Journal of Engineering https://joe.uobaghdad.edu.iq/index.php/main <p>The Journal publishes 12 volumes annually; each volume consists of 10 - 12 scientific papers in all engineering specialties.</p> College of Engineering | University of Baghdad en-US Journal of Engineering 1726-4073 <div style="left: 196.033px; top: 432.093px; font-size: 16.6px; font-family: sans-serif; transform: scaleX(0.913569);"> </div> <div style="left: 773.5666666666666px; top: 432.09273333333334px; font-size: 16.6px; font-family: sans-serif;"> </div> Numerical Investigation of Aerodynamic Characteristics of Supercritical RAE2822 Airfoil with Gurney Flap https://joe.uobaghdad.edu.iq/index.php/main/article/view/1553 <p><strong>G</strong>urney flap (GF) is well-known as one of the most attractive plain flaps because of the simple configuration and effectiveness in improving the lift of the airfoil. Many studies were conducted, but the effects of GF on the various airfoil types need to be further investigated. This study aimed to clarify the effect of GF in the case of the supercritical airfoil RAE2822. This research includes a steady, two-dimensional computational investigation carried out on the supercritical airfoil type RAE-2822 to analyze Gurney flap (GF) effects on the aerodynamic characteristics of this type of airfoil utilizing the Spalart-Allmaras turbulence model within the commercial software Fluent. The airfoil with the Gurney flap was analyzed for three different height values 1%c, 2%c, and 3%c, and five mounting angles (30°,45°,60°,75°, and 90°) with the axial chord for angles of attack (-1°,-2°,-3°,0°,1°,2°,3°). The calculations showed that when GF height is increased, the maximum suction pressure on the upper surface increases by 25.4%, 36.5%, and 68.83% when the height of the Gurney flap is 1%c, 2%c, and 3%c, respectively, compared with that on the airfoil without GF. The lift coefficient was also increased, and the shock waves moved downward by increasing GF height. As Gurney flap heights increase, the drag coefficient increases gradually for positive angles of attack but for negative angles of attack. The drag coefficient also decreases with increasing the GF heights. As long as the angle of the mounting is between 45<sup>o</sup> and 90<sup>o</sup>, the lift coefficient does not differ on a large scale. For mounting angles less than 45<sup>o</sup>, the lift coefficient drops quite fast. As a result, reducing the Gurney flap’s lift enhancement and the drag coefficient increases gradually for positive angles of attack, but for negative angles, it can be noted that the drag coefficient decreases with increasing the mounting angles of GF. The calculated values of the lift and drag coefficients with an attack angle and pressure coefficient compared with the experimental values, and a good agreement was noticed. </p> <p><strong> </strong></p> Iman Jabbar Ooda Copyright (c) 2022 https://creativecommons.org/licenses/by/4.0 2022-06-01 2022-06-01 28 6 1 14 10.31026/j.eng.2022.06.01 The Design and Simulation of a Novel Optical Adder Depending on Optical Tri-state Gates https://joe.uobaghdad.edu.iq/index.php/main/article/view/1536 <p><strong>E</strong>ssential approaches involving photons are among the most common uses of parallel optical computation due to their recent invention, ease of production, and low cost. As a result, most researchers have concentrated their efforts on it. The Basic Arithmetic Unit BAU is built using a three-step approach that uses optical gates with three states to configure the circuitry for addition, subtraction, and multiplication. This is a new optical computing method based on the usage of a radix of (2): a binary number with a signed-digit (BSD) system that includes the numbers -1, 0, and 1. Light with horizontal polarization (LHP) (↔), light with no intensity (LNI) (⥀), and light with vertical polarization (LVP) (↨) is represented by -1, 0, and 1, respectively. This research proposes new processor designs for addition. As a result, the design can achieve m addition operations with an operand length of n bits simultaneously. To explain and justify the theoretical design idea, the three steps of adding a BSD are numerically simulated. The constructing process is thought to be more precise and faster because the time to add does not depend on the length of the word. For all entries, all bits are implemented simultaneously, boosting the system's efficiency. A simulation model for six addition processes with a total bit count of 15 bits across all entries is presented in this work performing in a one-time parallelism manner.</p> Qabeela Thabit Issa Ahmed Abed Alaa A Al-Saffar Copyright (c) 2022 https://creativecommons.org/licenses/by/4.0 2022-06-01 2022-06-01 28 6 15 26 10.31026/j.eng.2022.06.02 Evaluating the Moisture Content Variation on Critical Strain of Geo-materials: A Case Study https://joe.uobaghdad.edu.iq/index.php/main/article/view/1516 <p><strong>T</strong>he tunnel’s stability during construction is a very important matter. Some methods have been proposed for stability evaluation, but the hazard warning levels (HWLs) are more applicable among these methods. Despite monitoring and applying HWLs, several collapses in Shibli twin tunnels in Iran have cast doubts on the accuracy of this criterion in the presence of water. In this study, the critical strains under different water contents were measured through uniaxial compressive strength tests on 11 different shale and marl samples. A comparison of laboratory tests and numerical results shows that the influence of the moisture content on the critical strain is negligible. In addition, the results show that there is no direct relationship between the critical strain and uniaxial compression strength.</p> Dlshad Khurshid Al-Khailany Mohammed M. Saleh Ako Daraei Copyright (c) 2022 https://creativecommons.org/licenses/by/4.0 2022-06-01 2022-06-01 28 6 27 38 10.31026/j.eng.2022.06.03 Extraction of Manganese Element from Electric Arc Furnace Steel Slag (EAFS) by Liquid-liquid extraction (LLE) method https://joe.uobaghdad.edu.iq/index.php/main/article/view/1587 <p><strong>T</strong>his research investigates manganese (Mn) extraction from Electric Arc Furnace Steel Slag (EAFS) by using the Liquid-liquid extraction (LLE) method. The chemical analysis was done on the slag using X-ray fluorescence, X-ray diffraction, and atomic absorption spectroscopy. This work consisted of two parts: the first was an extensive study of the effect of variables that can affect the leaching process rate for Mn element from slag (reaction time, nitric acid concentration, solid to liquid ratio, and stirring speed), and the second part evaluates the extraction of Mn element from leached solution. The results showed the possibility of leaching 83.5 % of Mn element from the slag at a temperature of 25°C, nitric acid concentration 2 M, time 90 min, S / L ratio 1/100, and stirring speed 700 rpm. 94.7% extraction of Mn was accomplished from nitric acid solutions by using Octyl Pyro Phosphoric Acid (OPPA) in kerosene at contact time for 12 min, 50%OPPA -kerosene, stirring speed 900 rpm, and organic to the aqueous phase (O/A) of 4/1. Kerosene was the most important diluting agent in extracting Mn, compared to benzene and toluene.</p> Waleed Turki Copyright (c) 2022 https://creativecommons.org/licenses/by/4.0 2022-06-01 2022-06-01 28 6 39 52 10.31026/j.eng.2022.06.04 Assessment Strategies of Fixed Firefighting system in Residential Multi-Story Building for Improving Fire Safety: A Review https://joe.uobaghdad.edu.iq/index.php/main/article/view/1584 <p><strong>A</strong> fixed firefighting system is a key component of fire safeguarding and reducing fire danger. It is installed as a permanent component in a structure to protect the entire or a portion of the building and its contents. The study aims to review the previous studies that deal with the evaluation of fire safety measures and their use in resolving problems associated with fire threats in buildings. For this reason, a number of previous studies in this field were reviewed compared with the NFPA code. The findings revealed that regulatory developments over the last several decades had created an atmosphere conducive to innovation. This has resulted in a growth in the number of fixed firefighting system types now obtainable. These solutions provide substantial distinction in terms of performance and hence safety. Not only is the availability of different fire risk alleviation systems important, but so is the election of the most convenient solution for the job. This is typically seen inside regulatory procedures and basics of thumb or heuristics and depends on the knowledge and expertise of divergent specialists. When several perceived danger and results thresholds are surpassed, fixed firefighting systems are frequently included as extra fire protection and resilience measures</p> Waleed Ahmed Basim Huseen Khudair Copyright (c) 2022 https://creativecommons.org/licenses/by/4.0 2022-06-01 2022-06-01 28 6 53 64 10.31026/j.eng.2022.06.05 Roller compacted concrete: Literature review https://joe.uobaghdad.edu.iq/index.php/main/article/view/1530 <p><strong>R</strong>oller compacted concrete (RCC) is a material with no slumps and is made from the same raw materials as conventional concrete. The roller compacted dam method, the high paste technique, the corps of engineers method, and the maximum density method are all ways of designing RCC. The evolution of RCC has resulted in a substantial change in construction projects, most notably in dams, because of the sluggish pace of conventional placement, consolidation, and compacting. The construction process was accelerated by incorporating RCC into dams, resulting in a shorter construction period. Research shows that the dams that used RCC had completed one to two years sooner than the dams that used regular concrete<strong> (Bagheri and Ghaemian's, 2004)</strong>. The application of RCC has risen significantly during the past several decades, particularly for pavement applications. It has a lower construction cost than asphalt and may be completed fast. It is extensively used in areas/roads that transport big goods at moderate speeds. RCC is increasingly being used in metropolitan areas, particularly on roadways and streets. RCC has shown great interest in asphalt roads in terms of durability, compressive strength, prolonged service life, and lower maintenance costs. Fibre addition is frequently favored in RCC, just as in traditional concrete. Fiber inclusion contributes to the mechanical qualities of RCC as well as its long-term sustainability. Within the focus of this research, RCC is reviewed based on four factors: environmental effect, cost, fiber addition, and country-specific RCC use. This study is unusual in this sense and provides researchers with valuable information</p> <p> </p> anwer ali Zena K. Abbas Copyright (c) 2022 https://creativecommons.org/licenses/by/4.0 2022-06-01 2022-06-01 28 6 65 83 10.31026/j.eng.2022.06.06