar air heater. The heat stored in the solar air heater can be used to produce useful heat for several hours after the absence of solar radiation and raise daily efficiency.

Studying The Effect of Intake Channel Angle on the Sediment Transport Branching Channels

Ehsan Elewy Salman; Mwafaq Younis Mohammed

Al-Rafidain Engineering Journal (AREJ), 2020, Volume 25, Issue 2, Pages 60-65
DOI: 10.33899/rengj.2020.126731.1018

An experimental investigation was conducted to observe the connection angle effect of the branched channel front with the main channel on the entering sediments amounts into the branched channel. Three angles were taken to the branched channel inlet (60°,45°,30°), that connected with the main channel from the left side with two concentrations of sand at a granular diameter rate (D50=0.5mm). The concentration flow rates were 1.8 and 2.22(g/s), respectively. The sand was fed and organized by a speed regulator to main channel to obtain the concentrations. The results showed that the 60° was better than the rest in the sediment numbers. Compared to the 30° and 45° angles, the reduction at the 60° was at (32-40)% of 40% of the discharge rate. Besides, at the 30% discharge rate, the reduction was (16-19)%. Within the study limits, it has indicated that the greater angle is the better and it reduces sediments.
 

Study of Scour Around Cylindrical Bridge Piers with Circular Openings

Mays Ibrahim Alsaidi; Ghania Abd Al-Majeed Hayawi; Mena Ahmed Alsawaf

Al-Rafidain Engineering Journal (AREJ), 2020, Volume 25, Issue 2, Pages 66-74
DOI: 10.33899/rengj.2020.126863.1029

            To reduce the local scour around bridge piers and ensure their safety, an experimental study was conducted to examine the effect of a single tubular hole that faces the flow direction through three successive cylindrical bridge piers. In order to reduce the local scour, occurred because of the collision of the flux. Two groups of successive piers were used, both had diameters of 5, 11, 16 cm. First group of piers with internal tubular opening which had 20% diameter of the pier and located at half the water depth. The second group just solid pier for comparison. The spacing between them was varied to be 30, 40 or 50 cm for each group. As well as the discharge was varied. The used moveable bed material classified as non-uniform coarse sand, which had 0.5 mm mean diameter. The results showed that the presence of the openings helps effectively to reduce the depth of scour and its effect increases as the diameter of the opening increases, as the highest reduction reaches 55.56%, 53.33% and 10% for diameters 16, 11 and 5 cm, respectively. The scour depth increases when the diameter of the pier the increase of and the short distance between the successive piers.

Slope Stability Study of Al-Qaim Dam that Proposed to be Constructed on Khosar River – Case Study

Farah K. Saeed; Kamel A. Almohseen; Abdulwahab M. Yunis

Al-Rafidain Engineering Journal (AREJ), 2020, Volume 25, Issue 2, Pages 75-83
DOI: 10.33899/rengj.2020.127023.1034

It is extremely significant during the design stage of an earth dam is to analyze the seepage and slope stability. The proposed Al-Qaim dam on  Al Khoser river was used as a case study to apply Geo-Studio 2012 program and its appendices Seep/w and Slope/w. Some minor modifications to the original design suggested by SOGREAH company have been proposed. The Geo-Studio 2012 program was used to analyze three states of Al-Qaim reservoir i.e. (end of construction، steady-state، and rapid drawdown). Seep/w and Slope/w have used to analyze the seepage and the stability of the slopes، the results reveal a good agreement between this analysis and the design company's results. Moreover، the present analysis achieves the requirement of safety with less volume of embankment which reduces the cost of construction substantially.
 

Modelling of Wetting Front Advance and Discharge Change of Subsurface Line Source

Abdulghani Kh. Mohammed; Entesar M. Ghazal

Al-Rafidain Engineering Journal (AREJ), 2020, Volume 25, Issue 2, Pages 84-92
DOI: 10.33899/rengj.2020.127221.1042

Sub-drip irrigation is one of the most important and the latest high-performance irrigation systems that are characterized by a high ability to reduce losses of deep percolation and evaporation from the soil surface. Twelve laboratory experiments were carried out to study the effect of soil texture, dripper depth and initial water content on the wetting pattern, dripper discharge. Further, non-linear regression approach was applied to predict empirical relationships for estimation the wetting pattern dimensions and actual dripper discharge. The results showed a significant match between the observed and estimated values ​​of the wetting front advance and the dripper discharge change. At a specific volume of water application, the size of wetting soil increased (8-20%) with the initial water content increase and (2.5-6.25%) with dripper depth increase and this size decreased (4.5-36%) with the clay content increase. The rate of vertical upward advance decreased with increasing the initial water content. The dripper discharge gradually decreased with the continuation of water application due to positive pressure increase at the dripper opening, and this decrease increased with increasing dripper depth, clay content and the initial water content of the soil.

Effect of Nozzle Angel & Cyclic Pressure Head Variation on Water Distribution Uniformity for Stationary Sprinkler Systems

Esraa Ali Younis; Haqqi Ismail Yasin

Al-Rafidain Engineering Journal (AREJ), 2020, Volume 25, Issue 2, Pages 93-104
DOI: 10.33899/rengj.2020.127209.1040

The present  research included studying the effect of the sprinkler nozzle angle and cyclic variation of the operating pressure head on the uniformity of water distribution for many sprinkler heads spacing with rectangular  and triangular sprinkler heads arrangement for different sprinkler heads. The research conducted 40 tests to measure a single sprinkler water distribution pattern under similar climatic operating conditions by adopting the water distribution pattern along a beam that represents the radius of the wetting circle which its center is a sprinkler head for different sprinkler nozzle angles (Ɵ + 5 °, Ɵ + 3.5 °, Ɵ, Ɵ -3.5 °, Ɵ -5 °) and the constant-cyclic operating pressure head conditions for different sprinkler heads. 320 patterns were found for field water distribution pattern and uniformity coefficient for four different spacing  with  a rectangular and triangular sprinkler heads arrangement for   the sprinkler heads and  the measured water distribution patterns.
The research revealed that 70% of the uniformity coefficients in the rectangular arrangement are greater or equal to its value in a triangular arrangement. The increase in the nozzle angle results in increasing the uniformity coefficient of 1.4% for each degree, an increase in the nozzle angle, and can reach 2.4% for each degree for a specific spacing, arrangement, and sprinkler head. Also, the difference between the two water distribution patterns in the case of operating with constant pressure head  and variable pressure head is slight, but it shows in the values of the uniformity coefficient, where the maximum difference reaches 10%, and in general, the best in the values of the uniformity coefficient requires determining the nozzle angle, the spacing and the arrangement of sprinkler head as well as the case of operating pressure head constant or variable.

Analysis of Rainfall Data for a Number of Stations in Northern Iraq

Ihsan F. Hasan; Younis N. Saeed

Al-Rafidain Engineering Journal (AREJ), 2020, Volume 25, Issue 2, Pages 105-117
DOI: 10.33899/rengj.2020.127531.1044

This study aimed to analyze the rainfall time series data for 9 stations in the north of Iraq, namely (Sulaymaniyah, Darbandikhan, Dokan, Duhok, Erbil, Kirkuk, Mosul, Sinjar, Tal-Afar) from 1979 until 2014 using the Multiplicative model of time series, this is for the purpose of identifying the reality of the time series variables (general trend, seasonal, periodic, random) which affected by the rains, and the prediction of monthly rainfall data for the  selected stations. The rainfall characteristics of the northern region of Iraq were also studied in terms of daily, monthly and annual distribution of rainfall rates and a relationship between intensity-Duration-Frequency (IDF) at different return periods (2, 5, 10, 15, 25, 50, 100) years has been found to identify the reality of rainstorms and provide solutions  to a number of design problems related to management and treatment of water for Basins in general and ungauged Basins in particular such as surface runoff discharge and erosion control.

Surrogate Worth Trade - Off (SWT) Method and the Decision-Making Process in Water Resources Planning and Management

Mohammed Awni Khattab; Kamel Ali Almohseen

Al-Rafidain Engineering Journal (AREJ), 2020, Volume 25, Issue 2, Pages 118-126
DOI: 10.33899/rengj.2020.127592.1049

Multi-objective decision-making methodologies are one among widely researched areas in recent years. As a result, many technologies have been developed. Among these, is Surrogate Worth Trade - Off (SWT). SWT has emerged in the areas of water resource planning and management, and is one of the multi-objective analysis methods described as an interactive method. This study includes reviewing and applying (SWT) method to optimally operate the Mosul Dam Reservoir. This operation policy sought to achieve two contradictory objectives: diverting water from the reservoir for irrigation purposes and releasing water from it for the purpose of hydropower generation. A comparison was also made of the results that were nominated from the application of this method, namely (allocating million cubic meters/ year for irrigation and generating 1572 GW-hour/year for power generation) with the results of the research [3] which four methods for solutions have been implemented. These are: weights, constraints, goal attainment, and step method. The results reveal that the used methods gave the optimal solution by (allocating 5906 million cubic meters/ year for irrigation and generating 1,600 GW-hour/year for power generation), (6236 ,1555) , (6188 ,1558) and (6121 , 1568) respectively. from the comparison It can be concluded that (SWT)  is an efficient and promising method in identifying an operating policy for a single reservoir system with competing objectives.

Design of an Efficient Network Monitoring System Based on Agents

Ahmed Mohammed Basheer; Turkan Ahmed Khaleel

Al-Rafidain Engineering Journal (AREJ), 2020, Volume 25, Issue 2, Pages 127-135
DOI: 10.33899/rengj.2020.126754.1020

In this paper, a network service monitoring system was proposed by relying on the agent for several reasons, including the possibility of providing effective control over the network, preventing penetration, reducing complications, ensuring the continuity of service on the network, permitting quality of service, reducing downtime and system cost. The proposed network management and monitoring system includes a set of tasks such as (monitoring the network service using a simple interface, the ability to add and delete new users, provide security, and the ability to distribute monitoring tasks to many agents and make adjustments independently without user intervention). The proposed monitoring system can be applied to the internet or local networks. The agent monitors and observes events on the network and collects information from all parts of the network and sends it to the server to convert it to a page that is designed to display this information in real-time to the administrator. Event monitoring information on the network is collected at the user's request or on a scheduling system created by the network manager and sent this information to the server to alert the manager when a fault occurs. By providing the ability to make some decisions without consulting the manager. This system has been designed to be general in all types of networks in the sense that it can be used in monitored and manage the network activated or passive, and it can be applied in the local networks and global networks.

ESP32 Microcontroller Based Smart Power Meter System Design and Implementation

Issa Ahmed Abed; Hayder Yasir Naser

Al-Rafidain Engineering Journal (AREJ), 2020, Volume 25, Issue 2, Pages 136-143
DOI: 10.33899/rengj.2020.127111.1038

Every house and workplaces should install electricity energy meter to evaluate the electricity consumption.  Finally of consistently, a large number of us get stressed over the high power bill and it is need to check the energy meter once in a while. In this work a smart electricity energy meter using ESP32 microcontroller which monitor energy through the PZEM-004T at any time and send to the office. Where this PZEM -004T is used for voltage and current measurements. Then the records will send to the office and store in the SQL database and also web page which is used specific IP. The results have been generated using MYSQL and the curves of the values with the time are also plotted using Microsoft Excel 2010. 

Weighting Signal Error Reduction

Abdelkader Faris Al Shalji; Dr. Fakhrulddin Hamid Ali

Al-Rafidain Engineering Journal (AREJ), 2020, Volume 25, Issue 2, Pages 144-151
DOI: 10.33899/rengj.2020.127309.1043

The paper presents and discusses how to use some techniques to reduce the effect of error in the weighting signal which is produced from a load cell. The load cell is one of succeful sensors which is used to transform the weight to an electrical signal.  In industry the production of an accurate signal suffers from a problem of noisy environment. Different source of noise like electromagnetic fields from motors, machines, power lines and microwave in addition to humidity and tempreture variations have significant effects on weak electrical signals produced by load cells.Both hardware and software filtering are adopted to reduce the un wanted effects.

Comprehensive Study and Evaluation of Commonly used Dimensionality Reduction Techniques in Biometrics Field

Shahad A. Sultan; M. F. Ghanim

Al-Rafidain Engineering Journal (AREJ), 2020, Volume 25, Issue 2, Pages 152-163
DOI: 10.33899/rengj.2020.127581.1047

 In biometrics field, usually feature vectors have major length and contain ineffective information. This problem is so called “curse of dimensionality‟. Hence, there is a need for efficient dimensionality reduction technique to remove the redundant features and reduce the size of feature vectors to get high accuracy rate with fast performance. In this paper a comprehensive study of commonly used dimensionality reduction techniques: Principle Component Analysis, Linear Discremenant Analysis, and Generalized Discremenant Analysis, have been handled.  Theoretical background of these techniques is illustrated along with the methods used to calculate their projection spaces then; practical implementation is conducted to find out and adopt the best one for retina based biometric authentication system. From this extensive study, it has been concluded that PCA technique has a number of problems make it has a bad classification power. LDA technique has a number of problems make it impossible to implement in most cases of biometrics field, while GDA technique is more efficient than the PCA and LDA techniques for dimensionality reduction purpose. It has high classification power and consumes less computational time. Hence, GDA technique is adopted in the proposed authentication system.   

Faults Diagnosis in Robot Systems: A Review

Muhamad Azhar A.Alobaidy; Dr. Jassim M. Abdul-Jabbar; Saad Zaghlul Al-khayyt

Al-Rafidain Engineering Journal (AREJ), 2020, Volume 25, Issue 2, Pages 164-175
DOI: 10.33899/rengj.2020.127782.1051

Any robot system consists of mechanical and electrical components. . Mostly and with time obsolescence, faults and errors are happen in robot systems lead to work problems. Many years ago, scientist and researchers are working in this field. In this paper, a review study focuses on this field is introduced to make classifications between different types of faults and diagnosis methods those used in the field of robotics. Many types of faults are studied, according to some previous and recent works. The most detected faults can be classified into two parts: hardware and software faults. The hardware faults part is further classified into two main types; the first one is represented in sensors and actuators, while the other is included taking into consideration both position and velocity in joints. These joints which usually connect the links of the arm with each other and ensure contentions to motors, controllers, and many sensors, are really represent the most important side have to be studied. The software faults part includes those errors occurred during programming such as any error happen in signal translation, signal classification or signal identification is considered as a software fault.

Simulation and Experimental Gait Cycle of Two Types of Degree of Freedom Bipedal Robot

Ali Fawzi AbulKareem; Ahmed AbdulHussein Ali

Al-Rafidain Engineering Journal (AREJ), 2020, Volume 25, Issue 2, Pages 176-188
DOI: 10.33899/rengj.2020.127579.1046

Another type of legged robots is a bipedal walking robot or humanoid robot, which can be designed to implement various functions as necessary and mimic like a human. Often, balance while moving and when the first leg in the swing process and the second leg on the ground is difficult than most other kinds of robots. Two bipedal robot prototypes are designed with 10 degrees of freedom and 17 degrees of freedom to fulfill a gait cycle. The robot's locomotion can also be controlled via two types of microcontrollers, Arduino microcontroller and LOBOT LSC-32 driver. So, the KHR-2HV simulation model by Webots is used to simulate the experimental results of the bipedal robots. The results showed that the cubic polynomial foot trajectory for 10 degrees of freedom and 17 degrees of freedom bipedal robots are (  with regression 0.9276) and (  with regression 0.939) respectively.After several methods for programming, the bipedal robot by LOBOT LSC-32 driver model is the better than Arduino with PCA 96685 driver-16 channel servo driver.Experimental results carried out during the KHR-2HV simulation model by Webots program. This model gives a better estimation and a fast response to confirm the stability of the10 degrees of freedom and 17 degrees of freedom bipedal robots.

Analysis of Rainfall Drought Periods in the North of Iraq Using Standard Precipitation Index (SPI)

Anass M. M. Rasheed

Al-Rafidain Engineering Journal (AREJ), 2010, Volume 18, Issue 2, Pages 60-72
DOI: 10.33899/rengj.2010.28187

In this research, the standard precipitation index (SPI) was used to analyze rainfall records between 1941 - 2002 for nine metrological stations in the north of Iraq. In addition, digital maps of average drought magnitude and average drought intensity for the study region had drawn by using geographic information system (GIS). It is concluded that 56% of the study period were drought years.

The Effect of Power Swing on Distance Relays Performance

Atheer Habash Abosh; Abdul Ghani A. Abdul Ghafoor

Al-Rafidain Engineering Journal (AREJ), 2009, Volume 17, Issue 5, Pages 43-48
DOI: 10.33899/rengj.2009.43386

Abstract
The distance relay is suffering from under-reach in its performance. This is because of some transient disturbance, which may happen when the power flows and swings. Besides that the power swings as a consequence of some fault cases. In this paper a new distance relay has been suggested and modeled for detecting stable and unstable power swings.
This relay is known as out of step relay (OOS). The method employed is to measure the rate of change of the positive sequence impedance of the relay which supervise the trip signal that comes out of the distance relay. It allows the distance relay to work, if it detects an unstable power swing or a fault. On the other hand it blocks it if the power swing is stable. The new relay have been modeled and simulated using MATLAB-SIMULINK software programs.
The performance of this relay has been tested on an equivalent two sources system. The results prove that the suggested relay is active and fast. Thus overcoming the limitation of the distance relay in case of under-reach. The results also show that the new relay has the ability in discriminating between the types of faults, that occur during power swings.
Key Word: Power swing, Distance relay , Out of step protection technique.

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-Rafidain Engineering Journal (AREJ), 2010, Volume 18, Issue 4, Pages 1-9
DOI: 10.33899/rengj.2010.31560

Abstract:
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-Rafidain Engineering Journal (AREJ), 2006, Volume 14, Issue 4, Pages 46-58
DOI: 10.33899/rengj.2006.45374

Abstract
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-Rafidain Engineering Journal (AREJ), 2010, Volume 18, Issue 4, Pages 33-43
DOI: 10.33899/rengj.2010.31631

ألخلاصة
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.

Evaluating performance of Hydrus-1D model in simulating evaporation from soil surface for different wetting intervals

Muzahim M. Abid; Eftikhar A. Alani; Entesar M. Ghazal

Al-Rafidain Engineering Journal (AREJ), 2015, Volume 23, Issue 2, Pages 31-43
DOI: 10.33899/rengj.2015.101073

In this study, Hydrus-1D model was used to simulate the evaporation from the soil surface for different wetting intervals for northern region(sandy loam and clay loam) using input for climatic data , and data of class Apan evaporation.The results showed that data of pan evaporation class A can be relied on in simulating and calculation of evaporation from the soil surface, where the standards of statistics (IOA, R2) calculated on the basis of evaporation pan class A data are better for the wetting intervals (2,4, 8, 16 ) days compared with the values of those standards based on full climate data and both types of soil. The study also showed that the wetting intervals and their impact on evaporation from the soil surface and evaporation stages reasonably agree with the results of field experiments that have been made in this area.

Concepts Architecture For Architectural Students

Imad M. M. Azhar Al-Bakari

Al-Rafidain Engineering Journal (AREJ), 2007, Volume 15, Issue 4, Pages 80-93
DOI: 10.33899/rengj.2007.45256

Abstract
Formation of concept in Architecture Design is something unusual to many student and most projects been designed with no knowledge of how to use concepts properly.
This research introduce meaning and form of concepts in Architecture. Range and scope in Academic and professional work. Also problems, which face student such as Communication, Adaptation, and the correct type, show types of concept. Research also shows types of concept and concepts hierarchies.
Applied part of this research will deal with some student' projects. Who adapt concepts. And to analyze forms and types of their concepts through different tables. Inter views have been made with students of fourth year to discover how students had been arrived to final solution

Corrosion Protection of Steel Pipe Samples Buried in Soil

Haitham M. Wadullah

Al-Rafidain Engineering Journal (AREJ), 2010, 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

Freehand Drawings versus CAD Drawings in the Conceptual Architectural Design Phase

Dr. Dhuha Abdulgani Abdulaziz Al-kazzaz

Al-Rafidain Engineering Journal (AREJ), 2014, Volume 22, Issue 1, Pages 56-79
DOI: 10.33899/rengj.2014.87025

In the last decade, the value of freehand drawing as a design tool in both education and
practice is open to debate as a result of the accessibility of digitised drawing tools such as
CAD systems and the relative ease with which a design can be presented and realised
using computerised techniques such as parametric modelling and rapid prototyping.
The conceptual design stage is the most critical in the design process. Despite the fact
that most of the widespread computer aided design systems (such as AutoCAD and
3DSMax) are primarily directed towards the more detailed stage of design process. Even
so, there are architects today who have abandoned the use of a pencil and paper, turning
to the computer during the creation of their design concepts.
The paper investigates the limitations of Computer Aided Drawing (CAD) systems
which make them unable to satisfy what freehand drawings are doing for the initial
design phase. To achieve this aim, the first section of this paper puts forward a
framework for the main roles of freehand drawings through the conceptual design
process. The second section investigates the capabilities of computer aided drawing tools
to achieve these roles by depending on the theory and practice of the use of CAD tools at
the initial design stage. The third section concludes the weakness and strength of
computer aided drawing systems in the conceptual design phase. The paper ends with
recommendations.

Friction and indicated power measurement for diesel engine by ( aerial dynamometer

Mohammad Sami Ahmad

Al-Rafidain Engineering Journal (AREJ), 2012, Volume 20, Issue 2, Pages 106-115
DOI: 10.33899/rengj.2012.47288

Abstract:
The conventional methods - used for - measuring brake, friction, and indicated power are based on brake - off dynamometers which use hydraulic or electrical dynamometers .
The mentioned above methods use the measured torque to calculate the related power.
The present method and instrument are characterized by measuring the amount of pressure opposed by a compressor joined to the engine and a reservoir for a compressed air, thus; the engine speed decelerates with the increasing pressure . For a specified pressure and engine speed, power could be calculated.
In addition, friction power in the engine could be estimated by measuring the consumed current and effective voltage on an electrical driving motor when the diesel engine at run – off situation; no fuel supply. The whole present dynamometer had been designed and performed by the researcher as explained.

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