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Aims and Scope
Editorial Board

1. CFD Analysis of Spread COVID-19 with Air Conditioning Systems

Maher A.R. Sadiq Al-Baghdadi ^1,2

1 Kufa Centre for Advanced Simulation in Engineering (KCASE), Faculty of Engineering, University of Kufa, Najaf, Iraq.

2 Computational Fluid Dynamics Center, International Energy and Environment Foundation, Najaf, P.O.Box 39, Iraq.

Abstract: Droplets and aerosolized viral particles expelling from the body through coughing or sneezing and it is spreading to nearby surroundings. Two-phases, three-dimensional, Computational Fluid Dynamics (CFD) model using Reynolds Average Navier Stokes (RANS) equations has been developed to simulate the air flow and the transport and dispersion of the aerosolized viral particles and fine droplets suspended in the air particles through the office. The study presents two cases involving the spreading limits and pathways of the aerosolized viral particles and fine droplets suspended in the air in a place; without and with air conditioning unit. The results showed that the use of air conditioning systems can increase the chances of spreading COVID-19 virus infection. The air-conditioning unit recirculates the same air inside a room, and this has the potential to create a virus-laden environment. Air circulation indoors such as using air conditioning units should be avoided in closed places. Existing ventilation systems should be expanded to include extraction and air filtration systems and/or germicidal, ultraviolet light. Also, opening a window can help bring in fresh air from the outside and disperse stale air inside, and that could help reduce the possibility of the spread of the virus particles in the closed place. Lastly, crowds of people in closed public places should be avoided. This work is beneficial for the ventilation strategy design for mitigating COVID-19.

Volume 12, issue 2, 2021, pp.63-72.

2. Deposition Tantalum Pentoxide Coating on 2101 Lean Duplex Stainless Steel by Reactive Sputtering for Biomedical Applications

Nesreen Dakhel Fahad¹, Jassim M. Salman Al-Murshdy², Ali Sabea Hammood¹

1 Department of Materials Engineering, Faculty of Engineering, University of Kufa, Iraq

2 Babylon University, College of Materials Engineering, Iraq.

Abstract: The most recent advancement in implant development is to meet materials that accelerate bone formation at the interface of bone implant and improve Osseo integration. Lean Duplex Stainless Steel as an implantation material needs several enhancements to the surface's properties chemically and physically. The application of surface modifications over the implant is an important method for improving the surface properties of LDX. Reactive Sputtering has some benefits for surface modification, including changing surface topography, increasing hardness and surface roughness, improving surface antibacterial activity and adhesion strength. Coating LDX 2101 DSS with Ta2O5 at times (2,4,6,8, and 10) hrs was used by a modified reactive sputtering technique. Analysis of surface characterization for samples before and then after the sputtering process was performed by micro hardness test, "x-ray diffraction", XRD analysis, "scanning electron microscope", SEM, and "field emission scanning electron microscope" (FE.SEM), "energy dispersive spectroscopy" (EDS), "Atomic force microscope" (AFM), Antibacterial study and Adhesion strength were done on the samples surfaces and compared to uncoated one. The current results indicate that the formation of Ta2O5 layers on the surface of the alloy was achieved, which would improve the surface characteristics, hardness, inhibited bacterial activity and adhesion strength of LDX 2101 DSS for orthopedic applications.

3. Fatigue Characterizations Modifying for Below Knee Prosthesis Composite Materials by using Natural Knitted Kenaf Reinforcement Fibers

Sumeia A. Mechi, Muhannad Al-Waily

Department of Mechanical Engineering, Faculty of Engineering, University of Kufa, Iraq.

Abstract: This research approach of several composite materials with 12 layers were suggested from perlon, kevlar and woven carbon fibers, and natural knitted kenaf, the purpose findings mechanical, physical properties and fatigue life that help to use the socket with good design at longest period.  There are two best types of composite materials are used for to analysis of the fatigue and tensile properties of prosthetic socket below knee which laminated by using vacuum system. The pressure inside the stump of patient and the socket was 165 kpa. Originality of using natural kenaf fibers led to the improvement of the maximum tensile strength 39.35% and safety factor of 2.52, with research limitations at the lowest costs and longest period of time. So, the experimental and numerical techniques were used to calculate the fatigue characterizations for effect of kenaf reinforcement fiber of composite materials used. Therefore, the experimental work included manufacturing for composite samples with different lamination layers and various layer number of kenaf fiber, in addition to, calculated the mechanical properties and fatigue life of its samples. The experimental results of fatigue have a good agreement with those obtained using the Finite Element approach. It was found that sample with kenaf has a maximum number of cycles up to failure =18.35 × 105 cycle at stress ratio (R= -1). The analytical part, using ANSYS2020 R2 to model (BK) from suggested materials with and without kenaf for the patient suffering from lower knee amputation for diabetes. Practical implications of experimental and numerical methodology showed that kenaf fibers have achieved the requirements of safety.

4. Enhancement of Desulfurization Process of Gray Cast Iron by using Different Concentrations and Materials

Ali A. Mnati, Kadhim K. Resan

Materials Engineering Department, College of Engineering, Mustansiriyah University, Iraq.

Abstract: This research aims to best of the desulfurisation process through crucible furnace using waste oil motor. The best of desulfurisation process has been studied in crucible furnace of the melting shop with respect to the amount of desulfurising agent, control of carbon, and the temperature as well as the composition and the sulfur content. The results refer to the desulfurisation efficiency of calcium carbide is lower compared to burnt lime. The latter as well as desulfurisation, also has the ability to deoxidize and eliminate of oxygen that has a negative effect on the cast product. In this research, a study of recycling gray cast iron to purity gray cast iron and its effect on mechanical properties. Four kilograms (4.0 Kg) scrap were charged crucible furnace of ten kilograms (10.0 kg) capacity, where furnace using of waste motor oil for scrap heating and melting. The scrap in crucible furnace was heated to a temperature of 1400 °C and inserted thermocouple to monitor the temperature.  For desulphurization, 0.2 kg calcium carbide (CaC2) and burnt lime (CaO) were added to the molten in the furnace at 1400 °C melt. Then, ladle was used to eliminate of slag on the surface of the molten scrap resulting from desulfurizing agent.

5. A Study on the Influence of Stress Ratio and Loading Mode on Fatigue Life Characteristics of Porous Functionally Graded Polymeric Materials

Emad Kadum Njim1, Sadeq H. Bakhy1, Muhannad Al-Waily2

1 University of Technology, Mechanical Engineering Department, Baghdad, Iraq.

2 Department of Mechanical Engineering, Faculty of Engineering, University of Kufa, Iraq.

Abstract: In this paper, fatigue life tests on 3D printed plain cylindrical specimens made of porous functionally graded polymeric materials (PFGPMs) at room temperature were carried out. Test results are obtained for constant amplitude load in fully reversed bending with mean stress equal to zero with various porosity and gradient index parameters. Fatigue characteristics were evaluated experimentally using the stress life approach. FEA simulations have been performed for smooth specimens using three types of loading modes (Reverse Bending, Reverse Axial, and Reverse Torsional). Numerical Analysis (FEA) and experimental results are used to highlight the effect of stress ratio (R) on fatigue life. Five values of the stress ratio were used in the reversed bending test (R = -1, 0, 0.25, 0.5, and 1). Test results showed that specimens subjected to reversed bending had a greater life than those subjected to axial and torsional loading modes, respectively. According to the results, the specimen's life increased as load ratios increased, and there was a maximum discrepancy of 8% between experimental and numerical work. The fatigue limit value is influenced by both the porosity parameter and the gradient index.