Amirkabir University of TechnologyAUT Journal of Mechanical Engineering2588-293710220260401Toward Sustainable Machining: A Comprehensive Review of Surface Modification Techniques for Cutting Tools139152589710.22060/ajme.2025.24320.6191ENJavvadi EswaraManikantaDepartment of Mechanical Engineering, Shri Vishnu Engineering College for Women, Bhimavaram, India.0000-0002-0881-4899Birudugadda KrishnaMurthyDepartment of Mechanical Engineering, Sasi Institute of Technology and Engineering, Tadepalligudem, India.NitinAmbhoreDepartment of Mechanical Engineering, Vishwakarma Institute of Information Technology, SPPU, Pune, India.0000-0001-8468-8057ChitradaPrasadDepartment of Physics, Aditya University, Surampalem, India0000-0001-8205-427XNaveen KumarGurajalaDepartment of Mechanical Engineering, CMR College of Engineering and Technology, Hyderabad, IndiaJournal Article20250625Cutting tools are subjected to severe wear during machining operations, especially when processing hard-to-machine materials. This wear primarily results from the intense friction and heat generated at the tool–chip–workpiece interfaces. To mitigate these effects and extend tool life, numerous strategies have been developed to modify the rake and flank surfaces of cutting tools. These include surface texturing and advanced coating techniques aimed at enhancing tribological properties, chemical stability, and resistance to mechanical stresses. This review provides a comprehensive analysis of such surface modification methods, highlighting their role in reducing friction, minimizing tool wear, and improving cutting efficiency. A detailed classification of cutting tool materials, such as ceramics, carbides, and polycrystalline cubic boron nitride used in recent studies for machining hard materials is presented. The paper also identifies current challenges and research gaps, particularly in the context of superalloy machining. Finally, it outlines promising future directions, including the development of functional tool surfaces, integration of data-driven optimization approaches, and the exploration of novel tool materials and geometries. The overarching aim is to promote sustainable, cost-effective, and high-performance machining practices aligned with modern manufacturing demands.https://ajme.aut.ac.ir/article_5897_f9fd5ec4c141a95257aa99ef1b590672.pdfAmirkabir University of TechnologyAUT Journal of Mechanical Engineering2588-293710220260401Transient Natural Convection and Entropy Generation Analysis in a Stratified Square Enclosure153166585710.22060/ajme.2025.24319.6190ENMd. NayemHossainDepartment of Chemical Engineering, Z. H. Sikder University of Science and Technology, Shariatpur 8024, BangladeshSyed Mehedi HassanShaonDepartment of Computer Science and Engineering, Z. H. Sikder University of Science and Technology, Shariatpur 8024, BangladeshMd. MahafujurRahamanDepartment of Mathematics, Jagannath University, Dhaka 1100, Bangladesh0000-0002-7101-3314Journal Article20250625This study examines transient natural convection (NC) heat transfer (HT) and entropy generation (<em>E<sub>gen</sub></em>) in a square enclosure containing thermally stratified water. The model considers uniform heating at the bottom wall, stratified vertical walls, and a cooled top boundary. Governing equations are addressed through the finite volume (FV) method, with simulations performed across a range of Rayleigh numbers (Ra) from 10<sup>0</sup> to 5 × 10⁶, a fixed Prandtl number (Pr) of 7.01, for water. Various physical quantities were analyzed across the spectrum of Ra to capture the complex dynamics of convective flow. This encompasses streamline and isotherm plots, the temporal evolution of temperature, phase-space representations via limit cycles and limit points, along with spectral analysis, including the average Nusselt number (<em>Nu</em>), local entropy generation (<em>E<sub>l</sub></em>), and local Bejan number (<em>Be<sub>l</sub></em>). The results reveal successive bifurcations with increasing Ra: a pitchfork bifurcation (Ra = 8 × 10³–10⁴) leads to symmetry breaking, a Hopf bifurcation (Ra = 2 × 10⁵–3 × 10⁵) induces periodic oscillations, and chaotic flow emerges at Ra = 10⁶–2 × 10⁶. The average Nusselt number at the bottom wall increases from 5.84 for Ra = 2 × 10<sup>5</sup> to 15.87 for Ra = 2 × 10<sup>6</sup>, corresponding to a 171.75% enhancement in the HT.<sup> </sup>The numerical framework was validated by comparing it with existing numerical literature, confirming the results’ reliability.https://ajme.aut.ac.ir/article_5857_2fb544a21e8cb8768b80cc231ca2f691.pdfAmirkabir University of TechnologyAUT Journal of Mechanical Engineering2588-293710220260401Experimental Study on Stall Cell Formation in High-Wing Commercial Jet under Take-Off Conditions167178583710.22060/ajme.2025.24353.6195ENHamedRezaeiDepartment of Aerospace Engineering, Amirkabir University of Technology, Tehran, IranMostafaKazemiDepartment of Aerospace Engineering, Amirkabir University of Technology, Tehran, IranMahmoudManiDepartment of Aerospace Engineering, Amirkabir University of Technology, Tehran, IranMohammadAliVaziryDepartment of Aerospace Engineering, Amirkabir University of Technology, Tehran, IranAlirezaJahangirianDepartment of Aerospace Engineering, Amirkabir University of Technology, Tehran, IranJournal Article20250704This study investigates the flow physics of a high-wing regional jet aircraft under stall conditions. The main aim of this research is to study the effects of nacelle-pylon configuration and trailing edge control surfaces on flow characteristics, particularly the formation of stall cells, during the takeoff and landing phases of the flight envelope. Oil flow visualization techniques were employed to conduct experiments in a low-speed subsonic wind-tunnel at low Reynolds numbers, with angles of attack ranging from 0° to 20°. The study also explored the influence of forced transition achieved by using trip strips, flow physics at different angles of attack, and two slotted trailing edge flaps with deflection angles of 15° and 40° on flow separation. Results from multiple wind-tunnel tests revealed the existence of mushroom-shaped structures, knowns as stall cells, on the wing surfaces of the typical jet aircraft. The size and strength of these structures increased by increment of the angles of attack. Additionally, the slotted flap effectively mitigated stall cell formation by injecting high-pressure flow through the slot and modifying the wing’s effective camber line.https://ajme.aut.ac.ir/article_5837_d1e39c9bda5c80ac3d8ea9d658163967.pdfAmirkabir University of TechnologyAUT Journal of Mechanical Engineering2588-293710220260401Enhancing Thermo-Electrical Performance of Solid Oxide Fuel Cells through Multi-Channel Cooling System Analysis179198579810.22060/ajme.2025.23880.6164ENMohammadTaghilouDepartment of Mechanical Engineering, Faculty of Engineering, University of Zanjan, Zanjan, Iran.VahidBaratiDepartment of Mechanical Engineering, Faculty of Engineering, University of Zanjan, Zanjan, IranJournal Article20250202Thermal stresses in solid oxide fuel cells, caused by differential expansion during thermal cycling and coefficient of thermal expansion mismatches, lead to material degradation, cracking, voltage instability, and reduced reliability, hindering commercial viability. This study introduces a novel six-channel active cooling system for solid oxide fuel cells, aimed at lowering peak temperatures, improving thermal uniformity, and stabilizing voltage output. Using three dimensional numerical simulations with hydrogen/water vapor and oxygen/nitrogen as reactants, it systematically examines how cooling parameters such as flow rate, temperature, and flow configuration affect electrochemical performance. Key results demonstrate that co-current cooling (600 K, 1×10⁻⁶ kg/s) reduces peak temperature by 9% (to 1387 K) but at the cost of a 133% increase in temperature non-uniformity and a 55% voltage drop due to elevated overpotentials. Conversely, counter-current cooling (1000 K, same flow rate) achieves a more balanced performance, lowering peak temperature by 6% (to 1389.11 K) while reducing non-uniformity by 21.5% and increasing output voltage by 5.5% (0.2933 V). A critical finding is that excessive cooling (1×10⁻⁵ kg/s) leads to premature voltage collapse, with co-current flows failing at lower current densities (e.g., 9800 A/m² at 600 K) compared to counter-current configurations. This study pioneers an active cooling optimization framework for solid oxide fuel cells, demonstrating how precisely adjusted cooling parameters balance thermal control with electrochemical efficiency.https://ajme.aut.ac.ir/article_5798_ba4002d88b8860b6a684ade8357aba56.pdfAmirkabir University of TechnologyAUT Journal of Mechanical Engineering2588-293710220260401Impact of Angle of Attack and Relative width of V-Shaped Ribs on the Thermo-Hydraulic Performance of a Solar Air Heater199210586910.22060/ajme.2025.24344.6194ENHananehGhasemiDepartment of Chemical Engineering, Amirkabir University of Technology, Tehran, Iran.Leila NAzadaniDepartment of Chemical Engineering, Amirkabir University of Technology, Tehran, IranJournal Article20250702Solar air heaters offer a low-cost way to convert solar energy into usable heat, but their efficiency is limited by the inherently low heat transfer coefficient of air. To address this limitation, artificial roughness elements such as V-shaped ribs are commonly added to the absorber plate to boost turbulent mixing and improve thermal performance. This study numerically investigates the thermo-hydraulic characteristics of a solar air heater duct equipped with V-shaped ribs by analyzing the combined effects of angle of attack and relative rib width using computational fluid dynamics. The results demonstrate that both thermal performance and flow characteristics are influenced by rib geometry. The Nusselt number reaches its maximum enhancement of 2.8 times that of a smooth duct when using a single V-rib with a relative width of 1 and a 30° angle of attack. However, reducing the relative width results in progressively diminished heat transfer effectiveness. The thermo-hydraulic performance parameter peaks at 1.63 for the optimal relative width of 1 at a 30° angle of attack, indicating the most favorable ratio of Nusselt number enhancement to friction factor increase. These results offer essential guidance for optimizing roughened solar air heater designs, suggesting that a single, properly oriented V-rib offers the most favorable compromise between thermal enhancement and energy efficiency.https://ajme.aut.ac.ir/article_5869_4c26774d852f62440fc746ea4cdd57f6.pdfAmirkabir University of TechnologyAUT Journal of Mechanical Engineering2588-293710220260401Hybrid Nonlinear Model Predictive Control of a Flexible Satellite211230587410.22060/ajme.2025.24218.6184ENMortezaSalehipourDepartment of Aerospace Engineering, University of Isfahan, Isfahan, IranMaryamMalekzadehDepartment of Aerospace Engineering, Sharif University of Technology, Tehran, IranMahdiMortazaviDepartment of Aerospace Engineering, University of Isfahan, Isfahan, IranMohammadSayanjaliSatellite Systems Institute, Iranian Space research Center, Tehran, IranJournal Article20250603This paper provides a hybrid control strategy for the aim of nullifying the vibration of flexible appendages in satellite structures. These vibrations often occur during the deployment of satellite panels. To maintain performance and ensure attitude stability, a robust control framework is essential. To achieve this, piezoelectric actuators are incorporated into the panels to actively suppress structural vibrations. Lyapunov Nonlinear Model Predictive Control (LNMPC) is introduced in order to guarantee satellite stability and robustness. This algorithm is similar to the Piece-Wise Affine (PWA) method, but the nonlinear dynamics of the system is used instead of linearization. Additionally, Anti-Unwinding Sliding Mode Control is employed into this algorithm and combined with LNMPC to neutralize the vibration actively, furthermore this composite controller assists to control both kinematics and dynamics properly also steering the reaction wheels to zero after every maneuver to save energy in the presence of uncertainty, external disturbance and actuators dynamics considered into the algorithm. Furthermore, close loop stability analysis is provided by utilizing a candidate Lyapunov function.https://ajme.aut.ac.ir/article_5874_85d6e9c8255c0364fb67b5ac8a25eea3.pdfAmirkabir University of TechnologyAUT Journal of Mechanical Engineering2588-293710220260401Balance Control Ability Evaluation & Center of Pressure (COP) Classification with Machine Learning Methods231242589210.22060/ajme.2025.23930.6165ENOmidFeiziAdvanced Instrumentation Laboratory, School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran, Iran.AliRaiyat-khakiAdvanced Instrumentation Laboratory, School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran, Iran.MoosaAyatiAdvanced Instrumentation Laboratory, School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran, Iran.Journal Article20250219Athletes’ balance control ability is essential in different sports. Effective analysis of athletes' balance control ability is an effective way for coaches and sports teams to identify subjects' skills. In the last few years, with the rapid growth of technology in sports, the necessity of using intelligent methods has increased. This study compares different artificial intelligence approaches to evaluate balance control ability by processing time-series data from the center of pressure. A recording pad collects center of pressure data from four types of subjects, ranging from professional skiers to non-athletes. Several experimental feature-extraction techniques were applied to the data, and the resulting features were used as input for artificial intelligence methods. This paper utilizes a multi-layer perceptron to classify subjects’ skill levels. Compared with other methods, the multi-layer perceptron achieves more than 92% accuracy in classifying subjects' proficiency, yielding the best performance. Other methods, including k-nearest neighbors and support vector machines, achieved 72% and 69% accuracy, respectively. Analysis of center of pressure data can help identify promising individuals for real-world applications.https://ajme.aut.ac.ir/article_5892_f1daf122cde863010844459363cd31db.pdfAmirkabir University of TechnologyAUT Journal of Mechanical Engineering2588-293710220260401Copper’s Influence on Reactions in the Fe–Al Equimolar System: Microstructure and Phase Development243252593010.22060/ajme.2025.24226.6185ENRaziehKhoshhalDepartment of Materials Engineering, Birjand University of Technology, Birjand, Iran.Ahmad RezaFakhrabadiDepartment of Materials Engineering, Birjand University of Technology, Birjand, Iran.Seyed VahidAlavi Nezhad Khalil AbadDepartment of Civil Engineering, Birjand University of Technology, Birjand, IranJournal Article20250605Due to their suitable properties, iron aluminides have found numerous applications in various industries such as in the production of gas turbines, automotive combustion systems, corrosion-resistant coatings, heat exchanges, electrical and magnetic devices, and energy storage technologies. The aim of this research is to investigate the effect of copper content on the phase formation path and microstructure of products resulting from reactions that can be carried out in the Fe-Al-Cu powder system. For this purpose, samples with different copper contents (<em>0,</em> <em>0.2, 0.32</em> and <em>0.4</em> atom percent) and equimolar Fe and Al were prepared from elemental powders. The powders were compressed into disk shapes after mixing. Then, they were sintered at <em>950</em>°C for 24 hours. The type of phases produced was determined using X-ray diffraction (XRD) analysis and the microstructure of the samples was determined using a scanning electron microscope (SEM) equipped with (EDX). The results showed that the type of phases produced changed depending on the amount of copper. The sample without copper only led to the formation of the FeAl phase. The addition of <em>0.2</em>% copper also resulted in the formation of the CuAl₂ phase alongside the iron aluminide. Further increase to <em>0.32</em>% copper led to the formation of the ω phase and at <em>0.4</em>% copper, the I phase. Also, the amount of copper affected the amount of porosity produced in the samples.https://ajme.aut.ac.ir/article_5930_3b199f42a9909061516b6ce6d334af6d.pdf